boost dropping in high rpm???

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Jul 29, 2007 | 11:20 PM

92eh3si

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From: 206/425, Wa, U.S.A

boost dropping in high rpm???

i am having a problem.
While tuning, found out that the boost dropps in high rpm around 7500 rpm.
Was running about 18~20 psi then dropps to 10psi in 7500 rpm.
any idea why??

Jul 29, 2007 | 11:23 PM

96vtecI4

Joined: Jan 2007

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From: Regina, SK, Canada

Turbo's to small.

Jul 29, 2007 | 11:49 PM

numbnuts22715

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From: TX, USA

Re: (96vtecI4)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96vtecI4 »</TD></TR><TR><TD CLASS="quote">Turbo's to small.</TD></TR></TABLE>

exactly what im thinking... What size is the turbo?

Jul 30, 2007 | 12:09 AM

riceball777

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Joined: Mar 2002

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From: Los Angeles, CA, U.S.A

Re: (numbnuts22715)

something is wrong

when running a small turbo. the boost may taper and drap a few psi by redline
but there no way you should be going from 18 psi to 10psi

Jul 30, 2007 | 12:19 AM

96vtecI4

Joined: Jan 2007

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From: Regina, SK, Canada

You are very high into your RPM's, whats your redline set at. Possible boost cut? Need much more set up info here.

Jul 30, 2007 | 03:25 AM

Kyle R

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From: VA/FL

Re: (96vtecI4)

Sounds like your turbo has asthma

Jul 30, 2007 | 06:52 AM

Supacharge

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From: Concord, NC, USA

Re: (herecomesboost)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by herecomesboost »</TD></TR><TR><TD CLASS="quote">Sounds like your turbo has asthma

</TD></TR></TABLE>

lol

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Jul 30, 2007 | 07:08 AM

dpetro1

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From: Tracys Landing, MD

Re: (Supacharge)

what are you using for boost control?

Jul 30, 2007 | 12:14 PM

0morgan@synapse motorsport

Joined: Oct 2004

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From: upstate, ny

Re: (dpetro1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpetro1 »</TD></TR><TR><TD CLASS="quote">what are you using for boost control?</TD></TR></TABLE>

Jul 30, 2007 | 12:51 PM

#10

92eh3si

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From: 206/425, Wa, U.S.A

Re: (mike@synapse motorsport)

okay here is more info on my set up.

Sleeved GSR motor
GT30R (too small for y'all?? lol)

As far as the boost controller, i am just using cheap manual boost controller
with ball and spring u know..

Redline set at 8400rpm

I was thinking about the WG spring issue,
It was reading 10psi so i am assuming .7bar or soemthing?
I boosted it up to 18psi and i was it dropping it to around 10 or 11psi.

Any other thoughts??

Jul 30, 2007 | 01:19 PM

#11

0morgan@synapse motorsport

Joined: Oct 2004

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From: upstate, ny

Re: (92eh3si)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92eh3si »</TD></TR><TR><TD CLASS="quote">okay here is more info on my set up.

Sleeved GSR motor
GT30R (too small for y'all?? lol)

As far as the boost controller, i am just using cheap manual boost controller
with ball and spring u know..

Redline set at 8400rpm

I was thinking about the WG spring issue,
It was reading 10psi so i am assuming .7bar or soemthing?
I boosted it up to 18psi and i was it dropping it to around 10 or 11psi.

Any other thoughts??
</TD></TR></TABLE>

saw a similar problem on my friends car with a gt30r, but not as bad. boost was set for 21psi, but dropped off to 16psi by redline at the track. put a bigger spring(13psi) and it helped a ton, only dropped 1-2psi at the top end.

Jul 30, 2007 | 06:27 PM

#12

importsautomotive

Joined: Feb 2007

Posts: 19

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From: concord, ca

what kind of blow off valve

Jul 30, 2007 | 06:39 PM

#13

96vtecI4

Joined: Jan 2007

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From: Regina, SK, Canada

I agree, it should be your spring, if not might be the MBC.

Jul 30, 2007 | 08:50 PM

#14

92eh3si

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From: 206/425, Wa, U.S.A

Re: (importsautomotive)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by importsautomotive »</TD></TR><TR><TD CLASS="quote">what kind of blow off valve </TD></TR></TABLE>

Turbo Xs RFL

Jul 30, 2007 | 08:57 PM

#15

Kyle R

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From: VA/FL

Re: (92eh3si)

I agree with what was stated above. Try a wastegate spring that is more stiff.

Jul 30, 2007 | 10:27 PM

#16

Fo-Do Fanatic

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From: Lovin the EF, Wa

Re: (herecomesboost)

and get rid of that POS blow off valve.

Aug 1, 2007 | 01:59 PM

#17

full Circling

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From: That's the wrong tone... I'm Skunk2 certified.

and make me a sandwich. pb&j.

Aug 19, 2007 | 10:34 PM

#18

mormonboy

Honda-Tech Member

Joined: Feb 2007

Posts: 2,092

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Re: (full Circling)

peter, you need to take it easy with the turboz man!

you need to come out to the ht meets!

Aug 20, 2007 | 11:24 AM

#19

JDMisGOOD

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Joined: Jun 2003

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Re: boost dropping in high rpm??? (92eh3si)

Loose the cheap boost controller. Buy a bigger wastegate spring too.

Aug 20, 2007 | 11:47 AM

#20

big-cat

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Joined: Feb 2006

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From: Florida

Re: (full Circling)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by full Circling »</TD></TR><TR><TD CLASS="quote">and make me a sandwich. pb&j.</TD></TR></TABLE>

damn that sounds good right now(i appologize for the no tech)

Aug 20, 2007 | 11:58 AM

#21

avoturbo

Joined: Aug 2007

Posts: 7

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From: atwater, ca, usa

Re: boost dropping in high rpm??? (JDMisGOOD)

its your boost controller....when at low rpm you will see 18psi becuz theres not that much pressure to your boost controller. when you reach high rpm.. so many pressure is built so there going to push down on your boost controller like crazy this is wat causing your boost to drop down.to is wastgate spring or almost to it....i have same problem change to electronic and solve my problem..........

Aug 20, 2007 | 01:42 PM

#22

rdssk8rcs1

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Re: boost dropping in high rpm??? (avoturbo)

Yes, i had teh same problem with my levels of boost towards redline and it would cause the pressure to fluctuate a lot. I went with a stiffer spring and all my problems were solved. I was using the Apexi AVC-R and that couldnt even compensate for all the added pressure at higher RPMs

Aug 20, 2007 | 04:38 PM

#23

blackeg

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Joined: Feb 2003

Posts: 9,820

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From: schooling kids in ny, usa

Re: (riceball777)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 »</TD></TR><TR><TD CLASS="quote">something is wrong

when running a small turbo. the boost may taper and drap a few psi by redline
but there no way you should be going from 18 psi to 10psi </TD></TR></TABLE>

volkswagon 1.8T motors do it all the time.

if you are pushing the boost controller to make too much boost over the spring thiss could happen.