# S15 BOV Install



## davidpavel (May 20, 2016)

Hey guys,

So I imported myself an S15 and I bought a Blitz BOV that came welded onto an elbow joint. I looked up how to install one and found this: http://www.turbosmartusa.com/wp-content/uploads/2011/12/FG-ADM-200SX.pdf which came close to what I am trying to do.

I did everything in that setup manual except using the "blank off assembly" since I don't actually have their kit.

However, after I installed it, started the car and the car was very boggy, the engine was not running properly, RPMs kept dropping randomly and I was blowing black smoke out the back. All this means I was running really rich and that something was up. However, I am not sure why that would happen. So, I took off the BOV and went back to stock and it ran perfect again.

As you can see in 1st photo, I remove the 'factory vacuum line' from the stock BOV and installed a new one, which I ended up connecting to the Blitz BOV.
In the 2nd photo, you can see that I detached the 'factory BOV return pipe' and 'plumb back hose' and plugged both of them (as the setup manual showed - they just used a different part instead of my white cap).

After I went back to stock, I looked at the Blitz BOV and saw that it was locked shut and couldn't push it down. So, I got an allen key and loosened it from the top so that it was pushable. Could that be why? That the BOV wasn't opening at all? But that wouldn't make my engine run THAT boggy right?

Do you have ANY idea what could be wrong? Any input is appreciated and if you need any further clarifications, let me know!
Thanks in advance!

 http://postimage.org/
 http://postimage.org/


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## rogoman (Dec 16, 2004)

The underlying objective of a blow-off valve (BOV) is to protect the turbo against damage while ensuring smooth and reliable drivability. It just so happens it makes a loud sound that gets everyone’s attention! But the noise it makes shouldn’t be what you’re most concerned about; you have to make sure you have the right valve for your ride. Every component of a turbo system needs to work together. But when there’s compressor surge, it can create headaches, mess with performance and even cause damage to your car. Compressor surge occurs when you suddenly lift off the gas pedal and the throttle plate closes. A rush of boost heads into the engine and when it hits the closed throttle plate, it has nowhere to go but back into the turbo.

The type of engine management your car runs will come into play when choosing a valve. If you have a MAF-type system, it meters the airflow after it enters the intake system. In this case, when a blow-off discharges to the atmosphere, the ECU isn’t able to properly fuel the engine resulting in rich AFRs, hesitation, bad idle and even stalling. In these systems the excess pressure must be plumbed back into the turbo system before the compressor inlet, which is what a bypass valve does.

My question is why did you replace the OEM blow-off valve with a Blitz bov.


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## davidpavel (May 20, 2016)

Thank you for the reply! I mainly got one because I wanted to hear the "pshhh" sound when letting off the throttle. I knew that I was going to run a bit rich and that's why I was planning on getting a tune for the car to flash to ECU to full atmosphere.

However, the part that mind boggles me is that in this setup manual -> http://www.turbosmartusa.com/wp-content/uploads/2011/12/FG-ADM-200SX.pdf , they do exactly what I did and they don't mention anything about running rich or major engine bogging. That's why I was thinking I have something set-up wrong that's causing the major issue.

The Blitz BOV is S15 specific as you can see the elbow joint fits perfectly.


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## rogoman (Dec 16, 2004)

davidpavel said:


> After I went back to stock, I looked at the Blitz BOV and saw that it was locked shut and couldn't push it down. So, I got an allen key and loosened it from the top so that it was pushable. Could that be why? That the BOV wasn't opening at all? But that wouldn't make my engine run THAT boggy right?
> 
> Do you have ANY idea what could be wrong? Any input is appreciated and if you need any further clarifications, let me know!
> Thanks in advance!


With the Blitz BOV shut, the engine should idle smoothly; if not, there may be a vacuum leak in the hot pipe or the Blitz itself. Connect a vacuum gauge to the pipe. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. If readings are under 18 InHg, check the pipe clamps. Also the Blitz may not be sealing up properly, cause a major vacuum leak.


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## Asleep (Jan 19, 2003)

Sounds like there was a huge boost leak or a huge vacuum leak. I always check the bov first. I had 2 that would leak really badly that were supposed to be brand new. Are these issues only happening at idle and deceleration? Or are you also have problems with acceleration? Boggy on accel or decel?


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