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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 26 May 2010 :  10:11:48 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Low vacuum because of larger cam is insufficient to fully power my brake booster on my 79 TA (4 wheel disc brakes). Has anybody had the same problem and if so has anyone overcome the low vac by using a Comp Cams vac canister. I'm not experienced with this and it's important to know whether the saved vacuum will replenish itself for repeated stops. I don't want a system that will store vacuum for only one or two stops and then have the brakes feel like manual ones.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.

Phil
The Great White Buffalo

USA
6273 Posts

Posted - 26 May 2010 :  1:53:48 PM  Show Profile  Reply with Quote
I've had this problem since the early 80's. Back then it started when I put a Crower "Monarch 280" cam in my old 350. The two noticable things that went bye bye was the power brakes and the low end torque. I've just gotten so used to it over the years that each engine hasn't presented a significant difference from the original low vacuum condition.

The vacuum canister will reduce the amount of vacuum loss occurring with each brake application, essentially fooling the brake pedal by creating a larger volume of vacuum. The saved vacuum will replenish itself between pedal applications. To me it is more like a treatment than a cure, that more often than not produces satisfying results.

"Chevy": even the name sounds cheap.
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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 26 May 2010 :  2:24:33 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
"To me it is more like a treatment than a cure, that more often than not produces satisfying results." That sounds kind of "Philosophical."

If the vacuum charge replenishes quickly there won't be a problem using one. If it only stores higher vacuum and is slow to replenish, it really is of little use. Christ mentioned in another thread that he was one and is not using it. He hasn't replied yet as to why he discontinued using it.

A reserve canister like the one from Comp Cams is 5" in diameter and 7" long. I would imagine it would be best located close to the brake booster. Well, there's not a lot of room under the hood so I make up a 5" x 7" cardboard tube and see where it might fit.

The TA's MC and booster were rebuilt just before my retirement in '03. So, I think the booster and MC are probably in good shape. After all the original parts lasted 23 years which included one 3-year period of non-use.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.

Edited by - Bill Boyle on 26 May 2010 2:25:38 PM
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Kiwi Mal
Cochise

New Zealand
679 Posts

Posted - 27 May 2010 :  02:13:35 AM  Show Profile  Reply with Quote
I had the same problem. I never tried the vacuum canister. From what I read they are a bandaid. I tried the pump, but as I said in another post, they are noisy and viabrate. Baer told me about the Hydraboost. He told me my brake problems are now going to be a thing of the past. He was right. He also said that it is because of the lack of vacuum from performance cams, was the reason he was in buisness. http://www.hydratechbraking.com/
Some people pull them of diesels in the wrecking yards and fit them. It would require some research.

Edited by - Kiwi Mal on 27 May 2010 02:39:32 AM
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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 27 May 2010 :  07:43:28 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
An electric powered vac source should be reliable and do the job. The problem I presently see with it is properly locating it under the hood of the TA. The space required is 6.5" H x 7" W x 10" deep. The way it functions is that it provides the sole source of vacuum to the brakes instead of the engine. So once again we have, location, location, location. A place that it might fit is the current location of my remote oil filter. This unit resides above the valve covers in a horizontal position mounted to the firewall. My new Headman headers allow enough room to use the stock oil filter on the oil filter housing. My Hooker Super Comps did not provide enough room between the tubes to install or remove a filter (the reason for the remote).

As for a vacuum canister, the 5" wide x 7" long cylinder will fit in the space between the fan shroud and the charcoal canister on the passenger side of the car. There's a void there for it. However, this is several feet away from the brake booster; it should be closer. This location would be more fitting for a "cool can." I believe a canister could be mounted were the remote is as well. I need to do more checking.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Phil
The Great White Buffalo

USA
6273 Posts

Posted - 27 May 2010 :  09:50:22 AM  Show Profile  Reply with Quote
Hey Bill, it's probably more "Yogi Berra" than "Philosophical"!

Another thought: If the extra length of hose were to be cleverly between the check valve and the booster tank you would be adding capacity.

"Chevy": even the name sounds cheap.
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Taman
Red Bird

USA
834 Posts

Posted - 29 May 2010 :  3:37:48 PM  Show Profile  Reply with Quote
I run the SSB electric vacuum pump and a cannister. It is VERY noisy. I have both mounted behind the pass. side headlight where a battery would be on a camaro. I run a line from the pump to the brake booster. I have the pump isolated and have a towel wrapping around the pump to help keep it quiet. Works great. I have 22" of vacuum 10 seconds after I turn the key on.I have a spare pump for sale. I am converting my TA to 4 wheel manual brakes. If you have the proper master cylinder manual disc are very livable. The hydroboost is ok for street use but can have problems keeping up on an autocross course.

Everything Under The Sun Is Intune
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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 29 May 2010 :  8:40:19 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Very noisy? That is relative. Please clarify. As noisy as an electric fuel pump? A vacuum cleaner?

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Taman
Red Bird

USA
834 Posts

Posted - 29 May 2010 :  9:47:57 PM  Show Profile  Reply with Quote
Makes an electric fuel pump sound as quiet as a mouse. I have Flowmaster 3" and I can hear the vacuum pump over the exhaust. I do have awesome brakes so, it's worth the noise. I use a vacuum canister to store some vacuum. This way the pump cycles less frequent. If I was doing the electric pump again, I would find one off of a Cadillac. Some Caddy's have pumps.


Everything Under The Sun Is Intune
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Mark S.
Cochise

USA
430 Posts

Posted - 30 May 2010 :  02:32:14 AM  Show Profile  Reply with Quote
Bill, Have you considered running/retro fitting a GM hydroboost set-up? Runs vacuum off the PS pump. You've got PS in your T/A, yes?

I went with 4 wheel manual disc's on my '66 GTO for this very reason. Car stops WAY better than the 4 wheel drums (which weren't all that bad for DD use but at the strip... Hoo boy!) without a whole lot more effort.

I gotta say though the 228/236 duration shouldn't cause that much of a reduction in vacuum. Double check to be sure your booster isn't leaking down, the MC is not leaking internally, the booster check valve is functioning properly and you're plumbed directly to manifold vacuum (I'm sure you are, just throwing things out to check).

I've run a 230/230 cam and a 232/242 cam and my power brakes in my '70 GTO functioned pretty well even after repeated stops w/no canister, FWIW...

PSP Member since 1996

Never enough cubes...

"The difference between genius and stupidity is that genius has its limits." - Albert Einstein


Edited by - Mark S. on 30 May 2010 02:48:40 AM
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Kiwi Mal
Cochise

New Zealand
679 Posts

Posted - 30 May 2010 :  04:16:02 AM  Show Profile  Reply with Quote
Taman said
quote:
The hydroboost is ok for street use but can have problems keeping up on an autocross course.


How's that ?. They work on hydraulic pressure from your power steering pump. The assist is always there unless the engine stops, then they have a reserve canister for safety. They are not to assist the vacuum booster.
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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 30 May 2010 :  07:41:18 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Mark, Taman--I'm weighing all options. Space is limited under the hood as you all know, so fitting a canister or pump is a concerning. A hydroboost set up could work. Mark are you using a hydroboost system?

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.

Edited by - Bill Boyle on 30 May 2010 07:45:28 AM
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Christ
Howling Wind

USA
1804 Posts

Posted - 30 May 2010 :  11:58:58 AM  Show Profile  Visit Christ's Homepage  Reply with Quote
quote:
Originally posted by Bill Boyle

Mark, Taman--I'm weighing all options. Space is limited under the hood as you all know, so fitting a canister or pump is a concerning. A hydroboost set up could work. Mark are you using a hydroboost system?




Bill, Ill donate your the vacumm canaster. I have no use for it anymore.Plus you can tuck it up under the fender wall and attach it to your brace. So it won't show!
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Mark S.
Cochise

USA
430 Posts

Posted - 30 May 2010 :  4:07:00 PM  Show Profile  Reply with Quote
quote:
Originally posted by Bill Boyle

Mark are you using a hydroboost system?



Bill,

I went with 4 wheel manual disc's on my '66 GTO. The MC I chose does have a larger piston so I feel it gives me more to work with. Pedal effort is not as bad as I thought. Actually feels much like the old drum setup which was quite easy to apply and modulate.

I am working towards a new top-end setup (Aluminum heads, EFI and roller cam) and may well change the brakes over to power. When I do, I'll more than likely go the hydroboost route.

PSP Member since 1996

Never enough cubes...

"The difference between genius and stupidity is that genius has its limits." - Albert Einstein

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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 30 May 2010 :  5:17:32 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Christ--that would be great. I'll give it a try and see if it helps. I will email you with the address.

Bill

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Taman
Red Bird

USA
834 Posts

Posted - 30 May 2010 :  9:40:30 PM  Show Profile  Reply with Quote
Mal I have been told by guys at the auto cross events the power steering pump couldn't keep up with the breaking and steering.

Everything Under The Sun Is Intune
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rockstar
Tribal Scout

1 Posts

Posted - 29 Jun 2010 :  2:53:46 PM  Show Profile  Reply with Quote
Hello, I have just installed a Comp vacuum canister on my 73 LeMans (455 auto, 6X heads, comp 274XE cam). It doesn't seem to have made a difference--no better, but no worse. I installed the fittings w/teflon tape and put a clamp on the hose where it comes out of the can (to the brake booster). Hoses look good. Sprayed starting fluid around the fittings while running to try to detect leaks, but the idle doesn't change so it doesn't seem to be sucking in the fluid. But I can hear hissing when it runs, and for a few seconds after it shuts off. Shouldn't it hold vacuum (for a while at least) after I shut it off? I have an inquiry into comp's email tech help, but figured I might get a quicker answer here. Thanks a lot for your help!
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dgray
Cochise

845 Posts

Posted - 29 Jun 2010 :  3:15:23 PM  Show Profile  Reply with Quote
Thats about what happened when I tried one out too. I ended up getting the booster rebuilt and everything has been good.
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Christ
Howling Wind

USA
1804 Posts

Posted - 29 Jun 2010 :  10:43:27 PM  Show Profile  Visit Christ's Homepage  Reply with Quote
quote:
Originally posted by dgray

Thats about what happened when I tried one out too. I ended up getting the booster rebuilt and everything has been good.





To things to check one is the check vavle to make sure it is closing properly. The other is to make sure you have the lines hooked up correctly
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clintww
Cochise

USA
565 Posts

Posted - 29 Jun 2010 :  11:12:32 PM  Show Profile  Reply with Quote
I have one on my GTO. I have 15 inch vacuum at idle. Works ok for me. I still have vacuum a day after running the car. You will have enough storage to fulley depress pedal twice if engine dies

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Taman
Red Bird

USA
834 Posts

Posted - 10 Jul 2010 :  3:55:31 PM  Show Profile  Reply with Quote
Bill, I converted my TA to 4 wheel manual disc brakes. Not having power brakes is not as bad as one would think. It doesn't require much more leg pressure, when matched with the correct master cylinder, then a power setup. I like the feel and locking the brakes up is know problem. Plus I lost a bunch more weight and more room. If you want I have my vacuum pump and canister for sale. Only 4 months of use.

Everything Under The Sun Is Intune
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clintww
Cochise

USA
565 Posts

Posted - 06 Aug 2010 :  11:30:55 PM  Show Profile  Reply with Quote
Hey Bill Did you try the vacuum can yet? Did it help?

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welchcp
Buffalo

USA
80 Posts

Posted - 10 Sep 2010 :  01:07:13 AM  Show Profile  Reply with Quote
quote:
Originally posted by clintww

I have one on my GTO. I have 15 inch vacuum at idle. Works ok for me. I still have vacuum a day after running the car. You will have enough storage to fulley depress pedal twice if engine dies


I have one of this on my firebird as well. I twold have to agree with most of what is said on here. I only make about 13" of vacuum and i ussually get about 2-3 full presses before i have a stiff pedal. Im really contemplating on getting a pump as well however you need a canister to store the vacuum anyway so i wanted to try this and see if i could just use the canister and not get the pump. It did make a big difference for me but when im in town i do get the occasional stiff pedal. If your on the open road it works great. If your going to traffic my want to get the pump as well. Or do like me and get the can and see i that made enough difference for you.
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cortcomp
Coyote

USA
4232 Posts

Posted - 10 Sep 2010 :  10:28:17 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I have a 67 with 4 wheel drum brakes, manual, and that thing can WAY out stop my 71 with power front disc. Pedal isn't too stiff either. Matching the right mater cylinder/proportioning valve to the right application is a MUST when talking brake systems. They're not all the same just because they look the same on the outside.

I'm getting 15-17 vacuum on the 71 and i'm sure the brakes need bled and the new booster whistles. It may do a lot better once i get those issues sorted. But if i ever build another Pontiac and go with a bigger cam and less vacuum, i'm just going to switch things over to manual brakes. They're not bad at all when done correctly.
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Bill Boyle
Horse Feathers (Charter Member)

USA
3992 Posts

Posted - 10 Sep 2010 :  10:56:32 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Clint--have not done anything with the brakes at all. But will finally have new rotors and discs put on the front of the TA. It still all original. Once that is done...more to think about.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Heddman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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Lee
Buffalo

70 Posts

Posted - 16 Sep 2010 :  9:23:31 PM  Show Profile  Reply with Quote
Bill, did you put a larger cam in your car?? No way that old 270 is NOT making enough vacuum. Is the pedal really hard, with no travel? No chance of a frozen or mis-adjust rear caliper (I have NEVER liked that design!)?

Lee

67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP http://www.highperformancepontiac.com/shootout/0502pon_lone_star_pavement_shootout_2/drag_racing.html
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR http://www.popularhotrodding.com/features/1002phr_1969_ford_falcon/index.html
72 Cutlass Convertible, first car, owned since '82
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Taman
Red Bird

USA
834 Posts

Posted - 26 Sep 2010 :  10:09:05 AM  Show Profile  Reply with Quote
If you don't make enough vacuum, the canister can't create more vacuum. It's just a storage device. They can only hold what's created by the engine. Run an electric vacuum pump. 21" even if you stall. That's what I ran for years.

Everything Under The Sun Is Intune
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