Hi, I am new here. I did a search for my question, but could not find any postings.
I need to hear from anyone on this site if they are running either an MPbrake 8 inch dual diaphram or other company and an electric vacuum pump.
My question is, how effective are they on a big block with little or no vacuum. HOw noisy is the pump when it turns on. The pros or cons of an 8 inch dual, is it sufficient vacuum with the pump.
Please do not recommend the hydro boost, I hear its a great system, but I want to retain some of the factory "look" (even though I know 8 inch is not factory size) and I really dont want to install the hydro.
If anyone is running a smaller booster and pump, I would sure appreciate hearing from them.
Thanks
P.S. its going in a 69 468 hyrolic roller setup, tall valve covers, approx hp of 500 if that helps.

I ran one for quite a while on the yellow car in my webpage. The 8" booster because of the big block and valve cover clearance issues, and the pump to give some additional vacuum. It worked fine and the only reason I removed it is because of a clearance issue between the air inlet for the blower and the master cylinder; ended up with manual brakes.

If you rubber bush the mounting of the pump it takes a lot of the noise away. Also you run a vacuum line from the engine to one port of the pump and from the other port to the booster. This way the pump isn't the only source for vacuum, the engine helps too. This really cuts down on the amount of times the pump will kick on.

Jody

Thankl you, not sure though what you mean "Also you run a vacuum line from the engine to one port of the pump and from the other port to the booster"
I looked at the photo on MPbrake site and there is only one port that I see on the pump, which I assume would run directly to the booster.
Can you explain the above.
Many thanks.

I'm also running a 8" dual diaphram pump and an electric booster-- I didn't bother tapping the motor, but I'm sure it could help. Noise isn't too bad, I can't hear it over the motor, but its not exactly a 'quite' car. I am just getting ready to change from the old style pump to the new one, and can report better on noise in a week or two. By the way, the pump Master Power now sells looks like it is a GAST pump, which is available through industrial supplier for a little over $100. I bought that and a vacuum switch from a supply company rather than $369 from Master power. -Dan

68 six speed I owe you a round graemlins/beers.gif . I was just about to plunk down almost 400.00 thanks for the idea. I just sent off a e-mail to tech at gast mfg. Okay maybe two rounds graemlins/beers.gif graemlins/beers.gif

I am interested too in that pump, can you tell me where to buy this one that you mentioned ? I would rather not spend $400 at MP brakes

Yeah, what everyone else said. Give up the info, PLEASE.

Ok... but I want real beers, the virtual round doesn't count!

Gast mfg part #:22D1180-201-1002 It looks like the same as Master Power is using, same mounting pattern, etc. I know I get a OEM discount through work, but I paid around $140 for the pump.

http://www.gastmfg.com/pdf/mini/specsht/22d.pdf


You will need a vacuum switch, I bought one through MSC Industrial Supply www.mscdirect.com (http://www.mscdirect.com)
part #: 56499197 NASON VACUUM SWITCH for $29

MSC may also be able to supply the pump too.

I you want to wait about 2 weeks I should have it tested... Dan

Thanks for the link. Can you send beer in the mail? It might be awhile though it turns out I have bigger problems than low vacuum, look in performance under please help crate fails on first run :eek: .

Ok, it took me more than 2 weeks to get around to testing the pump, but it does work very well. Builds 22" vacuum no problem, pedal feel is good, even using 1" bore master cylinder on C4 corvette brakes. Only possible issue is the vaccum switch setting vibrating, I'm going to try some loctite on the screw, if that doesn't work I'll use another brand of switch. -Dan

68 Six Speed, it's been a while since you installed this pump, is it still working well for you? Did you change out the vacuum switch, or did the first one work? Also, I am looking at the C4 disk brakes and was wondering what 1" MC you are using, I would like to use a MC that would fit the older ('73) booster direct instead of having to turn down the S-10 MC. Thanks much.

Vacuum pump has been working well. Switch has been fine too. I found it works best in conjunction with engine vacuum, even on a radically cammed motor. (using a check valve of course) At 2000 rpm when you let off the gas, the engine has a good amount of vacuum and that helps the pedal feel on long hills, where the pump alone can't keep up.

I did have a typo above, the master cylinder I am using is a 1" bore supplied by master power-- the 70's corvette style. I do have a smaller bore C4 master cylinder to try out, but likely won't swap until this winter. The mounting pattern on it is the same, but the lines are totally different.

-dan

Hey guys just wanted to let you know that we are now carring BRAND NEW dual ported master cyls. They are made by CPP, lifetime warr. and avail for man. or power brakes...They are really cool plus no worries about rebuilt stuff!

Matt