Basically here's the deal, I have my ITR nearly finished being prepped(track only) but am still running on my OEM shocks and springs, as I have been since day one(including on my first ITR which was a street car).. which are not so bad, but I think it's time to move on to something stiffer.. I read the FAQ stuff, searched a lot, and even talked to Lee over at Koni(who has been ULTRA helpful/informative even if I haven't yet bought an item/service from them)..

Current setup, suspension wise:
OEM ITR shocks and springs(246 lbs linear front, 140 -> 246 progressive rear)
No front swaybar
OEM ITR rear swaybar(22mm)

I am happy with the rotation of the car right now and want to try and stay as close to that as possible(oversteering slightly), with higher spring rates.. I am trying to avoid changing swaybars to maintain the amount of oversteer, mostly because I'd like to change one thing at a time.. Once upon a time I was dead set on getting some Buddy Club one piece coilovers, but have since decided that the more popular Koni/GC setup is a better way to go due to customer service, easier to make changes later, etc..


Assuming at this point that I have a set of Koni yellow externally adjustable shocks, with OTS valving(but that can be revalved later):

-Should I go for a higher front spring rate, or higher rear? Over everything I've read, I've heard it put both ways and couldn't figure out why..

-IF I did decide to do swaybars as well, and did a smaller than OEM front bar and bigger than OEM rear, how badly am I going to screw with the distribution front to rear of the springrates? Would it effect it that drastically? This is assuming that I'm still trying to maintain that same amount of rotation..


Thanks, if I've left anything out that would be helpful to know, please say so and I'll answer/add it..

-mark, who still has a lot to learn about suspension tuning..



Modified by mstewar at 6:55 PM 8/20/2004

 

Stiffer is better!

 

But don't go too stiff!

 

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

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">But don't go too stiff!</TD></TR></TABLE>

The irony is that these two statements are based on years of testing, tons of research, and a whole lot of money spent.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by travis &raquo;</TD></TR><TR><TD CLASS="quote">
The irony is that these two statements are based on years of testing, tons of research, and a whole lot of money spent.</TD></TR></TABLE>

ain't that the truth!

 

do you scrape your mirrors with that setup?

 

I loved, and I mean loved, the way my car behaved on track with 400f/500r and OTS Konis, and the front swaybar connected. Still a good amount of body roll but it was predictable and easy to drive and the tail would do whatever I wanted it to, including oh-noes-my-student-crapped-his-pants-in-my-passenger-seat drifting a couple times.

If you're willing to just go nuts and forget about ride comfort, I'd go with some stiffer shocks and springs because, well...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Stiffer is better.</TD></TR></TABLE>

 

ride comfort is a far lesser issue..

so you're saying go with heavier rears than fronts? and that it will still rotate?

would the addition of the aforementioned sway bars change this behavior much(small front, larger rear)?

 

Larger rear spring rate = less rear mechanical grip = more oversteer, as a general rule.

With your front swaybar disconnected it'll rotate quite a bit, depending on alignment.

 

so, ignoring alignment, having no front bar, but a heavier front rate(or small front bar and larger rear) would still allow some oversteer? or would it get more neutral?

 

My 2cents...

If you have the time, money and inclination to experiment... I think you should set the car up initially with close to equal spring rates, then gradually step the rears up to see the effect of the change.

 

springs and swaybars are only a small part of the chassis balance equation. i'm running a 24mm front bar/23mm JDM ITR rear bar, with softer rear springs then front springs. you'd think it would push like a pig, but it's the loosest i've had it yet. at the peru pro i was actually dropping my rear tire pressures so that the car was a little less loose in steady state sweepers. i'm still lifting the inside rear off the ground too, so i'm not giving up anything in mechanical grip either. i also run my front shocks full stiff, rear shocks full soft so that the car is tame enough in slaloms. any less front shock or more rear shock and the car is just too loose everywhere.

i kinda agree with JeffS on this one. put some 500lb springs on the car, all around. reinstall the front swaybar. use about -3* of front camber, and maybe -.5* rear camber. if you are using r-compound tires, bump the fronts up to at least 700lb springs. if you're really driving the car hard, get the shocks revalved and then go to 900fr/600rr, with the same alignment i mentioned before.

nate