Slow s2k
 

Hi guys, i run a ap1 s2k which i am having trouble squeezing down the lap times from. The car is a stripped down and caged car but is about 2-3 seconds off pace. My specs are as follow so i would welcome any open ended recommendations. I know it is a tough question but any suggestions would be greatly appreciated.

Ap1 chassis
Stock 04 f22, aem ecu, 76mm exhaust. 205 bhp at the wheels (does this output look correct)
Adjustable camber top front arms
Rear bump steer kit
Front wheels 17 x 8 offset -38
Rear wheels 17 x 9 offset -50
Tires 235/40 17, 255/40 17
Suspension nitron 3 way, 18kg/mm front/rear
Camber front 3.25 rear 2.75
Toe front out 9mm rear in 7mm
Caster 6.25
Type cr kit
4.3 final drive
1.26 primary drive
Comments: the car handles great and turns in on demand, but mechanical grip somehow remains low. At the same time, the car is having trouble keeping up with stockish fd2rs or dc5 type rs, and even some b18 eks and eg civics.
In short, mechanical grip is nt great and i am concerned if the power outputs look right. Race rules where i come from mandate stock engines and stock bodywork.

what is your driving experience? I'd say driver improvement is enough to get you on pace...

Just to confirm that is negative camber.
Springs sound way to stiff to me for the weight of the car.

could be driver experience but out of curiosity what kind of tires do you have on?

Hi Thanks. Appreciate your feedback thus far. We've had a number of different drivers drive the car thus far and the lap times seem reflective of varying driver competence, but largely inline 1-1.5 second difference. We are trying to suss out if it could possibly be mechanical here. For color, pbox data is indicating the car is about 0.9 seconds faster from 75 mph to 112mph compared to a bone stock S2000.

The car currently weighs 2420 lbs sans driver. Again, we recognize this is an extremely difficult issue to pin point, but i am hoping to put out as much information as possible and if someone can hopefully suggest if anything stands out as significantly incorrect.

We've run the car on 14kg springs before, and to be honest, the lap times were the same, which is leaving us scratching our heads. Is there a methodical way of figuring out if we should go harder or softer from here beyond randomly trying different spring rates?

The tires currently being used are Federal FZ201s. There has been some chatter about using A050s to see if better lap times emerge, and admittedly we have not done this. IF anyone has had experience with these tires, we'd be happy to hear their feed back

Many thanks in advance.

A video would be nice or a couple of pictures. Is the track surface fairly smooth or bumpy?
What's your ride height center of hub to fender or caster bolt to ground? and do you know how much damper travel remains?
Seems like quite a bit of toe out and toe in especially with a bumpsteer kit, I would free it up a bit. Have you adjusted the bumpsteer kit to get the toe change you desire if so what was it?

The tires are a major, if not the biggest factor in performance. I would only compare the laptimes to other cars with the same or very similar rubber. Figure out what your competition is running, and make sure you aren't giving up time with the compound. I've got to think a Hankook RS3 at the minimum, or even some sort hard of dedicated R-compound tire would be a great match for those monster spring rates that you have.

Figure out the tire situation and go from there. Seconds and seconds from the tires.

What tires are on your car? Tires are the most critical component to fast lap times. A bone stock S2k on Hoosier A6s will go faster than your car on all-season tires or even mid-grade summer performance tires.

Really should be more like 10K and 12K.
https://www.s2ki.com/s2000/topic/839...#entry20077309

edit:
Interesting reading from Longacre: http://www.longacreracing.com/articl.../SoftSetup.pdf

Seems to me that this is explains the concept used by the Mugen S2000 and to some degree the CR.

Thanks guys, we will be trying benchmark tyres soon. Any comments on the power outputs and the alignment settings thus far? I will try to get a video up.