supercharged with sd issue

[blownlxvert]

i have an 88 sd with a vortech set up. i rebulit the motor this winter and the only different parts i added were headers and a cobra intake. everything else is the the same with the exception of a fresh longblock. you have to give it a little gas right at startup and hold it for a second and then it will come down and idle. the motor sounds and runs really strong, and doent miss a beat just cruzin around. but as soon as you start to step down on it and it starts to climb into the boost range it will fall right on its face. i guess this seems like a serious running lean situation. im trying to find a mass air set up to off on the right foot. i hope mass air will help take alot of the guess work out of driveabilty issues. anyone with some insight please trump in. thanks.

 

[Daggar]

Do you have a one way check valve installed between the manifold and the BAP sensor?

Are your plugs closed up to .035?

 

[blownlxvert]

the plugs are close, but that valve should be run between bap and the intake right? the only way the car seems to run right is with that valve removed.

 

[352Ford2]

Do you have a one way check valve installed between the manifold and the BAP sensor?QUOTE]



does that actuly work? I have always though of trying it with a boost senstive fuel press reg and bigger injectors, but never tryed it.

 

[troyGT03]

you need the check valve. the map sensor freaks when is sees boost instead of vacuum. check my sig

 

[Daggar]

the plugs are close, but that valve should be run between bap and the intake right? the only way the car seems to run right is with that valve removed.

If you're getting into boost and the car is freaking out then it's likely the result of the BAP seeing boost. I've come across valves from Vortec before that were either not large enough or didn't function correctly if not placed in the correct position. By that I mean that if it were a PCV (very similar) then the valve should be placed in the up and down postion so that the ball will unseat when it see pressure. If that valve is upside down and the ball is unseated due to gravity then funky things can happen because the tolerances are not so good that the vac pressure will seat the ball.

Disregard the inlet manifold in this diagram as it does not apply to a Vortec. Position the check valve so that the ball is seated by gravity then let us know how you made out.

 

[troyGT03]

daggar is correct as always. i have been playing with check valve setups with mine. that is my setup minus the .070 orifice. my setup runs great but i am still refining. vortech still sells a check valve kit for sd setups.

 

[blownlxvert]

i have that valve but it does not seem to function if i blow through it on either end. i cant imagine that it is bad, it seemed to work fine last season.