Overboosting?

[vSICKsTURBO]

Hey turbobuick comrades, I met a neighbor the other day he seen my 87 gn in the garage and we started talking because he has an 86 gn. Long story short we met up and went for a little cruise to the local spot. I took him for a ride in mine and vice- versa. His drove "normal" only building boost when he got into the throttle. Mine on the other hand, I can only give the throttle about a 1/8 inch of movement any more than that will build boost and dump it. If I floor it, it goes as it should but the problem is trying to drive it normal with no boost building is a task. It builds boost to fast. 1/4 throttle and it sounds like a spaceship just trying to accelerate 5mph. So basically I can only just barely give it throttle or floor it, thats the only 2 ways to drive my car and its way diff than my neighbor's 86. What would / could cause this?

 

[Sneezy6]

Any scanmaster numbers? Do you have an aftermarket boost gauge? What does it say? I am kind of stuck in this problem as boost is built with rpm and at low acceleration should not be a problem. Do you have a monster stall in your converter?

 

[vSICKsTURBO]

Scanmaster numbers for what specifically? I have logged data and I have seen spikes to 28.2 #s of boost then drop to about 27.3#s for the 1/4 mile pass. It has a stock converter dc or d5 or something. Ta 49 turbo , gn1 piping, zo6 maf, maf translator. No knock at all in the data i do know its running rich. Blm at 118 at wot.

 

[mikestertwo]

You don't mention "how much" boost you are getting at 1/4 throttle. The turbo is always spinning when the engine is running it just may not be making positive boost pressure. Are you just going by the way the two cars differ in the sound? What's the difference in the builds between your car and your neighbor's?

 

[vSICKsTURBO]

You don't mention "how much" boost you are getting at 1/4 throttle. The turbo is always spinning when the engine is running it just may not be making positive boost pressure. Are you just going by the way the two cars differ in the sound? What's the difference in the builds between your car and your neighbor's?

Its not a sound its more like at 1/8 to 1/4 throttle i have seen it go to 8#s or so. I have to let off all the time because its building boost and im not even into the throttle

 

[vSICKsTURBO]

You don't mention "how much" boost you are getting at 1/4 throttle. The turbo is always spinning when the engine is running it just may not be making positive boost pressure. Are you just going by the way the two cars differ in the sound? What's the difference in the builds between your car and your neighbor's?

Im not explaining it properly. Its hard to put in words. All i can say is if i gave it say 1/4 throttle if i didnt lift it would go upwards of 27 #s. Which 27 is normal when im on it. . But im not trying to build boost at all. I can only put my foot on the pedal a slight bit for it to not build boost. And when its building its horse sneezing it right out. As my mph climb. Does that make sense? Lol

 

[vSICKsTURBO]

Let me try again. .44 tps is idle (ima throw some numbers out for reference point) at lets say 1.6volts on tps its building way to much boost for the throtttle im giving it. But if i stay around lets say 1.0 tps volts it will drive building no boost or minimal.

 

[vSICKsTURBO]

Let me try again. .44 tps is idle (ima throw some numbers out for reference point) at lets say 1.6volts on tps its building way to much boost for the throtttle im giving it. But if i stay around lets say 1.0 tps volts it will drive building no boost or minimal.

Just accelerating slowly as it should. If i let a 90 year old women drive she would be at 27 #s of boost before she crossed the intersection. All while sneezing the whole way. Lol.

 

[vSICKsTURBO]

I guess partially what im saying is its steady building and steady blowing off boost at the same time. But the boost is climbing also at that same time even while dumping it .

 

[DarthBuick]

What are you using for a boost controller?

 

[vSICKsTURBO]

..

 

[vSICKsTURBO]

BstC boost command is what it says on the controller. But its turned off per previous owner.