TorqProject

HI guys,

Tracked my Type S for the first time in Sepang Circuit on Good Friday and experienced really bad understeer. Hope to get some pointers here from the experts.

My ride has the following:

2008 JDM S2000 Type S
Stock Engine with speed limiter removed
3inch header back exhaust
JIC FLT RS Coilovers 14kg Springs full stiff on damping
17x8 with 225/45/17R Advan A050 Medium compound fronts
17x9 with 255/40/17R Advan A050 Medium compound Rears
Dixcel slotted front and rear rotors with Z pads all round

Alignment specs stock road going setup with 2degree front and 3degree rear camber

The rears are noticeably higher after fitting the wider A050 tyres. There is a 2 finger gap from the fender now.

I am running 30psi hot.

First of all, my engine power was lacking especially at the midrange areas so corner exit was really slow. Took forever to get into vtec!

I am very heavy on the brakes. The Dixcel setup held up really well. I was very hardworking with only 2 days of bedding in before tracking. I cycled through some hard braking to bed the pads and disc during the 300plus Km drive up to the circuit and i think that helped with its performance on track.

The friction curve on the pads sort of allowed me to trail into the corner while maintaining my pedal pressure as it reduces its bite deep into the corners but there was no fade. I hammered the hell out of them and never had it fading. However, i would like more initial bite and more braking force during the initial phrase to shave off as much speed as possible and its ok to lose some braking as i trail into the corner. Maybe i will try the race pads next time.

I was battling with understeer all the way. Front turn in to mid to high speed understeer. T5 and T6 the front was floating so much that he entire car was using the entire width of the track and i couldn't accelerate early.

Should i go for a non-staggered setup with perhaps 255 fronts?

Here's the lap you can see the massive understeer. SOrry for the bad video, i'll find a better location to mount it next time.

http://www.youtube.com/watch?v=sOA_7...=youtube_gdata

ZDan

I wouldn't have started with the dampers set at "full stiff". I'd start at the softer end.

More front camber. Not sure how much A050's want, but if you could get 2.5-3 that should help.

You might run higher hot pressures until you get it sorted. I see two different Yokohama sources, one does recommend 30psi hot, another 32-34psi hot: http://www.advanwheels.com.au/tyres/race.aspx
I usually stay a little on the high side until I'm happy with the setup, then drop pressures. Based on the Yok recommendation above, I'd probably start at 34psi hot.

If you have understeer, you might try 34psi rear and 32 (or 30) front.

Of course going to 255 fronts should help if you're on 225s now. It sounds like your setup is biased for more front roll stiffness, so bigger fronts to handle that would make sense.

c32b

U can get spc joints up front to give you more front camber. Most importantly is to check your current alignment and see if the alignment is still correct. I ran similar settings on a non type s and there is significant understeer.

What do you mean that T5 and 6 you were floating?

Not sure fitting wider tyres would raise your ride height. U might want to refer to JIC recommended ride heights and tweak from there.

As for brakes, I think I can see u braking around the 150m marker? With a050 you can probably do shorter. Just be careful of the pad and fluid fade as that will be pushing the limits.

rohde88

I see what he's talking about, the car doesn't take the line he initially sets up. However, i think this is due to taking too sharp of an angle. the car should use the entire width of the track in that section. You seem to me like you're squaring off the turns instead of using minimal steering inputs.

Sure 255s up front would "solve" this problem, but smoother driving could also solve it (and make you a faster driver).

My $0.02.

samsam5886

225 and 255 is too much stagger IMO since even the stock AP1 setup only differs 20mm F and R (205 225). For damping, try lowering the front little by little until you decrease the understeer. And like previously mentioned, full stiff damping probably isn't ideal. And this isn't relevant but maybe try running higher tire pressures. I don't know what the optimum pressure for your tires are but for the ones I've used they seem to like at least 35 psi hot. And having less pressure in the F vs R would also decrease understeer.

Antonov

I am a proponent of running non-staggered, but I've tracked/owned plenty of setups (staggered/nonstaggered stiff/soft....) including small (215) front tires with less negative camber (1.7), and I've never had understeer like that. I mean, I can hear the disappointing sound of understeer in the video, must be really bad.

That being said, I would put the car in the air and check everything, sway bar endlinks etc...

Then I would work on the set up. Given your stiff set up (very little weight transfer), and your late/hard braking, I think the the front tires can only do so much (traction circle) and most of their grip is being used for stopping the car rather than turning it. I'm not sure, but looks like you could trail off the brakes a bit smoother, I think that would help too.

I would for sure try and get more camber via J's Racing camber joint. What are alignment specs, specifically castor and toe? Stock sway bars? Ride height from the jack points? What are the rolling diameter of the tires, 25" front and rear?

razzele

Wow that is alot of understeer! You could certainly drive around the problem more, coming on the power lightly on turn in shifts the weight rearwards and would help alot but there is certainly something unbalanced in your setup.

Far be it from me to tell you what it is though, there are many old boys on this dark corner of the site that can probably tell you exactly what it is though!


I use 215/255 r888s and have exactly the opposite problem! Infact i never experience understeer in the dry. So It is something in your setup rather than just tyre size alone. Ofcourse you could band aid repair the problem by fitting bigger grippier fornt tyres, slicks even but that wouldnt be fixing the problem.

thomsbrain

Holy moly. There is something seriously wrong with that setup. I have 225/255 stagger and far less understeer using Eibach bars and 12k/10k springs. If anything my car "should" be understeering more than yours, but that video is ridiculous.

I would check your sway bar endlinks, especially on the rear.

TorqProject

I see what he's talking about, the car doesn't take the line he initially sets up. However, i think this is due to taking too sharp of an angle. the car should use the entire width of the track in that section. You seem to me like you're squaring off the turns instead of using minimal steering inputs.

Sure 255s up front would "solve" this problem, but smoother driving could also solve it (and make you a faster driver).

My $0.02.
[/quote]

Hi guys,

Thanks for your input really appreciate it! Its my first time on track with the S2000 and 2nd time on this circuit in 4years. So i need to really learn the track well.

I managed to do around 24 to 26laps from that 3hr track session and i was improving the lap times as i got more track time. I am still in the process of trying different lines. It was only evident after the session and watching the video that i was caught up with the front end push most of the time.

The reason why i went with full stiff was T5 and T6 where i encountered excessive body roll. I didnt have a bucket seat so i was struggling to keep myself straight upright and maybe that was why i felt the car was rolling too much.

I will soften the front dampers, hopefully dial out some of the understeer.

Rohde88 also pointed out a flaw which i totally concur. I was too aggressive with the turn in, my steering input was too vigorous and it wouldn't help the situation when the front end is already way past its traction circle.

Trying to be fast and too hasty into corners and overdriving the tyres is a major problem which i need to 'tune' myself to avoid. Its like golf, gotta have the patience!

I have another track session coming up next week will report on progress.

c32b

I see what he's talking about, the car doesn't take the line he initially sets up. However, i think this is due to taking too sharp of an angle. the car should use the entire width of the track in that section. You seem to me like you're squaring off the turns instead of using minimal steering inputs.

Sure 255s up front would "solve" this problem, but smoother driving could also solve it (and make you a faster driver).

My $0.02.
[/quote]

Hi guys,

Thanks for your input really appreciate it! Its my first time on track with the S2000 and 2nd time on this circuit in 4years. So i need to really learn the track well.

I managed to do around 24 to 26laps from that 3hr track session and i was improving the lap times as i got more track time. I am still in the process of trying different lines. It was only evident after the session and watching the video that i was caught up with the front end push most of the time.

The reason why i went with full stiff was T5 and T6 where i encountered excessive body roll. I didnt have a bucket seat so i was struggling to keep myself straight upright and maybe that was why i felt the car was rolling too much.

I will soften the front dampers, hopefully dial out some of the understeer.

Rohde88 also pointed out a flaw which i totally concur. I was too aggressive with the turn in, my steering input was too vigorous and it wouldn't help the situation when the front end is already way past its traction circle.

Trying to be fast and too hasty into corners and overdriving the tyres is a major problem which i need to 'tune' myself to avoid. Its like golf, gotta have the patience!

I have another track session coming up next week will report on progress.
[/quote]

I'm no pro but u have quite a few unknowns to sort out ie ride height, rake and alignment which could very well be the main causes of your understeer. Sort those out first would be the first on list if it were me.

The dampers should have a recommended stock setting and I would think that might be a good baseline to tweak from. I have seen cars on softer suspension setups clock similar times so I doubt it's necessary to do full stiff.

Final bit is there are quite a few early apexes that u had so more seat time for a better line with will yield you huge gains in time I bet.

And above all, relax and have fun