1st, don't send Frank please...I've been searching for a couple hour for a decent answer/theory on this one but all I found was questions that have obvious answers...

Right now I'm at the point where I'd like to stiffen up the car... again... The car is a dedicated track car so no need to get into the street driving thing...

My current set up is: chassis DC2, GC f600 r800 mate with koni race and a 22mm rear sway bar. The car is stable right now and is really responsive to my style of driving. I've been driving it like that for 2-3 years now...

I'd like to stiffen up thing up a bit so I could avoid the car from diving to much on hard braking and hard cornering... I'm thinking on getting 2x1000 for the rear and swap the 800 up front... My concern is about the rear sway bar... When is it time to go bigger? I know it's a technical question and that why I'm asking it...

Since I start lapping/autoX/racing, I've been trying all kind of set up during the last 9 years and what I have found is that the more I've been stiffen up the car the less I have feel the "snappy" nature of my 22mm rear sway bar that's being swap there at the begginning... I've learn that sway bars and spring rates needs to work togheter as whole and not independantly from each other. I have a lot of succes right now with the set up...

But it's time to go wider in front and I'm concern about rubbing... My 15x8 with 225 hoosier fit really tight under my front fender when car's diving... I have plan to put wider fender to fit the 15x9 with 275 but I think that stiffen up things wouldn't be a bad thing too... But i'd like to keep the balance I have right now... I know I'll have to deal with camber too later on but one thing at the time...

So the question is: Where I can find that miracle formula to mix match swaybar and spring rate?

And since where there, an other question I'm asking my self is the car weight distribution vs the frt/rear spring rate... the car weight 2250 lbs right now and the weight distribution has change quite much since I start lighten up the car when it was 2675lbs... Now I'm at 65/35 % and I'm planning to go around 2150 witch would keep it legal in E-prep with 15x9. Should I take this into consideration when choosing to stiffen up front vs rear since the car's rear is getting so light vs the front... for exemple I thought trying 900 all around to compensate the rear weight lost...

So many questions, sorry to ask guys, but as a competitive racer we all get there one in a while and here it is for me... again... thanks for sharing your experience/tips/knowledge...

 

Sorry my friend now you are in racing setup territory and the only way you will find out your answers is by testing . There is no one setup that will fit all. It all depends on your driving style and suspension set up. I can tell you that you are in the right track but detailed setup settings will be closely kept by each competitor since it has taken a lot of time and testing to get there. Try the 800 front and 1000 back with no sway in the front and big adjustable sway in the back. Play with your alignment.

 

Frank is on vacation....
But like Marcel says you are now in a test and see what works for you stage.
Small changes, and record everything you do.
Also keep in mind that each track you visit will have changes you will have to make to the car that effect that car on that track.
You have enough experience now I belive that you can easilly find your happy medium.
Play with what you have in varying degrees.

Im going to go hug my race car now.

 

I don't want secret, I have my own... : P

I'd like to undertand the swaybar... how to calculate the difference between a 22 vs 23 vs 24 vs 26... I know how it works, but how much more load resistance will there be in between the different size... There must be a mathematical rule...

I should have ask the question this way, but everytimes someone is asking a single question, peoples always want more info about the set up so I have put the essential and the reason why I'm planning to upgrade so there will be less waste of time...

 

X2

 

Honnestly I never played with the sway bar it self and change everything around it so the car would respond to my imputs... Now I feel that stiffen up the suspension migh leed to a sway bar not working anymore.... That's why I 'm concern about sway bar rate...

 

here you go buddy. this is just for the arb, i will leave the rest to you.

http://www.lumenique.com/Cars/mcoupe...tirollbars.htm

 

Thanks, it give good indication in stiffness increase... I'll put this to good use!

 

More front spring, maybe more front compression damping, depending on how your shocks are valved.

Check your front suspension travel. A common Honda-tech problem is running out of front suspension travel, and then complaining of understeer, and then stiffening the rear, whereas the correct solution is stiffen/raise the front.

 

While you are trying things, try the 1000lb on the front and the 800 on the rear. 4 tire grip > 3 tire grip:

 

again everything is relative of what kind of setup you like, 1000 in the front and 800 in the back sounds ok, but it might give you push if the back is too grippy, I can probably type 2 pages of this stuff, but it will be nice if someone like Johnny Mac explains it to you. It takes a long time to get your car set up, and not two cars are the same.
Try what you think is best and go from there.
Are you here Johnny?

 

I'm aware of this and i agree with you on this... tie-wrap are zip around my shock strut for many years now...

I do have undesteer like every fwd car if trying going in the corner entry too fast... Like most of you know trail braking and fast but smooth brake to gas transition is your friend there...

Like I said above the balance of the car is quite good now... It is easy to drive at the limit but I'd like to stiffen up everything let's say by 20%...And this is where my knowledge is limited... When it is time to think bigger sway bar?

 

when ever you want. Just put on a big sway bar and go test.

 

I respect your point, now why just a big sway bar and not just stiffer springs... I don't just put stuff on the car without understanding how it will affect the rest... this is my point...

It's not just a matter of adding a bigger swaybar or not, it's how will it affect the weight tranfer from corner entry up to the apex so I can generate less lift from the inside tire, generate more grip and be faster at the exit... the basic...

Now if you can't explain me why putting a bigger swaybar in the back might help me solve that prob at slow speed and not upsetting the car in transition... When the spring's works, when the sway bar's works, how they work together... Then you should pass your turn cause you don't know much more than me about the relation in between sway bar and coil spring rate... I want to understand... Sway bar are tricky and bigger is not always better... So unless you can tell me something usefull, please...

 

When setting up your car, don't think of Front suspension vs. Rear suspension being exclusive from each other. Think about how your spring rate/sway bar on your left front affects the suspension characteristics on your right rear... during transition, under load etc.

 

I think u will need to answer this question yourself by finding out the reason why each end will lose traction first, e.g. suspension bottom out, de-cambering, wheel lifting, rear toe, etc.

Also, just because a car feels "stiffer" does not mean it will corner faster.

I doubt a stiffer rear swaybar is going to make much of a difference. Your rear spring rate currently is 800, which means your wheel rate is about 400 lbs/in. Each rear corner weights about 4xx lbs, so your rear suspension going from about 1 inch compression to 2 inch compression when cornering. That's not a lot of movement. Your rear tire spring rate itself is about 1000 lbs/in, the chassis stiffness is xxx lbs/in, etc.

 

I'm sorry but the language barrier make me a better reader than writer and I might not have explain correctly what I'm looking for for information... I'm not gonna write down all my backgroud on track, but let's just say I'm no rookie... I'm on track at least an hour a week and not always in the driving seat for more than 8 years...

Being a good pilot and good instructor dosen't make me understanding everything about suspension géometry... especially on every car... I understand weight transfer, it's how it's been control by coil vs swaybar that i'm interest in... At one point, the 22mm sway bar might not do anything anymore if I put let say 1500lbs at the back.... What's the point of having a swaybar once the body roll is totally control by spring... What would be the difference in the feeling of driving a car that have no sway bar, only very stiff springs... I hope i'm more clear... If not I'll give up!

 

Finally founds my answers https://honda-tech.com/forums/showth...light=sway+bar

Just too bad I didn't found it in my first search... I guess I should stop doing search after 11pm... I'll take the blame...

 

You don't need to link bar and spring rate changes, you can do one without the other, and in a race car it is usually preferable (unless you are going from some weird soft spring big bar aero setup) to have the springs dictating most of the stiffness and the bars acting as trim devices.

They don't need to be linked, certainly not in any kind of mathematical sense, the tyre only cares about how much load it gets, not where it comes from. All you need to do is make sure the roll stiffness at each end is correct in total, and as said, make sure you are not running more bar than spring, but this is probably because of the damper valving than anything else. By my calculations a 22mm bar has an equivalent coil spring of about 600lbs, if you dampers are only valved for controlling a 600lb spring, then they are being overloaded 100% in roll. Chuck a 1000lb spring in and it's only 60% overloaded. The stiffer you go, the closer the actual damping comes to the ideal, and so it feels better. This is a crude explanation, but I believe the theory is correct...

There is no one formula, but there is a combination of many that will give you the answers you seek.

According to my clusterf**k of calculations (and making a few assumptions on the DC2, as mine is set up for my EK4) at 1G lateral, you are already fully unloading the rear, so searching for anything more there is pointless. Your 'Magic Number'/TLLTD at 1G is 47.7%, and at .85G just before you fully unload that inside rear, it is 42.9%, so these are the numbers you should be looking to match if you want to retain the current balance. Going to 800/1000 will net you 47.7% at 1G again, and 43.6% at .87G just before wheel lift, so a slight increase in understeer before a slightly later wheel lift, and the same thereafter.

Your roll angles on you current setup (tyre deflection excluded) are 1.506° and .984° respectively. As you can see, you have gained over half a degree of roll with just .15G increase in lateral acceleration after wheel lift, therefore it is the front where I would be searching for more grip now, to prevent it de-cambering by too much or bottoming out. Considering you want to reduce dive under braking also, bigger front tyres, stiffer front rates and a close eye on the dynamic camber would be my focus from this point on. The rear can't help you now...

 

You just want somebody to tell you exactly what you need to do with your car. Like I said before it takes a long time and testing to find the right combination. You want someone to tell you at what point you need a bigger sway bar. I don't know!!!!! Heck I don't even know if you know how to drive . If you say your car feels very stable at the "limit" then you have not reach the limit yet. You have 8 years of track experience and you are asking questions of a person that is going on his first hpde . Sorry I can't pass my " turn " when a couple of the guys here that are racers tell you to test and you refuse to listen instead you need someone to tell you what to do.
But you won't swap parts if the the opinion doesn't come with full tecnical explanation of how and why. Tell you what and this I think will be the best advise I can give you. Get your self about 5 to 6 thousand dollars and buy yourself a decent suspension . Jrz or Koni will do. I'm talking about Koni 2812 not your race Koni. About $900 a piece with no springs. Then buy yourself an adjustable rear sway bar and upgrade / refresh all your suspension. And finally hire somebody to help you with data logging and driving your car so they tell you exactly what the car needs. Other than that we can't setup your car in a forum.

 

Thanks for your time...It's appreciated. I will have to digest it to put it to good use... On the other hand, I will surely have more questions... I hope you'll still have a little time!

As for M. know it all, Are you such agressive everytime with everyone who's asking for help? What are you trying to proove? You came on my tread, I never ask you anything so if you don't want to help just look at an other tread... What's wrong with the fact of asking people who knows more than you on a topic to help you? And FYI It's not because you can buy you self 2812, Penske or Moton that it means you know how to get the most out of it...Seat time does... If your car is not stable at the limit it's because you should keep on reading about suspension set up or you drive it beyong it's limit and you're slowing down your self body... been there...Don't fight the car...

BTW being smooth is not only good behind the wheel... It's a positive way to live...

 

This is what most forget along the way.

 

All I'm saying bud is that if you don't want to hear it don't ask it. Dont mistake a sincere advise with being aggressive . If I tell you to test is because we all have been down that road and spent a load of money doing it.
Honestly I can care less what you do with your car and if you want somebody to tell you exactly what to do then it's up to you. Unfortunately to be fast you have to spend the money. No two ways around it. I wish I could tell you to try a specific set up so you can be really fast. I don't think there is anybody here that honestly can do that. I have been doing this for a little bit and not one set up works for two different cars.

 

I think u can pay JMac for his consulting services.

 

^^This...


^^...and this...


And a lot of it is derived and explained in the thread below. Read every single page as there are a ton of notes about different setups and what worked and what didn't and why for that particular driver. The thread talks about sping bias, roll stiffness, roll coupling and the affects of anti-rollbars. Although I drive a completely different chassis (Prelude) this thread was incredibly useful in helping me understand what to feel for, how to evaluate where more grip was needed and how to get it.

https://honda-tech.com/forums/showth...ght=suspension


-b.