turbo newbie psi question
03-16-2005, 01:08 AM
#1
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turbo newbie psi question
Hi. I was just wondering if it is normal for the psi to fall off as your revs increase? I have my boost dialed in to 14psi max right now and I see it fall off a lb or so as I approach redline. Just wondering (hoping) if this is normal behavior. Thanks for the help!
03-16-2005, 01:25 AM
#3
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Only 1 psi drop is really good. The roll-off is due to increasing exhaust pressure, which pushes on the wastegate valve and adds to the opening force provided by the boost pressure.
03-16-2005, 01:29 AM
#4
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Supposedly I have a Powerhaus K27 quickspool turbo (I have yet to verify). I have a dyno chart, supposed to be from my car, and what I believe I see is the powerband from 4K to 6K - that's where the lines more or less flatten out - hp/torq seem to be on the rise below that. Also, I'm in CA and the car passed smog, so I'm not sure if there was any tuning to accommodate that. Sooooo, with the K27 quickspool, should I still see a dropoff in psi? Or should I be seeing 14psi (or whatever I dial in) through 6K or so? Again, thanks from a turbo newbie.
03-16-2005, 01:31 AM
#6
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Originally Posted by mtnman82
Supposedly I have a Powerhaus K27 quickspool turbo (I have yet to verify). I have a dyno chart, supposed to be from my car, and what I believe I see is the powerband from 4K to 6K - that's where the lines more or less flatten out - hp/torq seem to be on the rise below that. Also, I'm in CA and the car passed smog, so I'm not sure if there was any tuning to accommodate that. Sooooo, with the K27 quickspool, should I still see a dropoff in psi? Or should I be seeing 14psi (or whatever I dial in) through 6K or so? Again, thanks from a turbo newbie.
Last edited by daniel951; 03-16-2005 at 02:24 AM.