Boosting problem Profec B II - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

sr20tom · 04-04-2006, 09:34 PM

i was runing in e-town this weekend with 100 octane after milking the car there, and wanted to bump up the boost to 18psi. I have a profec b boost controller. I raised the gain like crazy and all i got was a 17psi boost spike and then the boost ran at 12 psi all day. The book said if a boost spike occurs decrease the gain. The boost didnt fall of as quick but would only boost 14psi. So i added the % even more. The car went to 18psi and then the boost fell to 13psi. The book said if the boost falls off at high rpm add more gain. The gain is at the max 35% and if goes to 18psi and keeps falling after to 13psi. How do i fix this? If my BOV leaks or there is any kind of leak woudnt the car bog? I donno what the problem is????

12psi and 13.2 ET is still pretty good. at 18psi i should deffenatly be in the high to mid 12s.

SpeedMonkeyInc · 04-04-2006, 09:43 PM

What is your wastegate spring? I read that you can only boost twice your spring pressure.... I could be wrong about that though.

Don't you adjust boost pressure by turning the "volume" knob? On my Profec Type S gain is different than boost pressure. By turning up the gain you are just getting boost spikes, then leveling out to your set boost level.

slider2828 · 04-05-2006, 11:34 AM

sr20tom.... you are doing it all wrong and will risk of blowing your turbo..... there was a topic in the tech section yesterday in which I explained EXACTLY how to raise boost safely and boosting efficiently.... Do a search or just look down the next few pages. You will see the post.... besides the way you are raising gain, you aren't even really boosting.....

04-04-2006, 09:34 PM	#1
sr20tom Leaky Injector Join Date: Dec 2004 Location: Queens Posts: 147 Trader Rating: (0) Feedback Score: 0 reviews	Boosting problem Profec B II i was runing in e-town this weekend with 100 octane after milking the car there, and wanted to bump up the boost to 18psi. I have a profec b boost controller. I raised the gain like crazy and all i got was a 17psi boost spike and then the boost ran at 12 psi all day. The book said if a boost spike occurs decrease the gain. The boost didnt fall of as quick but would only boost 14psi. So i added the % even more. The car went to 18psi and then the boost fell to 13psi. The book said if the boost falls off at high rpm add more gain. The gain is at the max 35% and if goes to 18psi and keeps falling after to 13psi. How do i fix this? If my BOV leaks or there is any kind of leak woudnt the car bog? I donno what the problem is???? 12psi and 13.2 ET is still pretty good. at 18psi i should deffenatly be in the high to mid 12s. __________________ 91 SRtweezy powered sil-80

04-04-2006, 09:43 PM	#2
SpeedMonkeyInc Zilvia FREAK! Join Date: Apr 2003 Location: Oakland Age: 45 Posts: 1,271 Trader Rating: (0) Feedback Score: 0 reviews	What is your wastegate spring? I read that you can only boost twice your spring pressure.... I could be wrong about that though. Don't you adjust boost pressure by turning the "volume" knob? On my Profec Type S gain is different than boost pressure. By turning up the gain you are just getting boost spikes, then leveling out to your set boost level.

04-05-2006, 11:34 AM	#3
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	sr20tom.... you are doing it all wrong and will risk of blowing your turbo..... there was a topic in the tech section yesterday in which I explained EXACTLY how to raise boost safely and boosting efficiently.... Do a search or just look down the next few pages. You will see the post.... besides the way you are raising gain, you aren't even really boosting.....