koyv90

I am in the market for coils and see a lot of companies offering custom spring rates. But i have no idea what type of spring rates i would get. My car has a built engine and a turbo kit pushing 10psi and hits about 450-500 hp. Have not dynoed it yet. I am daily driving it and mainly want something that will have a more neutral setup. I want to drift and do autox on event days but will be using it mostly on a daily basis. Anyone have any idea on what rates would be good? I heard 10k/10k is good and would provide a neutral feel especially with my staggered wheels but I heard 10k/10k for a stock engine with no boost. Will this still be an acceptable spring rate?

terrasmak

iTrader: (8)

Spring rates are more dictated by tires, and vehicle weight.

koyv90

Okay well i have 18x8.5 +25F and 18x9 +22R with 245F/275R both by 45Rtires.
Also was told i should be getting better sway bars which i have no idea about haha!

terrasmak

iTrader: (8)

Not all tires are equal, you would want a different spring rate for the V12, RS3, R888 or R6.

Before you look into suspension, I would get the wheels straight, maybe move your 18x9 up front and get a 18x10 for the rear or just ditch the wheels all together.

koyv90

What's wrong with the wheel size and tire I have now ? I have volk ce28 rather keep them ha. And choose rates based of that or change tire sizes.

terrasmak

iTrader: (8)

An 18x9 with a 275/40-18 in the rear is really sloppy, not to mention not to many sticky tires are available in that size.

A common track/autocross tire is a 285/35-18 mounted on a 10.5 wheel, than many of us run the same width up front.

Even for a 275/35-18 , a great tire for front and back, you want a 9.5 at minimum. This would also be a good drift tire for the HP you say you have.

koyv90

I'm sorry gave you the wrong sizes 18x8.5 in front 18x9.5 in rear I believe have to double check on break

koyv90

Yea looked into it that's what they are. I asked fortune and the recommend like 11k 9k cause an even spring would cause to much oversteer?

terrasmak

iTrader: (8)

Well the Nismo T2 race springs are 690lb front and rear, and run with a square tire combo (stagger increases understeer, you seem to want a staggered setup) the 04.5 spring rates is 330 front and 450 rear and the Nismo package has even more rear spring rate.

Here are the questions to ask Fortune.
1. Target front frequency
2. Target rear frequency (both answered in Hz)
3. Ideal front to rear frequency to run neutral when running a non staggered tire combo.
4. How much you should maybe compensate for a stagger if desired.

If they can not answer the questions, you should be doing the research yourself and tell them what you want to run. Also, are you wanting OEM style rear spring placement or true coilover style, you will need to know the motion ratio for the one you decide to use.

FYI, just off the top of my head. My car is sitting at 2.17 Hz up front and 2.25hz rear, running equal tires front send rear.

koyv90

Its OEM style they said due to chassis you usually want to run stiffer fronts to prevent to much oversteer. I'm looking for a more neutral balance with stagggard so I can do both drift and auto x relatively well

terrasmak

iTrader: (8)

http://farnorthracing.com/autocross_secrets.html great reading, you may learn something.

Don't confuse neutral for oversteer. It takes a lot to make these cars naturally oversteer (throttle induced is easy ) even getting them neutral is a pain.

03threefiftyz

iTrader: (25)

I run a little heavy on front spring, but I have (compared to others here) a ton of front grip. Square ride frequencies in my car make it a hell of a handful...even with no rear bar.