What type of brake systems are you guys using for your turbo LS swap?

[chub406]

Hey Guys,
Like the title says. What type of brakes are you guys running? I'm starting my GN turbo LS swap. I have the stock vacuum brakes. I have the manual brake plate and a chrysler reservoir as well. Its got stock discs up front and ford 11" big drums on the back. New lines need to be run front to rear, so I want to do it all right the first time. What are you using and anything you would do different? Where do you get the vacuum from after the swap?

 

[Black Power]

those manifolds have a really good vac port on the very back by the firewall, that's what I'm going to hook up to. I'm running the swapped vac brake setup myself, I'm going to keep the rest of the brake system like it was. Not planning on having to slow down from 150 mph quickly in it, so I think it should be fine.

 

[chub406]

dumb question. lol Are you saying on the exhaust manifold? If the motor dies, you have a reserve with vacuum brakes don't you? I hope to be trapping around 135-140. Mainly street driven. All I cared about when I was younger was going fast. Now as I'm older, now I want to know I can stop it. lol I figure the drums will work fine. Not worth swapping to discs. The turbo cars are the ones with PM's right? You went from that to vacuum?

 

[chub406]

I was reading on here vacuum brakes aren't good in boost cause you are pulling vacuum. What have you guys found? I want to be able to hold it on the line in boost.

 

[d0n_3d]

I was reading on here vacuum brakes aren't good in boost cause you are pulling vacuum. What have you guys found? I want to be able to hold it on the line in boost.

I would do a good manual brake setup and be done with it. With big rotors up front and discs in the rear, it will stop just fine and you don't need to ever worry about vacuum or something failing. Manual brakes are pretty fail safe. They take some getting used to on the street, but they are not that big of a deal. I run them on my car and love it. Cleaner under the hood too.

 

[Turbo6inKY]

I was reading on here vacuum brakes aren't good in boost cause you are pulling vacuum. What have you guys found? I want to be able to hold it on the line in boost.

If the check valve on the booster leaks, you can pressurize the booster and lose power assist.

 

[Black Power]

I was reading on here vacuum brakes aren't good in boost cause you are pulling vacuum. What have you guys found? I want to be able to hold it on the line in boost.

This is how I staged with the v6 and vacuum brakes. Pull up into the beams, try to light the 2nd beam before the other guy, and shift into neutral as you are creeping into the 2nd light. Rev the engine up some to get some good vac, stab the pedal, put it in drive, and start spooling it up. It works ok, it does try to push through the brakes when building boost, but it will even try to push through before it goes from vac to boost. Just because it's making some pretty decent torque and the brakes aren't exactly huge on these things.

 

[Black Power]

If the check valve on the booster leaks, you can pressurize the booster and lose power assist.

This^^^

 

[chub406]

What about when you are coming out of boost then? Do you lose the assist while it builds back up vacuum? When people are racing on the highway and refer to break boosting the car. Is that just getting on the brakes while in it to pull out vacuum to spool faster? I just read some of your build black power. Mind if I pm you with a few questions? Thanks guys!

 

[Black Power]

dumb question. lol Are you saying on the exhaust manifold? If the motor dies, you have a reserve with vacuum brakes don't you? I hope to be trapping around 135-140. Mainly street driven. All I cared about when I was younger was going fast. Now as I'm older, now I want to know I can stop it. lol I figure the drums will work fine. Not worth swapping to discs. The turbo cars are the ones with PM's right? You went from that to vacuum?

Sorry I missed this earlier. No, there's a big vacuum port (either a 3/8 or 7/16) on the back of the intake manifold, I think it's a 7/16. I am going to run that to my vac booster, and it has a check valve in the middle. The good thing is the vacuum will be helping you at the end of the track, because you'll be way out of boost and have plenty of vac down there. If it's 140 or more, you probably need better hardware on the brakes themselves, like ls1 rotors up front or discs out back, but I'm sure you could manage with the drums and stock stuff. If you go over 150 you have to have a chute anyway, lol. And yes, mine's an 87 gn. It had a power master until I almost died when it failed and I was driving in the snow, so I went vacuum. They work awesome.

 

[Black Power]

What about when you are coming out of boost then? Do you lose the assist while it builds back up vacuum? When people are racing on the highway and refer to break boosting the car. Is that just getting on the brakes while in it to pull out vacuum to spool faster? I just read some of your build black power. Mind if I pm you with a few questions? Thanks guys!

If you have an in car mechanical boost gauge, watch what happens when you take your foot off the gas under boost. It goes from xx psi to 15-20 inches of vac pretty much immediately. My brakes work great all the time, just get your foot off the gas and bam, you have plenty of vac. Brake boosting is when you go from a roll (say 30mph) and you are stalling up your engine and spooling your turbo by using the braking friction to load the exhaust system with heat and air. You would get rolling about 30 or so, one foot on the brake, one on the gas, and apply pressure to both until you are ready to smash gas and take your foot off the brake. It helps some with turbo lag, nitrous works a lot better though. Getting on the brakes during brake boosting isn't about trying to pull out vacuum from the engine and build boost, it's about putting the engine under a load to the turbo will hit quickly. You can brake boost with a power master, hydroboost, manual brakes, or vacuum brakes.

Any build questions you have, lay them on me, I'd be happy to help where I can. PM or you can keep it in this thread or another thread, whatever you want to do

 

[chub406]

LOL! I felt dumb for a min there. Im like.. how the hell are you pulling vacuum from an exhaust manifold?? That makes way more sense. This will be my first turbo car. I almost had a TR given to me years ago. Its was an 82 with Dark blue top half and gray on the bottom. With the gn wheels. I swear it said buick on the rear but could be wrong. All original. A friend got it out from underneath me. I built an 80 cutlass with a 406 sbc afr,scat, solid roller. all that. Same friend stole it and sold it for meth but I can't prove it. So I'm on my own for this build. lol Thank you for explaining that to me. I will def pm you with a few other questions about the swap.

 

[chub406]

What about in town? If you had to panic stop right out of boost. Is it just fine? Mine is an 85 n/a car. Im assuming its vacuum already?

 

[Black Power]

What about in town? If you had to panic stop right out of boost. Is it just fine? Mine is an 85 n/a car. Im assuming its vacuum already?

I'm not sure what type of brakes those had. I think it will be either a hydroboost or a vacuum, I'm guessing vacuum. I hated the power master, it was a piece of trash. I will never put it back on the car.

But yes if you were driving in town cruising, brakes work great because you are in vacuum when cruising. If you are stomping it and it's in boost, a dog runs out in front of you, they will still work because when you lift your foot off the gas pedal, you are in vacuum so you will have vac assist.

 

[chub406]

oh ok. Thank you for that. Know of anyway for me to look at the booster to tell what I have? Oh and when you were staging. If you just held the break and brought up boost. Would it still hold the car?

 

[Black Power]

take a pic of your booster and post it up.

Staging and boosting it is hard to keep it from pushing through the brakes, mainly because the rear drums have a hard time holding that much back so it rolls the rear tires. The boost wasn't causing the vac brakes to fail (mine has a check valve between the intake and the booster), its just hard to hold back a GN with its torque.

 

[Chuck Leeper]

Hydraboost off of an 85...If it works as well as the 1 on my 55, I'm GTG!

 

[meaclez]

i used vac brakes on my ls turbo setup with cross drilled rotors and good pads up front and alum drums in the back...i had no problem slowing down at the track in time or on the street.