Hydroboost mounting plate

Mike, this is the plate that came with my hydro boost - it's yours if you want it. I'm using Eric's plate so have no use for it.

Have completed the physical work for the HB unit install.
Have searched the threads and need info and pictures concerning truck coils and whatever is required to fit them higher on the engine.

My coils are now on the shock tower, but getting at the rear spark plug is going to be impossible from above. I had to refit the rear plug wire from underneath the car.
Guess I have to move the coils.

The coils bolt right on to the existing valve cover, you need to get the coils with the brackets. Here's a pic of mine:

https://944hybrids.forumotion.com/gallery/Personal-album-of-87-944S/Truck-Coils-Painted-Valve-Cover-Huge-Wires-pic_1085.htm

You also need longer wires, I used Taylor 409s.

Many thanks,
Do the truck coils fit with the LS1 fuel rail?
Can I use the LS1 coil connector loom? If not, is the LS2 coil loom plug compatable with the LS1 harness?
I have Accel wires which are longer than the stock LS1 wires.

I'm making a few of these custom Hydroboost firewall plates with adjustability (1/4") sideways movement. All 100% CNC'd billet aluminum Firewall plate and Steel HB angle plate. Price will be $200 shipped US-48. and I will need a head count of those interested in the first run. Will post pics soon.

Xschop, can u do one with the clutch slave hole built in also? For which HB unit is this for?

This is for the Mustang Hydroboost, but any other hydroboost unit that is flat at the mating surface and screws on with a large set-nut will work also

Specs.....FW Plate 3/8" T6061-T6 alloy
HB angle plate 3/16" tempered steel

I'm in.

Last call before I order more material.

This would definitely help with installation.. assuming the firewall plate can be bolted in first, and then the rectangular angle plate w/ hydroboost afterward. Problem I had was that the valve cover had to be removed to get the plate in (w/ HB unit bolted to it), but it's still a tight fit and I definitely scraped some paint in the process. I also welded the bolts to the plate, which gave me less room to slide it in. Do you have any pics of it installed?

That is exactly the way I designed it. It has slightly oversized holes at the firewall and slotted holes at the HB steel plate to ensure the rod side-side angle is adjusted easily before final bolt-down. The 12* is achieved/adjusted by washers on the lower two carriage bolts. I will send Allen button-head bolts on the next ones for even easier installation.

Eric Kramer should be getting his billet plate today and said he'll post final install pics.

Any more info on the hydroboost mounting plate? It sounds like the angle plate is flat and the angle is adjusted by shims/washers, is that correct?

Correct, it is adjustable by adding or subtracting washers on the longer bottom two bolts, which I now have special ordered Allen button-head bolts and locknuts for easier install. The Pic above had carriage bolts. I have two complete plates left. I honestly don't know when I'll be able to build more as I'm in limbo with new home construction/moving etc. I may even sell the 948 so I can start my next build immediately in my new "shop"

Only one left. I'm not 100% sure if the BMW system bolts on and what thru-hole diameter the angle plate would have to be for it and it's lock-nut. Anyone know?

I had to cut a 2 5/8 inch center hole for mine, with a 4 hole mounting pattern that is the same as Porsche cereal bowl to vacuum booster bolt pattern.

I'm a little confused so I apologize if this is a stupid question.

Why is the firewall plate necessary when using the hydroboost system? I thought the plate prevented the firewall metal from flexing when going with a strictly manual brake set up since a driver would be applying so much extra pedal pressure.

Does the hydrobooster use a different bolt pattern at the firewall than the Porsche system making the plate necessary as an intermediate mounting surface?

Also, if a hydroboost system is installed in whatever manner, as long as it is at the right angle (12 degrees), is it still necessary to relocate the pedal connection or is this to simply enhance the brake action?

Thanks in advance.

CB

Dont claim to be an expert, but have done alot of reading to prepare my car. So i could be wrong

The mounting plate is basically an adapter for whichever hydroboost unit you choose.

Check out this page for details about the Ford Mustang hydroboost. It is on fitting the Mustang hydroboost onto a Bronco, but the general idea of fitting the hydroboost on a non standard application applies.

http://classicbroncos.com/hydroboost_cobra.shtml

You can see this Ford setup uses a bracket with 4 studs to attach the hydroboost unit to the firewall normally. Instead of drilling these 4 holes onto the 944 firewall, you remove the hydroboost unit from the original bracket, and mount it on the 'angle plate'. Then bolt the angle plate to the firewall plate.

Relocating the pedal pivot shouldnt be needed, this mod is to increase the mechanical advantage if using non-boosted brakes.

OK, so if I understand, for the Ford system, the firewall plate is acting as an intermediate mounting surface. The square mounting plate, and associated washers/shims, give the whole set up the proper 12 degree angle.

Please look back in this thread and you will see my HB set up on the bench to measure the angle.
I then made 12 degree angle blocks drilled to match the HB mount plate (bought on Ebay).
I had to drill the firewall with four matching holes. I did not use the "cereal bowl" but I have a firewall stiffening plate to strenghthen the firewall.

Thanks; to be clearer, my last comment was referenceing XChop's system which has the firewall plate and the square four-hole mount that is shimmed out to 12 degrees. At the end of the day, I think I understand this set up an how its installed.

With regards to its operations, how are you handling the brake bias? I seem to recall a photo that plumbed in a Porsche bias valve inline with the rear outlet.

Yes there are 1.5" long bolts that attach the top of the plate and 2" bolts that attach the bottom with washers in between for the 12* angle.

Rob followed my method, he uses his alloy mounting plate that is attached to the rear of the HB unit by the large nut, that then mounts to the firewall with four bolts and his steel angle block is sandwiched between the alloy plate and the firewall. I used simple alloy wedges between the HB plate and the firewall. Note there is also a large stainless steel stiffener plate on my firewall.

Don't forget to replace the snap ring on the HB body in case the large nut backs off, the snap ring will prevent the HB unit moving forward in the mount plate should that happen.
Snap ring will prevent the large nut from undoing and coming off the HB.

[img][/img]

I have Robs mounting plate but it seems to tight to get it in between the firewall and the motor there is a bolt in the way -- thoughts

What's that bolt holding in? I don't have that on my 04 GTO engine.

I am not sure what it is holding in -- I have a shop doing the work -- They called me yesterday to take a look at it. I have an LM7 engine -- (5.3 aluminum block) Motor -- When we try to place the plate back there --- its too thick.