Guys who launch on 10 psi boost-how tight are your brakes?

[gnbooster87]

thats the wrong advise to give you need disc to drum. disc to disc is 2 psi in the front and 2 psi pressure to the rear as for disc to drum its 2 psi in front and 10 psi in rear. i got mine from fat rodders on e bay and vacuum brakes and s-10 rear cylinders and i hold 10 psi in my yard . no bull

thanks for the correction you actually advised me last year about this but i guess i got it mixed

 

[QUIP'6']

thanks for the correction you actually advised me last year about this but i guess i got it mixed

that happens from time to time

 

[Syclone0044]

It's been my experience that the stall of the torque converter has everything to do with how much boost your brakes can hold. A tight converter wants to turn the tires over when boost comes up, whereas a loose converter ain't going anywhere until you let off the brake.

Anyone else notice this same trend? It makes sense once you know a bit about converters.

 

[Chris Wh1]

This may sound stupid, but what do you mean by a loose or tight converter?

 

[GNRick]

It's been my experience that the stall of the torque converter has everything to do with how much boost your brakes can hold. A tight converter wants to turn the tires over when boost comes up, whereas a loose converter ain't going anywhere until you let off the brake.

Anyone else notice this same trend? It makes sense once you know a bit about converters.

I think that is correct. That is why my 3200-3400 converter allows the brakes to hold the car until about 3200 rpm with no boost. Then the car wants to push. I'll see what tightening up the brakes against the drums will accomplish.

This may sound stupid, but what do you mean by a loose or tight converter?

Higher stall (3200 rpm compared to say 2800 rpm) is refered to as being "loser" than a lower stall converter. That's all I know. Maybe someone here will give a more technical explanation of how the converter loads the engine and causes the transmission to engage. My 3200 stall converter doesn't seem to affect daily driving, except it seems to add to "turbo lag" since the turbo doesn't kick in until 3200 rpm.

 

[TurboDave]

With the S-10 drums and larger brake pads. I got mine tight enough to just be able to get the drums on.

Running the powermaster and a line lock I can hold 15psi on the footbrake .

Same setup I run, I've never suffered from the early rear lockup though.

 

[Chris Wh1]

Oh, ok, got it. I know how a converter works, I have just never heard a "higher stall" refered to as "tighter". thanks for the explination.

 

[Jerryl]

...... My 3200 stall converter doesn't seem to affect daily driving, except it seems to add to "turbo lag" since the turbo doesn't kick in until 3200 rpm.

Not trying to get of subject, but are you sure this statement is correct?
A higher (looser) stall typically helps the short times.
The boost climbs faster, which is referred to as "less turbo lag".

 

[Just a Six??]

Not trying to get of subject, but are you sure this statement is correct?
A higher (looser) stall typically helps the short times.
The boost climbs faster, which is referred to as "less turbo lag".

I agree! With a 3800 I can fry the tires Instantly with a 67 Q-Trim which is pretty slow on the bottom end but with a 3000 it takes forever to build boost to do that.

Back on topic. Line lock is a must! Heat Kills period. Bigger shoes maybe? But soft cheap shoes Definately!! Not super tight, just slide em on & off with it being as tight as you can but still go on & off easy. I can hold 15 easily on my 3800 & 10 easily on a 3000 so stall makes a difference. I have a 3000-3400 & 3800 & they change it up on the line with same big turbo. So there are a few things involved but Cheap Brake Shoes & Linelock are a Must to hold PSI on the line.

 

[GNRick]

Not trying to get of subject, but are you sure this statement is correct?
A higher (looser) stall typically helps the short times.
The boost climbs faster, which is referred to as "less turbo lag".

I was referring to city driving.

 

[Syclone0044]

Oh, ok, got it. I know how a converter works, I have just never heard a "higher stall" refered to as "tighter". thanks for the explination.

Just so we're on the same page, a tight converter is a low RPM stall speed. Loose = high RPM stall speed.

Think of tight as the converter is "restricting" the revs of the engine. Loose means it's liberal with the RPM - lets the engine rev more freely, etc.

Of course the tradeoff is always on the top end, a loose converter gets a bit "sloppy" at high RPM whereas a tight converter always has maximum efficiency at high RPM. A stock converter would typically have the absolute highest efficiency on top end but the worst launch.