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Forced Induction Turbochargers and Superchargers..Got Boost?

weather vs. boost psi

Old Jul 11, 2008 | 06:10 PM
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Default weather vs. boost psi

hey guys,

i searched the topic but really couldn't find the answer i was looking for .................i was running my car pretty hard today and i noticed that in high boost (14psi) that it was only getting up to about 12psi, in low boost it was right on at 8psi..............i popped the hood and didn't notice any vac.leaks or anything...............i did notice however that under high boost my A/F's were at 9.8 it was tuned at 11.4.........could the weather conditions have something to do with the change?...............it was 81 outside w/humidity at like 90%................any opinions or insight would be much appreciated
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Old Jul 11, 2008 | 09:34 PM
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From: SD SoCal | Jed, KSA
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In hotter wather you want it to be richer to avoid knock. the tuner must have added that in a different map in your ECU.
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Old Jul 11, 2008 | 09:53 PM
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Originally Posted by nomyth46
hey guys,

i searched the topic but really couldn't find the answer i was looking for .................i was running my car pretty hard today and i noticed that in high boost (14psi) that it was only getting up to about 12psi, in low boost it was right on at 8psi..............i popped the hood and didn't notice any vac.leaks or anything...............i did notice however that under high boost my A/F's were at 9.8 it was tuned at 11.4.........could the weather conditions have something to do with the change?...............it was 81 outside w/humidity at like 90%................any opinions or insight would be much appreciated
What is controlling your boost? Your ECU (open or closed loop)? Mechanical boost controller?
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Old Jul 12, 2008 | 04:38 AM
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Originally Posted by JETPILOT
What is controlling your boost? Your ECU (open or closed loop)?

my ECU is a Utec but i'm not sure what you mean by open or closed loop



Mechanical boost controller?
no, its a greddy profec B spec II


the rich part doesn't bother me as much as the boost psi lowering by 2psi
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Old Jul 12, 2008 | 04:39 AM
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its a Utec but i dunno what open or closed loop means...................i didn't mean to add that to your quote....sorry
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Old Jul 12, 2008 | 05:24 AM
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Details on your setup...
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Old Jul 12, 2008 | 06:14 AM
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I see up too 2 PSI dropping in heat. its normal, best was is think of alternatives too keep temps down.
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Old Jul 12, 2008 | 06:41 AM
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most boost controller are set by solenoid duty cycle. In the hotter weather, the same duty cycle is not going to achieve the same boost pressure as in colder weather.

What JEt Pilot was talking about "open or closed loop" is if you are using the "boost tuning" feature of the UTEC. The closed loop boost tuning provides feedback to compensate for different atmospheric/temperature conditions. Not many people use it though.....only a couple that I know of.
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Old Jul 12, 2008 | 07:23 PM
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Originally Posted by SlideFox
Details on your setup...


built greddy tt, utec, 750cc injectors, aam fuel return, and svr technologies open dumps
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Old Jul 12, 2008 | 07:25 PM
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hey question has anybody ever ran a duel 3" straight pipes.............if so is it crazy loud or something you can live with cuz i'm thinking about trying it
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