Boost Gauge or Supercharger problem? (Page 1/1)
TurboGN OCT 01, 09:25 PM
I have a 1988 Fiero GT with a 3800 SC swapped out of a 2007 Grand Prix. I just hooked up a boost gauge and KOEO it reads 0 as it should. At idle it's showing 20 VAC and at full boost it comes up to and stops at 0. Would this be a problem with the boost gauge or the supercharger?
pmbrunelle OCT 01, 10:05 PM
Is the gauge connected to a point in the intake that is between the throttle and the blower?
TurboGN OCT 01, 10:10 PM
It's connected to the same port that feeds the brake booster and supercharger bypass pod.
Dennis LaGrua OCT 02, 07:15 AM

quote
Originally posted by TurboGN:

It's connected to the same port that feeds the brake booster and supercharger bypass pod.



The boost gauge should be connected after the supercharger to the line on the LIM that feeds the MAP sensor. Put a T connection on that line and your problem is solved.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Mark_j OCT 02, 07:19 AM

quote
Originally posted by TurboGN:

I have a 1988 Fiero GT with a 3800 SC swapped out of a 2007 Grand Prix. I just hooked up a boost gauge and KOEO it reads 0 as it should. At idle it's showing 20 VAC and at full boost it comes up to and stops at 0. Would this be a problem with the boost gauge or the supercharger?



Actually, neither. As you stated in another post you have the gauge hooked to a point that provides VAC only. A boost gauge is designed to read the pressure POST supercharger. In other words it needs to read the manifold pressure. The place you have it hooked is designed to provide VAC only to operate the boost can on the brake booster.
TurboGN OCT 02, 08:55 AM
Thank you everyone for your help. Rookie mistake....lol
TurboGN OCT 02, 09:35 PM
I have it hooked up correctly now and it shows 5psi at full boost.