Aggressive GC street setup

[DrMcDave]

Looking for spring rates for an aggressive street setup. Plan to use for Autox as well but more street than anything at least for the time being. looks like for a 318is i should be around 350/450ish for front and rear. feedback welcomed. will be running GC koni's w/ this.

[Beej '86 325es]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

[DrMcDave]

so with 550 or 600 in the back what do you recommend up front. I want to be able to slam it but also be able to have it driveable so chances are it will only be slammed on special occasions. Ultimately i want the best handling not just looks.

[Jordan]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

You might want to mention your car is being consumed by rust, and the trailing arm was significantly weakened as a result.

Its not GC's fault.

[Mystikal]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

That is ONLY because you had the old style straight springs. With 475lb/in 5.5" and 440lb/in 7" barrel springs I have never had any coils touch each other. They've been shipping barrel springs for at least 2 years now.

Dave I'll have a set of 300/440 springs for sale in a week or so, I'll sell them for cheap in case you're interested.

[DrMcDave]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

That is ONLY because you had the old style straight springs. With 475lb/in 5.5" and 440lb/in 7" barrel springs I have never had any coils touch each other. They've been shipping barrel springs for at least 2 years now.

Dave I'll have a set of 300/440 springs for sale in a week or so, I'll sell them for cheap in case you're interested.

might be a good start, i'll let you know. seems a bit soft though, but it will be a daily. it will depend on how cheap and also how much the collars and such cost.

[Beej '86 325es]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

You might want to mention your car is being consumed by rust, and the trailing arm was significantly weakened as a result.

Its not GC's fault.

Either way, there was significant signs of coilbind. The springs had lost about half an inch in free length when I switched springs. Rust had little to do with it.

[Beej '86 325es]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

That is ONLY because you had the old style straight springs. With 475lb/in 5.5" and 440lb/in 7" barrel springs I have never had any coils touch each other. They've been shipping barrel springs for at least 2 years now.

Dave I'll have a set of 300/440 springs for sale in a week or so, I'll sell them for cheap in case you're interested.

Well, the fact that they're barrel shaped springs isn't necessarily the answer. You said they're 7", so you can get away with softer spring rates, because they have a farter distance to compress before they bind. I'm currently running a 6", 2.5 ID, 500 lb. linear spring and have no issues at all. I bought my G-C setup over 5 years ago, they obviously have been made aware of the problem like I had since then. When I said 450 for the rear was too soft, that was assuming it would be a 5" spring. What you have, Mystikal, I'm sure would be fine.

[Mystikal]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

That is ONLY because you had the old style straight springs. With 475lb/in 5.5" and 440lb/in 7" barrel springs I have never had any coils touch each other. They've been shipping barrel springs for at least 2 years now.

Dave I'll have a set of 300/440 springs for sale in a week or so, I'll sell them for cheap in case you're interested.

might be a good start, i'll let you know. seems a bit soft though, but it will be a daily. it will depend on how cheap and also how much the collars and such cost.

I've been running the 300/440 (or 475, not that I can tell a difference) since last April, no issues. I had a bottoming out problem for a long time, which I later attributed to worn dampers. Even since I put new Konis life has been grand. Especially with GC Konis, you really don't need/want too stiff of a spring rate - those shocks are STIFF.

When you find out the cost of the perches/sleeves/hardware, please let me know. In any case the springs are $110-120/pair at GC plus shipping, I'll sell mine for $100 for all 4 shipped.

[Mystikal]

That is pretty soft for G-C, that is what they recommended me and 350 is ok in front, but 450 is WAY too soft for the rear. After a few years, I had bottomed out so much (not the shocks, the springs), that it eventually broke the little nubs the perches fit around off of my trailing arms from the repeated impact. With the standard 2.25" ID, 5" long spring they use in back, you'll want at least 550-600. I actually switched to a different setup with a 2.5" ID, 6" long spring and it seems to work much better.

That is ONLY because you had the old style straight springs. With 475lb/in 5.5" and 440lb/in 7" barrel springs I have never had any coils touch each other. They've been shipping barrel springs for at least 2 years now.

Dave I'll have a set of 300/440 springs for sale in a week or so, I'll sell them for cheap in case you're interested.

Well, the fact that they're barrel shaped springs isn't necessarily the answer. You said they're 7", so you can get away with softer spring rates, because they have a farter distance to compress before they bind. I'm currently running a 6", 2.5 ID, 500 lb. linear spring and have no issues at all. I bought my G-C setup over 5 years ago, they obviously have been made aware of the problem like I had since then. When I said 450 for the rear was too soft, that was assuming it would be a 5" spring. What you have, Mystikal, I'm sure would be fine.

A 5" spring is way too short for most spring rates anyways. I'm running a 5.5" 475lb/in rear spring now, and all the way up WITH a 10mm pad I'm still slightly tucking the rear tire (my sig has the longer springs in). I know you have higher arches, but still, you must be all the way up the perch.

[Beej '86 325es]

A 5" spring is way too short for most spring rates anyways. I'm running a 5.5" 475lb/in rear spring now, and all the way up WITH a 10mm pad I'm still slightly tucking the rear tire (my sig has the longer springs in). I know you have higher arches, but still, you must be all the way up the perch.

Actually, I'm all the way down on the perch, and I still have a little rake. It's a little higher than most people prefer. I'm not using the G-C perches though, I'm using the H&R adjusters that BMP sells so that I could run a 2.5 inch or 60 mm spring, but the stack height of those isn't any higher than the G-C perches.

Here's a picture of how the car sits. (the pic in my sig is pretty old)

[Mystikal]

Something must be different there. When I put my perch all the way down, I completely engulf a 195/65 tire down to the rim with >1" of travel left (5.5" without pads).

I know Robert had 5" springs on his car, and all the way up he tucked at least an inch of the tire also. Our fenders are lower, but not to that kind of degree.