Ultimate E30 track setup???

and shirtless?

Unfortunately, I do have a shirt on.

[aaron.j]

and shirtless?

[aaron.j]

he's alive!

Are there that many people buying true rear coil-overs who do not also have cages that pick up the rear shock towers?

Yes, infact, there are many E30s in Europe that run the streetable Leda setups (unfortunately Leda is not in the Us) , which use almost a factory type mount. Not much extra support there! If you look around also, there are many E30 race cars running a full coilover in the rear, and the cage bracing does not do much to actually support the extra load of the spring.

A long spring does not have to be ran. I could use a 4 inch spring if needed -- talk about light! There are not too many benefits to a true rear coilover, that said. The Bilstein shock I am using is user revalveable and easly expandible to infinate compression/rebuild adjustability, if I wanted to get serious. Not too difficult. Even though, I believe my spring/shock setup is lighter than a stock shock and stock spring setup. Maybe I will weight my setup some day.

Also like the fact that having the spring actually work straight up and down a true coilover allows for more precise spring action along with cornerweighting. Having the spring on the trailing arm, and being "bent" leads to non-precise action. Articulating weight jacks are used to cure this, however, with most, these are not able to allow a car to be cornerweighted due to stack height and lack of adjustability.

Another advantage is being able to run a standard type spring, as we know the solution for an E30 is to run a "barrel" type spring, as we all know how the short springs on an E30 can coilbind.

Hmm..another advantage is travel. Rear travel, while not necessarly very important, is limited on a E30 with springs on the trailing arm. At idle, I have 6 inches of travel, UP! Lets see a trailing arm spring'd car do that. :)

I guess the next thing you guys say is that it would be over kill to put airjacks on a street car. :)

[SchnellerVert]

Longer spring but I'm leaning toward it weighs less. Also the E21 had this style rear suspension and did fine. I tried a VW rear Koni 1001R adjustable perch once in the rear but on a non modified car so I didn't play long decided the ride and motion was not controlled properly so I went back to stock.

This was on an Eta sport.

[IS]

I agree with Jeff - can you name a single advantage other than just "doing something different."

The disadvantages I see are more unsprung weight and having to use a longer (therefore heavier) rear spring.

[JeffRR]

Are there that many people buying true rear coil-overs who do not also have cages that pick up the rear shock towers?

The rear shock tower was not designed to react the spring load, but it was designed to react the full jounce bumper load (if you can call that hockey-puck a jounce bumper).

So the ultimate strength might be there but the fatigue life may be limited (you might notice cracking after a period of time) since the amount of time that the jounce bumper would be contacted will be a bit quite less than the spring loading which never goes to 0.

Now the other issue is that if the shock tower is less stiff than the org spring mounting area you might induce a delay (basically adding another spring in the sheet metal flex).

Good points, but engineers tend to completely over analyze these types of situations. When similar rear coilover setups have been working great for street and racers alike, why change these setups?

And yes, it does help to reinforce that area to spread load differences of a shock/spring vs shock only.

[JeffRR]

The rear shock tower was not designed to react the spring load, but it was designed to react the full jounce bumper load (if you can call that hockey-puck a jounce bumper).

So the ultimate strength might be there but the fatigue life may be limited (you might notice cracking after a period of time) since the amount of time that the jounce bumper would be contacted will be a bit quite less than the spring loading which never goes to 0.

Now the other issue is that if the shock tower is less stiff than the org spring mounting area you might induce a delay (basically adding another spring in the sheet metal flex).

If $$ is really no object and you really want to move the spring mounting location and do not want to install a cage, you should invest in discussing this with an engineer that can at least run a FEA on this.

What will you get out of going to a full coil-over that you won't get out of a GC style kit and a set of adjustable koni's? If you need it Koni can even revalve them for you.

A mono-tube shock set-up (moton's, JRZ, Penske, Koni mono's) is going to start in the $600 range/corner for konis and go up from there. And that's just for the rears.

[moatilliatta]

what part of indiana?

Nice !

Bilsteins ? What setup is that ? What shock mount are you using ?

I am also curious about any handling improvements - perceived and/or laptimes ?

thanks,
Bala

The setup is a design I have been working on for a while. The Bilstein is a custom built to order race shock that is expandible. The upper shock mount is a CNC designed mount. I will be selling this setup very soon.

Handling is nice, as you can build this setup as per your driving style.

[bala_eos]

http://www.barnyarde30.net/E30/hennarearcoilhide.jpg

Don't mind the rusty brake drum. Will be changed soon.

The fact that the rear shock towers are not strong enough is an old wives tale.

Nice !

Bilsteins ? What setup is that ? What shock mount are you using ?

I am also curious about any handling improvements - perceived and/or laptimes ?

thanks,
Bala

rear coilovers do not require a cage...






Don't mind the rusty brake drum. Will be changed soon.

The fact that the rear shock towers are not strong enough is an old wives tale.

[Jean]

Would like to hear more about this as well.

[Andreas]

Hi there, you may want to look at my post of a project that I am busy with to get some ideas. It's also a track car for open track days that instead of following rules breaks them - basically if I read somewhere that something is illegal, I try to find out what advantages it gives and then decide whether to use it or not, e.g. big rear diffusors are illegal in many race formulas because of the huge gains in downforce, so obviously I am getting one.

http://e30carclub.forumup.co.za/viewtopic.php?t=49&postdays=0&postorder=asc&start=15&mforum=e30carclub

In Holland, a guy is also putting some serious effort into his E30 and on page 1 of this thread you see a picture showing how rear ride height adjustment can be achieved on an E30

http://www.e30zone.co.uk/modules.php?name=Forums&file=viewtopic&t=34036

Words of advice : plan your car before starting. Start with mags and tyres, then suspension and brakes, then aerodynamics (how much downforce you want - careful that you don't unbalance the car by making too much downforce at one end only, best is to make it adjustable). Lastly, plan your engine to cope with the rest of the mods.