STS Suspension setup questions

[benjpi]

Okay, getting frustrated with the string of crappy finishes in STS. The car is decently setup, but it seems I just can't get a lot of grip. I get into the corners, the front starts to understeer/push, and that's as hard as it will turn without getting out of shape. This has led to a steady stream of mid-pack STS finishes at the big events, and one 2nd place in a less-well-attended event.

I've already got Tokico's with GC coilover springs, front camber plates, rear crash bolts, Falkens (205/50-15) on stock alloys, and a stock RB rear sway bar. I've also set the car up with about 1/8" toe out up front.

I run the car pretty high, near stock ride height to accomodate northeast roads. I can lower it for AX if it would help, but haven't so far.

I've got an MP3 front bar on the way, based on the last round of sway bar articles in GRM. I'm hoping that will help.

Where would the money go next? What would I gain from the fat AWR rear bar?

Also, I'm considering wheel/tire combo upgrades. I'd like to go up to the class-limit 225 width, but there's not much available there, so it will probably be 215 width. Will I get better grip from 16's or 17's?

Any insight appreciated.

Ben

 

[TinmanMS6]

A larger rear sway bar would help the car rotate/eliminate understeer. I'd make that investment.

All things being equal, smaller wheels are generally better for autocross, because of the reduction in unsprung weight. I don't know what tire options are available in each size, though, so that would be a consideration as well.

 

[moxnix]

How many miles/runs on the falkens?
Your wheels are only 15x6? wider wheels would be better.
How much camber front and rear? what rear toe? what tire pressures? what spring rates?
Have you had people that normally place ahead of you drive your car to see what they think of it?

 

[dmitrik4]

ben-

definitely have some other fast drivers take a spin behind the wheel. also keep in mind that, no matter what the setup, if you go into a turn too hard, the car is going to understeer. is there a chance you're overdriving a little? your car should rotate just fine, but you can't go in too hot.

one thing you could also try is a set of wider front wheels. i had 15x7s up front w/ a +35 offset (15x6.5, +48 in back). the increased width and front track made a big difference. also, there are a lot of ST tire options now, so i'd keep an eye on various message boards to see what might be available for you in a wider size. i would stick with the lightest, widest, shortest setup you can afford, keeping in mind that tire sizes are not always uniform (e.g., one company's "205" could be wider than another's "225").

 

[benjpi]

The Falkens have maybe 10K on them, they're at the wear bars. The push was the same when new.

Why would wider wheels be better? I've played around with tire pressures, haven't seen alot of difference. typically 37-38 front, and 34 rear. I've also tried 40 rear, again not alot of difference.

Front camber is about -2.5, rear maybe -1. Haven't messed with rear toe, but not sure why I would. If I changed it to toe-out in the rear, it might get it to oversteer more, but how would that increase front grip?

Spring rates are standard GC, I think 250F, 350R.

I got a roadracing guy to drive it once, and his only comment was it handled better than his road car. Haven't got any of the local fasties to test drive the car yet, maybe this winter, if Philly gets a winter series together.

I've really tried to reign in the overdriving, I just get to the front end push point, then I get no more. I've tried to keep the runs clean, no sloppy sliding about. Its frustrating cause it seems the gap is just huge to the front, like 6 seconds on a 42s course.

As far as wheel offsets, I need to keep the daily driver thing in mind. If I run different f/r offsets, it makes rotations difficult. With that in mind, though, if I go to a relatively low offset (like 40) on a 16 or 17 x 7, I guess that would widen the front track some.

 

[aMaff]

tall wheels are not the answer. You've got 2 conflicting goals in mind right now.

You keep voicing concerns about daily driving the car, however there's a good chance that you wouldn't be extremely happy with a 100% prepped car on the street.

If you've read some of the SP threads, folks who did the MSP front bar ended up going back to the P5/ES stock front bar b/c of too much understeer. I'd go with a big / adjustable rear bar.

 

[benjpi]

The car is already pretty uncomfortable, but its still drivable. At the last AX I was at, I know at least two of the finishers ahead of me brought trailer queens, and one was a two driver car. Plus another two civics, one owned by the guy who runs the PA lancaster region SCCA. Is that my place, then? Top three non-trailer queen?

With the roll bars, I saw that in some of the SP builds the front bars went in & out again, like the hokey-pokey. Maybe the race tires cause the difference?

Anyway, next investment looks like AWR fat bar for the back. We'll play with the front & see if it makes a difference.

 

[moxnix]

Better shocks will make it more daily driver friendly. I find the 700/450 rates in the miata fine for daily driving on revalved konis. Of course I also find the race seat more comfortable than the stock seat for long distance trips so I might just be a little odd.

 

[apexlater]

You mention not using toe out in the rear since that won't increase your front grip. A fat rear swaybar acts by reducing rear grip, just in a different way.

Using toe out will force the rear tires to follow a larger arc than the front tires, giving some rotation.

I have to agree that over-driving could be a culpret.

Also, if you are not willing to change your driving style, then you have to change your car set-up to compliment your style so that you are confident in the car, which will lower your times.

Just because "everyone" isn't using a big front swaybar shouldn't mean you should not explore that possibility as a solution. Granted, using the testing that others have done can be advantageous, just don't fall into the "lemming" mode. You still have to be able to drive the car fast.

 

[autoxes]

From what Rogue tells me, at least in the P5, you can get some serious OVERsteer from having the beefy rear bar with the stock bar in front.
From what everyone tells me, it looked like it was Rwd (Dreeeeeft!) when he was running it initially, so this could be your solution

 

[xelderx]

Spring rates are standard GC, I think 250F, 350R.

I think thats backwards. I checked with GC 4-5 years ago and they said their OTS coilover kit for the Protege was 350F/200R IIRC. Just for comparison...I was running 450F/600R on my FSP Pro5 as well as the Protege Jas00X placed 4th in at Nationals this year. I was on Konis and he was on Bilstiens. Both cars also had the AWR 21.5mm rear bar and stock front bars. I'm still a firm believer that we are the closest to having the ideal SP susension setup. For STS most of the same principals apply, but you don't usually need as much stiffness as the overall grip is lower.

I had to make a big adjustment in my steering inputs when I drove Jas00X's car. In my car I would use an aggressive initial turn in to force the rear end to rotate. He had way more front end grip than my car (wider front tires) and my inputs were causing the car to rotate too much. With a setup like yours, which from where I'm sitting looks like it's going to understeer a lot, I would be tossing the hell out of the car at corner entry to use the weight transfer to help get the rear around. I drive a lot of bone stock FWD cars on street tires at our yearly novice school and this is the technique you have to use to get the rear around.

 

[TinmanMS6]

From what Rogue tells me, at least in the P5, you can get some serious OVERsteer from having the beefy rear bar with the stock bar in front.
From what everyone tells me, it looked like it was Rwd (Dreeeeeft!) when he was running it initially, so this could be your solution

FTR, that's just how he drives. He could loop an HS Corolla.

 

[aMaff]

yeah, he spun my P5 when it was bone stock about 10 seconds into a run...

 

[low_psi]

How far are you off the pace of the top guys? Are you getting clean runs?

Are you using the RX7 Cusco camber plates? PM me some info if you don't want to clutter up this thread.

 

[benjpi]

5 seconds back from the trailer-queen, nats-level driver, co-driven civic (Cy Lee), on a 46 second course (for them, not me). 3.5 seconds would have gotten me second overall, ahead of at least one other trailer queen.

Generally I'm pretty clean on the cones.

The camber plates are my old plates from my BG chassis protege, they work with the GC coilover kit, but not the stock shocks (stock springs too big). I've got them almost as far in (negative) as they'll go. I might be able to squeeze another 1/4" up top of neg in, but that's all.

Xelderx, that's pretty much what it does: understeer everywhere. If I set up the tire pressures right (really high or really low in the back) I can get it to oversteer, but I don't think that's making it any faster, just decreasing rear grip to match the front. I'm really leaning towards wider tires, right now the 215/45-16 Falkens seem the best price/performance ratio. The Flik FTD from edgeracing seems to be a good deal, with the 42 offset it should widen the stance a little.

 

[low_psi]

You can't run wheel spacers in STS can you? The big AWR rear bar sounds like the first change to try unless you want to experiement with rear spring rates. It seems most Proteges are running higher rates in the rear than front for autoX.

So the camber plates work fine with Tokicos and the GCs? No mods? Just interested because it'd keep me from having to make hardware for the AWRs to work.

 

[xelderx]

I think you need to stiffen the rear of the car with either higher rate springs or a bigger rear swaybar. A larger rear bar will help keep the daily driver feel the same as it really only affects the car in turns.

 

[moxnix]

You can't run wheel spacers in STS can you?

Yes you can run any size/type of wheel spacers that you want in STS.

 

[Auto-Xer]

The camber plates are my old plates from my BG chassis protege, they work with the GC coilover kit, but not the stock shocks (stock springs too big). I've got them almost as far in (negative) as they'll go. I might be able to squeeze another 1/4" up top of neg in, but that's all.

What is the rear camber? Making that close to 0* will also aide in rotation.

Nevertheless, I would strive for increasing front grip over decreasing rear grip--but once you feel like the front is maxed, then things like BIG rsb's and uncambering can help.

By running the coilovers, you are also afforded the luxury of having your car cornerweighted--have you done this? There is not necessarily a direct correlation to solving an understeer issue, but general handing should improve by doing this.

 

[dmitrik4]

Why would wider wheels be better? I've played around with tire pressures, haven't seen alot of difference. typically 37-38 front, and 34 rear. I've also tried 40 rear, again not alot of difference.

wider wheels will put more tire tread on the ground, and increase grip. since the front off your car weighs almost twice as much as the rear (more like 60:40), it stands to reason that the front is going to need more rubber to grip. try running pressures like ~43 front and 25 rear...that's where i ran mine, and liked it much more than running very high rear pressures.

i don't think you want rear toe-out on a street-driven car...things can get really hairy at highway speeds, esp in the rain. ask me how i know.

i agree w/ justin; you probably need to adjust your style and get the rear of the car to move. are you trailbraking into turns? that's the best way to go fast in a FWD, IMO.

and don't feel bad if you're losing to Cy. his car makes as much or more power and weighs 400-500 pouns less, on wider, better tires and a much stiffer suspension. plus he's a REALLY good driver...placed 7th at nats in 2006. i think the other civic guy (from lancaster) is mike louie, who is also very good and has been autoXing for a long time.