Autocross suspension setup

[Brianawd]

So the time has come to change the cars set up. Just not into drag racing any more. So I am looking to see what some of the die hard Autocross guys are running for suspension. I'm already going to pull the 3052 and go to a 68HTA. Going to do a Quaife front diff and a Tre maxlock in the rear. Its what my friend Dallas said to us. Big autocross guy and really good. I have been looking at the hotbits dt2 or maybe have AMR build me a custom set of coilovers. Any input would be great.

 

[4thStroke]

What do you have for sway bars? Any plans on playing with those at all?

 

[Whoodoo]

Info on some shocks

Some custom stuff

 

[Brianawd]

Quote:
What do you have for sway bars? Any plans on playing with those at all?




I have Suspension Techniques swaybars. I only have the 26mm rear bar on. I need to find the front one and toss it in.

 

[JSchleim18]

It's not really necessary to run anything bigger than the stock front sway bar. If you want to go crazy, you can try to find a JDM Galant RS trans. They are close ratio and it'd be great for an auto-x course. Get the Jay Racing Rear toe elimination kit or one comparable to it. This will make the car more stable and predictable in the quick, tight turns.

 

[GreenGSX]

Put a lot of energy into picking the right size wheel. Go with the smallest rolling diameter you can get with the widest tire you can find. I would go back to stock brakes just to get a smaller diameter without a doubt. I've used a Quaife front diff for autocross and its really a mixed bag. It increases front end push but improves mid turn traction and corner exit speed. On a tight course I hated it on a bigger course I loved it. If I had to do it again I would put the $900 into a better set of tires. I've always recommended Koni's for our cars but seeing how the rears are no more you'll have to find something else. I pay close attention to the rear as anything that even appears to be stiff is going to be too stiff. I would also weld up those rear trailing arms which will make the car more predicable over different surfaces and make it easier to set the car up to rotate. Don't be afraid of body roll. You are going to need it to shift the weight around to get the most traction and rotate the car. Also, don't be afraid to experiment with alignment especially the rear toe.

Let me know when that FP3052 goes on sale.

 

[H05TYL]

Quoting JSchleim18:
If you want to go crazy, you can try to find a JDM Galant RS trans. They are close ratio and it'd be great for an auto-x course.




Make sure you get the right RS box, only ~ 1/3rd of them are close ratio.

only the post 90.10 RS's (Evolution) all have the 3.909 ratio driveline (same ratio's as evo 1 & 2 lancers), it may have been an option on the mid (89.10 - 90.9) RS's, or it may be that the last of those RS's got the new driveline - the majority and all pre 89.10 RS's have the regular old 3.545 ratio driveline.

 

[123abc]

I can vouch for poly bushings and welding the rear trailing arms. I just did this on my 91 Talon and what a difference it makes. It completely transforms the car.

 

[jepherz]

A steering quickener would fit you well, too. I used mine for a few auto-cross events and it was awesome.

 

[JSchleim18]

+ that...I want to do that eventually

 

[belize1334]

With your built motor and turbo you'll be in street-modified but you'll want to read the class rules carefully.

Things like solid metal bushings could potentially throw you into Prepared or Modified which are tougher still and at that point those little benefits aren't gonna be worth while. Besides, poly bushings will get you 90% of those benefits without classing issues.

A steering quickener would be AWESOME but you 'gotta realize that it'll probably overshoot the ideal ratio so you'll want to know what you're getting into. Also, a n/a ps pump (or else shimming the stock pump) will eliminate the dreaded hard-steer at high rpms.

Stock diameter brakes are definitely gonna be the way to go. Decreased rotor diameter will net you better acceleration and with Porterfield pads (or equivalent) you should have no braking issues on a

 

[thecman02]

Quoting Brianawd:
So the time has come to change the cars set up. Just not into drag racing any more. So I am looking to see what some of the die hard Autocross guys are running for suspension. I'm already going to pull the 3052 and go to a 68HTA. Going to do a Quaife front diff and a Tre maxlock in the rear. Its what my friend Dallas said to us. Big autocross guy and really good. I have been looking at the hotbits dt2 or maybe have AMR build me a custom set of coilovers. Any input would be great.



I just did an autocross about a month ago. Most of the things you addressed in your post are items I wish I had. I wish I had a smaller turbo. I wish I could get more negative camber. I wish I had a max lock clutch type rear disk.

The main thing you'll want to address is tires though. I don't exactly know what pro autocross guys do, but I had problems with my tires being cold for the first half of my run. This is just on KDW's. You want tires that heat up quickly, but take kindly to aggressive driving. I'd try to go just a tad bit quicker or brake a little bit later and the kdw's would get greasy. I don't know about now a days, but Azeni rt-615's were pretty much the gold standard for street legal autocross tires.

I can't imagine hotbits being a bad choice. Larry can get whatever spring rate you'd want and get them valved to compliment the spring rate quite nicely.

 

[alansupra94]

Quoting belize1334:
With your built motor and turbo you'll be in street-modified but you'll want to read the class rules carefully.

Things like solid metal bushings could potentially throw you into Prepared or Modified which are tougher still and at that point those little benefits aren't gonna be worth while. Besides, poly bushings will get you 90% of those benefits without classing issues.

A steering quickener would be AWESOME but you 'gotta realize that it'll probably overshoot the ideal ratio so you'll want to know what you're getting into. Also, a n/a ps pump (or else shimming the stock pump) will eliminate the dreaded hard-steer at high rpms.

Stock diameter brakes are definitely gonna be the way to go. Decreased rotor diameter will net you better acceleration and with Porterfield pads (or equivalent) you should have no braking issues on a

 

[belize1334]

Quote:

The main thing you'll want to address is tires though. I don't exactly know what pro autocross guys do, but I had problems with my tires being cold for the first half of my run.



Good point. Autocross runs are too short to heat up a conventional racing tire so you'll either need to run tires that are designed to perform cold (street tires) or tires that are designed to heat up quickly and then get cooled off after just a minute or two on the course (autocross specific tires). Now, in SM the competition is gonna be throwing down for expense autocross tires so if you want to be competetive you probably will too. Kumho V710 seems to be the dry tire of choice. For wet people can't say enough good things about the Hoosier DOT radial wet. But, sometimes local clubs will have a street-tires indexed class. Then everybody with street tires races against each other and you just adopt handicaps based on your cars preparation. This can be a nice alternative especially if you don't want to deal with having multiple sets of tires and changing them out when you get to the course. For street tires I'm a fan of the Dunlop Dirrazza Star Spec.

 

[turbofonz]

Quoting belize1334:
I have retrofitted Bilsteins (originally from a BMW 525)



More info?

 

Welding the rear trailing arms? Such as solid steel inserts or, welding the seams? It may be kind of a noob question, but I haven't seen much on this, so if you could briefly elaborate I'd appreciate it.

 

[atc250r]

If you want coil overs talk to Nate Crisman from DSMPartout, I believe he has a set that are coming off his GVR4.

John

 

[belize1334]

Quoting turbofonz:
Quoting belize1334:
I have retrofitted Bilsteins (originally from a BMW 525)



More info?



I didn't do the retrofitting. I bought them from NateCrisman and they're Bilstein HD which was never made for our platform. I searched the part numbers on the back shocks and came up with BMW 5 series. The lower bushings have been modified to fit our trailing arms. The fronts are inserts so I imagine they were installed like any other without modification. The PN for the fronts are under the OEM shock housing and I haven't taken them apart yet though so I can't say for sure that they're from the same 5 series lineup... but it seems likely. If I ever send them in for a revalving I'll do a more detailed writeup on what bits were used.

 

[GreenGSX]

Quoting Speed_Racer:
Welding the rear trailing arms? Such as solid steel inserts or, welding the seams? It may be kind of a noob question, but I haven't seen much on this, so if you could briefly elaborate I'd appreciate it.



I am talking about welding the forward link solid in the arm. The front joint which bolts to the underside of the car is isolated in rubber. Just imagine how you would freeze a Popsicle stick in a cup and you get the idea. To weld them you have to find a really big washer, cut it in half, grind off all the rubber you can get to, and then weld the washer around the end link so it can no longer move via the rear steering rack or by flexing (as in how the 1G DSM would).

 

[slugsgomoo]

I think there's actually a how-to on here somewhere. It's just the active-toe elimination mod. Definitely something worth doing, whether you're autocrossing the car or not.

Quoting atc250r:
If you want coil overs talk to Nate Crisman from DSMPartout, I believe he has a set that are coming off his GVR4.

John



I'm pretty sure Brian already has ksports (same thing as d2 just orange) and I'm guessing he's looking for something that's a bit more suited to turning... maybe with separate compression & rebound settings perhaps. /ubbthreads/images/graemlins/wink.gif