[Cjstratton]

Hello all Ive got a vortech v1 t trim with a draw thru setup and a Bosch bypass valve. I have about 12 in. Of vacuum at idle and about 1 or 2 #s of boost at 4500 rmps shouldn't I be reading more boost? I have had it tuned and the tuner told me I was running 10 psi. I just recently installed the gauge. What are you other vortech guys getting for boost at 4-4500 Rpms?

[RyanGT]

That depends on your pulley you have. But if tuner reads 10 psi, and you are only getting 1-2 psi on gauge there can be a few things wrong.

1) Gauge is busted/wired incorrectly.
2) You tapped a wrong line for vac.
3) Leak in the vac/boost line (12 in vac is low)

Where did you tap the line? The frps? Or manifold? Both of those are optimal.

[wishIhada5.0]

kinked tube going to the back of the gauge?

[sharkbait]

It should be about 22-20 hg at idle.

where did you tap the vac line in?

[Cjstratton]

Tapped it where it goes into the map sensor

[Cjstratton]

TTt

[Eagle2000GT]

Originally Posted by sharkbait It should be about 22-20 hg at idle. where did you tap the vac line in?

Mine reads 17-18 at idle. I'm running 8.9 psi at 6000 rpms. Actually that what the tuner said. The gage sweeps up near there but at 6000 rpms I don't have time to look at it. The boost gage reads around 5 1/2-6 psi at 4500 rpms. Since your gage shows vacuum and boost I would suggest that you have a bad gage. I got a bad fuel pressure gage from Autometer. They replaced it under warranty.

Edit: I have a question. When you are at 4500 rpm are you WOT? If not you are restricting air flow into the motor.

[mustanginky]

you probably have a pinched/broken line. if they get pinched they tend to break where they kink. mine did the same thing and i had to replace the line.

[Cjstratton]

4500 rmp is all I can run it until I get it broke in. I just finished up the mmr 600 shortblock install spun all the bearings on the stock bottom end. It was tuned with the stocker and was pushing 10 psi.

[sharkbait]

Originally Posted by Cjstratton Tapped it where it goes into the map sensor

Map sensor?!

We dont have one of those man, our cars use MAF sensors. The best place to take it is either your vacuum harness (red vacuum lines) or the vacuum line on the back of the T/B

[Cjstratton]

T'd from the red vacuum line on the sensor behind the egr valve

[Cjstratton]

Could it possibly be an intake manifold leak causing it to only read 12 hg at idle?

[RyanGT]

IMO that egr line is WAY to small to read boost, or even vac accurately. Thing is tiny. Tap it to the back of the plenum/manifold. If you can.

[sharkbait]

Originally Posted by RyanGT IMO that egr line is WAY to small to read boost, or even vac accurately. Thing is tiny. Tap it to the back of the plenum/manifold. If you can.

Most kits say to use that line in the directions. The boost gauge line is no larger. I use the red and black line on the back of the T/B and that gives me accurate readings.

[RyanGT]

My boost gauge is 5/16. I think. That thing is just so tiny! And if it is tapped after it plugs into the egr bracket (before the actual egr) I think it would give false readings. We talking about the same tiny line that plugs into the egr?


Also another question, did you have boost gauge hooked up on the dyno or after? And you still pulling like on the dyno? If so you have boost and it is the 3 options i stated earlier . If you are getting 12 vac that is pretty low, so a leak somewhere. I get 14-15 with stage 2 cams.

[Cjstratton]

Retapped vacuum line at frps and now reading 22hg at idle. I guess I had the wrong line. Haven't driven it yet b/c I'm at work. Hopefully I'll be showing some boost when I drive home. Thank you guys for all of your help.