Suspension Tuning Setup Advice Needed..., went from a swinger to a plow... Options

[cha914]

Ok, did the first autox with the new suspension on sunday, and I wasn't overly impressed with the results, but since I changed almost everything, I cant realy expect to have it right the first time.

So here goes, the car had very sluggish turn-in responce, and wanted to plow through every corner. I really couldn't even get it to rotate under trail braking. Here is the setup:

Koni Yellows all around
Poly bushings all around
Fully adj rear perches w/175lb springs
22mm solid torsion bars
22mm weltmeister front bar set full soft

Ride height = 4.75 up front and ~5.25 rear (measured to the donuts)
Camber = -1.5 up front -2 rear
Toe = 1/16th toe OUT up front and 1/16th toe IN rear

With the Koni's set to full hard the car seemed to improve a little, but not much. Also, the course was on a fairly slick parking lot, and I am running 2year old pirelli tires (205/50/15s with plenty of tread, just hard).

Finally, I want this car setup mostly for track driving, so I know autox performance is going to suffer some, but it seemed pretty poor overall yesterday (it was definately more fun with the ass up in the air sliding everywhere (IMG:style_emoticons/default/tongue.gif) now I want it to be fast)

Any suggestions on where to go from here, or what to try in the future (I know I need better tires).

Tony (IMG:style_emoticons/default/smash.gif)

[ChrisReale]

You might need heaver rear springs. Also, many people like closer to -2 camber up front and a tad less in the rear. A proper corner balance will also help

[machina]

I agree with chris about more camber up front but I wouldn't change anymore hardware until you run the car on the track.

Auto-X setup is very different than roadracing setup. Most cars tend to plow at lower speeds.

Your setup looks pretty good as a baseline.

dr

[john rogers]

I'd say it is the tires and a pretty good lack of grip. Since the suspension has been tightened up pretty well but you still have the same old tires that are slicker than snot on a glass door knob, they are now showing their true value. I'd say try some V700's or other new sticky tires and then you should have a good starting point. You could try shaving off most all of the tread on your old tires and there might be some soft rubber in there but I'd doubt it. Good luck.

[J P Stein]

I'm with stupid...er, Chris.
Better tires will just make it plow at a higher speed (IMG:style_emoticons/default/laugh.gif)

I'm running 200lb (non progressive) rears & 21 mm T bars.
It still pushes in the tight stuff. I have a fair amount AR softening adjustment left and will do so for next season.
AFIK, 200 lb springs are as stiff as I can go with stock dia 914 (the big OD) springs. For my set-up (AX being the main focus), 225 or 250s would be better....*I think*.
The present set-up seems very nice for the big track.....dead neutral, but I ain't worth spit at that stuff.

Negative camber is good for tires that *require* it. Rspec Kumhos & Hoosiers fall into that catagory.

[cha914]

*sigh*

yeah, I need tires, but I have already bought 2 sets of tires the past 2 months (too many @@#$% cars) ... oh well, I guess I will try and shave these some (where is a drifting competition when you need one (IMG:style_emoticons/default/tongue.gif)) and then hopefully by Jan I will have enough coin for some V700's or something like that.

I am maxed out with camber up front untill I start cutting or get some expensive bling like JP...and in the rear, I am going to need to get some shims if I am going to lessen the camber without jacking the rear up...

I guess I am against going stiffer in the rear at the moment cause my co-driver thinks its too stiff as it is, but neither one of us are pros at this yet, and we havn't been on the track yet.

Would tires effect turn-in that much? I was expecting that to be much improved with the toe out in the alignment, but it really wasn't.

Thanks for the replys,

Tony

[MJHanna]

A proper corner balance will also help

(IMG:style_emoticons/default/agree.gif) I would do this first. Do you have access to any scales? You really need to do this to establish your baseline. (IMG:style_emoticons/default/pray.gif)

[aufaber]

I guess I am against going stiffer in the rear at the moment cause my co-driver thinks its too stiff as it is, but neither one of us are pros at this yet, and we havn't been on the track yet.

Well, that is what you need more than suspention setup advice.. Track time.

Could be your just over cooking it into the corners. Though it does look to me like you have a relatively stiff front end for your rear setup, which would make it push.

-Aaron G.

[cha914]

Here are a few shots of the car in action...somebody at the event took several pics of my car!

[cha914]

lifting the inside front?

[cha914]

turn damit...turn ...

[cha914]

I guess I will leave it as is for now, and get some seat time on the track (and also try and get on some scales) ... but I have a couple quick questions:

i could just as easily go down to 19mm torsions, rather than put heavier springs on the rear...correct...similar result?
And two, many of you have said I am now under sprung in the rear, and I have seen several racers run very heavy springs in the rear, any particular one reason for this type of setup? or you guys just like really stiff cars?

Thanks again,

Tony (IMG:style_emoticons/default/MDB2.gif)

[DuckRyder]

Does it have a rear bar?

For Autocross I think it needs one.

(I have no clue what it needs for open track)

If it were me, the first thing I would change is tires, then add a rear bar (even if was just someones cast off stocker)

[cha914]

Nope, no rear bar...I think I have actually heard that most autoxers don't use a rear bar...but maybe I am confused...

I agree though...I need tires before I do anything more with the car...

Dear Santa... (IMG:style_emoticons/default/spank.gif)

Tony

[ChrisReale]

(IMG:style_emoticons/default/barf.gif) .....you need more rear spring.......... (IMG:style_emoticons/default/barf.gif)

[SirAndy]

front is loose, tighten the back
back is loose, tighten the front

now, with the front already full soft, you've gotta go and get yourself some heavier rear springs.

(IMG:style_emoticons/default/smilie_pokal.gif)

Andy

[J P Stein]

Heavier rear springs keeps the inside front wheel on the ground. NOGO on rear bar, that'll lift the inside rear wheel...ulsess ya got LSD, you don't go any where....but the front will stay down.

AX life is hard. (IMG:style_emoticons/default/laugh.gif)

[SirAndy]

NOGO on rear bar, that'll lift the inside rear wheel...ulsess ya got LSD, you don't go any where....but the front will  stay down.

a really good driver (one with lotsa (IMG:style_emoticons/default/smilie_pokal.gif) ) once told me a rear bar for AX
can help you to get the ass sliding around the corner. but i think you have
to be REALLY good before you can take advantage of that. that's why i
don't have a rear bar in my car (IMG:style_emoticons/default/wink.gif)

Andy

[fiid]

I was also told that a rear bar was good for getting the ass to come around for AX and that it is easy to unhook it for track and street driving.

I don't know shit though - so don't listen to me on this particular topic. My GFs stiff sport package miata has a rear bar in it which I found quite suprising. It's only a dinky one though.

Fiid.

[Brett W]

With 22mm bars up front you need to be running at least 200s and maybe even 250s in the rear. I was running my four cylinder car with 180 rears on Carreras, no rear bar, stock tbars up front and a 23mm sway bar set at half way. You could run a rear bar and for go the heavy springs, this could lead to lifting the inside rear tire though on a tight course.

What tire pressure were you running? Run as much caster as you can get, set the rear to zero toe and run as much camber as you can get. Run your fron tire pressure lower in the front than in the rear. Also set the front shocks to full soft and see what happens. Are you running with a full tank of gas? Lose the passenger your car will handle very differently with a passenger. Make sure you can grease the poly bushings and do so before each event. Are you running a limited slip?