oveboosting

[matthew]

Hi I have a 86 s/c with a t3/t4 and powerstroke(modded to fit) and 3" exh no muffler. I am using a stock glhs computer. I cant keep it from spiking I tried the zener diode but it is worse ( i may have bought the wrong ones). I justwant to drive it for a while until I can save up the $$ for my new cal. Any ideas?

[Dave]

Try a better boost controller. Theres not much else to say. Those Zener's are cheap too arent they?

[DakotaKid]

Spiking? explain a little further please.

The diode is not a boost controller, it is to stop overboosting.

[RSTURBO]

start with the basics and give more info....did you check for vac leaks, have run the wg to intake manifold and only gotten 5-7 psi only, does it over boost at 4000 rpms or only when you get to 5300+? more info please
zdiode removes over boost just like he said above me

[matthew]

I installed a 4.3v zener and the boost cut out started sooner. The car would cut out really bad. I am using the stock wastegate can set up (computer controlled). I tried a potentiameter with the two diodes and it worked, It cut out the spiking but now boost will rise to 19psi. I only hit 19psi for a sec and disconnected the cut out. I have an adj actuator arm, I'm thinking it might be too tight. With nothing done to prevent the cut out, the car will boost to 16psi cut out and drop to 10psi, if I keep it floored it spike again I can only give the car about 3/4 throttle(the car seems slow when it drops to ten psi, slower than normal). I'm just trying to get it run stock for now until I get my new computer.

thanks matt

[CaptTurbo]

computer controlled wastegate could be a problem as well, get a boost controller, don't rely on the computer to control boost once you've modified the car in any way....just my opinion, but a simple grainger valve or MBC could fix your problem.... what's going on with your diode is another question...you sure you have it hooked up right.... with a diode, you shouldn't have any boost cutout whatsoever, it just shouldn't exist.

[RSTURBO]

how about your wg soleinod? is it working?