Survey, Are you using a vacuum pump?

pooreds · #1 (**permalink**) 07-15-2008, 10:27 AM

Are you running a vacuum pump? I would especially like to know if you do or don't, and you have Roush 427R in a SPF. I've got 11-12 inches of vacuum at sea level. My car is one of 60 units that rolled out of SPF with the PBR rear brake, which I'm not fond of. Barry Bloch of SPF claims the old style four piston Wilwood rear still needed a vacuum pump to operate, I have seen and heard otherwise. SPF keeps pointing fingers at me. What is your opinion?
And I have read all of wannab5150's post's. thanks ED

CSCHWER · #2 (**permalink**) 07-15-2008, 11:17 AM

Ed,
I have the PBRs and can not find a front pad that works well with them. I have a set of
Wilwood pads backordered for the PBR caliper. We'll see if that works. I think the only
thing that will satisfy me is Wilwoods all around with a independent ebrake caliper. It's
just finding someone with the brackets for both calipers. It looks like they both could be
mounted OK.
Chet

pooreds · #3 (**permalink**) 07-15-2008, 11:03 PM

Well, I want SPF to spend their money to figure this out. When I ordered the car, it was advertised as having Wilwood 4 piston on all four corners. So, I thought the 427r would be fine. Then they told me I needed at least 10 inches of vacuum operate. I got that. Then they told me I needed different front pads. It helped. Now I need a vacuum pump? whoa... they also told me I was the "only" car with PBR'S that had a problem. holy cow when does it stop. SOOO I did some hydraulic math, I sell hydraulics for a living!
With 800 psi pedal pressure, this is what you get with the piston sizes!

41mm float style single piston= 1632 lbs force (PBR)
41mm dual piston = 3264 lbs force
Four Piston Wilwood, smallest size avail, Dynalite 1.375" piston = 4768 lbs force. Pretty big difference, almost three times the force.

Now you know why I'm *****in as much a wannab5150.
Thanks for your post! now there are two of us, I hope more will join. ED

FWB · #4 (**permalink**) 07-16-2008, 10:45 AM

first off yes i do use a vacuum pump......to elaborate on your car.
a power booster will not operate properly on 11-12 in of vacuum i dont
car what calipers or pads you use. your brake will feel hard as hell and if
you weigh less than 650lbs you wont be able to stop very well.
get a vacuum pump!!!!!!
you will find your face will hit the steering wheel with all the stopping power
you will have. there are plenty of brake tech sites out there to support
what im posting, i have 10 in of vacuum without pump, brakes sucked.
i installed this pump....
http://www.metricmind.com/pump.htm
the top one pictured,
costs more than the belt driven ones, but designed for an electric vehicle
that generates no vacuum, so it can be run in line without a vacuum canister
i love it.

Hammer65 · #5 (**permalink**) 07-16-2008, 11:08 PM

I have SPF #2743 with the Willwood combination E-Brake on the rear with 34mm pistons. I'm running the Roush 427SR and Superformance recommended a vacuum pump which the dealer installed. It's an Electric Vacuum Pump Kit 28146 manufactured by Stainless Steel Brakes Corporation (SSBC). The new calipers with 41mm pistons provided by Superformance will be installed within a few weeks.

I haven't tried any aggressive braking as of yet but under normal driving everything seems fine. The fronts do lock up before the rears.

RICK LAKE · #6 (**permalink**) 07-17-2008, 04:43 AM

pooreds If you are looking for an assistance pump, they have small ones that mounted to the GM diesel motors in the 80-early90's. They have gone to electric ones that work on the demand only when needed. If your car has a P/S system, the better thing if you have the room, is to add a hydro boost system to the car. Your caliper force is a question, the clamping force does increase, but not double. When you get to 3 and cup calipers they have different size cups to even out the pressure on the pads. I also think you can over brake the car with 14" rotors and 6-8 cup calipers. Most cars have an ABS system, If you have one no problem if not, you may have to learn about controlling lockup. Rick L

pooreds · #7 (**permalink**) 07-18-2008, 09:51 AM

thanks for all of your input, I guess I better decide if I want an electric pump or a v-belt driven one. Do the electric pumps make any noticeable noise?
The v-belt driven unit a friend has, is perfectly quiet and no switches to fail. Not the best looking thing hanging off the motor. ED

emberglo66 · #8 (**permalink**) 07-18-2008, 10:50 AM

I have read the electric pumps make noticeable noise. I heard one on a SPF Coupe that was at my installers shop, kind of loud. Mike @ Vintageupgrades was standing there and said they only use belt driven unless the customer request electric.

FWB · #9 (**permalink**) 07-18-2008, 11:56 AM

i cant speak for other electric pumps, but the metric mind pump has rubber feet i have mine in the trunk, with the deck lid open i hear the fuel pump not the vacuum pump, its been in the trunk for 3 years, the first year a fuse blew,
since then no sound no issues. go to their web site and read, it lists what
DB's the pump puts out, its made in switzerland, need i say more?