making the car turn!!

[CSG Mike]

Originally Posted by puma

we are currently running DTC60 but entry isn't the problem he says it is on exit that the car understeer, he has to wait too long to apply the throttle.

A few things.

- Enter the corner slower
- Get the weight transfer performed in a matter that takes you into the corner with more yaw
- change your spring balance
- add rear camber
- add front toe out
- Add rear sway
- Add rear tire pressure or subtract front pressure

You've giving me ZERO details about your setup so I'm stabbing at the dark.

[rice_classic]

Originally Posted by Racecomp Engineering

More caster. (#1 thought)
Stiffer rear compression damping.
Softer front rebound.
Raise the rear of the car slightly.

Originally Posted by Racecomp Engineering

BTW if the driver is coming from a fast FWD racecar that I assume is extremely loose on entry (as those platforms should be), then there may be some driver adjustment as he adapts to a different RWD platform. It sounds like your results are still very good so I wouldn't get too drastic with changes.

To the OP..

Start with RaceComp's advice here.

A fellow racer who's "one of the fast guys" runs a 944 and him and I will rent each other's cars on occasion (I have a CRX that's setup fast/loose). I have RWD and FWD experience so I can hop in his car, I adapt my driving habits immediately and can match his fastest times but when he drives my car it's been difficult for him to adapt to this very unforgiving type of setup, in fact he just had to rebuild my splitter because of this.

Show him what it's like to do a slower corner quickly from a RWD driving style and he will may see the error of his ways and adapt. I suspect he's struggling to adjust to a car that has more rear grip than front grip as he's coming from a car that's probably setup with more front grip than rear grip.

[wparsons]

Originally Posted by CSG Mike

A few things.

- Enter the corner slower
- Get the weight transfer performed in a matter that takes you into the corner with more yaw
- change your spring balance
- add rear camber
- add front toe out
- Add rear sway
- Add rear tire pressure or subtract front pressure

You've giving me ZERO details about your setup so I'm stabbing at the dark.

Doesn't help you with details, but this might give you more clues:



I'm going to say less front sway or more rear roll stiffness.

[puma]

Originally Posted by CSG Mike

A few things.

- Enter the corner slower
- Get the weight transfer performed in a matter that takes you into the corner with more yaw
- change your spring balance
- add rear camber
- add front toe out
- Add rear sway
- Add rear tire pressure or subtract front pressure

You've giving me ZERO details about your setup so I'm stabbing at the dark.

well check post #15, what else do you want to know?

We were running pretty equl pressure font to back, maybe a little higher in the rear could help.

i would also like to remind everyone that he is the driver out of a field of 30 cars that won the championship in 2013, came in 2nd in 2014 and is currently leading in 2015 so he is no rookie either. Of course he has an adaptation period but he is no newbie to racing.

About the lifted wheel, what can we do other than going to a smaller swaybar? Is there such a thing as a smaller swaybar than OEM? Are the adjustable one on the softer holes softer than stock?

About the rear camber, at which point would it becomes kind of a negative effect on braking or power delivery? What would you guys run in terms of rear camber with those shitty tires?

We are going to practice maybe next monday or in two weeks, we will try a lot of the things that were suggested here.

[rice_classic]

If I had to drive around that issue I would try trail braking a bunch more in those turns right down to the apex.

I would start with zero rear toe with the expectation of increasing rear roll resistance. However, for an easy test of roll resistance you can unbolt your front sway and do a couple laps and see if that provides enough additional droop too keep the inside front tire on the ground.

Considering I run 600 and 750lb springs on a 2100lb car it stands to reason that you're way under sprung especially if you're on R-Comps or slicks. The lack of rear roll resistance could be reason of front tire lift and understeer and/or lack of front roll resistance means you're losing too much camber under compression (mac struts)... However I'd start by going around the corner with all 4 tires on the ground.

[puma]

we are far from being on slicks, we are runing Falken FK453, those are pretty much all season tire, like 300 threadwear.

i agree i didn't really see it that way and thought a wheel in the air made a good picture but yeah it would turn better if the wheel was touching the ground... I'll try to take the swaybar off, it doesn't cost anything and will probably tell us if we are going in the right direction.

[raul]

Originally Posted by Racecomp Engineering

BTW if the driver is coming from a fast FWD racecar that I assume is extremely loose on entry (as those platforms should be), then there may be some driver adjustment as he adapts to a different RWD platform. It sounds like your results are still very good so I wouldn't get too drastic with changes.

- Andy

This sounds really likely. Need to rely a bit more on weight transfer, and that takes adjusting.

[raul]

Originally Posted by wparsons

Doesn't help you with details, but this might give you more clues:



I'm going to say less front sway or more rear roll stiffness.

Oh wow, this tells a story. Only 1 tire is doing work in the front. Front swaybar definitely needs a softer setting. I've never lifted a front wheel like that.

[Racecomp Engineering]

Yeah that's the picture I was referring to as well. Needs less front rebound for sure. That's a surprising amount of grip honestly for crappy 300 treadwear tires. A little more rear roll resistance would help and I'd add a little more front camber.

- Andy

[Mad_Mike]

Originally Posted by strat61caster

Rear toe out will definitely help rotation, looks like it's a track only car so definitely try it. Zero toe in the rear was rather darty and unstable feeling on the freeway to me so I've got some toe-in for DD purposes, I may be reducing it in the future...

I'm running 0 toe around and experience exactly that on highway. I commute on highway to work, and it kind of bugs me especially in the rain. What did you change your toe to? And is it much better once you changed it?

[strat61caster]

Originally Posted by Mad_Mike

I'm running 0 toe around and experience exactly that on highway. I commute on highway to work, and it kind of bugs me especially in the rain. What did you change your toe to? And is it much better once you changed it?

I want to say it was ~1/32" (~0.8mm) toe in on the rear and it was stable like it was from the factory, there is still a little bit of wandering as it follows the pavement which I think is just in the nature of the car. It may be as high as ~1/16" (~1.6mm) but I'm not sure, definitely less than 1/8" (3.2mm).

[puma]

well folks we just came back from a new day of practice and we did a whole bunch of things and the car now runs better, we gain 0,5 seconds on a 10 degC hotter day.


we started by trying some toe out in the rear and immediatly the driver said the car felt better. We than tried to put the stiffer springs in the back and it helped also a little bit but the best mod ended up being the the toe out. We lacked some time at the end of the day but we might reduce the toe out a little next time to see how much it slows us in the sraight lines but at least now the car turns better.


About the lifted wheel, we finally realised that the picture was taken at a place on track where there is literally a jump, we don't see it much with our low grip tires but the CTCC which runs in Continental slicks, the Minis completly lift off all 4 wheels at this place so this was the reason of the lifted wheel.


We also used some really old tires with lots of heat cycle (wanted to finish them during a practice) so we are confident the car is going to be faster for our next event on a track that also has a lot of thight curves and hairpins.


thanks everyone for your feedback.

[Racecomp Engineering]

Good to hear! Yeah I had a feeling something was up with a jump or something...lifting a front tire on those low grip tires would be surprising.

How many laps are your races?

- Andrew

[zdr93523]

I agree with CSG Mike's advice to enter the corner slower... we have found that on the slower long corners we encounter a great deal of understeer through the corner if entry speed is too high. It is usually ideal to take a wide, slow entry, to get braking done and then turn and get on the power immediately. You will likely be running a very different line to many of the other cars but this will give you a much higher speed down the following straight by eliminating the understeer.

If you watch how late the entry is in the very 1st left hand turn in the video vs. the entry into the same corner at 5:28, the first line / technique is 6mph faster down the very short straight on this track configuration. You can hear the understeer with the tighter line in the second example. (Ignore the use of slightly more than the track, I'm simply showing the result from different lines.)
[ame="https://www.youtube.com/watch?v=SN7EIqAqqB0"]Using more than the track... - YouTube[/ame]