Setup issues: oversteer

[Def]

Trying to get some feedback on a setup issue. Drove my car at an autox type event and it was wicked loose. Loose on power, loose when lifting, really loose with slight trail braking etc. Also had an overall lack of grip in corners and braking.

Few details:
Koni 8611 frt 8610 rear. 500 lb/in frt 380 lb/in rear springs, stock frt 25mm bar drilled about 6% stiffer, no rear bar. S14 rear subframe, rssbs, rlca delrin bushings.

Alignment zero toe frt about 1/8-3/16" toe in rear. About -3.5 deg frt and -2.8 rear camber(need to take some out all around). Front tension rods a hair shorter than keeping the flca perpendicular with the frt subframe to reduce bushing bind. Rear traction arm 8" total length.

I was running 235/40-17 Hankook RS-2s, pretty worn out, but should have given more grip.

I know I need less camber in the rear, and possibly in the frt, but any other thoughts?

[SoSideways]

Hmm... sounds like you should have plenty of grip... with the exception of the -2.8 degrees of camber in the rear. That might have something to do with it.

[jmauld]

I was running 235/40-17 Hankook RS-2s, pretty worn out, but should have given more grip.

I know I need less camber in the rear, and possibly in the frt, but any other thoughts?

IMO, I wouldn't do anything besides take out a little rear camber until you get on good tires.

Old worn out tires are a very good cause of the symptoms that you describe.

[eye-5]

You have adjustable suspension, did you try softening up the rear and stiffening up the front? Everything outside of the camber looks good. I am running -2.5 in the front and -1.5 in the rear with good results. I found running a stagger tire setup helps. I run 275s in the back and 245s in the front.

[McCoy]

That describes my car with dead RA-1's on them...

[Def]

Maybe it was the tires, they are a few years old and have had many heat cycles by now. Shouldn't matter much for a street tire, but something was definitely up. I'm inclined to think it's more than just old tires though...

I'm really wanting to go to a square tire setup just so I can rotate them front to rear. I'm leaning towards 17x9's with 255/40 NT-05s all around.

I've done the alignment by myself, and as much as people tout the DIY alignment, after doing it to various degrees of success over the years I'm of the opinion it's not that effective as getting everything truly dialed in. There's a lot more variation than I'd like after rolling the car around and putting things back up and checking stuff again.

What's everybody's feeling on the rear toe? It seems similar to what everybody else is running with good effect, but some people with other cars were suggesting trying more toe-in the rear.

[jmauld]

For autocross, I run a bit of toe-out in the rear, but I enjoy scaring the piss out of myself.

[Def]

That's the thing, I drove an H-Stock setup Civic which has A LOT of rear toe out, and while it'd rotate off throttle, my car was 10x more violent and would want to come around with almost everything you did. Generate any lateral grip and the rear end wanted to lead the way.

I was sawing like a n00b on the wheel just trying to keep the thing in check, and actually spun it a few times driving it at maybe 7/10ths. It was really that out there.

[jmauld]

Beg, borrow or steal a set of good r-comps and see if that goes away before changing anything.

[Def]

Some action pics:







Looks like a little too much rear negative camber, but the front looks reasonable in a corner. The last two are showing it going a little crazy I believe.


One thing I am thinking of is that I have approx 1.5" of rear travel before I start hitting the untrimmed bumpstops on my 8610's(the bumpstops are long, about 2.5" when uncut). It doesn't look like the car is rolling that much to immediately be on the bumpstops, but I do plan to take those out and take off almost an inch just to make sure they're not coming into play unless I get on a big bump.

Nevermind the dirtyness of the car either, it likes to wear excessive brake dust on the side...

[RBbugBITme]

What changes have you made since you last drove it and liked it? Tire temps that day?

[Def]

The car was all over the place last time I drove it due to a bad rear wheel bearing allowing toe changes(would go from understeer to oversteer at random intervals). So I tore it all apart and put in an S14 rear subframe, Z32 rear uprights, rear 8610 Konis, RSSBs, and adjustable suspension links with rod ends in the rear.

So essentially it's a completely new setup, so I can't pinpoint it to one change.

No tire probes available, but it didn't seem the tires were really that hot with the super scientific hand pyrometer. It was only 3 ~1 min laps at a time, and in addition to the lack of grip, there was a lot of sand and gravel so grip was already reduced.

[RBbugBITme]

Well then, you're gonna have to go driving again mister. Try and eliminate some of those variables. Tire temps across the tread would be the easiest, then avoid autoxing on the beach.

[JRas]

I'm gonna have to agree.. you have too much rear toe

try putting a little toe out in the front. How much caster are you running?

[WishIHadaSilvia]

I'm no expert on grip set ups, but I would think if you took a deg of camber out of the back (perhaps it would be add a degree since we're talking about neg camber), got some fresh tires, and possible ran 0 toe you'd have a less oversteer.

I recently bent one of my RUCAs, which gave me some crucial toe in as well, and my car had a lot more snap oversteer. I run -2 camber and 0 toe out back for drifting. I think the alignment is extremely stable and wouldn't have a problem doing some grip driving with it.