I have a Synapse BOV, people say run it recric even Synapse says so, but is there really a harm to VTA? Also, can't running Recirc cause the Turbo to run backward?
There is really no performance difference is there?

 

the Stock one is recirc. when the recirc. bov opens the air go back into the intake side. it's when it doesn't open, that's when all the pressure go backward. That's the basic of it from my understanding.

 

Recirculate it

 

Recirculate it for sure, I had one on my car it was great, nice sound and no idle issues.

 

Running your car with a VTA bov might cause stalling when quickly stopping at lights, etc.

Evo X's have a maf and are tuned with a recirculating valve. If the air that is normally recirculated is lost it will cause the car to run rich between gears (and may stall).

 

You need to recirculate it. The info others are giving regarding weird running issues is correct. It's never a good idea to vent metered air.

 

I have a HKS SSQV which is setup to vent to atmosphere. I have been running this setup for 11 months now. My car does not hesitate or stall. I will say there are some slight differences with how the car reacts with VTA and recirculated. With VTA I had to modify my driving style with throttle usage but its so minor it has become second nature.

As for performance, I put down 359whp and 370tq with only intake, TBE and a tune. If I have lost some power due to not recirculating, I can live with those numbers.

 

Recirculate it; venting to atmosphere is basically like creating a large boost leak every time you shift.

 

A retune can help minimize the effects of VTA, but you're doing it wrong. Metered air is just that. Your ecu is expecting it. Help me understand the benefits of your setup. As I understand it, there aren't any. If you want to VTA, go SD.

 

i was just wondering what was better for performance wise, a while back Turbosmart did i peice on Youtube as far as VTA/Recirc/ diverter and they all performed the same... and all were done on a dyno. all they did between runs was change the BOV set-up. So is there any REAL reason why one should run recirc besides the fact from what you stated above? and plus i could always change my set=up in the future, but before i can install it i would love to know what the absolute pros and cons are of VTA and Recirc.

 

You can turn that around and say "is there any REAL reason you should run VTA instead of recirculated like the car is designed?" People above listed REAL reasons you should run recirculated, what is the plus side to VTA other than being fast and furious?

 

One less pipe to clutter the engine bay? Joking obviously...


On a more serious note... I ran the TiAL 50mm without a speed density setup. You won't physically notice a difference when driving. It's all in the logs and fuel economy.

 

like everyone else said_ recirc.

btw, Im running the synapse DV and its ****ing awesome.

 

As others have stated, its like introducing a giant boost leak. Boost leaks are bad for performance. Your ECU has already metered or "counted" that air. When you VTA rather than recirc, your vehicle expects more air, so it applies more gas. Without the air it's expecting, you have moments (like every time you VTA) where the car runs much more rich than it needs to. This hurts your mileage, fouls your plugs more quickly, and likely affects throttle response. If you want to VTA, you should look into a speed density setup. VTA can be tuned to minimize this impact. That's up to you. Why spend money tuning out a problem you intentionally created that can be avoided by keeping things as they were intended? Bottom line, if your car recirculates air *after* the MAF, it's air that it your ecu is expecting. I would argue there isn't a good reason to go VTA, unless the sound it makes is your sort of thing.

 

I have the small Synapse DV, not the BOV, so no option to VTA. But it works really nice. Recirc if you can.