# BOV Help.



## Nismotune86 (Jul 23, 2005)

I own a 86 z31 Turbo, Do I have to recalculate on my Greddy Type S BOV ?


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## asleepz (Feb 24, 2004)

You don't have to, but you'll run rich after each shift and it may possibly die at idle right after it goes off.


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## Nismotune86 (Jul 23, 2005)

*Any problems.*

Have you had any problems with your TurboXS?


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## JAMESZ (Mar 12, 2004)

asleepz said:


> You don't have to, but you'll run rich after each shift and it may possibly die at idle right after it goes off.


It shouldn't cause to much of a problem. Yes it may go rich, but alot of guys run uncirculated BOVs on MAF cars. Mine is uncirculated, but then again my Z is MAP.

I would suggest recirculating it like asleepz said, but if you don't I doubt you will have any noticeable issues. To tell you the truth though you don't need one.


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## Zen31ZR (Mar 24, 2004)

Not unless you are running significantly over stock boost. I was running 16 psi and didn't notice anything in the way of compressor stall, which the BOV is supposed to prevent, and which would also cause the turbo to spool up more slowly after a shift. Of course, I also tend to NLS, so not much chance of that anyway......


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## asleepz (Feb 24, 2004)

Yeah I believe never letting your foot off the gas during shifting doesn't really allow compresssor stall.

I have yet to have a problem besides my car pulls anywhere from 20-22 inches of vaccume and I had to add another shim to my spring to make it a bit harder and not open during idle.


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## Zen31ZR (Mar 24, 2004)

asleepz said:


> You don't have to, but you'll run rich after each shift and it may possibly die at idle right after it goes off.


Here's the reason why he probably wouldn't run rich, though.

The intake piping on the Z31s is amongst the shortest of all turbo cars, being as there is no extra intercooler piping. The intake piping on a DSM is almost 2 times longer, because it must go from the turbo over to the IC and then up to the intake. There is a lot less chance of running rich on a non ICed car for just that reason. Less missing air when the throttle plates are closed, probably less than 2 cubic feet altogether = not much extra fuel dumped and wasted. On an ICed car, the missing air figure is 5-10 times as much, because of all the air in the IC as well.


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## Nismotune86 (Jul 23, 2005)

*Venting a BOV to atmosphere.*

Venting a BOV to atmosphere will lose all boost vented therefore causing the turbos to have to recover from the lost boost pressure, so recirculating it makes sense to maintain performance.


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## asleepz (Feb 24, 2004)

Yes but right when it closes it should be at about the same RPM (the turbo turbine) so when you step on the throttle again, there still isn't much spool up


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