So wtf is with the mysterious inserts for shortened struts?

[2002maniac]

So, besides just ordering from gc, does anyone know what struts to get for a shortened setup? I've seen some people mention corrado inserts but i found another thread claiming than they didn't fit. Anyone have first hand info? Tia.

[Aptyp]

anyone?

[HST]

What is the reason behind doing this?

[jtb_29]

So once and for all the G60 Corrado inserts are the shorter inserts to get?

[gearheadE30]

No, the GC inserts are the ones to get. They are valved for much stiffer springs than the corrado ones are.

[jtb_29]

No, the GC inserts are the ones to get. They are valved for much stiffer springs than the corrado ones are.

I realize the valving would be different but I am referring to fitment only. The GC inserts are revalved corrado shocks, no?

[Hellabad]

From the horses mouth

I realize the valving would be different but I am referring to fitment only. The GC inserts are revalved corrado shocks, no?

Not exactly. I will explain, and because I am the guy who tried all the various ideas on a dyno, and designed the damping and negotiated with Koni to build them, then I am a really good guy to get the explanation from!

OK. the 1198 digits on the strut insert. They are there because it is easier by a mile to start with one thing and then have it modified by Koni. If I say "1198", then I do not have to say "43 mm body, 1.5mm wall thickness, 480mm length, crimped in four places, stepped flange etc. etc." So we just say "1198" and that gets the ball rolling.

Virtually everything else on a Ground Control 8641-1198 SPGC is different.

Obviously the extended and compressed lengths are different, as well as several other dimensions, but the biggest thing (which takes the most research and testing) is the damping.

Damping is not just "stiffer" or "softer". It is a little bit difficult to explain, but when you remember that damping is usually described as "a curve", then you can imagine that damping levels are much more complicated than a straight line.

A small change in one certain spot on "the curve" can drastically change the characteristics of how the car handles, rides, and performs. This is even more critical on a combination street / track type car where compromise are made.

Sooo. The standard Koni 8641-1198 sport was good starting point for a "shell" simply because it is so generic. There are many other choices in the Koni catalog, I just chose this one because I had several of them and we could take them apart and change the valving inside. It could have just as well been a 1085, or a 1021 or many others, but its only the changes to the valving that are important.

After deciding what I wanted, we ran them on the dyno, tested them in cars, and then commisioned Koni to "PREvalve" them to my specs.

So the bottom line is that if you want Konis that have been tested and designed for an e30 by one guy, and you trust that guy, then the SPGC valving is better. If you don't trust the guy, thats fine, but I would hope then, that you would choose a different strut based on another mans opinion of what works in an e30. I would not want you to choose a strut just because some website says they "discovered" something that fits in the hole.

I hope this explains the 1198SPGC, I see a lot of posts about this, and I have no idea how much (if any) money is saved when someone buys the regular 1198.

If somebody posts the best price they can buy them for (not a website link because so many are the wrong price) I can make a comparison for you of cost/benefit.

Jay Morris
218

[jtb_29]

Not exactly. I will explain, and because I am the guy who tried all the various ideas on a dyno, and designed the damping and negotiated with Koni to build them, then I am a really good guy to get the explanation from!

OK. the 1198 digits on the strut insert. They are there because it is easier by a mile to start with one thing and then have it modified by Koni. If I say "1198", then I do not have to say "43 mm body, 1.5mm wall thickness, 480mm length, crimped in four places, stepped flange etc. etc." So we just say "1198" and that gets the ball rolling.

Virtually everything else on a Ground Control 8641-1198 SPGC is different.

Obviously the extended and compressed lengths are different, as well as several other dimensions, but the biggest thing (which takes the most research and testing) is the damping.

Damping is not just "stiffer" or "softer". It is a little bit difficult to explain, but when you remember that damping is usually described as "a curve", then you can imagine that damping levels are much more complicated than a straight line.

A small change in one certain spot on "the curve" can drastically change the characteristics of how the car handles, rides, and performs. This is even more critical on a combination street / track type car where compromise are made.

Sooo. The standard Koni 8641-1198 sport was good starting point for a "shell" simply because it is so generic. There are many other choices in the Koni catalog, I just chose this one because I had several of them and we could take them apart and change the valving inside. It could have just as well been a 1085, or a 1021 or many others, but its only the changes to the valving that are important.

After deciding what I wanted, we ran them on the dyno, tested them in cars, and then commisioned Koni to "PREvalve" them to my specs.

So the bottom line is that if you want Konis that have been tested and designed for an e30 by one guy, and you trust that guy, then the SPGC valving is better. If you don't trust the guy, thats fine, but I would hope then, that you would choose a different strut based on another mans opinion of what works in an e30. I would not want you to choose a strut just because some website says they "discovered" something that fits in the hole.

I hope this explains the 1198SPGC, I see a lot of posts about this, and I have no idea how much (if any) money is saved when someone buys the regular 1198.

If somebody posts the best price they can buy them for (not a website link because so many are the wrong price) I can make a comparison for you of cost/benefit.

Jay Morris
218

Thank you for explaining that. I'm sure this will help many others as it helps me to understand exactly what insert we're buying from you guys. Thanks!