vacuum brake setup

[john h]

I installed a vacuum brake master and having probs with not enough vacuum
does anybody have input on this

 

[Red Regal T]

First is you engine stock? A high performance cam will lower your vacuum. If you don't, do you hear any leaks around your booster, or inside the car by your brake pedal when the car is running? Booster is suspect when you don't have adequate vacuum brake assist.

 

[john h]

vac brakes

I have 7 in. of vac at the booster i was told i needed 15 (3/8 hose teed off @
pcv

 

[bmackinnon]

I have 7 in. of vac at the booster

Someting wong.... very wong..... you should have alot more vac than that.... more like 17-18" minimum.... you must have a MAJOR vac leak somewhere... bet your car idles like crap too??

 

[Red Regal T]

I have 7 in. of vac at the booster i was told i needed 15 (3/8 hose teed off @
pcv

That's where most guys pick up their vacuum from. Any leaks audible around the booster?

 

[john h]

no all seems well ex crappy brakes

 

[john h]

inside the car when i step on the pedal... but 7 isnt enough to make brakes work

 

[john h]

many engine mods all atr

 

[Red Regal T]

I guess you'll have to go with hydra-boost. Plenty of help here with those setups.

 

[john h]

tell me more or e- mail

 

[Red Regal T]

Just search hydro-boost in this section of the forum. There must be hundreds of threads about this system. Because of your mods, vacuum is out for you. Hydro-boost is the logical alternative.

 

[TurboBob]

T-ing in at the PCV can be an issue. The PCV can steal some of the vacuum you need for the brakes.

What cam are you running, and what idle speed?

try connecting the brakes directly to the vacuum source without the PCV.

How are you measuring the vacuum?

Bob

 

[john h]

Idol prob could be raised atr mild cam ported heads and intake measuring with a good vac gauge.

 

[TurboBob]

any of the mild-ish cams that any of us run should have 'reasonable' vacuum. Do you have any specs on the cam?

7" is probably not right, -7 psi maybe (which would be 14")

I would keep troubleshooting. I really think the PCV is stealing your vacuum.

Bob

 

[Nick Micale]

T-ing in at the PCV can be an issue. The PCV can steal some of the vacuum you need for the brakes......Bob

After doing 100's of vac conversions using a T at the PCV, never had a problem. There is the same amount of vacuum at the PVC port as all the other ports on the throttle body vac manifold

With only 7" of vac, there would be no power assist, and the car would run like crap, if at all?

Use another port or line to verify engine vac.

It is possible if you used just a regular 3/8" rubber line, it could have collapsed internally?

 

[TurboBob]

my statements are all folklore (I have not done a vacuum conversion myself).

But we are in agreement. 7" of vacuum doesn't sound right.

Good call on the vacuum hose collapsing.

I'm anxious to hear the outcome, as I will probably do a vacuum conversion when my PowerMeister finally quits.

Bob

 

[john h]

ty bob i will isolate vacuum and take a Real good look at the gauge

 

[Nick Micale]

my statements are all folklore (I have not done a vacuum conversion myself).........Bob

Don't you just love internet folklore?

 

[Red Regal T]

T-ing in at the PCV can be an issue. The PCV can steal some of the vacuum you need for the brakes.

What cam are you running, and what idle speed?

try connecting the brakes directly to the vacuum source without the PCV.

How are you measuring the vacuum?

Bob

Just to nip this myth in the bud once again, because apparently, it still lives, I actually prefer using the "T" fitting above the PCV rather than using a TTA vacuum block because it's less visually obtrusive. There is no downside to acquiring vacuum from that location (PCV). :smile:

After doing 100's of vac conversions using a T at the PCV, never had a problem. There is the same amount of vacuum at the PVC port as all the other ports on the throttle body vac manifold

YUP!

 

[cruzn57]

sumthin is wrong...

with only 7 in vac,
vac leak, or timing way off, or???

I run a 214 roller and get over 13in vac,
so look for the leak,