I'm still having a bit of trouble getting my 2000 Si to do what I want it to on the autocross course and I could use some advice.

Here's a bit of history:

STS Class
Springs - 550f / 750r
Camber - 2.2f / 1.6r
Toe - 0 all around
Stock swaybars
Tires - Azenis Sports (not the new 615's)
Koni Sports
Loose nut behind the wheel - 6 years autocrossing, currently Novice Chief at SASCA (San Antonio Sports Car Association)

Setup #1 used all last season:
OTS Konis that were obviously overpowered by my rear spring rate. Car had a lot of oversteer and was a bit twitchy when off the throttle. I knew the car needed work. I still placed first in STS here at SASCA.

Setup #2 used in the first event this season:
New revalved and shortened Konis (Thanks Lee!!), Mugen rear trailing arm bushings, and front Delrin bushings on the lower control arm. Car has lost a lot of it's oversteer and has in fact developed a serious problem of pushing in the turns! I was told (incorrectly) to stiffen the front shocks and it didn't help.

Setup #3 used in the second event this season (practice event with 20+ runs):
Correctly set the shocks to near softest front and near firmest rear. Helped a little but still pushing very bad. I had a competitor drive mine and he agreed that the car wasn't set up correctly. I tried everything, max firm on both ends, max soft, and everything in between. Still no help. Then I started getting wierd. I usually run 36f, 30r for tire pressures and I bumped them up to 46f, 50 rear and it helped a lot! Car still has a lot of push but it's a lot better than before.

So what now? Did my revalved Konis affectively lower my rear spring rate since the springs are now under control? I'm guessing that I will need a new rear sway bar (the stock one is about as big as a pencil) but I have heard that I shouldn't need it since I have such a heavy rear spring bias. I will listen to the H-T guru's advice before I spend the money on the bar....

Thanks in advance and sorry for the long post,

Kevin

 

Spring rates that hight are better suited for R compound rubber. If it were me and I was sticking to STS, I'd go get softer rates.

Also, what tire pressures are you running? That's going to have a lot to do with it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by madhatter &raquo;</TD></TR><TR><TD CLASS="quote">Spring rates that high are better suited for R compound rubber. If it were me and I was sticking to STS, I'd go get softer rates.

Also, what tire pressures are you running? That's going to have a lot to do with it.</TD></TR></TABLE>

wah??? 750lb rear spring is NOT excessive for street tires. i won the Petersburg Pro in 03 with 700lb front springs/800lb rear springs and the lot at Petersburg is a bumpy, oily, POS lot with no grip.

did anything in the alignment change with those delrin bushings? how much bind did those bushings introduce to the front end? i'd be looking there before i look anywhere else. a rear bar would be a good idea regardless of what you do to the front end.

nate

 

Madhatter - read "Setup #3", it talks about the tire pressures.

I should probably clarify something here. Niether myself nor this car are getting bad times while on course. I was only 2.X seconds behind TToD (Lance Adams in an SS prepared Z06 on race rubber) and won my class. This is more of a preference thing. I prefer to have more oversteer (not as much as I had before but I really hate this pushing that the car is doing now) and I'm trying to find out what to do. I also feel that the tire pressures I was running to get those times were a bit odd, though I could be mistaken.

Thanks again!

Kevin

 

solo-x - The alignment and corner balancing was done after everything was done to the suspension including the bushings. We tested for any binding while we reassembled that car and they actually were better then the OEM ones.

BTW - those bushings made a HUGE difference in the launching of the car. The only ones we made were the big ones at the rear of the front lower control arms. I would highly recommend them to anyone that is able to do them in thier class.

 

ah, i was thinking you did the other bushing or both lca bushings. you didn't change caster or anything like that while you were in there though, right? changing you caster setting will really screw with your bumpsteer unless you also shim the rack to fix that.

if all the above checks out, try the rear swaybar. everything else seems alright (though depending on ride height i might also suggest increasing front spring rate)

nate

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blue Si #72 &raquo;</TD></TR><TR><TD CLASS="quote">Madhatter - read "Setup #3", it talks about the tire pressures.
</TD></TR></TABLE>

Doh. Missed that.

And I'd agree with Nate about the rear bar BTW.

Good luck!

 

Ok, so now comes the next question (you saw this coming didnt you?):

What bar? I imagine I should also get the subframe bracing while I'm at it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blue Si #72 &raquo;</TD></TR><TR><TD CLASS="quote"> Then I started getting wierd. I usually run 36f, 30r for tire pressures and I bumped them up to 46f, 50 rear and it helped a lot! Car still has a lot of push but it's a lot better than before.
</TD></TR></TABLE>

This may be your issue. I usually run less than 40f and around 45-48 rear with my Azenis. Shocks near full stiff rear, 1/4 -1/2 stiff on front with a comptech rear bar. I can still get a little push, although my springrates are OTS, so they are setup the 'wrong way'. I'm thinking you may just have to dial in your pressures; I'm still working mine out.

 

The Comptech unit is really nice! I have one on my 92 hatch and like it a lot!

John

 

(ST Speedtech sway/tie, BTW) Improved everything.

Granted, I run a WAY softer setup than Nate does (I'm sure he's ashamed of me), but my car is now so flat and balanced through the slaloms and sweepers that it makes me do the pee pee dance. In slaloms, the tail wags just enough to get teh car around the cones. If I overcook it in a sweeper, the car does a 4-wheel drift instead of plowing into oblivion.

Setup is OTS Koni yellows (full turn up front, 1/2-3/4 turns back), Neuspeed Sofsports (sitting on the bottom perch up front and middle perch out back) and the ST sway out back. That's it.

Oh yeah--Yoko ES100's (need to upgrade) and 39F /37R

If this helps at all, then

(now Nate can shake his head at me )

 

*shakes head*

you coming out next sunday? weather 'pose to be good!

i'm using the same tie-bar but with a JDM 23mm rear bar. a little on the heavy side for my taste (13lbs bar+tiebar) but works good. i'm looking into modifying it to cut that down 5lbs or so.

nate

 

id rip the front bar off... im poor and thats free

 

Ooohhhh shinny stuff.... I like shinny stuff.....


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gamby &raquo;</TD></TR><TR><TD CLASS="quote">

(ST Speedtech sway/tie, BTW) Improved everything.

Granted, I run a WAY softer setup than Nate does (I'm sure he's ashamed of me), but my car is now so flat and balanced through the slaloms and sweepers that it makes me do the pee pee dance. In slaloms, the tail wags just enough to get teh car around the cones. If I overcook it in a sweeper, the car does a 4-wheel drift instead of plowing into oblivion.

Setup is OTS Koni yellows (full turn up front, 1/2-3/4 turns back), Neuspeed Sofsports (sitting on the bottom perch up front and middle perch out back) and the ST sway out back. That's it.

Oh yeah--Yoko ES100's (need to upgrade) and 39F /37R

If this helps at all, then

(now Nate can shake his head at me )</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">*shakes head*

you coming out next sunday? weather 'pose to be good!

nate</TD></TR></TABLE>

Still working on the spousal blessing, but I'm thinking I'll be there. My car still isn't even out of winter storage mode yet. I gotta get my *** in gear on that.