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Tracking / Autocross / HPDE / Drifting What these cars were built for!


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Old 09-17-2019, 12:55 PM   #3725
tony_r
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Seems to me like you need to work with the rear end more and not the front. Try stiffening it and then changing the rake angle.

The car doesn't trail well, imo. Need to be soft with it and have a softer brake compound.
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Old 09-17-2019, 01:05 PM   #3726
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Originally Posted by Lincoln Logs View Post
It will depend on the course, but I'd wager the 255 is going to be more advantageous than not. I've driven some 13-16 cars the same day as my 17 and there is a big advantage to less shifts.

well i was talking to some people last week and non of them run 255 but they dont have 17+. someone said that 255 contact but i dont seem to be having an issue but then again i dont have REs yet. im just trying to figure out what im going to get this winter
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Old 09-17-2019, 01:10 PM   #3727
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Originally Posted by steverife View Post
I haven't started with STX suspension yet, so this is just general....

Where is your front toe? I feel like toe out causes mid-corner push.

Also, what happens when you stiffen the front bar or spring?

Also, is this solely inspired by Lincoln? Or does the car generally handle that way?
Front toe is 0. Rear toe is slightly in.

Tried the bar stiffer at a local even before nats and it was no good. Softened it some immediately. Ended up softening it much more at nats with some improvement.

It is based mostly off of Lincoln. The long courses there really brought out the weaknesses I think. Generally at local events I was getting some push on certain turns but usually just one or two turns on a given course. At nats there were just a lot of those turns. Basically, the more I have to turn the wheel, the more it pushes, which is to be expected.
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Old 09-17-2019, 09:11 PM   #3728
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Basically, the more I have to turn the wheel, the more it pushes, which is to be expected.

This is another reason why I was not fond of 7+ degrees of caster when I had adjustable front LCAs. With 4 degrees of static camber and 7 degrees of caster, your front wheels will cut increasingly sharply diagonally into the pavement the more steering input you give. With that much camber and caster, the effect is akin to an alpine skiier digging their edges into the snow. Your contact patch becomes more compromised the more you have to turn the steering wheel.



If you're not willing or able to experiment with something closer to OEM caster, I would try taking a wider arc through tighter corners to minimize steering input.
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Old 09-17-2019, 09:34 PM   #3729
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This is another reason why I was not fond of 7+ degrees of caster when I had adjustable front LCAs. With 4 degrees of static camber and 7 degrees of caster, your front wheels will cut increasingly sharply diagonally into the pavement the more steering input you give. With that much camber and caster, the effect is akin to an alpine skiier digging their edges into the snow. Your contact patch becomes more compromised the more you have to turn the steering wheel.



If you're not willing or able to experiment with something closer to OEM caster, I would try taking a wider arc through tighter corners to minimize steering input.
No dialing the caster back was another option I had considered. I just hadn't thought that one degree was enough to make much difference either way so it was toward the end of the list. Though, maybe the better option would be to keep the caster and dial in less camber to improve straight line braking?
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Old 09-17-2019, 09:40 PM   #3730
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No dialing the caster back was another option I had considered. I just hadn't thought that one degree was enough to make much difference either way so it was toward the end of the list. Though, maybe the better option would be to keep the caster and dial in less camber to improve straight line braking?

I found the difference between 6 degrees and anything 7 or higher pretty noticeable, in terms of steering self-centering force and the jacking up of the inside rear in tighter corners due to the cutting effect if I turned the wheel too much. The difference between 6 and 6.5 degrees maybe not so much.

For me, I'd prefer to keep the camber and dial back the caster, but I don't run as much camber as you (3.8), so I haven't found it to affect braking performance enough for me to want to dial it back.

In any case, good luck man -- I hope you can sort out this understeer issue.
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Old 09-17-2019, 10:02 PM   #3731
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Thanks for the input. I will try dialing back the caster.
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Old 09-19-2019, 09:49 PM   #3732
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Does adding more negative camber on the front throw the toe off significantly? I thought it would but someone recently told me that it doesnt on these cars.
I have coilovers and camber plates. Thinking about trying a bit more to see if i like it.
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Old 09-20-2019, 12:03 AM   #3733
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Does adding more negative camber on the front throw the toe off significantly? I thought it would but someone recently told me that it doesnt on these cars.
I have coilovers and camber plates. Thinking about trying a bit more to see if i like it.
Yes it changes enough where I would adjust the toe back to zero, I've done it and not noticed the toe change as a driver but in hindsight, imho a set of $60 toe plates is worth the investment to periodically check your alignment anyway and adding a few ticks of camber and zeroing out the toe diy is a worthy experiment between spending the money to put it on a rack
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Old 09-20-2019, 07:16 AM   #3734
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Originally Posted by bmacfrs View Post
Does adding more negative camber on the front throw the toe off significantly? I thought it would but someone recently told me that it doesnt on these cars.
I have coilovers and camber plates. Thinking about trying a bit more to see if i like it.
Using toe plates I have a 6mm difference in toe from maximum negative camber to minimum negative camber when adjusted at the camber plate. YMMV.
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Old 09-20-2019, 09:41 AM   #3735
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Originally Posted by CoolHandMoss View Post
Thanks for the input. I will try dialing back the caster.
I like caster, but as mentioned 7* with -4.1* of camber is quite a bit.

"As much caster as possible" has been a popular way to go on the internets but a motorsports engineer would tell you that caster is course dependent.

- Andrew
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Old 09-20-2019, 09:33 PM   #3736
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"As much caster as possible" has been a popular way to go on the internets but a motorsports engineer would tell you that caster is course dependent.

- Andrew

I think the internets may also be overlooking the vehicle context for high caster settings: usually it's heavy German cars with 0 negative camber and little or no ability to add more from the factory that come with 7 or 8 degrees of caster. It's the only way those cars can get turned in to a corner. On a car as light and nimble as ours, and given the ability to add adequate negative camber via plates or slotted struts, I find the factory caster to be plenty.
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Old 09-21-2019, 11:00 AM   #3737
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Originally Posted by H1C View Post
I think the internets may also be overlooking...
Yeeeeah that'll happen.

- Andrew
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Old 09-21-2019, 02:36 PM   #3738
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Originally Posted by Racecomp Engineering View Post
I like caster, but as mentioned 7* with -4.1* of camber is quite a bit.

"As much caster as possible" has been a popular way to go on the internets but a motorsports engineer would tell you that caster is course dependent.

- Andrew
Coincidentally, caster is one element of my setup that was set based directly on the advice of a reputable motorsports engineer. I think he was thinking more about optimizing behavior on track though. The car does handle very well on track!

I'm going to bring the caster back to OE before the next event and bring the rear toe to 0 also.
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