e21 booster on e46 sheel

[Massive Lee]

Currently building an e46 racecar. The cage extends to the engine bay and strengthen the shock towers. Two bars in diagonal from the underdash crossbar to each shock tower. The bars will clear the stock e46 brake booster but it will not be possible to remove it. Ever. Unless we cut the bars, which is not an acceptable solution. So, I then test fitted an e21 brake booster, which is 1" shorter, and much, much smaller in diameter. It can be removed easily and I only had to drill two extra mounting holes on the firewall and in the aluminum pedal bracket.

The masters that I have tested (23 and 25mm from e28 and e32) are... too long and won't clear the front bars. The original e46 MC will clear, but had mounting holes at 45º. I designed an adapter (e46 MC on e21 booster) but would prefer to use a direct bolt-on MC.



It should be short like the e46 MC - 120mm
It should have horizontal mounting holes - 60mm center-to-center
It should be 23mm

Does Ate or Girling make such a beast?

[Mike B.]

How about a dual master setup? ;-)

Let me check my Ate catalog and see what I can come up with.

[Massive Lee]

Dual masters? We don't have gorilla legs yet. But it's a scenario we are looking at for the long term.

BTW I have seen some nice Porsche 944 MCs, but couldn't verify the length. Worst case scenario if I cant find a bolt-on, I'll have a couple of adapters machined.

Ee were four busy guys working on the racecar this weekend. Welding, making gussets, test fitting parts, removing calking. And it seems that we did not advance that much. Argh. Spring is coming too soon.

Lee

[gobuffs]

My non-boosted setup doesn't really require that much more effort.

[BimmerTom]

Have you looked at early 911 MC's? I think they are in the 23mm range (914's are 17-21mm) and are very compact. However, I am not sure on the mounting flange. Going way back to my 914 days, I think they are a horizontal mounting hole arrangement.

Thanks,
Tom

[Massive Lee]

Thanks Tom for your suggestion.

I will look at this option right away.

Lee

[AWDE30]

325iX booster too big?

Tom-are you a BMWCCA member?

[Massive Lee]

The iX booster is longer than the e21 booster.

Lee

[BimmerTom]

Tom-are you a BMWCCA member?

No, not yet. I do participate in the BMWCCA/Porsche Club events (as a guest) down at the Tire Rack in South Bend, IN. We get over 8 runs per day, sometimes they are even 2 day events.

Last time I went, I let my friend co-drive... Imagine 32 auto-x runs on your car in two days. It was awesome!

Tom

[BimmerTom]

Massive,

Most 911/914 boosters have remote reservoirs for the brake fluid. That may be a huge help for you.

911's have great brakes unboosted, I would seriously consider that over running your booster. Weight and space savings.

However, I'm not sure how they are balanced (ass dragger over your front engine setup), but you could solve that with a bias valve.

Thanks,
Tom