EP3/DC5 Suspension Tuning Basics/FAQ's (As told by Mustclime)
12-08-2009, 06:22 PM
#51
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I would, droppin the rear a little could give you some castor and thats nice on a car that comes stock with about 1 degree but my cars are always set flat.
12-18-2009, 10:12 AM
#52
I said I don't want a title!
Re: ep3/dc5 suspension tuning basics
Sways make your cars suspension less independant. Independant suspension is good for grip. I have had people on this forum tell me that sways do ont effect a cars ride, that BS if you are using big sways. If you were biulding a prepared autoX car that would not be driven on the street much, your goal would be to pick springs that would allow you to run no sways at all....with high grip street tires, something like 450-550lb ft and 1100-1300lb rear would do it depending on how much weight you tear out of the car....you would be forced to get some custom rear shocks for that and you are right on the limit of the koni insets for the front....but if you are going to run your car as a dd, yea, you want to run sways. You still want to run as little front sway as you can get away with.
Also, you need a spring/shock combo that will allow the suspension to move and work with the car. That means that if you're on a course that is anything but glass-smooth, you probably won't be able to use super-high springrates as the car won't be able to keep all 4 tires down in any section not entirely smooth. This = time lost. And this is where a properly-sized swaybar will help. You can run slightly less springrate and shock valving and adjust the swaybars as needed.
Also, it is true that swaybars on the front of a car do adjust where the weight is planted--and this is particually noticable on a car with an open diff in a tight turn. However, a car with a proper limited-slip diff can benefit from a front swaybar--and some even a much larger one in certain cases (soloII stock classes, for instance).
An RSX/EP3 doesn't need a huge bar up front, but it does need one. In the back, absolutely you need a huge bar back there. Honestly, the less the rear moves, the better. As soon as the rear end starts to compress, you are that much closer to shock binding and wonky geometry.
12-18-2009, 07:00 PM
#53
Honda-Tech Member
Re: ep3/dc5 suspension tuning basics
Well...yes and no. No swaybar, unless it is the size of a sewer pipe, will make the suspension significantly less independant.
Also, you need a spring/shock combo that will allow the suspension to move and work with the car. That means that if you're on a course that is anything but glass-smooth, you probably won't be able to use super-high springrates as the car won't be able to keep all 4 tires down in any section not entirely smooth. This = time lost. And this is where a properly-sized swaybar will help. You can run slightly less springrate and shock valving and adjust the swaybars as needed.
Also, it is true that swaybars on the front of a car do adjust where the weight is planted--and this is particually noticable on a car with an open diff in a tight turn. However, a car with a proper limited-slip diff can benefit from a front swaybar--and some even a much larger one in certain cases (soloII stock classes, for instance).
An RSX/EP3 doesn't need a huge bar up front, but it does need one. In the back, absolutely you need a huge bar back there. Honestly, the less the rear moves, the better. As soon as the rear end starts to compress, you are that much closer to shock binding and wonky geometry.
Also, you need a spring/shock combo that will allow the suspension to move and work with the car. That means that if you're on a course that is anything but glass-smooth, you probably won't be able to use super-high springrates as the car won't be able to keep all 4 tires down in any section not entirely smooth. This = time lost. And this is where a properly-sized swaybar will help. You can run slightly less springrate and shock valving and adjust the swaybars as needed.
Also, it is true that swaybars on the front of a car do adjust where the weight is planted--and this is particually noticable on a car with an open diff in a tight turn. However, a car with a proper limited-slip diff can benefit from a front swaybar--and some even a much larger one in certain cases (soloII stock classes, for instance).
An RSX/EP3 doesn't need a huge bar up front, but it does need one. In the back, absolutely you need a huge bar back there. Honestly, the less the rear moves, the better. As soon as the rear end starts to compress, you are that much closer to shock binding and wonky geometry.
The real jump that Steve made was how to work out your spring rates for each corner...say you have a fwd car with a total weight of 2000 with a driver in it with a 60/40 weight distro and a 1/1 motion ratio in its suspension...common thought would say that if you wanted no body roll you would put 600lb springs in the front and 400lb in the rear.....Steve's brakethrough was you put the 600lb springs in the rear and the 400lb springs on the drive wheels. The non drive wheels are doing most of the body roll limiting and the spring rates in the front soft enought to put the power to the ground and no sways to add up force to the inside wheels...wow, what a concept, really having 4 full patches of rubber on the ground.......note: I really over simplefied and this setup would be for autoX car that spent very little time on the street. You can set up a track car this way but you may have to add a rear sway for the higher speeds...
Oh and about this...
No swaybar, unless it is the size of a sewer pipe, will make the suspension significantly less independant.
12-18-2009, 07:44 PM
#54
I said I don't want a title!
Re: ep3/dc5 suspension tuning basics
Todd, have you ever set up a car to not run sways? If you do it right, it really will open your eyes, it did for me. I was pretty much of your frame of mind till I ran across this guy Steve Hoeschler on mr2oc.com. He was posting about setting up mr2's like he had set up his old dp x1/9. It was a little strange till he talked about using the non drive wheels to control body roll and allowingthe drive wheels to have the softer springs...that got me thinking....I have always done that with huge sways in the rear with a fwd. He then knocked me on my but with the concept that sways are really grip reducing devices. I mean I leared in skip barber racing school that all that holds a car on the road in a turn is 4 patches of rubber...now steve was telling me that with sways applying up force to the inside tires in a turn, I might be lucky to have 3 patches of rubber holding you to the road. Why would you want to reduce grip on a car you want to handle?
The real jump that Steve made was how to work out your spring rates for each corner...say you have a fwd car with a total weight of 2000 with a driver in it with a 60/40 weight distro and a 1/1 motion ratio in its suspension...common thought would say that if you wanted no body roll you would put 600lb springs in the front and 400lb in the rear.....Steve's brakethrough was you put the 600lb springs in the rear and the 400lb springs on the drive wheels. The non drive wheels are doing most of the body roll limiting and the spring rates in the front soft enought to put the power to the ground and no sways to add up force to the inside wheels...wow, what a concept, really having 4 full patches of rubber on the ground.......note: I really over simplefied and this setup would be for autoX car that spent very little time on the street. You can set up a track car this way but you may have to add a rear sway for the higher speeds...
Oh and about this...
Next time you are messing with your car, jackup one side of the car, pull a wheel, disconect the strut from the knuckel....now try to move the lower control arm with the sway attached....is it indepent?
The real jump that Steve made was how to work out your spring rates for each corner...say you have a fwd car with a total weight of 2000 with a driver in it with a 60/40 weight distro and a 1/1 motion ratio in its suspension...common thought would say that if you wanted no body roll you would put 600lb springs in the front and 400lb in the rear.....Steve's brakethrough was you put the 600lb springs in the rear and the 400lb springs on the drive wheels. The non drive wheels are doing most of the body roll limiting and the spring rates in the front soft enought to put the power to the ground and no sways to add up force to the inside wheels...wow, what a concept, really having 4 full patches of rubber on the ground.......note: I really over simplefied and this setup would be for autoX car that spent very little time on the street. You can set up a track car this way but you may have to add a rear sway for the higher speeds...
Oh and about this...
Next time you are messing with your car, jackup one side of the car, pull a wheel, disconect the strut from the knuckel....now try to move the lower control arm with the sway attached....is it indepent?
The HART guys, on their RSX-S, ran at least 3000lb springs in the rear and as large of a rear bar that they could find. They used a stock bar up front. You do want to "reduce grip" on the rear of an RSX (for the sake of rotation), and you also want it not to move (if you are serious about handling with this chassis).
There is a ton of difference between a swaybar allowing your wheel to droop when the car is jacked vs. real-world suspension independence. Even a 32mm swaybar is not going to stop your front end from working seperately from one another.
And I also don't think Steve has ever setup a FF Honda. All of the experienced chassis tuners and top-level soloII guys in SP and ST classes run large rear swaybars, with a smaller front bar, depending. You just don't want to use too much springrate as this not only compromises suspension compliance over bumps, but it also starts to envoke chassis flex. This is where you can get a good baseline setup, then fine-tune with swaybars.
Again, Steve's experience is with cars that aren't powered by the front tires. The rear tires on a FWD car are just along for the ride. And sometimes you *don't* want them to grip. Heck, even the top japanese tuners use a smaller tire on the rear of the car. Too much rear traction = a car that'll push. That's why good tuners always reduce rear camber on a FF car, especially the RSX/EP3 chassis.
The front of a FF car is trickier. You want a car that'll put down the power, but you also want one that won't skitter over bumps, push like a pig or roll too much. Finding a good compromise between shock valving, springrate and swaybar settings takes a lot of trial and error.
12-18-2009, 08:27 PM
#55
Honda-Tech Member
Re: ep3/dc5 suspension tuning basics
Setting up an RSX is worlds different from setting up an X 1/9 or MR2. I don't care what Steve says, the RSX needs swaybars (especially the rear)--and that's the context we are speaking about here.
The HART guys, on their RSX-S, ran at least 3000lb springs in the rear and as large of a rear bar that they could find. They used a stock bar up front. You do want to "reduce grip" on the rear of an RSX (for the sake of rotation), and you also want it not to move (if you are serious about handling with this chassis).
There is a ton of difference between a swaybar allowing your wheel to droop when the car is jacked vs. real-world suspension independence. Even a 32mm swaybar is not going to stop your front end from working seperately from one another.
And I also don't think Steve has ever setup a FF Honda. All of the experienced chassis tuners and top-level soloII guys in SP and ST classes run large rear swaybars, with a smaller front bar, depending. You just don't want to use too much springrate as this not only compromises suspension compliance over bumps, but it also starts to envoke chassis flex. This is where you can get a good baseline setup, then fine-tune with swaybars.
Again, Steve's experience is with cars that aren't powered by the front tires. The rear tires on a FWD car are just along for the ride. And sometimes you *don't* want them to grip. Heck, even the top japanese tuners use a smaller tire on the rear of the car. Too much rear traction = a car that'll push. That's why good tuners always reduce rear camber on a FF car, especially the RSX/EP3 chassis.
The front of a FF car is trickier. You want a car that'll put down the power, but you also want one that won't skitter over bumps, push like a pig or roll too much. Finding a good compromise between shock valving, springrate and swaybar settings takes a lot of trial and error.
The HART guys, on their RSX-S, ran at least 3000lb springs in the rear and as large of a rear bar that they could find. They used a stock bar up front. You do want to "reduce grip" on the rear of an RSX (for the sake of rotation), and you also want it not to move (if you are serious about handling with this chassis).
There is a ton of difference between a swaybar allowing your wheel to droop when the car is jacked vs. real-world suspension independence. Even a 32mm swaybar is not going to stop your front end from working seperately from one another.
And I also don't think Steve has ever setup a FF Honda. All of the experienced chassis tuners and top-level soloII guys in SP and ST classes run large rear swaybars, with a smaller front bar, depending. You just don't want to use too much springrate as this not only compromises suspension compliance over bumps, but it also starts to envoke chassis flex. This is where you can get a good baseline setup, then fine-tune with swaybars.
Again, Steve's experience is with cars that aren't powered by the front tires. The rear tires on a FWD car are just along for the ride. And sometimes you *don't* want them to grip. Heck, even the top japanese tuners use a smaller tire on the rear of the car. Too much rear traction = a car that'll push. That's why good tuners always reduce rear camber on a FF car, especially the RSX/EP3 chassis.
The front of a FF car is trickier. You want a car that'll put down the power, but you also want one that won't skitter over bumps, push like a pig or roll too much. Finding a good compromise between shock valving, springrate and swaybar settings takes a lot of trial and error.
Dude, i totaly respect where you are coming from, this is tinfoil hat stuff. Just remember, in the early 60's, running wide tires was thought to be stupid because of the high wind resistance. Then some fool had some made and went faster around the turns than everyone else...next thing you know everyone was running them.... may I sugest you read for yourself rather from getting it from me and decide....it starts here...
http://www.mr2oc.com/showthread.php?t=298272
and continues here...
http://www.mr2oc.com/showthread.php?t=313691
Its a free forum and not a bad read...btw...steve is Xhead on the forum.....
12-20-2009, 08:15 AM
#56
I said I don't want a title!
Re: ep3/dc5 suspension tuning basics
*Sigh* all those people that had to run huge spring rates were running lowered....once you scew up your lca angles, partys over, just mount steel blocks in the place of springs....911 racers know this, m3/3 series racers, heck even the fools in the evo's and sti's are figuering this out, but f-ing honda people that grew up with suspension designes just improved with lowering the car can't seem to get their heads around this. As for the differance between a x1/9 /mr2 and a fwd car....both of those cars are just fwd cars driving backwards....their drive trains were fwd drivetrains, their suspensions were mac strut suspensions f&r pulled of fwd cars in the makers lines... as for steve not trying this out on fwd cars...he has setup several fwd cars as well as a rollex car with this theory...
Dude, i totaly respect where you are coming from, this is tinfoil hat stuff. Just remember, in the early 60's, running wide tires was thought to be stupid because of the high wind resistance. Then some fool had some made and went faster around the turns than everyone else...next thing you know everyone was running them.... may I sugest you read for yourself rather from getting it from me and decide....it starts here...
http://www.mr2oc.com/showthread.php?t=298272
and continues here...
http://www.mr2oc.com/showthread.php?t=313691
Its a free forum and not a bad read...btw...steve is Xhead on the forum.....
Dude, i totaly respect where you are coming from, this is tinfoil hat stuff. Just remember, in the early 60's, running wide tires was thought to be stupid because of the high wind resistance. Then some fool had some made and went faster around the turns than everyone else...next thing you know everyone was running them.... may I sugest you read for yourself rather from getting it from me and decide....it starts here...
http://www.mr2oc.com/showthread.php?t=298272
and continues here...
http://www.mr2oc.com/showthread.php?t=313691
Its a free forum and not a bad read...btw...steve is Xhead on the forum.....
Steve likes to toot his horn a bit, but a MR2 or X 1/9 is not a FWD Macstrut or double-wishbone Honda, period. Physics comes into play and I don't care where the engine sits, as long as the drivewheels are on the rear of the car, you have rotation with the mash of an accelerator pedal and front tires that are only asked to do one thing (turn the car). Not so and never will be so with a FWD Honda.
I'm not sure what you're referring to with stiff springs and lowering, but I'm speaking specifically with the rear of an RSX/Ep3. Basically, you don't want the suspension to compress much back there, regardless of what ride height you're at. Whatever theory you want to apply back there can't be done. The suspension has inherent problems, including a poor motion-ratio, poor camber curve and a design that leads to binding. Suspension binding = a car that's unpredictable. The only way to fix this is with proper bushings and keeping the suspension from moving as much as possible. Also, this includes a thick rear swaybar to try and tie both sides together as much as possible.
12-20-2009, 01:05 PM
#57
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Sway bars are part of the unpredictable feel you are talking about. The more you load the outside suspension in a turn, the more "up force" they generate on the inside wheels until they lift they inside wheel off the ground all togather. Haveing grip be constanly reduced in a turn is not a "good" feeling and could be part of that unpredictable feeling you are talking about. Add to this any bump in the turn that causes the outside suspension to compress more also causes the inside suspension to lift because of the swaybar ferther reducing grip.
You talk about suspension binding in the rear, thats a pretty easy fix really, you have to take the toe adjusting bushings the the flexable part of the rear lower control are out of the equation. Under heavy corning loads generated by high grip tires you can get almost a inch increase in the wheel base on the side of the car that is on the outside of the turn. Back when I first got the ep, I jacked up the drivers side of the car, put it on jackstands and pulled the wheels. I have a 5 ft long, 3/8th inch thick x 3 inches wide steel bar with tappered ends I use as a lever on suspensions. Everyone knows that the front compliance bushing adds toe-in under cornering load. I found that I could deflect the front controle arm quite a bit...about 1/2 inch off center. What a lot of people don't know is you can push the rear wheel backward(adding toe out) about 1/2 a inch. Most people also don't know is that flat steel part of the rear lca that everyone is replacing with blingie al parts flexes to the rear also. When I replaced the rear compliance bushings, I was shocked at the differance. I have to at some point figure out how replace the flex steel in the rear lca with something that will not flex under load.
But thats nether here nor there......bottom line, you can not allow mcstrut cars compress enought in a turn for the lac to angle up from the center of the car. Then cornering loads just get a bunch of leverage over the suspension and the party's over. Thats why you need control body roll with springs and not sways. Sways do nothing to hold hp the car, all they do is pull up the inside wheel to keep the car flat in a turn and thats just grip reduction....again, this is just for autoX/ track day cars....
You talk about suspension binding in the rear, thats a pretty easy fix really, you have to take the toe adjusting bushings the the flexable part of the rear lower control are out of the equation. Under heavy corning loads generated by high grip tires you can get almost a inch increase in the wheel base on the side of the car that is on the outside of the turn. Back when I first got the ep, I jacked up the drivers side of the car, put it on jackstands and pulled the wheels. I have a 5 ft long, 3/8th inch thick x 3 inches wide steel bar with tappered ends I use as a lever on suspensions. Everyone knows that the front compliance bushing adds toe-in under cornering load. I found that I could deflect the front controle arm quite a bit...about 1/2 inch off center. What a lot of people don't know is you can push the rear wheel backward(adding toe out) about 1/2 a inch. Most people also don't know is that flat steel part of the rear lca that everyone is replacing with blingie al parts flexes to the rear also. When I replaced the rear compliance bushings, I was shocked at the differance. I have to at some point figure out how replace the flex steel in the rear lca with something that will not flex under load.
But thats nether here nor there......bottom line, you can not allow mcstrut cars compress enought in a turn for the lac to angle up from the center of the car. Then cornering loads just get a bunch of leverage over the suspension and the party's over. Thats why you need control body roll with springs and not sways. Sways do nothing to hold hp the car, all they do is pull up the inside wheel to keep the car flat in a turn and thats just grip reduction....again, this is just for autoX/ track day cars....
12-21-2009, 10:35 AM
#58
I said I don't want a title!
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I'm not disagreeing with you on MacStrut cars, especially the RSX/EP3. You do need springrate up front to control lean and wheel travel, but you also don't want too much of it as some wheel travel and suspension movement is a good thing. And as long as you add a diff up front, a swaybar can be used to tune the chassis. But remember, street tires and true R compounds require a different setup. What rates work on R comps will not necessarily work on street tires.
As for the binding, the only true solution I've seen is the Comptech car that had the rear end completely redesigned. Otherwise, you can tweak things, but binding will still occur.
And every single RSX/EP3 chassis that I've seen come out of the top tuner shops in Japan have had swaybars (even the US Comptech cars). These are top-notch chassis engineers and they use a huge honking bar in the back with 0 degrees of camber. I can't discount this as a basis to copy from. And in my testing, a huge rear bar always made the car rotate closer to normal.
As for the RSX/EP3 being unpredictable, this is due to the front tie rods and where they are attached and the rear binding issues. The car either pushes, or it seems to want to snap. There is only a small area in between where I'd consider the car behaves as normal.
Every time I ran my RSX on a berm, it never gave me confidence as to where the car was going to be pointed when it came off. Everyone who owned that chassis has made the same comment. I did get it rotating well for autox, but I dared not drive that setup on the street as it would want to swap ends any time I let off the accelerator on an on ramp or something.
Ironically enough, the best autox/daily driven compromise that I found was the A-spec suspension with the Mugen 25mm rear swaybar (stock front bar). The Mugen SS kit was over-dampened and under-sprung, and the Progress, H&R Cup, Tein Flex and several other coilover kits made the ride too harsh for driving in the midwest, although the Progress kit wasn't bad.
The best iteration of the chassis came on the Civic Sedan platform. Out of the EP3/RSX/Civic coupe, the 4-door seemed to have the stiffest chassis out of all of them. It also handled the best due to the lightweight D-series motor.
As for the binding, the only true solution I've seen is the Comptech car that had the rear end completely redesigned. Otherwise, you can tweak things, but binding will still occur.
And every single RSX/EP3 chassis that I've seen come out of the top tuner shops in Japan have had swaybars (even the US Comptech cars). These are top-notch chassis engineers and they use a huge honking bar in the back with 0 degrees of camber. I can't discount this as a basis to copy from. And in my testing, a huge rear bar always made the car rotate closer to normal.
As for the RSX/EP3 being unpredictable, this is due to the front tie rods and where they are attached and the rear binding issues. The car either pushes, or it seems to want to snap. There is only a small area in between where I'd consider the car behaves as normal.
Every time I ran my RSX on a berm, it never gave me confidence as to where the car was going to be pointed when it came off. Everyone who owned that chassis has made the same comment. I did get it rotating well for autox, but I dared not drive that setup on the street as it would want to swap ends any time I let off the accelerator on an on ramp or something.
Ironically enough, the best autox/daily driven compromise that I found was the A-spec suspension with the Mugen 25mm rear swaybar (stock front bar). The Mugen SS kit was over-dampened and under-sprung, and the Progress, H&R Cup, Tein Flex and several other coilover kits made the ride too harsh for driving in the midwest, although the Progress kit wasn't bad.
The best iteration of the chassis came on the Civic Sedan platform. Out of the EP3/RSX/Civic coupe, the 4-door seemed to have the stiffest chassis out of all of them. It also handled the best due to the lightweight D-series motor.
12-21-2009, 10:01 PM
#59
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Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
So, I don't mean to break up the very enlightening little party, but rather direct it down a different rabbit hole.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
12-22-2009, 06:22 AM
#60
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I'm not disagreeing with you on MacStrut cars, especially the RSX/EP3. You do need springrate up front to control lean and wheel travel, but you also don't want too much of it as some wheel travel and suspension movement is a good thing. And as long as you add a diff up front, a swaybar can be used to tune the chassis. But remember, street tires and true R compounds require a different setup. What rates work on R comps will not necessarily work on street tires.
As for the binding, the only true solution I've seen is the Comptech car that had the rear end completely redesigned. Otherwise, you can tweak things, but binding will still occur.
And every single RSX/EP3 chassis that I've seen come out of the top tuner shops in Japan have had swaybars (even the US Comptech cars). These are top-notch chassis engineers and they use a huge honking bar in the back with 0 degrees of camber. I can't discount this as a basis to copy from. And in my testing, a huge rear bar always made the car rotate closer to normal.
As for the RSX/EP3 being unpredictable, this is due to the front tie rods and where they are attached and the rear binding issues. The car either pushes, or it seems to want to snap. There is only a small area in between where I'd consider the car behaves as normal.
Every time I ran my RSX on a berm, it never gave me confidence as to where the car was going to be pointed when it came off. Everyone who owned that chassis has made the same comment. I did get it rotating well for autox, but I dared not drive that setup on the street as it would want to swap ends any time I let off the accelerator on an on ramp or something.
Ironically enough, the best autox/daily driven compromise that I found was the A-spec suspension with the Mugen 25mm rear swaybar (stock front bar). The Mugen SS kit was over-dampened and under-sprung, and the Progress, H&R Cup, Tein Flex and several other coilover kits made the ride too harsh for driving in the midwest, although the Progress kit wasn't bad.
The best iteration of the chassis came on the Civic Sedan platform. Out of the EP3/RSX/Civic coupe, the 4-door seemed to have the stiffest chassis out of all of them. It also handled the best due to the lightweight D-series motor.
As for the binding, the only true solution I've seen is the Comptech car that had the rear end completely redesigned. Otherwise, you can tweak things, but binding will still occur.
And every single RSX/EP3 chassis that I've seen come out of the top tuner shops in Japan have had swaybars (even the US Comptech cars). These are top-notch chassis engineers and they use a huge honking bar in the back with 0 degrees of camber. I can't discount this as a basis to copy from. And in my testing, a huge rear bar always made the car rotate closer to normal.
As for the RSX/EP3 being unpredictable, this is due to the front tie rods and where they are attached and the rear binding issues. The car either pushes, or it seems to want to snap. There is only a small area in between where I'd consider the car behaves as normal.
Every time I ran my RSX on a berm, it never gave me confidence as to where the car was going to be pointed when it came off. Everyone who owned that chassis has made the same comment. I did get it rotating well for autox, but I dared not drive that setup on the street as it would want to swap ends any time I let off the accelerator on an on ramp or something.
Ironically enough, the best autox/daily driven compromise that I found was the A-spec suspension with the Mugen 25mm rear swaybar (stock front bar). The Mugen SS kit was over-dampened and under-sprung, and the Progress, H&R Cup, Tein Flex and several other coilover kits made the ride too harsh for driving in the midwest, although the Progress kit wasn't bad.
The best iteration of the chassis came on the Civic Sedan platform. Out of the EP3/RSX/Civic coupe, the 4-door seemed to have the stiffest chassis out of all of them. It also handled the best due to the lightweight D-series motor.
12-22-2009, 06:50 AM
#61
I said I don't want a title!
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Like I said, this whole no sway bars tuning thing is very tin-foil-hat stuff. If you ever feel like putting it to the test, try some 450-550lb springs with some stickie steet tires in the front with out a bar....just leave the rear how ever you like it. What I noted when I ran this is the spring rates felt lower than they were just driving down the road because the sway was not adding to single wheel impacts with bumps. Turn in was much faster and the cars set in a turn was more constant with less of a need for correction in mid turn....I think this is because there is no sway under there loading and unloading....but thats jmo. With out a sway tieing both sides of the suspension togather, singel wheel bump impacts in mid turn do not unstettle the car nearly as much and the front suspension follows ground much better even with the higher spring rates.....but don't take it from me, give it a try, you might like it.
However, I gave up on the chassis and now don't own a single one anymore (had 3 at one time). There was just no way to get it to do everything that I wanted it to because of all the inherent problems.
12-22-2009, 06:58 AM
#62
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
So, I don't mean to break up the very enlightening little party, but rather direct it down a different rabbit hole.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
Next, I alway like to quote a statics teacher...." mass is hates change"....It takes effort to get mass moving and once moving, it takes effort to get mass to stop moving. Take you heavy wheel rolling down the road, it hits a bump that forces it to start moving upward....you now have to put some kind of effort to get that sucker to stop moving...this = increased spring rates and more compresion damping to control that uppwards moving wheel....once you start upping spring rates, you have to up compression damping....you see a trend here? Racing/ preformance = not bleeding away effort of any kind doing things you do not need to do.
As for rim size/ sidewall size, The taller the side wall, the more gradual the loss of traction....short side walls tend to brake loose very fast, tall sidewalls are more "catchable".
12-22-2009, 07:02 AM
#63
I said I don't want a title!
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
So, I don't mean to break up the very enlightening little party, but rather direct it down a different rabbit hole.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
Things I believe I know about Tires and Wheels: My thoughts, and correct me where I go astray from truth. I am under the impression that a heavy wheel has more inertia and will resist coming off the ground after a bump, instead forcing the tire to deflect over the bump.
Also, weight towards the outside of a rotating body has more effect on it's rotational inertia then weight towards the center
Metal is more heavy than rubber.
Short sidewall tires are firmer when cornering and follow the rim more accurately than thick sidewall tires which would tend to roll or shift away from the rim.
Acceleration and Traction are opposite ends of a spectrum. An Abrams Tank has a lot of traction at rest because of it's inertia and large contact patch. A bike has amazing acceleration (bear with me) because of it's low inertia and tiny rolling resistance. So I'm assuming that when you move towards one side of the spectrum you inevitably move away from the other side of the spectrum
What I then deduce:
Most tuners gravitate towards very light large rims in an attempt to reduce unsprung rotational mass in hopes that they will be able to eek out faster acceleration times. However, with tiny tires they reduce the outer rotational advantage of having tire instead of metal, replacing it with heavy rim further from the hub. They also reduce the sidewall flex (which I would assume would decrease the possible advantage of having something that flexes, aka tall sidewall tire; and they replace it with a tire that no longer flexes and would move towards the acceleration portion of my spectrum, thereby reducing traction)
Also, a light rim would be more apt to hop after a bump, also reducing traction.
So why in the sam hell do you want a larger lighter rim?
I'm of the opinion that a car that corners will always be able to outrun a fast in the straights car, because there are more corners in the world than drag strips.
P.S. Thank you so much for taking an intelligent approach to tuning, rather than the typical "grunt grunt beat chest, more horsepower" approach. You are an inspiration to a thinking mans tuner like myself.
Now, super-large wheels on a race-car are for bling. You do need some sidewall, but you don't want a huge sidewall, either. You also want a very stiff sidewall, as most all R-compound tires have.
Honestly, I'm really not sure what you're asking. The proper wheel/tire combo for best lap times is one that'll fit on the car (within the rules of the class you are running), is as wide is as needed for the tire that you want to use and is as light as possible.
Note: The lighter the wheel/tire combo that you have, the better your suspension will work, the faster a car will accelerate and the better it will turn. A light wheel/tire does not "bounce" off of something. Good shocks control suspension movement.
12-22-2009, 07:14 AM
#64
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I did try it, but I settled on a smaller Civic front swaybar. Without a front sway the car gave up a little in slaloms. The smaller front bar, I felt, gave me the best of both worlds. Turn-in was crisp, the car didn't push that bad and slaloms were acceptable.
However, I gave up on the chassis and now don't own a single one anymore (had 3 at one time). There was just no way to get it to do everything that I wanted it to because of all the inherent problems.
However, I gave up on the chassis and now don't own a single one anymore (had 3 at one time). There was just no way to get it to do everything that I wanted it to because of all the inherent problems.
12-22-2009, 07:20 AM
#65
Function > Form
Thread Starter
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Sooo, basically this is all a preference thing? Driving styles and technique might not be as unique as finger prints, but I'm sure that not all people will like one persons set up opposed to their own, correct?
12-22-2009, 07:26 AM
#66
I said I don't want a title!
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Too much springrate in the front started to introduce other handling problems, however. This is why I said finding a happy medium was a lot of work.
The older wishbone Honda chassis don't have any of the problems the RSX/EP3 has. I'll put it simply: Someone is not being honest to themselves if they think they can ever setup an EP3/RSX to handle as good as a DC2 or EF/EG chassis. The only drawback of that chassis is that it is FWD. Otherwise, a better FWD production chassis does not exist, period.
12-22-2009, 07:32 AM
#67
I said I don't want a title!
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I've seen track cars setup completely different and tested with the same driver, yet lap times were almost identical. There is always a give and take. One setup does better in one area, one does better in another. That's why you have to setup the car to what you'll be doing with it.
Or, as you said, some people prefer a car (and can drive it faster) that has a certain tendenacy.
There is always a good baseline. From there, you just have to experiment and find out what works best for yuo or the venue you are driving the car in.
12-22-2009, 07:37 AM
#68
Function > Form
Thread Starter
12-22-2009, 07:59 AM
#69
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
The older wishbone Honda chassis don't have any of the problems the RSX/EP3 has. I'll put it simply: Someone is not being honest to themselves if they think they can ever setup an EP3/RSX to handle as good as a DC2 or EF/EG chassis. The only drawback of that chassis is that it is FWD. Otherwise, a better FWD production chassis does not exist, period.
Last edited by mustclime; 12-22-2009 at 02:39 PM.
12-22-2009, 01:08 PM
#70
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Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
I'm not sure what you're getting at, but I can't think of one single situation where I'd rather have a heavy wheel/tire combo than a lightweight one. Not one.
Now, super-large wheels on a race-car are for bling. You do need some sidewall, but you don't want a huge sidewall, either. You also want a very stiff sidewall, as most all R-compound tires have.
Honestly, I'm really not sure what you're asking. The proper wheel/tire combo for best lap times is one that'll fit on the car (within the rules of the class you are running), is as wide is as needed for the tire that you want to use and is as light as possible.
Note: The lighter the wheel/tire combo that you have, the better your suspension will work, the faster a car will accelerate and the better it will turn. A light wheel/tire does not "bounce" off of something. Good shocks control suspension movement.
Now, super-large wheels on a race-car are for bling. You do need some sidewall, but you don't want a huge sidewall, either. You also want a very stiff sidewall, as most all R-compound tires have.
Honestly, I'm really not sure what you're asking. The proper wheel/tire combo for best lap times is one that'll fit on the car (within the rules of the class you are running), is as wide is as needed for the tire that you want to use and is as light as possible.
Note: The lighter the wheel/tire combo that you have, the better your suspension will work, the faster a car will accelerate and the better it will turn. A light wheel/tire does not "bounce" off of something. Good shocks control suspension movement.
lets see......for me, rim size is set by brake size. I would love to run 15 inch rims on on the ep, but a 2900+ lb curb weight on track days kinda requires bigger brakes for consistant braking( even more so for me cuz I like to left foot brake).
Next, I alway like to quote a statics teacher...." mass is hates change"....It takes effort to get mass moving and once moving, it takes effort to get mass to stop moving. Take you heavy wheel rolling down the road, it hits a bump that forces it to start moving upward....you now have to put some kind of effort to get that sucker to stop moving...this = increased spring rates and more compresion damping to control that uppwards moving wheel....once you start upping spring rates, you have to up compression damping....you see a trend here? Racing/ preformance = not bleeding away effort of any kind doing things you do not need to do.
As for rim size/ sidewall size, The taller the side wall, the more gradual the loss of traction....short side walls tend to brake loose very fast, tall sidewalls are more "catchable".
Next, I alway like to quote a statics teacher...." mass is hates change"....It takes effort to get mass moving and once moving, it takes effort to get mass to stop moving. Take you heavy wheel rolling down the road, it hits a bump that forces it to start moving upward....you now have to put some kind of effort to get that sucker to stop moving...this = increased spring rates and more compresion damping to control that uppwards moving wheel....once you start upping spring rates, you have to up compression damping....you see a trend here? Racing/ preformance = not bleeding away effort of any kind doing things you do not need to do.
As for rim size/ sidewall size, The taller the side wall, the more gradual the loss of traction....short side walls tend to brake loose very fast, tall sidewalls are more "catchable".
A taller sidewall is easier for a novice driver to keep under control because it loses grip slower. But a firmer (not neccesarily shorter or taller is advantageous).
So chasing after a light wheel/tire is more of a wasted effort in the suspension world. I did some research into rim sizes and it seems that larger rims typically come with wider rims, which allow for the wider tires you talked about. Spring rates, and good shocks are a better investment in time and effort though.
I was under the assumption that lighter rims would be flightier, and therefore a bad idea.
12-22-2009, 01:14 PM
#71
Function > Form
Thread Starter
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Even if your bump theory were/is true. I think the benefits of a lighter wheel/tire combo out weigh the negatives. The only downside I can think of for a lightweight wheel is that it would be easier to loose traction on a launch from a high hp car, then again... an experienced driver would learn to have a controlled launch regardless of the set up. Your theory has good intentions, but not much water.
12-22-2009, 01:30 PM
#72
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Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
Okay. I got my physics crossed up somewhere. Thank you for setting me up with a better revision of my theories.
12-26-2009, 06:33 PM
#74
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Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
So what do you think of tein s-tech's on oem struts? looking @ 17" x 7 (42 offset) 225/45 17 dont know which tire yet... If SB is an issue could get my hands on an rsx rear...
Oh, not looking to do track or anything close! Just riceeee and get my **** broken into.
Car is an 02' EP3
Oh, not looking to do track or anything close! Just riceeee and get my **** broken into.
Car is an 02' EP3
Last edited by Pauls EP3; 12-27-2009 at 01:35 PM.
12-27-2009, 02:48 PM
#75
Honda-Tech Member
Re: EP3/DC5 Suspension Tuning Basics (As told by Mustclime)
So what do you think of tein s-tech's on oem struts? looking @ 17" x 7 (42 offset) 225/45 17 dont know which tire yet... If SB is an issue could get my hands on an rsx rear...
Oh, not looking to do track or anything close! Just riceeee and get my **** broken into.
Car is an 02' EP3
Oh, not looking to do track or anything close! Just riceeee and get my **** broken into.
Car is an 02' EP3