Need a solution for low vacuum - Third Generation F-Body Message Boards

esc · 08-31-2009, 08:06 AM

First there is not a problem with the motor, it has low vacuum by design. No amount of "tuning" is going to make an appreciable difference.

Right now, idling with the AC on, I have 3" to 4" of vacuum.

I had been looking at a "Hydro Boost" power steering pump powered solution. but they have their own set of issues, not the least of which is price.

I am currently looking at electric vacuum pumps. Summit sells 3 types ranging from $230 to $330:

Right stuff detailing, lowest price, looks small, never heard of the manufacturer before.http://www.summitracing.com/parts/RS...1/?image=large

Stainless steel Brakes, medium price, read some good reviews, big and noisy.
http://www.summitracing.com/parts/SS...6/?image=large

Classic Performance, Highest price, never heard of company, Looks OK, but what can you tell by looking at a picture?http://www.summitracing.com/parts/CL...P/?image=large

Right now, I'm leaning toward the one from SSB. Brakes are their primary focus, I have read good reviews and the price is right in the middle of the bunch. The only negative I've found on these relates to the size, weight and loudness. All of which make me think it is a heavy duty piece, so I see those as a benefit.

Anyone have first hand experience with any of these three?

esc · 08-31-2009, 08:21 AM

BTW, aside from one or two mentions here, these are the only reviews I could find of the SSB vacuum pump:

http://www.autoanything.com/brakes/6...customerReview

3.1EyeCandy · 08-31-2009, 09:18 PM

ESC - if you need a vac. reservoir, let me know. Not sure if yours is equipped with one, mine currently isn't. If you go with hydraboost and like it, I may be picking your brain (if I can fix the parking brake...)

esc · 08-31-2009, 09:30 PM

Thanks, but I already have a vacuum canister.

It worked OK, sort of, until I put the AC back in. That dropped my idle vacuum from 8" to less than 4". I used to just downshift before I needed to use the brakes and I would have sufficient vacuum saved in the canister to work the brakes a little. Now, with the AC on, no reasonable amount of engine braking seems to help.

If I don't get any more input by tomorrow, I'll probably go with teh SSBC electric vacuum pump.

esc · 09-01-2009, 02:07 PM

I ordered the SSBC vacuum pump this morning. I should have it on this weekend.

I talked to the tech guy at SSBC, he wouldn't say one way or the other if he thought my planned application was a good idea. I got the idea he was worried about liability issues if something DIDN'T work. The tech guy at Summit wasn't much help either (no big surprise).

I plan on T'ing the vacuum pump in between my vacuum canister and booster. This will allow for a larger volume of vacuum. It will also allow manifold vacuum to assist, when it is available, when down shifting while braking.

It also means that if the vacuum pump fails, I won't be any worse off than I am now.

I'll post here again after I've used it for a while and know if I like it.

esc · 09-06-2009, 09:00 AM

I installed the SSBC vacuum pump yesterday.

It was pretty easy to install. Everything was in good condition and worked as advertised. I don't like that they don't give you a relay harness. Also, the way they tell you to wire it up you would need a second relay to make it work right. Their wiring method requires you to supply all power from an ignition switched source. It should, IMO, be connected directly to the battery and the ignition switched source would just operate the relay. I'll be rewiring it one day soon when I have time.

NOTE: The mounting template in the directions is NOT printed to scale. If you use it your holes will be too close together. This is a serious oversight that could cause you to drill a bunch of useless holes in your car if you are not careful. Set the pump on top of the template and you will see that the template is too small. Luckily I did this before drilling any holes.

The vacuum pump works exactly as advertised. It isn't very loud, IMO. No louder than my fuel pump. You can feel the entire car vibrate when it is running, even when the engine is idling and I have solid motor mounts. I can't hear or feel it when driving around.

The pump takes about 15 seconds to go from none to full vacuum. The first time you apply the brakes they work properly. If you allpy them again within a couple of second there is only 1/2 boost. A third time within 8 seconds and there is no boost.

The boost it provides is about the same as what I got using engine braking and a vacuum canister. I'll be plumbing the vacuum canister back in today (I just need to get a T). That way the engine will still provide vacuum when possible and if the pump fails I won't be completely boost-less. The canister will also mean that I can apply the brakes a couple of times quickly with full boost.

So far it is performing as expected and I am satisfied that it (combined with a vacuum canister) will be a good solution to my low vacuum problem.