Ultimate E30 track setup???

[macnewma]

A little background:

I come from the Porsche world and I am hardly a BMW or E30 expert. I am looking into building a monster E30 for track days. I am currently in the planning phases.

Question:

I understand that true rear coilovers are difficult to do. I am looking for something in the Koni 28, Moton, or JRZ level of dampers. Has anyone adapted a true rear coilover? Is it even possible?

Finally, if anyone has any pics of a true rear coilover, that would be much appreciated.

Thanks,
Max

[e9nine]

--What year e30 and model? Where are you located region-wise.
--Intended club to race with? (check out Spec E30)
--Current resources available?
--Driving experience?

There's a lot of options available and you have rules to follow if you're going to be racing in the future for example.

Full coilovers require cages in order to have the most durable application in the e30 due to the shock tower design ESPECIALLY if you will use high spring rates. There's numerous e30s with full coilovers out there but not much public facts unless you can reach the respective owners. Another option is to visit www.s14.net and search for pics and discussion.

A call to the following can help you out from the approach of those who actually build the race cars or have sold a lot to racers over the past years. TC Kline - Bimmerworld - Turner Motorsports - Ireland Engineering - VSR -

Welcome and good luck.

[macnewma]

This will be a late E30, non-M3 located in Indiana.
Just a track day car, no actual racing.
Re$ource$ not a problem.

I will check out s14.net. Thanks for the pointers.

[jht3]

give Barry or James a call at RRT (www.roadracetech.com). they are very knowledgeable when it comes to e30's and the track

[Axxe]

G/C Semi Coilovers with their special valved Konis would make for a good setup for track with lots of adjustability without being too expensive. They're tried, tested and true 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/view...rum=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...wtopic&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.

[Jean]

Would like to hear more about this as well.

[trent]

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.

[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

[trent]

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.

[moatilliatta]

what part of indiana?

[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.

[trent]

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]

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

[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.