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motoiq project Honda S2000 

Project S2000: Part 2 - Suspension Tricks

By Khiem Dinh, photos by Jeff Naeyaert

Khiem Dinh is an engineer for Honeywell Turbo Technologies at the time of this writing.  All statements and opinions expressed by Khiem Dinh are solely those of Khiem Dinh and not reflective of Honeywell Turbo Technologies.

To read the rest on Project S2000 click here!

We chose our S2000 as a project car for its handling prowess.  With multilink suspension and a 50/50 weight distribution, the S2K has all the right stuff to carve corners with. AP2 S2K's like our car have revised rear toe link pick up locations so they don't exhibit the twitchy at the limit cornering issues that the older AP1 chassis has.  What's good can always be made better so we decided to spend our efforts in improving our car's suspension in the next round of mods.
 
If you’re observant and knowledgeable about S2000s, you’ll probably have noticed we went to a non-staggered setup for the tires.  The stock setup for a 2005 S2000 is a 215/45/17 tire on the front with a 17”x7” wheel, and 245/40/17 tire on the rear with a 17”x8.5” wheel.  The OEM tires are Bridgestone Potenza RE050s.  Our new setup is 245/40/17 Bridgestone Potenza RE-11s on 17”x9”, +63 offset, Volk RE30 wheels all around.

 MotoIQ Project S2000
 On Project S2000 we decided to run equal sized wheels and tires on both ends of the car.

Why did we do it?  For a number of reasons, with the primary reason being to increase mechanical grip.  Acura did it with their American Lemans LMP cars, so it can’t be that bad of an idea right?  A secondary reason is it’ll allow us to rotate the tires.  Tires aren’t cheap, so we might as well be able to maximize the life out of them!  (Of note, we have gotten extremely even wear front to rear with about 3k miles of street use.  The wear is within 1mm.)  However, just going to a non-staggered setup without any other changes is a shoddy idea, and we’ll get to that in a moment.

Using equal sized tires on all four corners makes some logical sense as the S2000 has a nearly perfect 50/50 weight distribution.  With the same weight on the front tires as the rear, it’s rational to put the same size tires front and rear.  This is a popular setup for S2000s that are tracked in order to maximize the mechanical grip available. 

 MotoIQ project S2000
 The stock S2000 has a staggered fitment with larger rear tires than the fronts.

Why is it a bad idea to mount significantly wider tires up front with no other changes?  Well, the S2000 is very well balanced in the stock configuration.  We found out on the track that it rotates very well on turn-in with trail-braking, is easily balanced between understeer and oversteer with the throttle mid-corner, and the tail can be coaxed out with the throttle on corner exit.  Going to a slightly wider front tire, such as a 225, would probably be okay, but we’re using a 245 (about a 14% increase in width).  With everything else remaining the same, oversteer is the end result.  At elevated speeds, the willingness of the front end to turn in and the rear feeling loose was quite evident.  Entering into a turn hot required extreme caution so as to not swap ends. 

 Project S2000
 We decided to run the same size tire front to rear and retune our suspension to exploit this.  A bigger front tire is not going to get overworked as easily and we figured that with a near 50/50 weight distribution this made more sense.

 

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Comments
wrappedinbacon
wrappedinbaconlink
Tuesday, June 15, 2010 6:45 AM
After driving the car, I can say that it definitely feels planted. Although it was just a short drive around our improvised test track, the modifications have made it very difficult to upset.
brainrush
brainrushlink
Tuesday, June 15, 2010 6:51 PM
"improvised test track"... is that engineer speak for a vacant parking lot?
spdracerut
spdracerutlink
Wednesday, June 16, 2010 3:32 AM
The 'improvised test track' is a series of turns near work.... I've dubbed them Cosworth Corners and A*(Alpinestar) Switchbacks.
brainrush
brainrushlink
Wednesday, June 16, 2010 7:46 AM
nice! I live on a private road with a 1/2 mile straightaway going into another 1/2 mile series of uphill sweepers with a change in surface.

for a more thorough test-drive there's what I call the "Napa Nurburgring" a 21 mile loop of mountain roads about 5 minutes from the house, check it out-->

http://maps.google.com/maps?f=d&source=s_d&saddr=38.318023,-122.344866&daddr=Dry+Creek+Rd+to:Redwood+Rd&geocode=%3BFUIISgIdtruz-A%3BFSK9SAIdeh-1-A&hl=en&mra=dme&mrcr=0&mrsp=0&sz=14&sll=38.326036,-122.349844&sspn=0.047942,0.077162&ie=UTF8&ll=38.371809,-122.374649&spn=0.191645,0.308647&t=h&z=12
Street Surgeon
Street Surgeonlink
Wednesday, June 16, 2010 11:07 AM
All this talk of KW suspensions finally sealed the deal and I was ready to buy, cash in hand!!! If only they made a set for 1G AWD DSM's :( Back to the drawing board...
spdracerut
spdracerutlink
Sunday, June 20, 2010 12:07 PM
Took the car out for a long (350 miles) drive today on all sorts of roads to tweak the suspension settings.

The starting recommend settings are: front(rebound: 9 clicks from full stiff compression: 0.75 turns from full stiff), rear(rebound: 15 clicks from full stiff, compression: 0.75 turns from full stiff).

The car was bounding a bit on the freeway 'humps'. I added 2 clicks of rebound on the front and 3 on the rear. So they are now 7 and 12 clicks from full stiff respectively. The front feels pretty good now, but the rear needs some more tweaking. For the fronts, I'm thinking of adding 0.25 turns of compression and leaving the rebound. On the rear, add 0.25 turns compression and 2 more clicks rebound for 10 from full stiff.
spdracerut
spdracerutlink
Sunday, June 20, 2010 5:09 PM
Opps, I made a typo! The nuts for the top hats are M10 X 1.5, NOT M12 x 1.5. My bad!
slowpoke
slowpokelink
Thursday, June 24, 2010 5:44 AM
It seems this package is ~$3k. have any suggestions for around $1500?

Mike Kojima
Mike Kojimalink
Thursday, June 24, 2010 2:04 PM
Good tires, alignment and some testing to find correct tire pressure. A stock S2K is pretty good and cheap stuff will probably perform worse.
slowpoke
slowpokelink
Thursday, June 24, 2010 5:52 PM
10-4!
spdracerut
spdracerutlink
Thursday, June 24, 2010 9:33 PM
Slowpoke: The KW V3s go for roughly $1800 I think. While not as track orientented as the Clubsports, they are still a significant improvement over stock.

If you want a good budget setup, find someone selling their stock S2000 CR edition suspension. OEM + upgrade :) They ride a bit worse than the KWs, and the springs rates fall between that of the V3s and stock, but it's a good value.

Whatever you do, don't buy cheap coilovers. Those are primarily designed just to dorp the car for looks. They'll ride like crap and not be durable. And lowering the car too far can create issues with the suspension geometry that you will then need to buy other things to fix. I mentioned the necessity of the axle spacers when the car is dropped too low, and you can see this in the picture of the rear axle of the N1 Concepts Time Attack S2000 (http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1606/n1-concepts-time-attack-honda-s2000.aspx) The axle is at a bit of an angle and hence the need for the spacers.
DaGou
DaGoulink
Friday, October 28, 2011 5:40 PM
I have read the article several times and I just keep missing the part where you said exactly how much you lowered it. The range is mentioned 0.9 to 2.1 and there is a picture of the process but you did not reveal the magic number...Can you let us know?
PTL88
PTL88link
Friday, October 11, 2013 6:44 AM
I was wondering if anyone can help me out with a suspension question for my 2004 S2000. Rear doesn't seem as stiff seems to ride softer than normal. Do I need new shocks? Front end was damaged at dealership and car hasn't driven the same since. Dealership fixed front end and did an alignment because the steering was off center. Rear seems to shimmy when I hit a bump. Had another dealership check it out and they redid the alignment but said the shocks were ok. The tech said that the wear on my tires was feathered. Any idea what the problem might be? Tech visually inspected the shocks but didn't take them off the car.
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