Eibach Pro Street-S -- Spring rate changes

[D-O]

Hello,

I want to try some changes to the spring rates on my Eibach Pro Street-S coilovers. The kit ships with 400 in the front and 450 in the rear.

I called Eibach support and was told "they have been tested to 1000 lbs." This is hard to believe considering the supplied spring rates.

Does anyone know what spring rate range the damper valving will support?

Thanks.

Jesse

[Tbonem3]

For a street car, you're not going to be getting anywhere near 1000lbs anyway, so I wouldn't worry about it.

Keep in mind, because of the location of our rear springs, even though they may be high on some people's cars, like 700lb, for example, the damper is only having to control about 2/3rds of that (leverage).

I bet a simple change of 450lb to 600lb in the rear would be a great change for you. I went lower than 400 in front, but about 400 is perfectly fine, especially if you have no notable weight loss.

Something else to keep in mind. You'll want a shorter spring the heavier you go or you'll have to at least move the height adjuster. Sometime you run out of adjustment and you need a different height. You can also get spring "blocking" if the spring is too short for a given weight. A 5.5" 800lb spring is fine, but a 5.5" 400lb spring would be a joke.

[D-O]

Tbone,

Agreed on the 1000 lbs. I explained that I wanted to lower the rate in the front and raise it in the rear. Their response was not helpful.

Like you, I am thinking somewhere around 600 in the rear. I would just like to know how far I can go, up or down, with the supplied damper valving. I know this was discussed on M3F. There were a couple of guys that went up in spring rate on both ends, but all of that is lost now.

Thanks for the rear spring height tip. Funny thing is that I think I need a taller spring in the front. I had to go to the top of the adjustment to get the front height at 13.5"

Jesse

[Tbonem3]

Do the eibachs have (rebound) adjustment? You could play with it.

Ya, I had to go to a 7" spring (325lb) up front from 6" 440lb.

Just a guess, I'll say your dampers true limit is like that of other s/a dampers for this car which is around 700lb iirc. But again, a 700lb rear spring isn't actually 700lbs.

[benzthis]

got 500/600 on my eibachs.lasted about 3 years of daily driving before blowing out the rear shocks.

[D-O]

Do the eibachs have (rebound) adjustment? You could play with it.

Ya, I had to go to a 7" spring (325lb) up front from 6" 440lb.

Just a guess, I'll say your dampers true limit is like that of other s/a dampers for this car which is around 700lb iirc. But again, a 700lb rear spring isn't actually 700lbs.

The Eibach's have no adjustment at all. With that in mind, I would imagine they are valved for a fairly narrow range - but that is just me guessing.

[D-O]

got 500/600 on my eibachs.lasted about 3 years of daily driving before blowing out the rear shocks.

Not encouraging, but many thanks for the information.

Jesse

[D-O]

got 500/600 on my eibachs.lasted about 3 years of daily driving before blowing out the rear shocks.

How appropriate. I walked out to the parking lot at work and find a wet spot under the passenger's side rear tire. Shock gave out. Oil all over it and the ground. 3 years and 17 days. A whopping 20,500 miles and it is dead. Awesome.

Jesse

[D-O]

Eibach was polite but firm. The warranty is expired. A rear shock is $196.00. Because I have proof of original purchase they reduced it to $111.00.

[benzthis]

Sucks your shocks blew out.at least you can by replacements.when mine blew they wouldn't sell me just the rear shocks.i had to buy the whole set up,front and rear.so instead I bought some koni adjustables.

[Tbonem3]

Those shocks aren't blowing out because of the spring rate fyi... 450lbs presents itself as about 300lb/in at the shock. Even Benz's 600lb is only about 400lbs to the damper.

[benzthis]

Those shocks aren't blowing out because of the spring rate fyi... 450lbs presents itself as about 300lb/in at the shock. Even Benz's 600lb is only about 400lbs to the damper.

so they blew out because they're not made well?not as robust as other shocks?

[r4dr]

What was your ride height set to?

[D-O]

13.5" front and 13" rear.

[Tbonem3]

so they blew out because they're not made well?not as robust as other shocks?

Ya or some sort of QC issue or something. 450lb-600lb is not excessive whatsoever. I had a rear koni s/a leak badly. I was only running 525 & 550. It happens.