# Boost Controller Question



## justin83 (Oct 3, 2003)

I'm from the great land of Oz and own a 1989 SSS Bluebird (CA18DET).

I've been reading recently that while a boost controller is designed to allow higher than stock boost to be run, some manufacturers also claim that even if run on stock boost, a boost controller will bring boost on earlier. I was wondering if anyone has experienced this with their ride, or can explain how a controller could do this? Are there any other ways of bringing boost on lower in the rev range?

CA18DET's are known for boosting high in the range, and I'm keen to try and counter this.

Any help would be great.


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## calvin200sx (Oct 14, 2003)

If I remember right, the boost controller can keep the wastegate closed longer than you can without it. Meaning the boost controller will not open the wastegate untill the boost level reaches a point a few psi before the set boost level. Remember, since the wastegate is actuated by vaccuum, it will oper slowly as boost builds. So it will take longer to build your boost level. A boost controller controls the vaccuum the wategate actuator sees. If you set the boost level increase at 0% (Greddy Profec-B spec-II) then you will be running at stock boost levels. Allowing the wastegate to stay closed longer will help with boost response and lag time. A boost controller will not help with initiating boost at a lower rpm. Only nitrous or a smaller turbo / ball bearing turbo will help here. Hope this helps.


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## James (Apr 29, 2002)

http://www.nissanperformancemag.com/december02/project200sx/


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## r_master (Apr 5, 2004)

calvin200sx is right on most parts but i believe you can control the response of the boost

on my sbc-id i have 2 settings 1) set 2) gain

1) set: it controls the max boost

2) gain: it controls how fast you build up your boost

just a quick warning tho.. if you set your gain too high you'll spike (or boost creep) it will shoot you over your setting and than settle down. best solution for this is to use lower gain or get an external wastegate. 

also you get PTFB (Partial Throttle Full Boost) which is bad because your EGT goes up on PTFB... fix for that is to get a closed circuit boost controller, but most boost controllers are open circuit.


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