Suspension

[Andrie Hartanto]

Tire pressure should be use only as the last resort. You should get the optimal tire pressure by using pyrometer.

First you have to get the optimal tire pressure. This is important for the duration of the race. Tire pressure that is not optimal can result in unmanageable tire temperature, thus deteriorating performance on the track.

Alignment is very important and can change the car characteristics significantly. But you have to find a compromise, where the alignment, combine with your suspension and tire setting resulted in optimal perfomance of your tire. Make sure that your alignment don't overheat the tires.

Dial your suspension using the known data for the tires.

First thing I would do, in your case is to put thicker sway bars at the front. If that don't work, it is time to play with spring rates.

 

[Gerard van Santen]

Originally posted by Andrie Hartanto:

I tried two different sway bars, and even go to the extreme by not having rear sway bars at all.

Hi Andrie,

I do the NSX Trophy on several European tracks like Monza and Spa Franchorchamps with my CTSC NSX and I am a bit surprised you don't even use sway bars for the rear.
I use track swaybars from Dali in combination with Koni dampers with racing springs from RM.

I turn the Koni dampers 1/2 turn from the stiffest for the front and 3/4 turn from the stiffest for rear on dry flat tracks with no bumps and low kerbs. It feels stabil and neutral with a bit tendency to oversteer, but that's what I like.
Tire pressure with Yokohama slicks for front 23 PSI (cold) and 25 PSI for rear. You can ad 7 PSI when the tires are on race temp.

On wet or bumpy tracks with high kerbs I go as soft as possible. The tire pressure I lower with at least 2 PSI.

I still want to know from you how come you have so much oversteer that you even drive without rear sway bars.

Have fun,
Gerard

[This message has been edited by Gerard van Santen (edited 12 September 2002).]

 

[Andrie Hartanto]

Hi Gerard,

Which koni dampers do you use? Off the shelf Koni yellow or their competition koni?

I used off the shelf koni mated with H&R springs, and Dali sway bars before and find it pretty good handling. Although it is on the softer side. About 5kg/mm front and 5.1kg/mm rear. This suspension require quite a bit of sway bars to help reduce the roll. When I used this suspension I was running 1.5 turns from full stiff in front, and .75 turn from full stiff in the rear. Front sway bar is almost full stiff up front and the rear sway bar is about middle.

The Tein comes with 10kg/mm front and 12kg/mm rear. Which is much stiffer than the one I had before. I experimented with different sway bars, and still have oversteer. With the rear sway bars taken out and the damper setting at 3 clicks from stiff front and 12 clicks from stiff rear, it is somehow managable. Still a bit nervous, but managable. Which I think might be pretty good, but maybe my skill is not up to par with the car handling yet.

However, after driving the Comptech race suspension car, I am convinced that the problem is not me. They are running much stiffer front spring 18kg/mm front and about 12 kg/mm rear. Yet the shock dampen the spring better, that the car don't feel as bumpy then my car with the Tein. My biggest gripe is The Tein skip and slides over bumpy surface, while the comptech suspension absorb it better. And this is with a much stiffer springs!

I understand that European tracks are much smoother than US tracks. So that might contributed on how damper makes handling different in different side of the globe.

I haven't have the luxury trying out slick tires on my car. But over here we have what we called R compound tires that we use. Not as grippy as slick tires, but much grippier than regular street tires.

 

[Gerard van Santen]

Originally posted by Andrie Hartanto:
Hi Gerard,

Which koni dampers do you use? Off the shelf Koni yellow or their competition koni?

Hello Andrie,

I use the yellow ones and I am very pleased with them, because they are a good match for both street and track use.

The front sway bars I have as stiff as possible and the rear the second hole.

If it is possible, try slick tires. You don't recognise your NSX anymore. It is a whole different world. I am sure all your problems would be over if you use slicks.

Another possibility is to try bigger front tires or wheels. You will get more understeer. Or give your front tires a bit more pressure.

Gerard

 

[Andrie Hartanto]

Hi Gerard,

We have problem here in the US getting slicks that fits NSX.

AS far as wide tires, I uses 245/45/16 up front and 275/40/17 in the rear. I think those are wide enough

 

[Gerard van Santen]

Originally posted by Andrie Hartanto:
Hi Gerard,

We have problem here in the US getting slicks that fits NSX.

AS far as wide tires, I uses 245/45/16 up front and 275/40/17 in the rear. I think those are wide enough

Hi Andrie,

I think you're going much to wide with your front tires. Probably that's the reason for your oversteer problems. I use for slick tires 225/610(height of tire in mm)/17 and rear 270/650/18.

Furthermore I have a CTSupercharged NSX, so you can believe, that I need all the grip I can get.

The guys with OEM rims use 210/590/16 front and 250/610/17 rear. It's gives them a more crispier behavier than my car, but I need the grip because of the HP's I've got.

For your front I would'nt go wider than 225/45/16

Why don't you buy slick from Europa? We have got several sizes and brands for the NSX.

I still don't get it, you not using rear sway bars. With sway bars and a good suspension setup and the right tires you will get a NSX that doesn't roll in corners and will stay horizontal like an iron.

Have luck,
Gerard

[This message has been edited by Gerard van Santen (edited 13 September 2002).]

 

[Andrie Hartanto]

Originally posted by Gerard van Santen:
Hi Andrie,

I think you're going much to wide with your front tires. Probably that's the reason for your oversteer problems. I use for slick tires 225/610(height of tire in mm)/17 and rear 270/650/18.

Furthermore I have a CTSupercharged NSX, so you can believe, that I need all the grip I can get.

The guys with OEM rims use 210/590/16 front and 250/610/17 rear. It's gives them a more crispier behavier than my car, but I need the grip because of the HP's I've got.

For your front I would'nt go wider than 225/45/16

Yep, I would rather use 225/45/16 too. But none of the manufacturer for R compound tires make that size. So, I'm stuck. I might opt to try 215/40/16 and 275/40/17 next time. As again that are the only size available. You see, we are tire limited here in the US

Why don't you buy slick from Europa? We have got several sizes and brands for the NSX.

Now, don't tempt me...
I will drop you a private email inquiring...

I still don't get it, you not using rear sway bars. With sway bars and a good suspension setup and the right tires you will get a NSX that doesn't roll in corners and will stay horizontal like an iron.

Yes with good suspension setup, and sway bars it will work well. But that's the key, good suspension setup, which I don't think I have. So I'm trying to make up for handling characteristics by playing around with the sway bars. Sway bars help to reduce body roll, but at the expense tying our beautiful indenpent suspension. This in return increase the load transfer from one wheel to another, which in return reduce the total cornering capacity. So there are always a trade off. If I go with stiff enough springs to reduce the roll, I can maintain minimal load transfer, and can have greater total cornering capacity. Of course, this is also a trade off, as the suspension will squat less, and I might compromise the acceleration at corner exit. It is all compromise, I just need to find a compromise that work for me. Unless of course I can alter the suspension pickup/mounting point. But I need to go back to school and review all my engineering book if I decide to do that. Even then, I don't think I'm smarter than those Honda engineers

Have luck,
Gerard

Thanks, I will need that

 

[Gerard van Santen]

Hi Andrie,

If track usability is the issue, I would go for the smaller 215 tires. I also wouldn't mind losing a part of my independent suspension. Because if you compensate leaving the sway bar with stiffer springs to avoid body roll, you don't mind independent suspension. You won't have any suspension.

Better to have comfort in your suspension with no body roll than no body roll with an independent suspension that doesn't work because of its stiffness.


Again,
Have luck,
Gerard


[This message has been edited by Gerard van Santen (edited 13 September 2002).]

 

[Andrie Hartanto]

Hi Gerard,

I agree with you that your setup might be the best compromise, which was also my old setup. You are making me regret doing all these things... Theory can say one thing and it means another in real world. I'm learning as I go along. But I'm glad I tried it. I will try to play around with my current setup to satisy my need since I sold my old setup already. Worse come to worse, I'll sell this setup and go with another setup.

Now, how bout those slick tires from Europe....

 

[Gerard van Santen]

Hi Andrie,

There is an old Dutch wisdom that says: "Better late than never".

But for the slick tires. Ask Mark Johnson. A friend of mine has send him a couple of slick tires from Holland.
He will be in Europe to compete against me and a lot of other Europeans in the NSX Trophy at Spa Franchorchamps (27th - 29th of september). Perhaps he can arrange some tires to bring with him to the USA.

Go for it,
Gerard

 

[ScienceofSpeed]

Ooops, sorry for taking so long to reply. Andrie is 100% correct. This was the verbatim explanation from TEIN.

Like Andrie, I had lots of oversteer problems. I tried all kinda of sway bar combinations, and ended up changing the spring rates. Now, the handling is amazing! I am working with TEIN to propose this setup to be offered through ScienceofSpeed at no extra cost.

Cheers,
-- Chris

Originally posted by Andrie Hartanto:
Hi Detlef,

I suspect they uses the lower pertion of the adjustment if you opt to use softer spring rates.

Anyway, I've done 2 days testing with Tein RA, and I must say I'm a bit dissapointed with their spring rate. I really think the car has too much tendency to oversteer. I suspect this is because the Japanese are big on drifting.

I'm gonna try different spring rate to see how the car handles and get back to you on that. I hate to be called the drift guy in the track

------------------
Revolutionize your NSX with ScienceofSpeed
www.ScienceofSpeed.com | [email protected] | 877-863-4520

 

[j14nsx]

Chris,

What was the spring rate that you tried and was so good?

I found oversteer, but thought it might be due to other factors than just the TEINs.

I noticed in my pre-purchase research, that most other spring systems are softer on the back than the front, except the TEINs.

Kevin

 

[POWERED by HONDA]

Ooops, sorry for taking so long to reply. Andrie is 100% correct. This was the verbatim explanation from TEIN.

Like Andrie, I had lots of oversteer problems. I tried all kinda of sway bar combinations, and ended up changing the spring rates. Now, the handling is amazing! I am working with TEIN to propose this setup to be offered through ScienceofSpeed at no extra cost.

Cheers,
-- Chris

Sorry to revive an OLD thread...

Chris, have you been able to work with TEIN so that we can get the 10kg/10kg Front/rear spring rate combo for the TEIN package at no extra cost?

--Conrad

 

[burbel]

Ditto what Conrad said, I was searching through Prime looking for information on changing the settings on my sway bars (or removing the rear sway bar entirely) to dial out the excessive understeer - Chris, any update on this?

 

[NSX-Racer]

burbel: To reduce understeer you can:
1. make the rear bars stiffer
2. increase rear tire pressure
3. make front bars softer
4. decrease front tire pressure
5. Use stickier tires overall (will effect the front more than the rear)

Usualy it's no problem to dial the NSX into a heavy oversteer animal...

If you remove the rear bar you make your problem worse.

 

[burbel]

Heh, only one word in that reply I posted was important, and it was *oversteer*. Leave it to me to put that incorrectly.

As a FYI, after removing the rear sway bar, the *edit* oversteer *edit* has gotten significantly better, as in it doesn't come into effect as often as before at low speeds (haven't been pushing the high speeds much lately).

Sorry for the confusion...

 

[NSX-Racer]

after removing the rear sway bar, the understeer has gotten significantly better

That's against about every theory I ever heard of....
or did you mix up the words again and you mean oversteer has gone better?