Ground control coilover conversion

[SNKPWR]

I feel like this has probably been covered, but I couldn't find a topic that brought this up in my searching for and hour+.

I bought a GC coilover conversion kit from a member on here, thinking I would give it a try to see how it rode, despite the general consensus that this is NOT an optimal setup. Seeing as it's a DD that i do not track at all, I figured I could live with it if the ride was ok. I mainly was was just going for the adjustable ride height aspect for aesthetics. I'm using the stock struts and shocks for now, knowing they are not going to last long with this setup but was going to upgrade later this summer.

The rear went without a hitch, as it is very straightforward. The front is where the issue is. The GC instructions say remove the upper perch, knock the dust cap off, slide on the sleeve, then reinstall the dust cap. The problem with this is that this basically renders the bottom third or so of the adjustment unusable. With the spring seat down all the way against the stock perch (as far down and you can adjust it in this configuration), the ride height is at best .5" lower than stock. Am I missing something or will I have to remove the stock perch and use the supplied weld-on sleeve mount to get the full lowering range? I'm guessing that if I were determined to use this kit I would be best to just get the proper struts without a perch that are made for sleeves like this?

Thinking of just going with Sportlines or super sports to get the even drop I want, probably much simpler for my non-autoX needs.

For now I'm just using the rear GC perch and spring so I could level out the height.

TIA for any help with this.

 

[SNKPWR]

I guess nobody has any experience with these?

 

[00blkvert]

Give me a few days. I'm waiting on mine to be delivered then I'll be installing them.

 

[FR500GT]

I have a brand new set sitting in the garage waiting to be installed this weekend but they are the actual coilovers, not the conversion. You probably have the wrong size springs.

 

[SNKPWR]

Maybe wrong size springs, but the kit I have is specifically for 05-09 GT. I don't see how you could have a much shorter spring without having a significantly higher spring rate. Maybe I have the springs mixed up front to rear, looks like they will physically interchange, just ones marked "rear" are 250#, "front" ones are 200#

 

[DRock]

I would swap them.

 

[Whiskey11]

Maybe wrong size springs, but the kit I have is specifically for 05-09 GT. I don't see how you could have a much shorter spring without having a significantly higher spring rate. Maybe I have the springs mixed up front to rear, looks like they will physically interchange, just ones marked "rear" are 250#, "front" ones are 200#

Yeah I think those are supposed to be the other way around. Are your rear springs taller or shorter than your front springs? You can find this out by reading the serial number on the Eibach spring. The first number (usually like 0800) is the spring length. 0800 is 8", 0700 is 7", 0900 is 9" and so on.

 

[SNKPWR]

Yeah I think those are supposed to be the other way around. Are your rear springs taller or shorter than your front springs? You can find this out by reading the serial number on the Eibach spring. The first number (usually like 0800) is the spring length. 0800 is 8", 0700 is 7", 0900 is 9" and so on.

I looked at them, the ones on the rear say 0800, but the fronts do not have a similar looking number they just say GC200.64.67

They are all the same length uncompressed though.

 

[Whiskey11]

I looked at them, the ones on the rear say 0800, but the fronts do not have a similar looking number they just say GC200.64.67

They are all the same length uncompressed though.

Yeah I just found out how the GC specific spring numbers are done.

200 is the free length (200mm which is basically 8"), 64 is the inner diameter of the spring (2.5" in this case) and 67 is the rate in N/m or roughly 380lbs/in.

You have them in the correct order then and you are limited in height because of the length of the front spring.

How do you have the spring perch installed? The rounded portion should be on top as that helps center the spring. The flat portion of the perch should be down.

Coilover springs are not terribly expensive FWIW, certainly less than the cost of a whole new set of springs. You could buy yourself some 7" long , 2.5" inner diameter 400 or 375lbs/in springs for not a lot of money. Hell, call up GC and order them direct. I think a pair is like $140.

 

[SNKPWR]

I might do that. That is how I have the perch.

I just worry about not having enough travel with a shorter spring.

 

[Whiskey11]

I might do that. That is how I have the perch.

I just worry about not having enough travel with a shorter spring.

The shorter spring isn't going to change any travel amount but amount of droop before the spring becomes unseated from the perches. What will change the amount of travel is the amount of lowering you end up doing with said spring. If your "drop" with an 8" spring is .5" from stock, and you keep that drop with a 7" spring it isn't going to change squat for bump travel/droop travel.

You'll have to experiment for yourself but my 550lbs/in 7" front springs don't fall out of my Ground Control Coilovers (the actual coilovers, not the sleeves) but I have shortened strut bodies. Shouldn't be an issue unless the car gets airborne somehow.

 

[jmauld]

I looked at them, the ones on the rear say 0800, but the fronts do not have a similar looking number they just say GC200.64.67

They are all the same length uncompressed though.

That translates to english like so.



7.8" long
2.5" I.D.
381 lb/in

 

[SNKPWR]

Thanks for the info guys