LS1Porch

I am using a 7/8 master due to the v8 swap, and i recently ran into the infamous firewall cracking issue (no doubt helped along by the larger master).

I've searched on here and seen the various ways people have fixed this over the years, and there are some pretty clever solutions.

Before i proceed with any of those, i was curious whether anyone has completely done away with the stock Porsche pedal and used an aftermarket floor-mount system. Like this:



I measured with the carpet it place last night and it seems like it could be close (dimensions here: http://www.wilwood.com/Images/PEDALS...469_dwg-lg.jpg).

There are some more ideal (compact) systems from companies like Tilton, but unfortunately they're all 3-pedal setups and i really only need the one.

At this point i think i have a good weld-in solution for the firewall, but i thought i'd check on this route first. Any ideas are welcome!

(Edit: i should also mention i'm 6'4", and my reasoning for being interested in this is that the stock pedal position...well, it kinda sucks. I hate the long throw on it, and i hate having to wedge my knee up under the steering wheel to use it. So if something like this would work, it would kill two birds with one stone for me!)

V2Rocket

I am 6'6 and, if I remove the driver seat entirely and sit up against the rear seat, I can still operate the pedals and drive the car. You might be able to mount this on the floor and just move the seat back another inch or so.

That said, floor-mounted pedals just feel sort of weird when you first drive with them...

That said I am considering the same type of thing for my eventual V8 swap, if the remote BMW-style booster doesn't work out.

MAGK944

Nicer weight balance too, you might be onto something lol. Will have to see if there is anything about this in pca rules.

Wtb: 6-point harness for rear seat

On the brake thing, I would just strengthen the firewall as I think it is stronger than the floor to start with. If you mount to the floor you might have to strengthen the floor anyway.

rlets

Porch, you mention that you're 6'4". I'm 5'8" and have barely made this work. The pedal box moved me 4" rearward which puts me 3 clicks from the end of the seat rails and 2" forward of the roll cage. My buddy who is 5'10" cannot get comfortable in my car.

Since you're only talking about the clutch, you'd probably have to modify the 45 degree angled portion of the footwell and move the pedal further forward to match the stock brake pedal. Doing a aftermarket hanging pedal setup might make more sense.

Rich

LS1Porch

Thanks guys. I don't think i can afford to lose that much pedal room, i'm already on the farthest back notch of the stock seats.

I did some more pondering and i think i have a good way of solving this problem using the stock pedal. I'll post up some results when i get it done!

968ls1

Here is the bracket I made to reinforce the firewall and mount the master cylinder. I am running a 7/8 master as well

LS1Porch

It looks like you just left your clutch master alone? Did the bracket add enough stiffness by itself?

bad_monkey

I'm 6'4" and was looking at this too. If you don't mind moving your weight further back, you could swap the lower seat rails (part that bolts to the car) for something longer, and slide on back. I think the driving position would look kinda goofy in a road car and your side mirror view would suffer.

You can gain back a lot of space by running remote reservoirs and mounting the master cylinders at 90 degrees. Was that the setup you were running Rich?

FRporscheman

And to think that my mom drives her 968 with the seat at the forward-most position... Not many sports cars offer this much versatility!

968ls1: I'm just curious why you didn't make the bracket support the clutch master cylinder as well. Were you worried that moving it forward wouldn't allow it to function? Most of the firewall cracks I've seen were from the clutch master.

rlets

Charlie, mine is the Tilton 72-603 pedal box. The masters mount horizontally and the limiting factor ended up being the adapters at the output contacting the 45 degree portion of the firewall. A setup like you describe would certainly make for less rearward movement of the driving position. But for me this all worked great. I built a new dead pedal, added a 3" quick release on the steering wheel and adjusted the shifter to the forward most position of the base. We'll see when I get this thing back out on track, hopefully next month.

Rich

968ls1

I cut the bracket out around the clutch master and used the factory studs. The bracket surrounds the MC and bolts through stiffening the brake and clutch firewall area. My car was a Tip that I converted so the firewall had no prior flex damage. Use the XS Chop plate it will solve your issue.

LS1Porch

Well, here's what i've got so far.

Problem:


Solution:


From the side:


If someone has enough stuff out of their car to measure, i'd love to know what the angle of the stock master cylinder is (compared to the firewall). I came up with about 5-6*.

Right now i'm at a "proof of concept" stage, no permanent changes have been made. I'm a little split on where to go from here. I had planned to weld this piece on, but I'm going to have to run bolts through the firewall, so i don't think that's necessary...but it wouldn't hurt either. I could make a similar piece of aluminum, then make a similar piece on the back end to sandwich the firewall (although, there are intricacies to the firewall that would make that a real pain). If i weld this piece on i will probably also weld another piece in to stabilize it along the strut tower.

I like the idea of having the bolts vertical instead of horizontal, i think that is the flaw in the stock system. It's also how the Wilwood system is designed to be installed--and it's really hard to get the air bubbles out of the master otherwise.

I had originally planned to install a longer master cylinder and picked up this Wilwood:
http://wilwood.com/Images/MasterCyli...60-3376-lg.jpg

The mounting holes in the master would have made it really easy to stabilize...but, no dice. It's simply too large, even after massaging the strut tower a little.

I'm all ears if anyone has thoughts.

hacker-pschorr

Send a PM to Lizard931, he converted an automatic 928 to a manual using a Wilwood floor mounted clutch pedal:

https://rennlist.com/forums/members/...lizard931.html

LS1Porch

Thanks, i did that. I'll see what he says.

Lizard928

Was gone for the weekend.

The wilwood only has a 3/4" bore for the clutch master w/ built in reservoir.
I'm not sure about the 944 floor pan, but on the 928 there is just enough room to do a very nice and clean install.

I bolted to the floor with large fender washers, and used a bulkhead fitting to pass through the floor.
I then TIG welded a fitting to the slave making it easy to adapt.