Just installed some gauges. I don't see any boost pressure unless I am getting on it pretty hard. I did see it get up to 30 psi. At 65-70 mph, I see 3 on level ground and no load. When I let off, it pulls a vacuum. Everything is stock. Is this normal to pull a vacuum? What are normal boost pressures?

 

boost pressure has a lot to do with exhaust temps and not rpm. on the dyno you can see an engine at 2200 free spinning basically no boost. as you add load the rpms come down and boost goes up. at 1400 rpm you are at 15 lbs boost. that is max boost on that setup not for the dodge.

 

3-7psi doing normal/econo city driving, 10psi + if your getting on it harder from the stop light. 10-17psi, 65-70mph hiway.

 

????????????????????I am pushing 3-5 easy driving 8-10 cruising at 65 but when I get on it I am getting 35lbs with my smarty set on economy. Either me and my buddies numbers are off or yours are.
I have gotten 40+ with smarty set on performance.
My numbers are close to economy when I set stock.

 

you saw 30 stock? you mean 28... cause stock mine dumps boost at 28..

 

I will set stock and recheck, your numbers stock sound about right. But what numbers are the other posts reading? Ours are way higher

 

just cruising 3-5, and it gets to 10 when you get on it alittle. ive peaked at 40 lbs with my smarty...

 

My commander can show 0 at 35mph. It just depends on how much foot you put in it. Don't forget if you have boost fooling your #'s may be different. Easily up in the high 20's getting on it hard.

 

1st, a rhetorical question - how can you pull a vacuum without a throttle plate?

2nd - did you install a gauge that reads boost AND vacuum?

3rd, have you checked for a collapsed/blocked air filter?

 

I can hear it pulling a vacuum on my gauge. Also, I took the airline loose and felt it sucking in.

I just wanted to make sure everything was ok because my truck smokes alot when I get on it.

Thanks for all the info.

 

I was not under the impression that a diesel pulled vacum. Just either static atmosphic press. 14.7 OR positive press. [boost]- if it really pulls vac. thats surely a new one on me.

 

Did you check for a blocked air filter yet?

 

They don't make boost at idle but they're still pulling in air. Take the boot off your intake horn at idle and put your had over it, the gauge will show that.

 

X2. That is the only way to pull a vacuum.

 

Air filter is clean.