vt951

Thought I'd post this up in case any of you high HP 951 guys with heavy clutches need one. I designed this for my v8 swap as a preventative measure (don't have any cracks yet, but I've heard it's just a matter of time).

If you haven't heard of the firewall cracking problem, here's my understanding... some cars (mostly ones with heavier clutches fitted) have developed cracks in the firewall around the clutch master cylinder due to the extra force exerted. I've seen a whole lot of crazy looking solutions to this that look only marginally effective. I wanted something cleaner looking and more of a bolt-on than weld-in.

Anyone who's interested in trying one, let me know. I am waiting on the fabricator's quotes right now. Figured I'd start with just a couple first to test fit them in a couple cars I'm working on. They will be laser cut from 13 gauge steel, press broken, welded seams, and then powder coated. I'm guessing they will cost about $150 each in quantity? **UPDATE** Price is $99 + shipping **

The basic idea is that it goes between the firewall and the MC, and the other end wedges up against the very sturdy strut tower. Optionally, a couple holes could be drilled to bolt it to the strut tower or through the wheel well. **UPDATE: After test fitting the prototypes, I do not believe that any drilling into the strut tower or wheel well will be necessary. The bracket feels very secure in its position against the strut tower. I plan to install it with just a layer of silicone between the bracket and the strut tower to prevent any marring of the surface from vibration during driving.**

Techno Duck

Alan, count me in for one. Firewall reinforcement is on my list of things to do.

Which clutch are you running on your LS swap? I have the Spec Stage 2, hope its not too heavy!

vt951

Cool, thanks! Will keep you posted.

Same here, Spec stage 2. It's a lot heavier than the stock 951 clutch, but I still think it's the best choice. Make sure you're using a bigger MC (like a Tilton 7/8") or it may not release completely.

V2Rocket

could you make the full firewall reinforcement plate?

Techno Duck

A Honda Civic clutch is heavier than the stock 951 clutch!

Im using Wilwood part # 260-6088 which is .7" bore with a 1.4" stroke. We figured the smaller bore should make the pedal feel lighter. My friend and i bench tested it with my clutch on his LS3 and it seemed to have plenty of travel to release the clutch fully. Did not get a chance to test it before i left, still had to get the NPT to AN fitting for the quick disconnect hose.

vt951

I could, but I am not convinced that it does much good. I know a lot of people use them (including me until recently). They are already made by others and sold by various v8 guys. Probably a good idea if you're running manual brakes, but with hydroboost, the brake MC shouldn't really be seeing any more force than the stock vacuum assisted brakes.

I think the firewall cracking problem has more to do with the heavier clutches and fast clutch actuation that we all do during races and DE's. And I think a bracket like this one does a better job at supporting the clutch MC than a flat plate on the firewall.

You gonna buy those headlight brackets I sent you?

theedge

I will probably be in for one too. How does it mount to the strut tower? You said wedge but is that sufficient strength and "grip" wise?

Only suggestion is that (and it might already have one, cant tell from the angle of the shot) it needs at least one drain hole or itll be a bucket for brake fluid.

theedge

Theres several of those available but the issue with them from my reading is they dont seem to keep the clutch master at the same angle as stock, so it wears out faster. I could be completely wrong but thats what I have read.

I was going to look at making a reinforcement plate that goes on the inside of the firewall somehow since my dash is currently out and ill likely take some of the wiring out and the steering column out for other work.

V2Rocket

holy cow, i had completely forgotten about those. i will have to look for them and send them back

Lemming

You are correct, I killed two master cylinders very quickly, finally got the angle right on the 3rd and no problems since.

reno808

Would this if you have a LS swap?

vt951

I'm going to test fit it without any fastening to the strut tower. There are a few options there... one is to coat the surface that pushes against the strut tower with something that has some grip to it, like a rubber bed liner coating. Another option, which I think will definitely work but requires more work, is to drill a couple holes through the bracket and into either the strut tower or the fender well, and through bolt it.

As for catching brake/clutch fluid, there is a drain hole in the design. Good catch, though.

vt951

Yes, forgot to mention that about the angle. My bracket retains the stock MC angle for this reason exactly.

When I used one of those big flat firewall reinforcement plates, the clutch pedal effort was not consistent, like it was binding or something. I figured it was probably due to the angle, but won't know for sure until I install this new one that keeps the proper angle.

vt951

Hey Reno... not sure if this is what you're asking, but yes this bracket works with an LS swap just as well as 4 cyl 944/951. It really depends on what MC you're using though. I know it fits with a Tilton 75 series (which I use) and the stock 944/951 MC. Not sure about Wilwood, etc. If someone can send me a part number for a typical Wilwood MC that LS swap guys use, I'll look into that.

Lemming

This is what I'm running for my clutch master.

http://www.wilwood.com/MasterCylinde...emno=260-10373