A different approach to the v8 swap brake booster...

[Exodus_2pt0]

I like this idea, but my only concern would be the two added single circuit M/C's and that if either of them fail you lose all braking. Prob would not be legal for any racing organization.

This is exactly why reservoirs are seperated front/back nowadays. That way if you spring a leak, you don't lose both front and rear systems.

Leaving all of your braking capabilities in the hand of one hydraulic circuit without any "plan b", would be a little scary at 100mph.

Aside from that, I love the idea. If there is a way to incorporate a fail safe, I would consider this for my own future plans.

[LJ851]

Any ideas on good cylinder sizes? :)

M/C size shouldn't matter. As long as the master and slave are the same size you will have no ratio.

I like this idea, but my only concern would be the two added single circuit M/C's and that if either of them fail you lose all braking. Prob would not be legal for any racing organization.

[JGood]

I have to disagree with this.

Fitting the E34 linkage (shortening and cutting a bit) is not too hard a job. Only challenge is doing the offset (as the brake linkage will be about 10cm to the left of the car from the brake pedal). The offset can be done either on the pedal (considering the space for clutch pedal as well) or as a separate linkage on the firewall.

Right, but modifications will need to be made to the pedal box in order to mount a brake master cylinder to it (safely), that are likely just as challenging as the modifications for offsetting the brake linkage pick-up point as with the e34 setup. That was my point. The front booster bracket and the pedal box are really all that need modified for the e34 booster setup, and you'd have to do that stuff anyway to get the hydraulic system fitted, if you want to keep that location. So you'd be removing the only "bolt-on" part of the e34 assembly, and replacing it with a hydraulic system that's going to require some $$$/research/fabbing.

To be honest, moving the clutch cylinder over and welding a tab on the other side of the pedal box is really pretty easy.

However, as you said, the trunk mounted setup would be nice, and a very good reason to go with a system like this. I'll be watching this thread to see how it turns out.

[Jonsku]

If your planning on keeping the e34 booster and bracket in that location in the front of the bay, I think you're creating more work and failure modes by doing a hydraulic linkage vs mechanical. The linkage itself basically bolts right in. It's fitting the booster bracket that's a PITA. Then it's just the pedal box mods, which you'd have to do anyway to run an internal M/C.

I have to disagree with this.

Fitting the E34 linkage (shortening and cutting a bit) is not too hard a job. Only challenge is doing the offset (as the brake linkage will be about 10cm to the left of the car from the brake pedal). The offset can be done either on the pedal (considering the space for clutch pedal as well) or as a separate linkage on the firewall.

I've done both and I'd say they are equally hard as both solutions have their own pros and cons.


Brake servo won't take too much space from the trunk so locating it there would be quite good idea actually. Helps with the weight distribution as well :)



Any ideas on good cylinder sizes? :)

[JGood]

There's a thread discussing the e34 linkage setup in an e30 in this subforum, I just finished mine up.

If your planning on keeping the e34 booster and bracket in that location in the front of the bay, I think you're creating more work and failure modes by doing a hydraulic linkage vs mechanical. The linkage itself basically bolts right in. It's fitting the booster bracket that's a PITA. Then it's just the pedal box mods, which you'd have to do anyway to run an internal M/C.

[mr walker]

LOL. Guys, I've got to be honest...I was being sarcastic about mounting it in the trunk. But you raise a valid point that folks may be looking for additional engine bay room.

I was under the impression that the linkage setup was a PITA...is the whole problem with the V8 braking setup an issue of space for the booster? Or do the linkage and booster kind of "negatively compliment" each other (i.e. in order for the booster to stay inline with the linkage, the booster must remain towards the middle of the engine)?

[JGood]

Ahh, I overlooked the mention of a trunk mounted booster in the OP. That would be nice if you don't require the trunk space. I think a guy on this forum who swapped in a Toyota V8 did that. I agree, it would be nice to free up the engine bay space.

[Jonsku]

Using "three brake cylinders" is a good idea that has been around for a while. As Garey said, the best option would be to mount the "first cylinder" somewhere under / over the glovebox with RHD-linkage (just played with one couple of weeks back, it's very simple and solid construction).
True pedal box is something totally different, so it should not be mixed with this.

I'd say this approach tidies up the engine room quite a bit as you could mount the booster itself to trunk for example, which gives you lots of more space to the engine bay (e.g. for S62 intake pipes, turbo or SC applications).

Maybe it's not the best solution for typical "bolt-on M60 applications" but for more exotic solutions it might well be viable thing to consider.

[JGood]

^^I edited my OP to better describe what I'm talking about. While a hydroboost setup would be totally feasible for say, a Euro S50 swap, I understand that due to the width of the V8 you basically can't have anything where a master cylinder would normally reside. It's not just an issue of the MC and the booster being there...nothing can be there.

I'm going to make a hilariously bad mspaint picture later to better illustrate what I've got in mind.

I know you didn't mean a hydroboost setup. If you want to find a home behind the firewall for your 'booster master cylinder', you've got your work cut out for you. You'll need to create some pretty solid brackets/linkages, probably more complex then what I had to do to get the e34 linkage connected to my pedal box.

I guess I just don't understand the reasoning. The main draw back to the e34 setup is the bulkiness of the booster and it's bracket. The linkage leading up to it occupies a space that is otherwise unused... the area just above the frame rail in front of the firewall. And it all basically bolts right in. You're bypassing the easy part of the e34 booster install, and replacing it with a rather complicated hydraulic system.

If you're doing all that, why not just throw in a Tilton/Wilwood pedal setup and call it a day? It's the easiest solution, the only drawback being your M/C's are inside the car, making replacement messy... but with your idea, you're doing that anyway...

[mr walker]

Meant to edit OP, sorry.

[sticksdaman]

'scribed!

[mr walker]

^^I edited my OP to better describe what I'm talking about. While a hydroboost setup would be totally feasible for say, a Euro S50 swap, I understand that due to the width of the V8 you basically can't have anything where a master cylinder would normally reside. It's not just an issue of the MC and the booster being there...nothing can be there.

I'm going to make a hilariously bad mspaint picture later to better illustrate what I've got in mind.

[JGood]

A hydraulically driven vacuum assist system for hydraulic brakes. Sounds like something that belongs on a BMW at least! :)

IMO, the main problem in all of this is that there's no room for a firewall mounted master cylinder. Otherwise people would just a run booster-less setup with the proper pedal ratio to retain decent pedal feel.

And if you're going through the trouble of mounting the remote booster assembly, you might as well just make the changes to the pedal box and just run the whole e34 system. You'd only be skipping out on the easy part of the install, and would be creating a lot of work for yourself with a hydraulic setup to replace it.

Just my opinions, of course. If you think you can make it work, have at it! If nothing else, it will be a fun learning experience.

[mr walker]

Yep, that's exactly what I'm thinking.

I believe the biggest issue faced with this idea would be properly matching the master and slave cylinders: you would (or at least I would) want to retain a semi-factory brake pedal feel and pedal travel. Otherwise, what's the point?

Thoughts?

[sticksdaman]

I see what youre saying... Instead of the rod coming straight from the pedal, a master cyl a hose (or hard line) and then another slave cyl at the booster.

Id be interested to see how this may be setup as i am dreading the brake setup of this car.