blow off valve

[burnout 180]

Can someone tell me whats the reason for using a recirculating blow off valve on a stock ca18det.

[Nunook]

sometimes when ppl use a bov that vents out, with an engine that uses a MAF, the mixture turns bad while changing blowing off.

so u can use a recirculating bov instead, and still stop compressor surge.

[c-rad]

The MAF counts the air coming in and the ECU uses that to calculate how much fuel to send.... if you vent the BOV to the atmosphere, some of that counted air is lost. The ECU still sends the amount of fuel and an overly rich condition occurs. This usually only happens in between shifts and makes for some nice flame-thrower action out the exhaust.

[rico05]

Also, if your compressor bypass valve is designed to be recurriculated (ARC) or just sucks (eBay special) then it will also leak at idle. Also, any time that the throttle plates are closed, like when coasting to a stop, in gear or downshifting, it will leak. It really is the best idea to recurriculate a BOV on any MAF equipped car. Me? I vent and while sounds pimp as hell, it really makes the car run rough.

[djmace]

im using 450cc injectors on my CA with stock ecu no tuning and an HKS Open Atmosphere BOV and im running fine..... my car dont run rough either..

[vis213]

my car smokes under heavy accel and hits a wall at about 3.5-4k

could it be running rich due to the BOV being vented and possibly leaking under full boost? or could i have a boost leak somewhere else

i run a Blitz SS bov

[c-rad]

my car smokes under heavy accel and hits a wall at about 3.5-4k

could it be running rich due to the BOV being vented and possibly leaking under full boost? or could i have a boost leak somewhere else

i run a Blitz SS bov

Sounds like a boost leak and you are hitting fuel cut from overrunning the MAF.

[burnout 180]

What is really messed up is that I changed my stock intercooling pipes and put in a skyline GTS recirculating blow off valve and now I have some problems.

when I start and idle, the engine runs normal then accelerates then runs normal then it accelerates and it keeps doing that while idling. also when it reves up by its self the engine shakes violantly as if its going to cut off.

Also when i start to move from a complete stop and press the gas it chocks then recovers and starts to go. it also feels like its down on boost and also the waste gate doesn't make as much noise as it used to so i think its down on boost.

I have three therorys that may be causing this:1) When i cut some of the aluminum pipes i didn't clean them out so some metal shavings may have gone up in the throttle body. how would this effect the engine and how can i tell if this happened?

2) their may be a vacume leak from the intake vaccum line near the throttle body also the size of the pipe that that vaccum line connects to has a samaller diameter and also its closser to the throttle body than the stock one was would any of those things cause that.

3) And finally there maybe a leak on the silicone boots that connects the intercooler piping. but heres the thing i have all the clamps tightend up. Is there anyway i can test for leaks or are there any tricks to preventing leaks.

I know this is alot of questions but i really need my car to turn back into the proformance car it used to be.

[rico05]

Get a can (or 2 ) of carb cleaner. Spray around the throttle body, all intake plumbing, etc (NOT the turbo...fire bad). If there is a leak, the carb cleaner will be pulled into the motor, and will cause the motor to surge for a moment. Sounds like a boost leak 100%.

[rico05]

im using 450cc injectors on my CA with stock ecu no tuning and an HKS Open Atmosphere BOV and im running fine..... my car dont run rough either..

Not that I am questioning you, but there is really no way that should even be possible. Sure that is a stock ECU? Cracked it open and peeked?

[djmace]

yea its a stock ecu....havent opened it up but rafi gave me the ecu and it was stock...i got both 78 and 98 ecus's... since i broke my 370cc injectors i had a friend give me the 450cc blue top dsm injectors and i install it... im serious my car runs fine and idles good... just a little rich when im on boost =P

[c-rad]

yea its a stock ecu....havent opened it up but rafi gave me the ecu and it was stock...i got both 78 and 98 ecus's... since i broke my 370cc injectors i had a friend give me the 450cc blue top dsm injectors and i install it... im serious my car runs fine and idles good... just a little rich when im on boost =P

You sure you didn't get a hold of a set of 1G DSM automatic injectors? Those are 390cc. Your car would sputter and backfire at idle with a set of 450s and no fuel control. Same with driving conditions. That's almost 20% more fuel per combustion cycle.

[rico05]

Exactly. We are not questioning you, but once again: it is not possible to have smooth driveability, with big injectors, and a vented BOV. There must be some magic at work here...Have any friends named Ron or Hermoine?

[djmace]

well according to the injector chart .."somewhere on this site in the stickies" its 450cc... im assuming their 450cc cause thats what ive been told..ill ask around in the dsm forums and let u kno..other than that...runs nice..

[cadet]

its defintely possible to vent and have no problems, I have friends that do it.. but sometimes it doesn't work and you do end up with driveability problems. I think it depends on your bov and how bad it leaks... for instance, HKS ssqv doesn't leak but isn't very responsive, whereas turbo XS have a rep for leaking at idle... but still, lots of people run sr's with rfl's and don't have problems, so your guess is as good as mine.

[float_6969]

I don't think that there is any consistant way to tell. I think that it just varies from car to car.

[flohtingPoint]

I've found it all depends on how much tension is on the spring. If you have a proper amount of tension, you shouldnt have problems stalling (I never have in my SR or my CA). Its those people with BoV's that blow off at 2.5k rpms that are stalling.