boost problems

[jerrad]

ok guys i have my boost turned up to 23#s but when im in first its at about 19#s then when the car shifts to 2nd it climbs to about 22#s and then it slowly starts losing boost(goes down to about 20#s) until the car shifts to 3rd then the boost climbs up to 23#s again. anyone know what causes this?

 

[Quick6'n'-K.C.]

ive got the same problem-

my boost fluctuates one to three pounds during a pass, up and down.
i think ive got some exhaust leaks, but not sure-

i also run a alky kit, and have erics chip-

my car did the same thing with another brand chip, but i havent fixed the problem yet-

my boost is set at 20 psi, with the RJC bleeder valve, once i lock the convertor, it shoots to 25psi

oh well

BW

 

[pwrhws]

subscribing

I have posted the same question a couple times before. I never seemed to find anything out though.

I have been fighting the same situation as you describe (for about 5 years now), I have tried everything from rearranging the hoses, to tuner style. I have recently switched to an external gate and still the same problem.
I have checked for exhaust leaks, cold air leaks, ran it with out a filter, you name it, no luck.

My car has GN1 Alum heads, 214/214 roller, hemco upper, 70mm TB, ATR headers, and a PT53.

The thought is that the exhaust backpressure is pushing the gate open at higher rpms. The Tial gate has 19# worth of spring pressure and will not stay stable even at the 19.
I have tried many things back to back on our dyno and have yet to figure it out. But it definitly repeats itself. Top end of each gear, boost drops. Screwy
Mine will drop back from 22 psi to 17 on the top of each gear.

 

[Quick6'n'-K.C.]

i did some research, and read one of Jason Cramers threads on how to get the boost set correctly with his bleeder valve.

i guess i need to lengthen my stock style wastegate more, because my car creeps alot with the convertor locked-

seems to me, that the boost rises when the car is under a heavy load such as the convertor locked-

when i make passes with the convertor unlocked, the RPMS never drop below 4,000 rpm- it has a 3600 PTS 9/11 stall convertor.


pwrhws- have you called, or heard of the way John Craig has everyone run there external gates?

does your external wastegate have 2 ports? 1 at the bottom and one at the top? a buddy of mine got the info from John at Limit Engineering and has it set up like this-

ATR delta gate mounted right at the turbo-
Compressor housing vacuum hose straight to the bottom side of the deltagate- T into that hose, and run a inline adjustable regulator to adjust the boost in the car , and run the other side of that regulator into the top side of the external gate-

last week, he just put in a RJC bleeder valve inline with the compressor to bottom side of his deltagate. spoolup is instant, and he is having 2psi of boost creep-
70 BB, stage 1 block, champ 14 bolt heads made to Red Armstrong specs,FAST, ect ect ect

my dads WE4 is rock solid at 20psi in all gears. he has a stock adjustable wastegate, RJC bleeder, erics chip and alky-

let me know how you come out
BW

 

[pwrhws]

I am using a ball valve piping some air pressure back to the front of the gate. It has yet to make any changes.

I may try a larger turbo, I think a 67 maybe in the works