engine and drivetrain Ground Control coilovers, strut housings and Koni inserts?

[blue7500]

Hey all, here's a question that I posed to the tech staff at Ground Control, but I thought I'd ask you fine folks as well...

I'm planning on doing a coilover conversion in the near future, and in the past have got conflicting information regarding what I want to do. While I know the common route for most people is to simply cut the stock strut tube by ~3" or so, and buy the shorter Mk1 VW Rabbit Bilstein Sports in order to gain more suspension travel, I noticed that Koni is having a sale on 2002 front strut inserts.

Now here's where I'm confused. I've been told that obviously the regular 2002 Bilstein HD and Sport strut inserts will work at certain ride heights, but once you begin to lower the car they run out of travel. I've also heard that it's possible to purchase the 2002 Koni inserts, and achieve the same result with coilovers but without having to cut the strut tubes as the Konis have better travel characteristics. Now, while I've heard this, I've also heard that this is not true, and that it is still necessary to get shorter shocks, be it Koni or Bilstein, and to cut the strut tubes to fit.

I tried searching the forum for information regarding this, but people are either running Konis and traditional spring setups, or simply haven't detailed their Koni+coilover configuration.

So my proposed setup consists of regular, uncut 2002 strut housings, 2002 Koni adjustable strut inserts, Ground Control coilover sleeves, and Ireland Engineering adjustable camber plates. Will this setup allow for appreciable lowering? Or will I run out of travel and bottom out the shock absorbers?

[cj]

I would suggest running the GC Koni insert with their caster/camber plate. Although a race-bred setup, the way GC plates carry the load is very unique and much more streetable. Their inserts are also valved to THEIR specs. They're NOT a off-the-shelf insert and will work well with their spring rate suggestions. I would send them a set of struts to modify with their large tubes and inserts. They also spec out a bumpstop rate that will work with the spring rate they suggest.

Just be true to yourself and let them know what the intent is of this car is. Occasional track, 100% track or a friends and family hauler with spirited driving. From there, they'll suggest a setup.

[TobyB]

So my proposed setup consists of regular, uncut 2002 strut housings, 2002 Koni adjustable strut inserts, Ground Control coilover sleeves, and Ireland Engineering adjustable camber plates. Will this setup allow for appreciable lowering? Or will I run out of travel and bottom out the shock absorbers?

There's a big part of your setup that's missing.

Springs.

What rate?

With an uncut strut, if you lower appreciably, you have to stiffen accordingly. The damned thing is just so long that it hits the underside of the fender.

For example, I run Sports with #325 front springs with uncut housings.

I can bottom if I'm tracking the car hard, or try ANY real curb climbing.

And I run with the front arms just a bit above parallel (engine cradle above

ball joints)

Race car, not much stiffer, with significantly shortened struts, never comes

near the limit of travel and that includes all sorts of sins, including

off- track, curbs, and bottoming (!) I'm not saying it's RIGHT, just that

the shock lets me get away with it.

If you're pretty sure you're going to lower the car, use shorter inserts and

shorten the struts. Keep in mind that the typical 8" spring has

maybe 5" of compression- you simply CAN'T use more shock travel

than you have spring travel.

Call Koni usa, ask for tech support. They DO know their shit.

You'll be surprised at what they recommend.

But cut the struts.

In my opinion.

t

[Guest]

Where did you find the Koni front struts on sale? tia.

mac.

[M3M3]

dont' try to second guess years of experience and mix and match various parts unless you are a suspension engineer or will be doing extensive testing. just call gc back (or ie) and order the full kit that they have put together and install it. you will not be sorry.

marshall

75 02 with full gc suspension on all four corners

[peteinjp]

The other part of the equation to consider is tires. If your going to run sticky tires you'll see more compression in a corner. I had major understeer issues because my front shocks were bottoming out. I had 300# springs and billy sports with yoko advan a048's and this was on the streets. The car was similar to Toby's in terms of ride height- slight downward angle on the control arms as the came to the ball joints. Shortened the housings and my radiator support is much happier.....

Toby- are your track car struts stock diameter? I'd love to hear what Koni recommended for you as I will be running a similar rate 350# on shortened housings with rabbit bilsteins re-valved per bilsteins recommendation.

Marshal- might you have pics of where the 50mm tubing is welded on to the CG struts? I like ther idea of going to a larger diameter strut but shipping back and forth to Japan is too expensive. I'm considering buying the inserts from GC and modifying the struts here in Japan.Also do the rear koni shocks allow enough travel with lowered cars using stock pickup points or will they need to be modified? Typically it seems that most rear set-ups for track usage need modified pick locations to get enough travel.

Pete

[M3M3]

that help?

the rears....the regular koni for 02's is too long for lowered cars. i have koni race shocks...one of these. forget exactly which one it is.

http://www.koniracing.com/oval30.cfm

[M3M3]

found old thread where i posted the koni part number...

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/p,663746/#663746

[jgerock]

Here is a picture I took of Marshall's car under construction ;-)

[Tommy]

Will this setup allow for appreciable lowering? Or will I run out of travel and bottom out the shock absorbers?

My opinion is that it allows normal lowering for street use well. 2 inch is not a problem. If you go to track and cut corners it might bottom up but for normal driving and even some track time it's fine. If your target is really low or plan to spend more time on track I would recommend shortened struts.

I don't see much difference between shocks. It's the strut tube itself that's limiting the travel. Of course some difference come's if you can use a bit shorter bump stops with Koni vs internal stops with Bilstein.

Edit: So basically I'm saying same thing as Toby and Pete.

Tommy

[TobyB]

Pete- before you cut...

think MR2 1st gen rears!

(there, a cat- free bag)

t

[Colin]

How low can one go in the rear before the stock billie bottoms out? Does trimming down the bumpstop help back there?

[peteinjp]

Question sent- racerY....

Pete

[Mike87]

Pete- before you cut...

think MR2 1st gen rears!

(there, a cat- free bag)

t

I have those in the front of my 02. They are the Koni Sports. Awesome for a street ride. You will have to modify the upper mount as the shock is too big to fit the stock bearing.

Then you can put early Mustang rear shocks in the rear with a slight modification.

[RacingAli]

I would suggest running the GC Koni insert with their caster/camber plate. Although a race-bred setup, the way GC plates carry the load is very unique and much more streetable. Their inserts are also valved to THEIR specs. They're NOT a off-the-shelf insert and will work well with their spring rate suggestions. I would send them a set of struts to modify with their large tubes and inserts. They also spec out a bumpstop rate that will work with the spring rate they suggest.

Just be true to yourself and let them know what the intent is of this car is. Occasional track, 100% track or a friends and family hauler with spirited driving. From there, they'll suggest a setup.

coming from the engineer that desinged the GC setup, me, go with the GC setup as stated above. The IE plate does not compare in quality, life, or comfort to the GC plate.

The larger GC setup is going to be the best bet. We spent months tuning the damping and geometry to get the ideal setup for street, track, or both.

The geometry is a Huge part of it. You run out of travel and you ride on the bump stops if you don't trim the struts.

This is one of those areas that will carry your car a long way, like a 5 speed conversion, do it right the first time and you will never have to think about it again, just drive it!