suspension questions.
05-30-2002, 03:09 AM
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suspension questions.
i have alot of questions about suspension mods for the eg8 or better yet general questions like how to tell which spring rates are for what use. the difference between a rear sway bar and tower bar etc.... this list can go on for days anyhow can some1 point me in the direction of a website or something.
thanks in advance
thanks in advance
05-30-2002, 01:29 PM
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Re: suspension questions. (nijia555)
so damn no 1 can help me on this one, i guess i will just have to ask all the questions i have here and annoy the hell out of all of you 
05-30-2002, 02:16 PM
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Re: suspension questions. (nijia555)
from the Type-R Section.....
Understanding Vehicle Dynamics
Before we start we have to have an explanation of common vehicle dynamics terms. We had better understand the common ways to describe the different aspects of vehicle dynamics before we even turn a wrench, so here we go:
Friction circle: This is basically a vehicles performance envelope. It's expressed in lateral G’s, accelerating and braking G’s. When graphed, the friction circle looks like an egg with the X axis lateral G’s and the Y access braking and accelerating G’s.
Understeer: This is when, at the limit of vehicle traction, the front of the car slides first before the rear. Race car drivers call this "push". This is the way that many cars come set up to behave from the factory as it is the most predictable for average drivers (like the Type R). The crash mode for understeer is that when the limit of adhesion is exceeded, the car will plow strait ahead off the road nose first. This is not the fast way to have your car set up, but is best if you are an inexperienced driver. When the car understeers you should regain control if you let off the gas, unless of course you run out of road first. (That is what air bags are for.) It is not efficient for extracting maximum lateral G’s because the car will dynamically use the front tires excessively for turning, overloading them while the rear tires basically just hold the back of the car up - scrubbing off significant speed. Front wheel drive cars tend to exhibit understeer as the final terminal mode of balance.
Oversteer: This is when, at the limit of vehicle traction, the rear of the car slides first before the front. Race car drivers call this "loose". The rest of us call this "spinning out", "spinning a shitty", "doing a brodie" or even crashing. The final crash mode of oversteer is backwards, tail first into the woods or in the worst case spinning round and round with the driver as a helpless passenger. Since the infamous days of Ralph Nader and the Corvair, most auto manufactures avoid oversteer like the plague. Oversteer is difficult for an inexperienced driver to handle because recovery requires judicious use of countersteering and throttle feathering to control; fine motor skills that only some of us can deal with. Although oversteer looks neat and macho it is really a slow way to drive except in maybe pro-rally on the dirt . Oversteer is slow on the pavement because hanging the tail out bleeds off a great deal of speed going through a corner. Conserving the momentum is the fast way around as turn.
Neutral: This is the fast way around a turn where all four wheels slide evenly. Since the total friction circle traction of each tire is being used, all the available grip that the tires have is being put to the ground. Racers call this "drifting". This not to be mistaken for the idiotic Japanese Option Magazine video stuff which makes a mockery of proper driving technique. Neutral is the fast way around a corner most of the time. Neutral is also the hardest handling mode to achieve for the suspension tuner.
Polar Moment of Inertia: Or PMI as we will refer to it, is a description of how a cars mass is distributed along the length of the vehicle. A car with a high PMI is like a rear engine, rear drive car like a Porsche 911 or a front engine, front wheel drive car like our beloved Type R, same thing only the poles are different, so to speak. A car with a low PMI would be a mid engine car like a Boxster. Low PMI cars have most of their mass about the middle, high PMI cars have the mass at one end or another. Low PMI cars are the easiest to get a neutral balance out of due to the balanced, centralized mass. High PMI cars like to oversteer, in the case of the 911 or understeer like our cars. To get a feel for this phenomena, hold a bowling ball in one hand and rotate it back and forth by twisting your wrist. Now get a set of dumbbells of the same weight, grab the middle of the bar and do the same th
Understanding Vehicle Dynamics
Before we start we have to have an explanation of common vehicle dynamics terms. We had better understand the common ways to describe the different aspects of vehicle dynamics before we even turn a wrench, so here we go:
Friction circle: This is basically a vehicles performance envelope. It's expressed in lateral G’s, accelerating and braking G’s. When graphed, the friction circle looks like an egg with the X axis lateral G’s and the Y access braking and accelerating G’s.
Understeer: This is when, at the limit of vehicle traction, the front of the car slides first before the rear. Race car drivers call this "push". This is the way that many cars come set up to behave from the factory as it is the most predictable for average drivers (like the Type R). The crash mode for understeer is that when the limit of adhesion is exceeded, the car will plow strait ahead off the road nose first. This is not the fast way to have your car set up, but is best if you are an inexperienced driver. When the car understeers you should regain control if you let off the gas, unless of course you run out of road first. (That is what air bags are for.) It is not efficient for extracting maximum lateral G’s because the car will dynamically use the front tires excessively for turning, overloading them while the rear tires basically just hold the back of the car up - scrubbing off significant speed. Front wheel drive cars tend to exhibit understeer as the final terminal mode of balance.
Oversteer: This is when, at the limit of vehicle traction, the rear of the car slides first before the front. Race car drivers call this "loose". The rest of us call this "spinning out", "spinning a shitty", "doing a brodie" or even crashing. The final crash mode of oversteer is backwards, tail first into the woods or in the worst case spinning round and round with the driver as a helpless passenger. Since the infamous days of Ralph Nader and the Corvair, most auto manufactures avoid oversteer like the plague. Oversteer is difficult for an inexperienced driver to handle because recovery requires judicious use of countersteering and throttle feathering to control; fine motor skills that only some of us can deal with. Although oversteer looks neat and macho it is really a slow way to drive except in maybe pro-rally on the dirt . Oversteer is slow on the pavement because hanging the tail out bleeds off a great deal of speed going through a corner. Conserving the momentum is the fast way around as turn.
Neutral: This is the fast way around a turn where all four wheels slide evenly. Since the total friction circle traction of each tire is being used, all the available grip that the tires have is being put to the ground. Racers call this "drifting". This not to be mistaken for the idiotic Japanese Option Magazine video stuff which makes a mockery of proper driving technique. Neutral is the fast way around a corner most of the time. Neutral is also the hardest handling mode to achieve for the suspension tuner.
Polar Moment of Inertia: Or PMI as we will refer to it, is a description of how a cars mass is distributed along the length of the vehicle. A car with a high PMI is like a rear engine, rear drive car like a Porsche 911 or a front engine, front wheel drive car like our beloved Type R, same thing only the poles are different, so to speak. A car with a low PMI would be a mid engine car like a Boxster. Low PMI cars have most of their mass about the middle, high PMI cars have the mass at one end or another. Low PMI cars are the easiest to get a neutral balance out of due to the balanced, centralized mass. High PMI cars like to oversteer, in the case of the 911 or understeer like our cars. To get a feel for this phenomena, hold a bowling ball in one hand and rotate it back and forth by twisting your wrist. Now get a set of dumbbells of the same weight, grab the middle of the bar and do the same th
05-30-2002, 02:17 PM
#4
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Re: suspension questions. (YodaIsGod)
Basic Rules (again adapted from material from elsewhere - edited for content)
Here are some general basic rules if you want to improve your cars handling:
If you race in sanctioned competition, read your rule book before performing any modifications at all to your vehicle. It would be a pity to buy a fortune in trick parts only to have them declared illegal by an official. Beware of SCCA’s Street Prepared rules as many hot and popular street car mods would put you out of this class.
Do not lower your car too much! This perhaps is the number one no no. It is a symbol of a truly ignorant person with regards to suspension dynamics. Lowering looks really cool and can make a significant improvement to a cars cornering capability but going too low is detrimental to both handling and even safety. Going too low can cause bumpsteer, where the tie rods and control arms are traveling different arcs resulting in the wheels steering themselves with no steering wheel input. When a car is so low that the suspension bottoms under cornering loads, the end of the car that bottoms first will violently slide out. Super low guys are convinced that they are driving super touring cars but if you take them out on the track they will suck incredibly. Our Type Rs have a short travel suspension as it is and cannot take being lowered more than 1.5-2 inches at the most. So install some good springs such as Eibach, H&R or Ground Control and DO NOT CUT THEM MORE TO MAKE YOUR CAR LOWER. If you have the Ground Control springs do not adjust them to lower your car more than two inches except if you are going to compete in car shows where the car will be a stationary display. You want to maintain at least 1-3/4" of travel.
Buy and install matched components from a single manufacture. For instance do not put H&R front springs in with Eibach rear or a Suspension Techniques front bar with a TMC rear. Suspension manufactures usually offer these parts as a tuned set with rates, etc. made to match each other. So unless you really know what you are doing don’t mix and match. Good stuff for our cars is made by Eibach, H&R, Mugen, Spoon, TEIN, Ground Control and Comptech.
If you are using high performance springs, try to wait until you can afford the shocks also. Performance springs store more potential energy when they are compressed. They need a shock with more rebound damping to keep the car from bouncing all over the place after you hit a bump. Really good shocks like Koni or GAB’s are adjustable so you can tune your shocks to the springs. Performance springs with stock shocks usually feel floaty on high speed undulations. I find that that feels a little spooky. Performance spring’s quicker rebound characteristics also seems to wear out stock shocks quickly making them get super floaty. I prefer Bilsteins because of their auto adjustability and durability.
Limiting body roll is good. Our Type R’s sit high, and have fairly soft springs from the factory. They roll quite a bit. Install stiff springs and swaybars with matching shocks, and lower the car to a reasonable level. Limiting roll keeps the weight from transferring excessively, allowing the inside tires to work more in a turn. Limiting roll also helps keep the car from bottoming in a turn and keeps the car out of the bumpsteer zone. Type Rs like ours do gain some negative camber under roll either so limiting roll helps keep the tires from folding over.
Having adjustably is good. Having the ability to adjust shocks, camber and toe is very useful when trying to extract G’s from your car. On a showroom stock racer optimizing the alignment and tire pressures alone can make the car corner a lot better and have faster lap times. As front camber is not adjustable on our cars (unless you purchase a kit) it is important to make it so. Mugen and Skunk make high quality camber kits. These will slightly harshen your ride but will sharpen turn in due to the elimination of squishy rubber with metal bearing
Here are some general basic rules if you want to improve your cars handling:
If you race in sanctioned competition, read your rule book before performing any modifications at all to your vehicle. It would be a pity to buy a fortune in trick parts only to have them declared illegal by an official. Beware of SCCA’s Street Prepared rules as many hot and popular street car mods would put you out of this class.
Do not lower your car too much! This perhaps is the number one no no. It is a symbol of a truly ignorant person with regards to suspension dynamics. Lowering looks really cool and can make a significant improvement to a cars cornering capability but going too low is detrimental to both handling and even safety. Going too low can cause bumpsteer, where the tie rods and control arms are traveling different arcs resulting in the wheels steering themselves with no steering wheel input. When a car is so low that the suspension bottoms under cornering loads, the end of the car that bottoms first will violently slide out. Super low guys are convinced that they are driving super touring cars but if you take them out on the track they will suck incredibly. Our Type Rs have a short travel suspension as it is and cannot take being lowered more than 1.5-2 inches at the most. So install some good springs such as Eibach, H&R or Ground Control and DO NOT CUT THEM MORE TO MAKE YOUR CAR LOWER. If you have the Ground Control springs do not adjust them to lower your car more than two inches except if you are going to compete in car shows where the car will be a stationary display. You want to maintain at least 1-3/4" of travel.
Buy and install matched components from a single manufacture. For instance do not put H&R front springs in with Eibach rear or a Suspension Techniques front bar with a TMC rear. Suspension manufactures usually offer these parts as a tuned set with rates, etc. made to match each other. So unless you really know what you are doing don’t mix and match. Good stuff for our cars is made by Eibach, H&R, Mugen, Spoon, TEIN, Ground Control and Comptech.
If you are using high performance springs, try to wait until you can afford the shocks also. Performance springs store more potential energy when they are compressed. They need a shock with more rebound damping to keep the car from bouncing all over the place after you hit a bump. Really good shocks like Koni or GAB’s are adjustable so you can tune your shocks to the springs. Performance springs with stock shocks usually feel floaty on high speed undulations. I find that that feels a little spooky. Performance spring’s quicker rebound characteristics also seems to wear out stock shocks quickly making them get super floaty. I prefer Bilsteins because of their auto adjustability and durability.
Limiting body roll is good. Our Type R’s sit high, and have fairly soft springs from the factory. They roll quite a bit. Install stiff springs and swaybars with matching shocks, and lower the car to a reasonable level. Limiting roll keeps the weight from transferring excessively, allowing the inside tires to work more in a turn. Limiting roll also helps keep the car from bottoming in a turn and keeps the car out of the bumpsteer zone. Type Rs like ours do gain some negative camber under roll either so limiting roll helps keep the tires from folding over.
Having adjustably is good. Having the ability to adjust shocks, camber and toe is very useful when trying to extract G’s from your car. On a showroom stock racer optimizing the alignment and tire pressures alone can make the car corner a lot better and have faster lap times. As front camber is not adjustable on our cars (unless you purchase a kit) it is important to make it so. Mugen and Skunk make high quality camber kits. These will slightly harshen your ride but will sharpen turn in due to the elimination of squishy rubber with metal bearing
05-30-2002, 02:17 PM
#5
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Re: suspension questions. (YodaIsGod)
Suspension Tuning Tips (part 3)
How to adjust your suspension
The previous discussion involved basic concepts and principles of suspension design theory. These principles work pretty well for most driving styles (as well as most of the good drivers that I have worked with) and preferences. Your preference could be different. To find the optimal settings for your personnel suspension set-up there are a few tricks that you can do to make the process less painful and quicker.
To adjust your suspension you need a just a few simple things.
First you need a good, accurate tire pressure gauge. A gauge with a bleeder valve is very useful. Gauges like this can be purchased at just about any racers supply house for about 20 bucks. Don’t waste your money on those expensive electronic gauges. Those are slow to use and never come with bleeder valves.
The next bit of stuff to have is a compressed air tank for adjusting tire pressures. Tracks almost never have a handy air tank. I got my tank from Sears for about 50 bucks. Fill it at a gas station or use your home air compressor before heading out. Make sure the tank you buy has a safety relief valve so you don’t blow the crap out of your self if you leave the tank in your hot car during lunch or something.
A digital tire pyrometer is very important. Get one with a wire bead probe. These are used for measuring tire temperature differentials across the tread which is a good tool for judging whether your tires pressures and alignment settings are right. You can get one of these at any racers supply house for 50 to 200 bucks. If you don’t want to shell out the bucks for this, bring a bottle of white out with you.
A notepad and pen are critical also. With so many adjustment parameters it is important to try to write everything down as you will never remember it all.
When at the track, first note your initial settings including the air pressure. Write it all down. Paint a stripe of white out on your tire’s sidewalls going down to the tread. It helps if you have someone do all these things for you as it gets pretty hectic when you are trying to get ready to run. Go out and drive the car, making mental notes on how it handles, what you like and what you dislike. When you pit or when your run is over, immediately measure your tire temperatures. You only have a few seconds to do this as the temperatures drop quickly. If the course is clockwise, measure the left side of the car first starting with the left front. If it is counterclockwise, measure the right side first starting on the right front. You want to measure the treads temperature in three places, the outside, the middle and the inside. Push the wire of the bead probe slightly into the rubber for the most accurate measurement. Measure all the tires quickly and be sure to write it all down. Next measure and record the tires pressure quickly before the tires have a chance to cool much. Look at the white out stripe that you made. It is there to indicate if your tires are rolling onto the sidewalls. The stripe should not be worn past the rounded corner of the tread- sidewall junction.
Now review your notes and the recorded data. How did you like the way the car handled? Did it push? Was it loose? Was it perfect? Look at your temperature distributions across the tread. Ideally it should be about 10 degrees hotter on the inside than the outside with an even gradient across the tread. *This is usually only attainable on a race car with optimized suspension geometry.* On a street, production based car that is totally modified for adjustably, even temperatures across the tread may be possible and on a FWD car usually the outside will always be a bit higher. On a stock car you cannot usually get better than a 20 degree gradient. Anyway, the camber and pressures might need some adjustment to get an optimal temperature gradients out of the tires. If the temps are fairly even, it means you are using the whole tread of the tire t
How to adjust your suspension
The previous discussion involved basic concepts and principles of suspension design theory. These principles work pretty well for most driving styles (as well as most of the good drivers that I have worked with) and preferences. Your preference could be different. To find the optimal settings for your personnel suspension set-up there are a few tricks that you can do to make the process less painful and quicker.
To adjust your suspension you need a just a few simple things.
First you need a good, accurate tire pressure gauge. A gauge with a bleeder valve is very useful. Gauges like this can be purchased at just about any racers supply house for about 20 bucks. Don’t waste your money on those expensive electronic gauges. Those are slow to use and never come with bleeder valves.
The next bit of stuff to have is a compressed air tank for adjusting tire pressures. Tracks almost never have a handy air tank. I got my tank from Sears for about 50 bucks. Fill it at a gas station or use your home air compressor before heading out. Make sure the tank you buy has a safety relief valve so you don’t blow the crap out of your self if you leave the tank in your hot car during lunch or something.
A digital tire pyrometer is very important. Get one with a wire bead probe. These are used for measuring tire temperature differentials across the tread which is a good tool for judging whether your tires pressures and alignment settings are right. You can get one of these at any racers supply house for 50 to 200 bucks. If you don’t want to shell out the bucks for this, bring a bottle of white out with you.
A notepad and pen are critical also. With so many adjustment parameters it is important to try to write everything down as you will never remember it all.
When at the track, first note your initial settings including the air pressure. Write it all down. Paint a stripe of white out on your tire’s sidewalls going down to the tread. It helps if you have someone do all these things for you as it gets pretty hectic when you are trying to get ready to run. Go out and drive the car, making mental notes on how it handles, what you like and what you dislike. When you pit or when your run is over, immediately measure your tire temperatures. You only have a few seconds to do this as the temperatures drop quickly. If the course is clockwise, measure the left side of the car first starting with the left front. If it is counterclockwise, measure the right side first starting on the right front. You want to measure the treads temperature in three places, the outside, the middle and the inside. Push the wire of the bead probe slightly into the rubber for the most accurate measurement. Measure all the tires quickly and be sure to write it all down. Next measure and record the tires pressure quickly before the tires have a chance to cool much. Look at the white out stripe that you made. It is there to indicate if your tires are rolling onto the sidewalls. The stripe should not be worn past the rounded corner of the tread- sidewall junction.
Now review your notes and the recorded data. How did you like the way the car handled? Did it push? Was it loose? Was it perfect? Look at your temperature distributions across the tread. Ideally it should be about 10 degrees hotter on the inside than the outside with an even gradient across the tread. *This is usually only attainable on a race car with optimized suspension geometry.* On a street, production based car that is totally modified for adjustably, even temperatures across the tread may be possible and on a FWD car usually the outside will always be a bit higher. On a stock car you cannot usually get better than a 20 degree gradient. Anyway, the camber and pressures might need some adjustment to get an optimal temperature gradients out of the tires. If the temps are fairly even, it means you are using the whole tread of the tire t
05-30-2002, 02:18 PM
#6
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Re: suspension questions. (YodaIsGod)
here's more stuff to read....
Shocks: http://www.grmotorsports.com/shockstech.html
Chassis tuning: http://www.grmotorsports.com/repent.html
Corner weighting: http://www.grmotorsports.com/cornerweight.html
Anti-roll bar tech: http://www.grmotorsports.com/swaybars.html
Shocks: http://www.grmotorsports.com/shockstech.html
Chassis tuning: http://www.grmotorsports.com/repent.html
Corner weighting: http://www.grmotorsports.com/cornerweight.html
Anti-roll bar tech: http://www.grmotorsports.com/swaybars.html
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05-30-2002, 07:50 PM
#11
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Posts: n/a
Re: suspension questions. (nijia555)
want to know about brakes & brake fluids?
some good articles....
http://www.teamscr.com/grmbrakes.htm
http://www.teamscr.com/rotors.htm
http://www.stoptech.com/technical/
brake fluid info... http://www57.pair.com/lane/bfluid.htm
some good articles....
http://www.teamscr.com/grmbrakes.htm
http://www.teamscr.com/rotors.htm
http://www.stoptech.com/technical/
brake fluid info... http://www57.pair.com/lane/bfluid.htm
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