HP loss with BOV??

[snooky]

WHAT! Loose HP? i was told it was beneficial when other mods are incorporated, i have a fujita CAI and an SU test pipe. So honestly whats the point? Ya the noise is cool, but I get a similar noise from my CAI $h!t

If anything I thought I was adding HP?

 

[VRMS6]

BOV will be beneficial in a high HP application. For stock/near stock application it will acctually have a negative effect . I did 4 dyno runs on my VRMS6 with and without the BOV and the dyno runs did show a loss with the TXS BOV installed....

 

[snooky]

that sux! Haha

 

[freekwonder]

Why would you lose horsepower with a BOV. The only reason I can see that happening is if the spring is to loose and it is releasing to early.

 

[VRMS6]

simple some air is vented to the atmosphere and not metered by the ecm, you will run a bit rich which isnt optimal for peak HP hence your power loss.

 

[FORZDA 1]

simple some air is vented to the atmosphere and not metered by the ecm, you will run a bit rich which isnt optimal for peak HP hence your power loss.

Makes no sense... On a dyno, you're measuring WOT from ~2500rpm to redline. Sounds like a bogus dyno session. (notcool) If you're dynoing, you MUST make sure the TMIC is cooled properly or your hp WILL go down on subsequent runs. As freekwonder said, the ONLY way you will lose hp with a BOV of ANY style/make is if it leaks under boost... (drive)

 

[elieleb1303]

maybe hes gettin confused between a bov and a bpv..

 

[freekwonder]

simple some air is vented to the atmosphere and not metered by the ecm, you will run a bit rich which isnt optimal for peak HP hence your power loss.

I can understand that for actual driving, but like Forzda said, you are going WOT for a RPM range, you are not letting off the gas to allow for the air to vent. If you are losing power just running through the one gear I would think that the BOV is loose and allowing air to leak out, or vent early.

And I would think while you are racing you would only be running rich after the vent for a few tenths of a second (if that if you are a good shifter). Nothing to loose 5 horse over. Especially true if they say our stock BPV leaks as much as it does at high RPMs.

 

[VRMS6]

Why would you lose horsepower with a BOV. The only reason I can see that happening is if the spring is to loose and it is releasing to early.

http://en.wikipedia.org/wiki/Blowoff_valve

"The unique sound caused by a blowoff valve (but not a compressor bypass valve) sometimes comes at a price. On a car where the blowoff valve is mounted after the mass airflow sensor, venting to atmosphere confuses the engine control unit (ECU) of the car. The ECU is told it has a specific amount of air in the intake system, and injects fuel accordingly. The amount of air released by the blowoff valve is not taken into consideration and the engine runs rich for a period of time. Engines with a manifold absolute pressure regulated ECU or where the blowoff is mounted upstream of the MAF sensor are not affected.

Typically this isn't a major issue, but sometimes it can lead to hesitation or stalling of the engine when the throttle is closed. This situation worsens with higher boost pressures. Eventually this can foul spark plugs and destroy the catalytic converter (when running rich, not all the fuel is properly burned in the cylinder which can allow unburned fuel to combust upon contact with and melt the converter or to cause incompletely combusted fuel to leave heavy carbon deposits).

One way to correct this problem is to reduce the boost going into your engine. This will cause the piston in the blow off valve to only open slightly. Another way to correct this problem would be to plumb the MAS after the BOV."

http://forums.nasioc.com/forums/showthread.php?s=&threadid=468038

"Are there any negative effects with aftermarket BOVs? Yes. The downside of releasing the air to atmosphere is that it has already been metered by the mass air sensor, and when it blows off, the ECU will be injecting the wrong amount of fuel into the cylinders. The engine temporarily runs extremely rich, meaning too much fuel is injected into the cylinders.

This temporary rich condition isnt usually that harmful, but it can cause bucking or hesitation on lift-throttle. If the condition is really bad, it can eventually foul spark plugs and even clog the catalytic converter as unburned fuel on the catalytic converter burns very hot, and too much of it can melt the cat."

 

[freekwonder]

Again stuff that would/could affect racing or daily driving, but I don't see how you would loss horse power on a dyno when you are doing a 1 gear WOT run. When I had my BOV on my car I never had any problems with it causing any hesitation. I know it was a big problem on the MSP, but I never noticed on my MS6.