when should I see boost?
02-01-2009, 04:37 PM
#1
Thread Starter
Join Date: Dec 2008
Location: Florida
Posts: 21
when should I see boost?
I just installed a boost gauge and my car is getting 12lbs of boost at 6300 rpm. My questions are; how soon in the rpm range should I see the motor switch from vacuum to boost? Should I see boost during normal acceleration or only at wide open throttle? Right now the only way I see boost is when I'm at wide open throttle. I'm running negative boost all the way to 4000 rpm and around 5lbs at 5000 rpm only at wide open throttle. If I run up to 6000 rpm at half throttle I never see the boost gauge move past 0. I'm almost always in the -10 to -20 vacuum range.
My mods are listed in my signature.
My mods are listed in my signature.
02-01-2009, 08:16 PM
#5
5th Gear Member
Join Date: Jul 2007
Posts: 3,731
how does that sound at all right? I see zero vaccum from 1500RPM all the way up to 6700RPM, at 40% throttle I can see boost at 3000RPM
You got something wrong bud, sorry to burst your bubble.
You shouldn't have to be at WOT to see boost, by any means. You should be able to control how much boost you see by the throttle pedal.
You got something wrong bud, sorry to burst your bubble.
You shouldn't have to be at WOT to see boost, by any means. You should be able to control how much boost you see by the throttle pedal.
Last edited by 2000AZ5.0GT; 02-01-2009 at 08:19 PM.
02-01-2009, 08:29 PM
#6
4th Gear Member
Join Date: Jan 2009
Location: California
Posts: 1,092
no that sounds about right, its your boost bypass valve doing that, you shouldnt be quite at WOT but if your lightfooted even all the way up to 6000rpm it shouldnt boost unless your foot tells it to.
i can drive my termi around all day without ever producing boost.
i can drive my termi around all day without ever producing boost.
02-01-2009, 08:31 PM
#7
4th Gear Member
Join Date: Jan 2009
Location: California
Posts: 1,092
crud, i just re-read your post, ya you actually do have something wrong, you should be producing boost much earlier if you put your foot into it.
02-01-2009, 08:51 PM
#8
Something definitly sounds really really wrong there. If youre not seeing boost by 4000rpms youre cars power curve is gonna be soooooooo weird so something is not right. I dont know whats wrong but i do know something is not right. What size pulley are you running and what kinda bpv/bov are you running and how strong of a spring is in there??? That could be your problem. My buddy had this problem with his turbo cobra. His bov was stuck open and thats why he wasnt making boost. When he got the bov unstuck and made sure it didnt stick open, he went from making like 8 psi to 30+psi(pegged the gauge). So check your bpv/bov springs to see if its stuck open depending on if your pulley is small enough to make some decent lbs of boost. I might even be posting some bad info but i thought think that some people run bpv/bov's on centri blowers.
02-01-2009, 09:27 PM
#10
5th Gear Member
Join Date: Jul 2007
Posts: 3,731
it's a little bit different when the throttle body comes after the blower, I do know what I'm talking about, unlike some of the novice members on the board, I've been using the same blower set up for over two years.
OP should be seeing boost, especially with a T-trim, at any point past 15% throttle.
If I go WOT, i can see 7PSI by 3400RPM, or I can close the throttle slightly and see 4PSI
Thanks for trying to tell me I'm wrong, that just isn't true.