What is better. To use your BOV's as full recircs or full atmo?

this isn't really how it works man, that's sort of like saying "if I get a vented nose panel and drive fast will I get forced induction?"

To really get into that you'd have to be looking at what direction the air is getting released from the valve into the intake... with the OEM pipework it's pumped in at a 90* angle and I wouldn't be surprised to hear it actually for brief moments reverses the flow from the AFM. The most even flow of air to the turbo produces the best results - this is why I went for mandel bent intake piping rather than cut/welded. all of this in reality would make absolutely no difference though.

Besides, when the throttle is closed the demand for air drops hugely - way, way below what the turbos easily suck through the pods. there's no strain on the turbos with such low flow demands.

 

The engine can't use that 'potential air' as you are off the throttle. If you pump it into the inlet, it will probably have enough flow to push it out past the filter anyway.

 

yes this is a part of the reason ...

BOV'S leak because there is 2 bits of metal rubbing on each other endless amount of times every time you drive your car, this is one of the leaks, that happens. ( if and when they become faulty ) and they will..

the idle leak is another leak ( its just to lose ) tightening it up may fix it , short term . ( if there not fault )

they are very inconsistent , you don't really know when they a good or bad , . leaking or not leaking .

there is literally no power to be made either way you go ,( plumb back or not )( top end dyno power ) you will still get your E.G 350 rwkw. give or take

its what happens in between all this 0 to 350 rwkw .
your engine will not respond well and also take its time revving up, when leaking .fact. ( lose over all power)

car some times goes hard, some times not .( inconsistent )

i took my valves out of the car years ago . and most of my tuning problems just went away. now i run turbo smart plumb back valves , not one time have they ever given me problems , on or of the dyno . on the circuit , or at the drags , my time are very consistent ( other then general problems ) .

they are simply shit , they are mostly all the same , just different brands .

 

Pump, dump, doesn't matter. Either way it's a large flow under pressure. You're going to have massive turbulence in the inlet whichever BOV you use. Whenever the throttle is shut quickly you are going to have at least some reversion.

 

This happens to me. When I brake hard with clutch in the car stalls every now and then so I have to quick give it a bit of a rev. How can I fix this?

By plumbing the BOV's back in, I will not get any pppshhhhh sound right?

 

Lol, thats awesome, could be it doesn't need one because it has no throttle plate....

 

So is it safe to say that with plumb backs you will have better throttle response?

Where as with atmo, you will sound like a total boss, but run lean for an insignificant amount of time?

 

No, you will run rich while it's venting (if your engine has a AFM, like most zeds). BOV will not cause any lean running unless jammed open.

 

No, because the draw on air at low RPM when the air from the recircs vent in will be met with or without the vent.

You'll never run lean, you'll run rich when they vent. Unless you have atmo's and a MAP sensor, in which case you'll have massive swag.

 

Yes there can be issues with tightening them up too much as I encountered this with my GFB Hybrids. If you tighten up the spring preload too much the BOV wont open and this in my case caused turbulance disrupting the AFM and giving me the same symptoms that you would get from a atmo BOV on a AFM car (i.e Stalling after a rev or while decelerating) After consulting GFB they helped my understanding of how a BOV works and assured me that if you run more boost that doesnt mean that you need to tighten the spring to the max.

In theory on a car running a MAP sensor, an atmo BOV would be better due to the fact that it isnt plumbing air back into the system causing unwanted turbulance.

Also I think I was reading somewhere that if you are able to make your BOV release only enough air to make it not flutter it will release that air and then close to have the system pressurised to a certain degree, ready for the next throttle press, supposedly giving you better throttle response, however I think that would be cancelled out by the fact that if you only let enough air out so that it doesnt flutter, surely it would still slow the turbo down enough to make the spool up time longer.

 

Only true fix is a full recirc valve. You could try one of those adjustable valves that do 50% recirc 50% atmo if you really want the noise.

 

You can bump the idle up, but that is not really fixing it. Just covers it up.

 

Argh I meant rich, not lean...

Thanks for the clear up though everyone

 

LOL- NICE ONE CHILLI ! +1

Finally - waiting for this to pop up sooner or later as I was thinking is illegal better or worse? But it took robbo260 to get there and keep the thread in context - +2

 

Nothing wrong with the sound my Z1 full recircs made, still enough to attract plenty of attention. Having a pod filter helps though

 

recirc or atmo......

All depends on whether you think SMIC or FMIC is better, or 2+0 vs 2+2.

Like the other rehtorical debates on here, it comess down to personal preference . Performance differences are likely too little to ever reliably measure.

 

Based on this video, if you tighten up the BOV a fair bit, won't it mean some pressure will still be stuck in therefor helping the car get on boost quicker one the accelerator pedal is pushed in again?

So is this thread done and dusted?

Recircs won't give you more power but will help throttle response and help you get to max boost quicker....?

 

you only tighten it enough so that the piston inside the BOV stays closed on idle. If you tighten it too much you may as well just block off the BOV completely as it wont open properly, which wont let out the pressure that it was supposed to causing the compressor to surge and then making the turbo need to spool up from a much lower speed resulting in more turbo lag.