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View Full Version : coilover option. 400lb spring rate or 455lb



administerturbo
04-17-2007, 02:17 PM
hopefully in the next month or so i'll have the $$ to purchase these. as the car will stay a daily driver i don't want to go too stiff. the KW v3's that i'm pretty much sold on have high speed (thing shock frequency speed not vehicle speed) compression preset and low speed compression is adjustable as well as rebound.

400lb spring rates come standard with the kit for my car while 455lb rates come with the kit for the 3.2litre version of my car (to support the heavier engine). i'm toying with getting the 455's for my car since i am autocrossing it. the vehicle is just south fo 3200 lbs with a 60/40 split. it will never be the perfect autocross machine but i'm trying to find the best medium for daily driving and autocrossing. i'm unable to find what my stock spring rates are to compare. the kw's front springs are linear. rears are progressive which is unavoidable due to their wound shape.

driving impression on the forums indicate that it "feels" softer than typical spring strut setups on the bumps and interstates until you get into the turns. seems to figure considering the trick valving they are using. appears as though they are trying to emulate a progressive spring with valving and cut out the negatives of it.

ground control doesn't appear to have an option and all other c/o kits seem to have progressive springs up front :(

miscelaneous stuff: will be lowering .9 inch (min). no camber plates up front don't want the NVH issues, should be able to get -2.0 with adjustments and lowering, some unusual trick bushings mods will be going in up front to emulate pre-recall a-arms(hello to steering feel), camber correction will be going in out back to bring the rear back into spec.

robert just put 500lb rates on his wrx which is of similar weight as the TT. his early initial impressions were that it was a little stiff, but that's without much fiddling. he may be able to dial that out with the compression settings

well this post is getting really long now so i'll make it longer. the other option is to not worry about and if they are too soft order some stiffer spring and hope that the valving has enough adjustment it in to handle them.

unfortunately there aren't many serious autocrossers who know what will work for this car so i'm in nearly uncharted territory.

oh and if anyone wants to loan me about 6 grand i'll get some ohlins from stasis and they will let me fiddle with spring until i'm competely happy.

thoughts/opinions/past experiences.

crobin4
04-17-2007, 02:25 PM
My $0.02. Go w/ the 455 lb per in. for the front. Robbs isn't "that" stiff. I think it can be dailed down to be reasonably soft for the street.

Davis K Powers
04-17-2007, 03:01 PM
Since we both have similiar type cars (AWD, heavy) I thought that you might like to see how what my path was.

BTW, I've only heard rave reviews of the KW v3's on other WRX's/STi's. I'm sure you'll love em.

I have around 400/480# on my car, with some custom dampening and rebound settings. (HKS Hipermax RS coilovers) Also have 29mm front white line sways and 26mm rears. 245 r-compound v710's.

Its my daily driver as well as track and Solo car. These springs are about as high as I would want to go (my 2 and 4 yr sit in back seats) for a car that sees 100% street use. I'd consider my setup a very good compromise. Its not going to be fantastic at Solo or track events, but decent enough to where I can also use it on the street all the time.

Thick adjustable sways bars, Coilovers (with -3 camber) and of course r-compounds is where I made up most of my time. To me, it looks like you are going in the right direction and should see some differences right away.

Ideally, for my car to drop more time and be more regionally competitive in the suspension are alone, it should have even higher spring rates (with proper dampening/rebound) and wider tires, probably in the area of 600-750# springs and 275 or 315 rubber on fat wheels. (But no way would that be streetable IMHO w/kids). Over the winter I decided that I would stop on the development of my car and get a dedicated car in the middle of the 2008 season.

Can't wait to see you car when it gets done.

Speed Safely!

P.S. Get a good alignment or even a good corner balance if you have a chance

administerturbo
04-17-2007, 04:05 PM
Thanks for the info!

davis, so yours are 400 on the front?

i totally agree with you. my car will be done after suspension. and i wouldn't even be going that far if it didn't increase enjoyment on curvy WV backroads.

sometime in the next decade hopefull i'll get something dedicated.

and yes, it will be corner balanced!!

hope you're feeling better

Davis K Powers
04-17-2007, 04:24 PM
Thanks for the info!

davis, so yours are 400 on the front?

i totally agree with you. my car will be done after suspension. and i wouldn't even be going that far if it didn't increase enjoyment on curvy WV backroads.

sometime in the next decade hopefull i'll get something dedicated.

and yes, it will be corner balanced!!

hope you're feeling better
Yes ~400# front.
On my street setup (camber -1.5, street tires, soft dampening) the car is VERY good on hilly areas. The "feel" of the car is totally trasnformed after coilovers and you can really direct the car to do whatever you want; drift the car thru turn, full traction high speed, and cruise around without all the bouncing/hopping.

I forgot to mention that I was expecting my street rain setup to be wayy too harsh, but it actually was VERY good on smooth wet street surfaces. I also imagine that this spring setup would be an optimal track wet setup. (I haven't had my newer setup on the track...later this year for sure.)

Talk soon!

P.S. Yes, I'm feelin better and should be back to normal in a couple weeks. Thanks for asking.

gtfour77
04-17-2007, 04:49 PM
Nate, sounds like a really nice setup. Personally I would go with the stiffer option but considering this is your street car also maybe 400 will be sufficient... It will make a huge difference regardless of what you choose to go with... Robert's car is a whole different car after his coilovers.(very, very predictable and I think it brakes so much better with teh stiffer spring rates...but you dorve it too so you know what I mean...;)
Like Davis said, camber and good sticky tires will be very important.... Hope you can stay away from those for some time so some of us have a chance... :D

Hillbilly
04-17-2007, 11:18 PM
I think 400 is pretty high for your daily driver, I wouldn't go any higher unless it was a dedicated auto-x car. If you want more roll stiffness go to bigger bars. Holler at me about the corner weighting.

administerturbo
04-18-2007, 04:43 PM
I think 400 is pretty high for your daily driver, I wouldn't go any higher unless it was a dedicated auto-x car. If you want more roll stiffness go to bigger bars. Holler at me about the corner weighting.

will do for sure man!

Jason V
04-20-2007, 08:12 PM
on the valving.. the high speed compression only comes into play with bumps in the road... the low speed (adjustable) valving comes into play in cornering... what is the spring diameter up front on the kws... (and the rear too) standard springs are 2.5" diameter and come in many lengths and rates... they are not expensive allowing one to buy many sets and play with what works and what does not... 400 should be a good place to start...

PS to davis.. from what I have heard some of the top BSP sti's are running front rates over 1000 pounds!!! (keeps the rear tires on the ground)