Header crack/low boost

[z1huggy]

My GN was making about 12#s of boost with my ds header crack almost all the way around the #5 tube. After getting this welded I was surprised to see my boost stay at 12#s.

I was thinking that was the problem with my low boost problem, currently I've got the thrasher 92 chip and only mods so far are the fuel pump/hotwire, afpr, and cold air.

Whats the stock boost at on a GN/TR anyways? I'm planing on putting on my adj wastgate but before I do this I'd like to find out why boost #s didn't change after getting the ds header welded. It was a large crack with a very noticable exhaust leak.

TIA

 

[Jimn8or]

There is a plethera of possibilities to your question. Are there any more/other leaks in your exhaust? How about those crossover connections? I believe that the factory boost setting was in fact 12lbs, thus the red at 15lbs on your factory gauge. You can make your wastegate adjustable for $2 if you like. Go to gnttype.org and follow the step by step instructions. Realize that you are now on your own as you will have successfully undone the factory precautions [chip, WG rod etc] and with out a scantool to detect knock you can easily grenade your engine!
HTH
Jim

 

[BLACK6PACK]

Get a scan tool before you adjust the boost!!!

 

[UNGN]

You can still reach max boost that is set with the wastegate with a header crack. The car will just be very lazy getting there.

Check to see if the Wastegate solenoid has a plug on it. One barb should be open to the atmosphere.

 

[z1huggy]

I've got turbolink on my laptop and its not showing any knock or rarely minor knock at WOT. If/when I start monkeying with the boost I'll be tuning with the TL instead of flying blind

I do have some other things done but I dont really consider them perf mods in the normal sense, Autometer boost/oil/temp gauges and Caspers knock gauge.

UNGN, the wastegate solenoid on the valve cover does not have a open barb, it has two vac lines, one to the wastgate and the other kinda loops under the Throttle body and Ys into another vac line that comes off one of the metal lines under the throttle body that goes to the square black gizmo on the back driver side valve cover . hmm, bit of a run on sentence
Is this correct or should I take it off and plug it up ?

Thanx

 

[UNGN]

Originally posted by z1huggy
UNGN, the wastegate solenoid on the valve cover does not have a open barb, it has two vac lines, one to the wastgate and the other kinda loops under the Throttle body and Ys into another vac line that comes off one of the metal lines under the throttle body that goes to the square black gizmo on the back driver side valve cover . hmm, bit of a run on sentence
Is this correct or should I take it off and plug it up ?

Thanx

I figured that's what the problem was

The barb needs to be OPEN. If it loops into a vacuum line, the solenoid is rendered basically useless and your boost will be lower than it should be. Disconnect and plug the vacuum line.

A word of caution, your boost will likely go to 20 psi (thrasher boost spike) when you floor the car and settle somewhere around 17 psi (this is what its supposed to do). Keep the scan tool running when you do this to keep an eye on knock.

 

[z1huggy]

wooohooo! UNGN you nailed it! You guys rock and this is why turbobuick.com members are invaluable. The wealth of knowledge out there on these cars in one place!

Thanx