Made changes, didn't go any faster. Track related.

[No Crust Racing]

Made changes, didn't go any faster. Track related.

Same Coilovers and tyres both times BC BR (8kg/6kg) and Federal RS-R 235s all round (4-5yrs old easily). 

Ran basically the exact same lap time give or take a couple tenths. Tried different lines and camber settings etc. Car has been tuned on a different ECU but max power was roughly the same (190-195rwkw) and max speed on straight is almost identical as is corner exit speed onto the straight. 

Old setup:

• Front: Whiteline swaybar, -2.5 camber from strut tops, approx 1mm toe out each side. 
• Rear: 32R swaybar, standard diff, -1.3 camber, approx 1mm toe in each side. 

New setup: 

• Front: Whiteline swaybar, cusco castor rods on 8.5deg, -3 camber from strut tops/whiteline bolts (mainly bolts as can use strut tops for more or less now), approx 1mm toe out each side. Roll centre adjusters (25mm), high misalignment tie rod ends, solid engine and box mounts. 15mm bolt on spacers to match rear increase in track from subframe swap, solid steering coupling. 
• Rear: s14 standard swaybar, s15 diff centre and solid bushes, s14 reinforced subframe and solid mounts (angled down at the front for better squat geometry), -1.3 camber, approx 1mm  TOTAL toe in each side, aligner got it wrong and gave me .5 each side. 

 

Issues:

• Car felt more planted in the rear and more forgiving in general, and less bounce mid corner, but still wanted to understeer. Tried different camber settings in smallish increments and 1 small damper setting with basically no change in lap time. Pic of tyres below, after 5yrs, are they just cactus and have no more grip? Front runs out of grip before the rear. Too much swaybar? too stiff coilovers?
• Car was a handful under heavy brakes, locking 1 or both tyres and squirming everywhere. Camber has the most impact on this. Will check ride heights to check corner weighting isn't throwing it out, any other way to stop the lock ups? 
• Tyre pressures were about 21-22psi hot (14deg ambient temp). 
• Pads (TRW) seemed OK (R33 brakes all round), but not a fast track and I have brake ducts on all corners. Given I'm locking up, tyres seem to be the limit?

 

Old laps. 

 

 

New laps. Fastest about lap 6-7. Need to skip in a few mins to lap 3 or so to see brake lock up on main straight. There were many worse examples of this. 

 

Pic of front tyres after a day on the new setup. 

 

 

[No Crust Racing]

Forgot to add, 8" front rim, 9" rear. Could the issue be sidewall flex on the 8s? 

 

I was considering going 9" front rims and 255's all round. 

[admS15]

As it was the first time you've driven the car for a long time, maybe you just needed the seat time and you'll go quicker next time. New tyres, even same size/type will make you go quicker for sure, they look pretty shagged. Only you know if the changes helped. Did the car feel better than before once you got used to the new setup? Could probably soften the front swaybar if it's adjustable and not at full soft already. Personally, I would just drive it again before judging it.

 

 

 

 

[No Crust Racing]

Swaybar is already full soft. 

MCA suggests stock swaybar is best for grip (but also want me to buy their coilovers and suggested lower spring rates better suit the car). 

The car feels more controllable and progressive on the limit of tyre grip than it did before. It didn't take long to get used to it and given how slow it corners/accelerates is not hard to reach max potential of whatever the limiting factor is. 

Can try going back to stock swaybar easily enough.

As for just driving it again, doesn't look that appealing given it's understeer city and once it starts sliding like that it cooks the front tyres and they are gone for grip. 

I did realise that 21-22 might be way too soft, I keep forgetting these are a road tyre and Federal states mid 30s hot, which is what it had last time, but still no faster. 

 

 

 

 

 

 

[admS15]

New tyres for sure then and see if it continues to understeer. Take stock swaybar along and change it if need be. Its hard to determine what has done what when you've made so many changes at once but new tyres will def show you if its been an improvement and how much. If it feels better it probably is.

[No Crust Racing]

I might just do the Swaybar first as the old tyres still have a few track days left in them.

then the question is, 255 RS-RR (so cheap!) or stay with 235 but go proper semis. 

[Steve85]

I'm no expert (I feel like I write that for every post), but my understanding is the more camber you run the more your brake locking will be a knife-edge. It's harder to control the braking force with more camber (as less contact patch in a straight line).

Toe in at the front will help the car turn in, but once it has moved it will try to slide the front end. Toe out will make the car harder to initiate the turn in. but be less likely to understeer once turned in. 

Toe in at the rear will also provide a more stable platform and the car will be more inclined to understeer. Given you have heaps of understeer already, having less than you asked for this is probably a good thing.

Swaybars will provide you with more or less grip at each end. So if you would like less understeer you can tighten the rear swaybar or soften the front sway bar or a combination of the two. 

In my very limited experience, changing your tire pressures up or down actually does produce a sizable difference. I was under the impression that starting the tires around the high 20s was ideal and work from there. The instructions i was given (from a professional race car driver) was to make changes up and down keeping in mind that the tires may be hotter on the track and may increase in pressure when at temperature. 

So: I would, change the toe in at the rear of the car to zero (leaving the front as is), I'd also pump the tires up to approx 28psi all round then try them out again. Of course, it's not really possible to judge without seat time and it's also about your driving style so feel free to ignore.

*Also same professional driver told me, one change per session. Except where you get it wrong, change it back to its original position then make one other change, then repeat.

[No Crust Racing]

Toe in at the front will not help the car turn in, I'm pretty sure it's the opposite. Toe out = better turn in. 

 

Rear bar is not adjustable, and having a higher rate bar in the rear made it want to drift everywhere. I know sway bars are about weight transfer but I think the spring rates might be too high to allow this to work properly. 

Tyre pressures were definitely overlooked. Maybe change to stock front bar and adjust pressures and try again.

 

 

[Steve85]

10 minutes ago, ActionDan said:

I'm pretty sure it's the opposite. Toe out = better turn in. 

Some quick googling suggests you are correct, my bad.

I should clarify the race driver only gave me instruction on tire pressures and when to make changes. All that other stuff about suspension is me...

[No Crust Racing]

Thanks for trying to get me killed

[Steve85]

8 minutes ago, ActionDan said:

Thanks for trying to get me killed

Haha! Just after some more parts cars in the world!

[niZmO_Man]

22psi hot sounds a bit too low for that type of tyre, but hey if you tried like 30 psi hot then...
I'd try one more day before changing tyres, but yes tyres play a huge part. I dropped pressures by 10 psi (was 40+ hot, oops, I pumped them up for rainy days, Hankook RS-3) and the improvement was very noticeable.

[GTofuS-T]

2 hours ago, Steve85 said:

I'm no expert

I'll also start with this... 

But doesn't tyre age also play a huge part in this? sure there appears to be plenty of tread left, but the heat cycling and age of them affect the grip if I'm not mistaken... not sure at what level and to how much this plays a part (slick/semi/road-semi, etc)

[ch12matt]

Suspension isnt setup quite right, the first tyre photo the raised on the backend is generally from rebound being too stiff. Try softening the damper.

[No Crust Racing]

She's already on max soft, but they are only BCs BRs

[Steve85]

She's already on max soft, but they are only BCs BRs

I have these and mine are on the softest setting possible always. It's ok for track but awful on the road.

[ch12matt]

She's already on max soft, but they are only BCs BRs

What weights 6/8?

[Dale FZ1]

The "hard points" of the car haven't really changed from before/after.  ie. same weight, same max power, same rubber, same shocks/springs.  And the driver may have been a bit rusty?  Achieving a large number of laps at or near your previous best pace means the day wasn't a waste, and you'd have to take a positive from that.  Where your best pace sits relative to others is a different issue

 

Pic on the second tyre doesn't look great (LH front?) with that lateral cut/split across the face.  Make sure it's not heading towards a failure.

If you do get something new, try the RSRR, or a set of NT01 or AR1. If 9" rims and 255 rubber would fit without clearance issues, go with them all round. Get into the habit of monitoring and managing pressures.

If MCA are giving advice about what an S13 needs re: springs/shocks/bars, it comes from plenty of experience.  You  don't have to use their gear, but I would make the change without hesitating. But be certain that you are speccing the car for a purpose.  If you require any on-road ride quality it's probably going to need the lighter spring rates.  More important IMO, is balance front to rear.

Get a plate style LSD (eg Kaaz, Cusco) to replace the helical S15.

Aim to get your ride heights in a happy area.  MCA can give guidance about this point. It is fairly (ie. really) important, sets the suspension arm angles, not referring to the way the body looks or how much room there is between guard and tyre.

All of the above is about making the whole car "less wrong" and more mechanically suited for the job.

Now - chase your alignment settings.  What you used should be a reasonable starting point.

 

When you're at the track, be prepared to alter ride heights to address under/oversteer.  Don't just make small changes to the shocks and expect to feel something hugely different.  I generally try mid range shock settings both ends, then one end go full hard, full soft to feel the difference.  And repeat for the other end. You will quickly find useable shock settings from that.

 

 

[R_34]

I found this pdf a while ago to help tune your chassis settings given how you feel the car and how it move around the track. Its best if you can have a mate taking pictures of the car on the track to see how it is planted on its wheels.

 

I tried bigger front sway bar et reverted back to factory one, a bigger one will just induce understeer.

suspensiontuningguidelines.pdf

[KiwiRS4T]

If you can get a spare set of wheels and fit slicks that should help a lot. Rear sway bar needs to be heavier - if there is adjustment left on your existing one then do that otherwise go heavier... initially on the softest setting.