Autocross Setup
05-13-2016, 11:54 AM
#1
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Autocross Setup I’m looking for some help on my new Autocross setup. I’ve been Autocrossing for 3 years and I can’t quite get my new setup working correctly. I’m about a second behind the 2015 track pack mustangs. PS I hate Mustangs this will not suffice.
I have not started adjusting my suspension yet. I was wondering what setting you guys might be running on your shocks. I would like some type of starting point and then fine tune it from there. Since my car is lowered, it’s hard to adjust the front suspension at the events. I know my tires aren’t the best but for the price of them they work pretty well.
My current set up:
1995 z28 A4 with cam and heads runs low 12.3 in the ¼.
3.90 gear through a ford 9” rearend
Koni sport shocks (single adjustable)
Strano Springs
Strano Sway Bars
UMI Adjustable Panhard Bar
Spohn Adjustable torque Arm
Spohn Sub frame connectors (not installed)
Federal 595 RSR tires 140 treadwear
I have not started adjusting my suspension yet. I was wondering what setting you guys might be running on your shocks. I would like some type of starting point and then fine tune it from there. Since my car is lowered, it’s hard to adjust the front suspension at the events. I know my tires aren’t the best but for the price of them they work pretty well.
My current set up:
1995 z28 A4 with cam and heads runs low 12.3 in the ¼.
3.90 gear through a ford 9” rearend
Koni sport shocks (single adjustable)
Strano Springs
Strano Sway Bars
UMI Adjustable Panhard Bar
Spohn Adjustable torque Arm
Spohn Sub frame connectors (not installed)
Federal 595 RSR tires 140 treadwear
05-13-2016, 09:16 PM
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I had a stock alignment when I put the motor in. This might sound stupid but I do not understand what alignment specs I should have. If you guys could give me some type of help in that area and what I should start with on the shock adjustments I'll do it this week and have it realigned and give you two an update next week.
05-13-2016, 09:32 PM
#6
Square tires? My car with r comps runs 2.3-2.5 degrees of camber. I believe FASTFATBOY ran 1.8 degrees on street tires which sounds a out right if they caused that much less roll. Point being 2 degrees won't have you that far off. If you're closer to 1 degree, you're off. I personally run 1/8" of toe out on my track only car. Compared to 1/8" toe in is night and day difference, the car's turn in was so dramatically improved.
05-13-2016, 09:51 PM
#7
If you have stock control arms your alignment will be camber limited. For stock arms, something like 4.5-6* caster, max negative camber, anywhere between 1/16" toe-in to 3/32" total toe out to help it turn in, dependent upon how you prefer it to behave. Try to keep the values equal side to side. If the vehicle sees a lot of street miles you may need to compromise a little if you are concerned about unusual tire wear outside of events.
I like to use a digital probe pyrometer to take contact patch temps right after I come off the lot to check tire pressures, trying to keep them linear across the surface. In my experience every 3* too high in the center I drop 1psi. If it's significantly hotter on the outside of the patch, and too cold on the inside, then it wants more negative camber, or vice versa.
If the front shocks are too stiff, the front end will skate (slip *briefly* at turn in, then grab and go). Try it at 50% (about 4 or 5 sweeps from full soft). If it skates, go softer until it doesn't. If it doesn't, go stiffer by a sweep or two at a time until it does skate, then back off a little
I don't know where you live, but if you can find them take a few of the Evolution autocross schools.
http://evoschool.com/
I like to use a digital probe pyrometer to take contact patch temps right after I come off the lot to check tire pressures, trying to keep them linear across the surface. In my experience every 3* too high in the center I drop 1psi. If it's significantly hotter on the outside of the patch, and too cold on the inside, then it wants more negative camber, or vice versa.
If the front shocks are too stiff, the front end will skate (slip *briefly* at turn in, then grab and go). Try it at 50% (about 4 or 5 sweeps from full soft). If it skates, go softer until it doesn't. If it doesn't, go stiffer by a sweep or two at a time until it does skate, then back off a little
I don't know where you live, but if you can find them take a few of the Evolution autocross schools.
http://evoschool.com/
Last edited by JimMueller; 05-13-2016 at 09:57 PM.
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05-14-2016, 08:12 AM
#8
TECH Senior Member
:facepalm: Thats more narrow than stock...
Play with the shock settings on the street while you can and see what you like the best in terms of feel. I would start in the front with full stiff, then back it down 3 or 4 sweeps. The rear i assume are 4th gens on car adjustable? I think guys were normally running a little stiffer than full soft on those. Start at full soft and go from there.
Is the torque arm a full length one?
Get a better alignment like others have said too.
Are your rear LCAs stock? You don't have those listed so I assume they are stock, Im just making sure you are not running some poly/poly LCA combo.
Play with the shock settings on the street while you can and see what you like the best in terms of feel. I would start in the front with full stiff, then back it down 3 or 4 sweeps. The rear i assume are 4th gens on car adjustable? I think guys were normally running a little stiffer than full soft on those. Start at full soft and go from there.
Is the torque arm a full length one?
Get a better alignment like others have said too.
Are your rear LCAs stock? You don't have those listed so I assume they are stock, Im just making sure you are not running some poly/poly LCA combo.
05-14-2016, 01:40 PM
#9
If you have stock control arms your alignment will be camber limited. For stock arms, something like 4.5-6* caster, max negative camber, anywhere between 1/16" toe-in to 3/32" total toe out to help it turn in, dependent upon how you prefer it to behave. Try to keep the values equal side to side. If the vehicle sees a lot of street miles you may need to compromise a little if you are concerned about unusual tire wear outside of events.
I like to use a digital probe pyrometer to take contact patch temps right after I come off the lot to check tire pressures, trying to keep them linear across the surface. In my experience every 3* too high in the center I drop 1psi. If it's significantly hotter on the outside of the patch, and too cold on the inside, then it wants more negative camber, or vice versa.
I like to use a digital probe pyrometer to take contact patch temps right after I come off the lot to check tire pressures, trying to keep them linear across the surface. In my experience every 3* too high in the center I drop 1psi. If it's significantly hotter on the outside of the patch, and too cold on the inside, then it wants more negative camber, or vice versa.
05-14-2016, 10:05 PM
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Gents,
Thank you for all the input. I left a few modifications out. I originally started building this car for bracket racing and then got introduced to autocross.
UMI road race K Member. So I do have some adjustments where the A Arms attach.
I do have Poly to Poly Spohn LCA's. My 9" has adjustable lca brackets welded on. Is Poly to Poly bad?
The torque arm is a crossmember mounted style.
Yes the tires are a square setup. I know they're small but at that time I had to cut costs somewhere.
Where do you guys typically go get your cars aligned at?
As far as the evo school. I'm planning on doing it at the CAM nationals in Indiana this year. Have any of you attended it?
Thank you for all the input. I left a few modifications out. I originally started building this car for bracket racing and then got introduced to autocross.
UMI road race K Member. So I do have some adjustments where the A Arms attach.
I do have Poly to Poly Spohn LCA's. My 9" has adjustable lca brackets welded on. Is Poly to Poly bad?
The torque arm is a crossmember mounted style.
Yes the tires are a square setup. I know they're small but at that time I had to cut costs somewhere.
Where do you guys typically go get your cars aligned at?
As far as the evo school. I'm planning on doing it at the CAM nationals in Indiana this year. Have any of you attended it?
05-15-2016, 07:09 AM
#11
TECH Senior Member
Gents,
Thank you for all the input. I left a few modifications out. I originally started building this car for bracket racing and then got introduced to autocross.
UMI road race K Member. So I do have some adjustments where the A Arms attach.
I do have Poly to Poly Spohn LCA's. My 9" has adjustable lca brackets welded on. Is Poly to Poly bad?
Thank you for all the input. I left a few modifications out. I originally started building this car for bracket racing and then got introduced to autocross.
UMI road race K Member. So I do have some adjustments where the A Arms attach.
I do have Poly to Poly Spohn LCA's. My 9" has adjustable lca brackets welded on. Is Poly to Poly bad?
With those brackets try and get the LCAs to be parallel to the ground.
And honestly if you have the stock rear end laying around I would switch back to that if you are wanting to get serious, you will save a ton of unsprung weight.
The torque arm is a crossmember mounted style.
Where do you guys typically go get your cars aligned at?
05-15-2016, 01:56 PM
#13
The last 'great' diff I had was a Torsen T2R almost 10 years ago before it died a horrible death on the street. I stayed away from them later as rumor had it they became less reliable due to changes made by Torsen.
I currently use an Eaton clutch-based posi. Auburn Racer's diff and Detroit Tru Trac also get good reviews, a lot is subjective opinion though and also dependent upon which rear end you have (10-, 12-bolt, 9", etc.)
I currently use an Eaton clutch-based posi. Auburn Racer's diff and Detroit Tru Trac also get good reviews, a lot is subjective opinion though and also dependent upon which rear end you have (10-, 12-bolt, 9", etc.)
05-16-2016, 10:47 AM
#14
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From my experience an alignment geared more towards autocross is going to be very beneficial, I run -1.5 camber and 1/8 toe out. The toe out really helps the turn in on these big *** cars.
Secondly, I fought it off for years and worst mistake I ever made. Get yourself a good set of tires. Considering you are running tires around the 265-275 range, you have tons of options. I ran pull offs and budget tires until this year I coughed it up and bought a set of Rival S and best money I've spent yet. people I've never beaten raw, I am now catching in pax.
Secondly, I fought it off for years and worst mistake I ever made. Get yourself a good set of tires. Considering you are running tires around the 265-275 range, you have tons of options. I ran pull offs and budget tires until this year I coughed it up and bought a set of Rival S and best money I've spent yet. people I've never beaten raw, I am now catching in pax.
05-16-2016, 10:50 AM
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As far as helping with adjusting shock settings, etc. We need more details, are you battling oversteer/understeer? Is it lateral grip, straight line? are you getting any brake hop or locking up brakes?