Recommended Spring Rates?

[Variance]

Hey everyone,

I've been looking into purchasing a set of coilovers fairly soon, but I'm not sure what spring rates I should go with. The car is primarily a daily driver, but I regularly attend autocrosses and drift events in it, so I want something at least a bit stiffer than your average street setup. When I posted this on BF.c, I received recommendations of 500 lb/in all around and 450/650 F/R; I'm not sure which would be a better setup, so I'm indecisive. I'd appreciate any knowledge and insight anybody could share with me on this matter. Thanks!

[Maverix]

Is money a issue?

[Variance]

I'm not sure what my budget has to do with spring rates?

[Maverix]

Oh, my bad. I kinda misread.

I'll be sure to....
http://img237.imageshack.us/img237/8...h4au311vr3.gif

[andy]

If you're making standard 318ti power and weight, then the 450/650 might work. But I've liked a setup much closer to the 500/500 one in my car. Especially if you run a fair amount of bar, that will work quite well on the track. I don't know as much about drifting, but I suspect that you could just swap out for a large bar in back (really easy to do on the ti) and you'd have all the tail-out behavior you could handle.

[mohaughn]

I'm at 550 front and 500 rear.. Large front bar, no rear bar. I run the front shocks at about 50-60% stiffness, and the rears at about 85-90% stiffness.

Don't listen to people that only know how to setup the standard E36 rear suspension as it is pretty common for E30 M3s to run stiffer springs in the front than the rear, which is exactly opposite of what most people do in a normal E36.

[andy]

True - the ti really is its own beast, even though it resembles both the e36 and e30. While it has the e30 style trailing arms, it has the 106" wheelbase, a full 5" longer than an e30...that can have ramifications.

[Variance]

I think I'm going to go with the 500 F/R recommendation, thanks guys.

[gimp]

Originally Posted by mohaughn

I'm at 550 front and 500 rear.. Large front bar, no rear bar. I run the front shocks at about 50-60% stiffness, and the rears at about 85-90% stiffness.

Don't listen to people that only know how to setup the standard E36 rear suspension as it is pretty common for E30 M3s to run stiffer springs in the front than the rear, which is exactly opposite of what most people do in a normal E36.

Bumping this... What type of racing do you do, mohaughn?

[mohaughn]

Been on vacation snowboarding and avoiding technology whenever possible.. I replied back to your PM, but right now I don't do any competitive driving. The car does not have the proper safety equipment to do any sanctioned road racing, and autocross is not really my thing.

So I mainly do DE's getting more experience at different tracks and I plan on joining NASA at some point in the future and competing in time trials.

The last BMWCCA sanctioned autocross I went to after my suspension was completed I placed 3rd in a pretty competitive group. 1st and 2nd went to a 325 e30 and a dinan 318ti. Both driven by much more experienced autocrossers than myself.

[gimp]

Very good information. What bar/shocks where you running? How would you describe the handling?

I'm trying to dial in my car for STS. I was looking at the 400 or 500lb VVS rear springs from TCKline, paired with some GC sleeves I have sitting around and some 450 or 550 front springs, keeping my Eibach front bar, and removing my rear bar. My car feels good now, but I need some more roll resistance.

Has anyone used the VVS springs before? Does anyone know the ride height difference between those and the "shorty" versions? I assume I need the regulars, as my car won't have that much weight out of the back (rules).

[mohaughn]

TCKline double adjustables with VVT front and rear springs. No rear bar, and a H&R 28mm front bar. I'm also using the tckline front camber plates and their solid rear shock mounts. My car is very flat and has no excessive body roll. It is impossible for me to lift the rear inside wheel off of the ground, unless I simply over drive the car. I get a very small amount of inside front tire lift in high speed sharp corners like #17 at Sebring. The car handles very well and is very balanced.

I'm using the regular rear springs with 5mm spring pads and I don't have an adjustable collar installed. My understanding is that the shorty springs are about an inch or so shorter and Pete at TcKline recommends running them with the adjustable collar. So they end up being about .5" shorter than using the regular springs without a collar.

Call the Ohio TCKline number and talk to Pete. He really knows his stuff, and they are very familiar with the Ti/Z3 rear suspension.

[gimp]

Originally Posted by mohaughn

TCKline double adjustables with VVT front and rear springs. No rear bar, and a H&R 28mm front bar. I'm also using the tckline front camber plates and their solid rear shock mounts. My car is very flat and has no excessive body roll. It is impossible for me to lift the rear inside wheel off of the ground, unless I simply over drive the car. I get a very small amount of inside front tire lift in high speed sharp corners like #17 at Sebring. The car handles very well and is very balanced.

I'm using the regular rear springs with 5mm spring pads and I don't have an adjustable collar installed. My understanding is that the shorty springs are about an inch or so shorter and Pete at TcKline recommends running them with the adjustable collar. So they end up being about .5" shorter than using the regular springs without a collar.

Call the Ohio TCKline number and talk to Pete. He really knows his stuff, and they are very familiar with the Ti/Z3 rear suspension.

...and that response is why I didn't ask in a PM. GREAT tech there!

[mohaughn]

Here is an older thread that I did when I was deciding what I wanted to do with the car, and my first impressions after installing the suspension.

http://www.318ti.org/forum/showthread.php?t=13174

Once I get the car back from the fabricator I plan on doing a beginning to current build thread to put everything into one place in regards to what I've done with the car, and my overall experience with the different products that I've used while tracking the car.