Hydroboost or Vaccum

[Pony Killer]

I have a 84 GN with no motor or trans. I was looking at redoing the brakes and i wanted to know what would be better, hydoboost or vaccum. Ive been reading threads and it seems to be an even opinion for both systems. Hydoboost systems break a lot and vacuum doesnt work that great with boosted vehicles. I was leaning more towards Vacuum but i was wondering if any one knew how to set them up. I was thinking of trying to use a vacuum pump lik diesels do. Any help on what system i should use i would really appreciate the help.

Jasen

 

[Red Regal T]

vacuum doesnt work that great with boosted vehicles.

Jasen

Just an observation, but I think it's funny when people who don't know anything about vacuum brakes keep making these statements. The only problem mentioned is that SOME people who install vacuum brakes, have trouble holding boost at the line while many others claim they can hold all the boost they need at the track. I don't know about them, but I drive my cars thousands of miles on the street and about 5 miles at the track. Ask me what I think is important.

 

[Robbie-87plz]

On my '85 Hydraboost, never had a problem with it....on my '87 I've switched over to vac. thanks to Geoff for answering my stupid q's...

 

[Pony Killer]

I wanted to use an 87 Intercooled engine and driveline in this car. Since i would be starting from scratch, i wanted to build the engine up. I want to make this a serious street/strip car, so i wanted to know what works best for 20+ psi cars. I still havent heard if anyone has used a vacuum pump before.

 

[Pony Killer]

Hydroboost sounds good but i dont want to have to shell out my cash more than twice to fix it. By reading the other forums it seems to be a problem area.

 

[FBSideoiler427]

I had a 98 Lincoln Mark VIII vacuum pump on my lumpy-cammed, twin turbo 91 Mustang and it worked wonders - 20" vacuum, good pedal feel, responsive pedal, very reassuring. That car racked up approx. 14K miles a year - so it wasn't a trophy or a trailer queen.

 

[GNVYUS 1]

The only issue with vacuum is if the hose blows off, so just clamp both ends and its all good.

I personally would not shell out the extra $$ for a new hydroboost considering that a whole new 87 NA vacuum kit will run you $225. Then get the NA pedal from either Bweavy or RedRegal and move on to the next braking mode to get that fat beast to stop.

The pump is only need if you have a big cam, which most GN's do not have that problem.

 

[Robbie-87plz]

Would a vac canister be a good idea for the normal street driven vac equipped TR?

 

[Geoff87]

Would a vac canister be a good idea for the normal street driven vac equipped TR?

I don't run one. But then again, I haven't tried it either. I have a new canister that I bought in '96 (and never installed) when I converted to vacuum.

 

[japSW20]

i just pulled all the vacuum parts i need to switch,Where should i plug the vacum line for the brakes?

 

[DCVING 6]

i just pulled all the vacuum parts i need to switch,Where should i plug the vacum line for the brakes?

Check this link out:
https://www.casperselectronics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=102090&Category_Code=

 

[japSW20]

Check this link out:
https://www.casperselectronics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=102090&Category_Code=

is that the only place i could tap it into? can i just run to any capped off port?

 

[John Larkin]

Once you install the vacuum brakes, leave the top off the reservior and depress the brake pedal. If fluid shoots up instead of just bubbling on the surface, go buy a NEW master cylinder. There is an internal valve that is not-servicable even on a reman. Once you have a good m/c, you can hold almost all the boost you can stand, provided you have your brakes adjusted properly and ALL related components are working properly. Just because the parts are all there does not mean they work properly. These cars are getting old. I fought this for a year myself. My parts list = new m/c, new S10 wheel cylinders, long shoes & reman calipers. All is well now.

 

[49-blues]

John- what new MC did you use ? any part numbers or what model car did it come from ?

 

[Red Regal T]

Correct master cylinder would be for a NA powered G-body, 83 thru 87, such as GP, Cutlass, or Regal, V6 or V8. Try to get one with an aluminum body. They may hand you one with cast iron body. I'm sure they work fine, just don't look as nice. If you want aluminum, you may have to shop.

 

[bruce]

I have a 84 GN with no motor or trans. I was looking at redoing the brakes and i wanted to know what would be better, hydoboost or vaccum. Ive been reading threads and it seems to be an even opinion for both systems. Hydoboost systems break a lot and vacuum doesnt work that great with boosted vehicles. I was leaning more towards Vacuum but i was wondering if any one knew how to set them up. I was thinking of trying to use a vacuum pump lik diesels do. Any help on what system i should use i would really appreciate the help.

Here is a snippet of a data log from my car, that has a vacuum brake set-up on it. While I do have slew of changes with the brakes, it's a vacuum booster, stock pedal, GM Master Cylinder, and all while the rotors calipers are late Camaro pieces, they still all just stock GM parts.

Run time is just that, this is after 22 minutes of running.
MPH is just your normal MPH reading, RPM well rpm, K/PA is a metric unit, but in easy to translate number 200 K/Pa is about 15 PSI of boost. TPS is % of TPS opening. CTsF is Coolant temp in dF, and MAT is plenum air temps.. While I use a code change to help with launching, I still have 0 MPH at about 13 PSI. For *justa* street car, IMO, this ain't bad.


EngRun Mph Rpm KPa Tps CtsF MatF
00:22:54 0 2675 151 100 192 107
00:22:54 0 2675 151 100 192 107
00:22:54 0 2800 157 100 192 107
00:22:54 0 2900 160 100 192 107
00:22:54 0 2700 162 100 192 107
00:22:54 0 2625 164 100 192 107
EngRun Mph Rpm KPa Tps CtsF MatF
00:22:55 0 2650 170 100 192 107
00:22:55 0 2775 171 100 192 107
00:22:55 0 2925 175 100 192 107
00:22:55 0 2800 179 100 192 107
00:22:55 0 2625 179 100 192 107
00:22:55 1 2700 185 100 192 107
00:22:55 1 2900 188 100 192 107
00:22:55 2 3025 196 100 192 106
00:22:55 3 2675 192 100 192 106
00:22:55 3 2525 194 100 192 106
00:22:55 3 2650 195 100 192 106

Yes, I did spend time getting this all to work, but it answers the basic question about the vacuum setup working. And no vacuum pump or other vacuum enchancing devises are used.

 

[John Larkin]

Just like John said. Mine ended up being a cast iron one from NAPA. It was about $75-80. But it's brand new and it works great. I went through 3 remans before figuring this out.