Help with spring rates: Car weighs 1500 front, 1360 rear

[Vivek]

So here's what I have. I can probably just get a set of used GE coils, 450/650, with bilstein sports all around and call it a day. BUT--if I wanted to match something a bit better, what would my options be like? I plan to do this well, weigh my front and rear individually, and use other people's advice for the best setup. I'll most likely go with KYB GR2 (Camaro rear shocks, MR2 rear struts up front) shocks, so I'd like to get spring rates that are matched decently well to those shocks and struts. I know that they're stiffer than the Bilstein sports. Does anyone know the ideal rate to run with those shocks? Is it more important that the springs are matched to the shock valving, or that they're matched to the weight/balance of the car? Are 450/650 good rates for Bilstein sports?

So I weighed my car. It's 1500 front and 1360 rear. That's with me in it (about 125), the hard top (40#), the about 50lb vert weight that I could remove in the back, and maybe 12 gallons of gas. I could set up the weight to be anywhere between around 1250-1420 in the rear depending on what parts I add or remove (soft top, weight)

[mbonanni]

bilsteins are valved for 350. 450/650 is too stiff.

That is why people get them revalved.

[Blackout]

How are you going to use MR2 rear on an E30 front?

[mbonanni]

They are a strut type.

[Blackout]

But he will need a custom collar nut though.

[mbonanni]

There is a whole thread about how to use them on an e30.

[Vivek]

bilsteins are valved for 350. 450/650 is too stiff.

That is why people get them revalved.

Thanks, so that basically rules out the GE setup. I'd rather spend the extra like $200 bucks, and get 100% new and more personalized stuff.

[E30_fiend]

bilsteins are valved for 350. 450/650 is too stiff.

That is why people get them revalved.

That is horribly inaccurate. Do your homework before you post misinformation.


Vivek, bilstein rears are pretty much maxed out at 700lbs/in.

The reason the rear can take so much is because of the rear suspension design on the e30. The trailing arms act as leavers. So even though the spring sees 650lbs/in, the wheel only sees ~292lbs/in. So since the wheel sees ~292lbs/in, then the shock only sees a bit more than that. In short, the shock doesn't support the weight of the car. So the rear rate can be somewhat high. I've even heard of guys that run 1000lb springs in the rear on stock valved bilstein sports.

I DD'd bilstein sports on 750lb rear springs with no problems whatsoever.

If you're wondering about the front, it isn't far away from the rear. Because it has all the weight of the motor over the front end.


Taylor

[mbonanni]

I was told over the phone by bilstein.

I told them I wanted to get them shortened to use with 550/700, and they told me that I will need to get them revalved as well.

If they are rated for 700lbs why the hell would anyone ever get them ravalved in the first place.

Unless they were lying and trying to get my money then idk what is up....

[Vivek]

So is that 700# on the spring or on the shock? I'd rather go with the custom GC's because then I got my shocks that I want to run (and I know they're stuffer than bilsteins), and I can pick any rate that I want. So the main question is, what would be the best rates to pick?

[mbonanni]

He is saying that the stock sport shocks can handle up to 700 lbs/in.

If it were me, I would get they revalved.

[mbonanni]

The reason the rear can take so much is because of the rear suspension design on the e30. The trailing arms act as leavers. So even though the spring sees 650lbs/in, the wheel only sees ~292lbs/in. So since the wheel sees ~292lbs/in, then the shock only sees a bit more than that. In short, the shock doesn't support the weight of the car. So the rear rate can be somewhat high. I've even heard of guys that run 1000lb springs in the rear on stock valved bilstein sports.

This makes sense to me.

Bilstein may have been taking what the actual weight each shock is going to be handling that is why they suggested revalve.

450/650 may be okay. just do it. If they blow then get them rebuilt.

This makes some sense to what taylor was saying.

http://www.r3vlimited.com/board/showthread.php?t=147707

[E30_fiend]

Exactly^^^^

Worst case scenario, you get them revalved anyway.

Although, bilstein is a business, of course they would recommend revalving simply because they can make more money per shock and there is a much smaller chance that the shocks will blow which means a much smaller chance that they will have to warranty the shocks.

In short, revalving makes them more money up front and it covers their ass in the case of a blow out.

I had bilstein tell me that I should revalve the rears for H&R sports which are like 360lbs/in...what's that tell you? Lol


Taylor

[Vivek]

Anyone have some good info for a car that weighs about 1500 front and 1300 rear? I'm looking to minimize oversteer. Just for this, take comfort completely out of the equation. I'm looking for coilover rates matched the best to 1500/1300 and KYB GR2 shocks and struts.

[LJ851]

That is horribly inaccurate. Do your homework before you post misinformation.


Vivek, bilstein rears are pretty much maxed out at 700lbs/in.

The reason the rear can take so much is because of the rear suspension design on the e30. The trailing arms act as leavers. So even though the spring sees 650lbs/in, the wheel only sees ~292lbs/in. So since the wheel sees ~292lbs/in, then the shock only sees a bit more than that. In short, the shock doesn't support the weight of the car. So the rear rate can be somewhat high. I've even heard of guys that run 1000lb springs in the rear on stock valved bilstein sports.

I DD'd bilstein sports on 750lb rear springs with no problems whatsoever.

If you're wondering about the front, it isn't far away from the rear. Because it has all the weight of the motor over the front end.


Taylor

I was told over the phone by bilstein.

I told them I wanted to get them shortened to use with 550/700, and they told me that I will need to get them revalved as well.

If they are rated for 700lbs why the hell would anyone ever get them ravalved in the first place.

Unless they were lying and trying to get my money then idk what is up....

I'm with mbonanni and what bilstein told him.

E30 bilsteins share the same valving HD or Sport (unlike some other cars) so the bilstein valving is what they sell for stock spring rates. If you think one non adjustable shock valving stack is even remotely ideal for stock spring rates and 700 lb rear springs you have some learning to do. Since bilstein designed the valving for stock suspension i will make an educated guess and suggest the person with nonstock spring rates needs the revalve not vice versa.

Will your car drive down the road with mega springs and stock bilsteins? Sure, but you are leaving substantial ride quality and performance on the table.