KONI Yellows + GC -- New FWD Setup

[tsunari]

My current suspension needs some revision. I've been doing some research and for my budget, it looks like JIC / FLEX coilovers are going to be a bit overkill. So I'm looking at getting a set of KONI Yellows and GC springs. Here's my current setup:

+ '97 GST
+ RMDSM Front & Rear Sways (With Poly bushings)
+ EnergySuspension Master Kit & Engine Mount Inserts
+ Ingalls Front & Rear Camber kit
+ Stock Springs & Dampers
+ 205/55/16 AV ES 100's

This one is a daily driver that I take regularly to the twisties and AutoX. So performance is a bit more important than ride comfort (although I would like to keep my kidneys intact on the terribly bumpy roads around here )

So . . . QUESTION is:

What kind of spring rates should I be looking at? Something like 450/400 fr ? (I'd like to try and get as close to a neutral handling as possible.) Also, what springs should I be looking at? Eibach, H&R, QA1?

Thanks for the space. I'll be the 1st to come out and say that setting up suspension is COMPLETELY foreign to me. So this will be the 1st that I've done.

 

[tsunari]

Also . . . would I need to get a pillowball mount for this setup?

 

[tylerdurden801]

Hm, conventional wisdom says ditch the bigger front sway and go for a rear biased f/r spring rate to go fast. On a FWD, loose=fast because it allows (or forces, depending on how loose) you to steer the car with the throttle and get back on the power earlier. But remember that loose could also equal dead if you're a noob. I'd start out with a equal f/r bias and see what the understeer situation is. 350/350 or 400/400 is quite stiff but shouldn't be a back breaker. Keep the thicker front sway also until you get used to driving you new setup and see if you need to go smaller. HTH.

 

[14.5 drift]

I would not recomend equal spring rates unless he has shifted some weight around in the car. Given the car is nearly 60/40 an even spring rate F/R would create a terribly loose car, too loose for comfort imo.

 

[tsunari]

Nope . . . I'm still running full trim. I'd like to move the battery to the rear at some point, or just get a dry cell.

As for the Konis . . . at what spring rate would I need to get them revalved?

Originally posted by 14.5 drift
I would not recomend equal spring rates unless he has shifted some weight around in the car. Given the car is nearly 60/40 an even spring rate F/R would create a terribly loose car, too loose for comfort imo.

 

[14.5 drift]

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=115431

 

[tsunari]

Originally posted by 14.5 drift
http://www.dsmtuners.com/forums/showthread.php?s=&threadid=115431

Great thread- Thanks I must've missed this one during my search. Would my spring rates be a bit different seeing as this is a FWD vehicle and not an AWD?

 

[tylerdurden801]

Originally posted by 14.5 drift
I would not recomend equal spring rates unless he has shifted some weight around in the car. Given the car is nearly 60/40 an even spring rate F/R would create a terribly loose car, too loose for comfort imo.

I would disagree. The ITR has equal F/R bias (275/275) and a very decent sized rear sway and the car is regarded as one of the finest handling FWD's ever made. It can be throttle steered and will spin if manhandled, but it isn't dangerous by any stretch. Honda guys (who also have a double wishbone setup) run 400/500 or even higher to get desired rotation. Those are for race cars, though. An equal F/R bias shouldn't result in a deathcart. Especially with a big front sway.

With regards to FWD/AWD, yes there is a difference. You'll need a more oversteer biased setup than an AWD if you want to be as fast because the AWD car won't have the same problems putting down power out of a corner as you will. All the advice I'm giving you is for a serious track car, but not all out racecar. If your goals are just to have a more entertaining car, but not necessarily be a front running car, then get a safer setup with less oversteer bias.

 

[14.5 drift]

I highly doubt the itr has any such spring rates. Thats the same as I i have on my S2k and it out weighs the itr by 200 lbs. I'd love to see this in writing.

 

[jtmcinder]

You guys need to stop talking about spring-rates as if these values are all that really matter. The keys are actually the wheel-rates, which are the spring-rates multiplied by the square of the motion ratio. The reason that we - as in 2G DSM owners - run rear spring-rates that are lower than the front is because our rear motion ratios are much higher (about .92 as compared with about .75 in the front). This is a major part of why 1Gs and 2Gs can't swap suggestions on spring-rates ... 1Gs have front and rear motion ratios that are closer together.

Also, corner weights play a much smaller role in setting the spring-rates than most people seem to think. I have higher wheel-rates in the rear, even though I'm front heavy. It's mostly a question of where you want the weight to transfer, not how much weight you need to keep off the ground. The one place where corner weights play a role in determining spring-rates is - IMO, at least, and here I'm a bit on my own - ride quality. The lighter the corner, you lower the max wheel-rate before the ride becomes too harsh. More on that in some other thread.

- Jtoby

 

[tsunari]

Well taking all of that into account, what ballpark should i start my spring rates at? Most of the threads I've come across in this board tend to refer to the AWD application.

Originally posted by jtmcinder
You guys need to stop talking about spring-rates as if these values are all that really matter. The keys are actually the wheel-rates, which are the spring-rates multiplied by the square of the motion ratio. The reason that we - as in 2G DSM owners - run rear spring-rates that are lower than the front is because our rear motion ratios are much higher (about .92 as compared with about .75 in the front). This is a major part of why 1Gs and 2Gs can't swap suggestions on spring-rates ... 1Gs have front and rear motion ratios that are closer together.

Also, corner weights play a much smaller role in setting the spring-rates than most people seem to think. I have higher wheel-rates in the rear, even though I'm front heavy. It's mostly a question of where you want the weight to transfer, not how much weight you need to keep off the ground. The one place where corner weights play a role in determining spring-rates is - IMO, at least, and here I'm a bit on my own - ride quality. The lighter the corner, you lower the max wheel-rate before the ride becomes too harsh. More on that in some other thread.

- Jtoby

 

[jtmcinder]

Personally, I would use the same springs in a FWD as in an AWD, so the other threads apply. The difference is that I would soften the front sway bar or stiffen the rear in a FWD car. To simplify matters, I would probably just leave the front bar alone and upgrade the rear to 24mm. So, it could be argued that setting up a FWD is easier.

But I haven't given this too much thought, as I really dislike FWD.

- Jtoby

 

[tylerdurden801]

Originally posted by 14.5 drift
I highly doubt the itr has any such spring rates. Thats the same as I i have on my S2k and it out weighs the itr by 200 lbs. I'd love to see this in writing.

My mistake, I just reresearched it and it's 250/250. It was close. This is taken from Honda suspension guru's, I can't point you to a magazine or tech article saying such, I just have a saved thread that lists spring rates for popular Honda/Acura cars and aftermarket springs.

Originally posted by jtmcinder
You guys need to stop talking about spring-rates as if these values are all that really matter. The keys are actually the wheel-rates, which are the spring-rates multiplied by the square of the motion ratio. The reason that we - as in 2G DSM owners - run rear spring-rates that are lower than the front is because our rear motion ratios are much higher (about .92 as compared with about .75 in the front). This is a major part of why 1Gs and 2Gs can't swap suggestions on spring-rates ... 1Gs have front and rear motion ratios that are closer together.

I was going to mention something about motion ratios, but I mistakenly assumed since they were both double wishbone cars that they would be similar. I stand corrected.