Why Can't I build up boost in my GN?

[NEARING]

Just installed another converter, AC 3500 and still can't build more than 5 psi before she breaks the Hoosiers loose even with the e-break and standing on the breaks
I'm only seeing like 3000 with the AC
The previous Pro Torque 3600 would only build up like 2psi!
I was only getting 2800 with this converter and thought it was the converter.

I don't have any exh leaks and I don't beleive there are any problems with the fel pro, breaks work good too.
Car will trap 120 on 20 psi in 85deg heat but 60ft's are poopoo!

I think I Have thrown $1500 in converters in the toilet Should
have kept the vig 3200 in it.
I think my T-type with a TA-49 would nearly beat this pig now!

87 GN pte63,V2,83'S,210/210 billet roller,P&P heads,hemco,Felpro,jace brace,ect$$$

I think I'm seeling the wrong car
I need help!

 

[.38 special]

I'm sure that it stops good, but it seems like it has to be in the brakes. Have you upgraded to the S-10 wheel cylinders? It's a cheap and easy modification that worked for me.
What tire pressure?

 

[NEARING]

Yes it has the s-10 wheel cylinders. Tire psi? I think about 18.
Figured should have gotton atleast 10 psi

 

[wagon]

You can throw a half dozen converters at it, if your tires are breaking loose, then you aren't putting enough load on the engine, to build boost. Fix the brakes. Tighten up on the shoes. My method is to tighten up on the shoes until there is a bit of drag, on the drums. Then drive around and let them 'self clearance' as I call it. If you are still not getting good stopping power, then pull the drums, and look at the wear on the shoes. If it is only a small pattern, you may have to go through the procedure a second time to get more of a contact patch. I have been able to get 25# in my driveway with just oversized wheel cylinders, and the soft compound shoes. I broke a rear end like that. Turned the axle tube in the housing. Now thems is good brakes. Good luck.

Brian

 

[NEARING]

Thanks I'll try all that.

 

[KEVINS]

You may be able to try a jumper valve to help hold the rear brakes even if it's just for testing..

ks

 

[1 RARE T]

WHAT??????????

I'm sorry Wagon, I really don't see how you could hold 25 psi. on your footbrake.

Not to flame you but.......

 

[wagon]

What!? You don't believe me!?
That's OK, I saw the boost gauge, for myself. That's all I need.

 

[NEARING]

I'd be happy with 10psi right now

 

[humberto]

Nearing try two soft compound secondary shoes and make sure your drums are not heavly glazed you may need to machine them as well and like it was said before ajust on the tight side make sure your s-10 cylinders are not leaking under the dust boot.Good luck.

 

[NEARING]

I'll try that also.
Thanks alot guys.
Nothing worse than a car that should be running hi 10's struggling in the hi 11's because of sorry 60ft times

 

[TurboDave]

As they've advised, for foot brake stalls, IT'S ALL IN THE REAR BRAKES.
If there's one thing I've learned over the last 17 years of GN ownership/racing, the rear brakes have to be perfect and cold to hold much boost over 8-10#.

ANY let me repeat, ANY heat built up in the rear drums/shoes, and you'll be pressing it to hold much over 5#.

You'll need two soft compound secondary shoes (no carbon fiber or metalics allowed here),

you'll need the S-10 cylinders (you already have),

you'll need the drums turned perfectly round and rough surfaced,

you'll need to adjust the new shoes out so far that you can JUST get the drum over them.

You'll need to have a line lock to do burn outs so as not to build any heat in the rears.

ABOVE ALL, YOU MUST REMEMBER, ANY USE OF THE REAR BRAKES JUST BEFORE TRYING TO DO A FOOT BRAKE STALL WILL HEAT THEM ENOUGH TO REDUCE THEIR EFFECTIVENESS BY OVER 50%!!!!

Example: if you want to try a foot brake stall in a parking lot, make sure they're cold.

If all is well, you should be able to hold 12-15# on a foot brake stall (brake pedal pushed HARD), especially with your converter. If you're braking the rears loose after all that, it's down to two possibilities.

1. The rear brakes still aren't right
2. The converter you have isn't as good as you think it is.

 

[NEARING]

Thanks for the info.

 

[Bmason]

Sat/Sun

Scott:

My wings have been clipped for an unknown amount of time. I'll be close to home, if you want to run by Sat/Sun.

-Bobby

 

[NEARING]

I'll do that