Psssssssssssssh

[aliencurv]

Re: Psssssssssssssh

Exactly. Sheesh DJ. Whats next, Tireflys and underglow??

lol i don't think anyone has yet to recognize what those are yet :P

let me know if anyone needs help to understand. i'll give u guys a bit longer

[R-Audi]

Re: Psssssssssssssh

I don't get it.
The cars ECU reads and accounts for the metered air... not sure why you would add these?

[Shoppingcart111]

Re: Psssssssssssssh

There is still a large volume of recirced air from this valve, the actual port that blows to atmosphere is very small vs the recirced air so it doesn't throw any codes and you get a blow off sound, plus you can dial in the amount of blow off and recirc.

[aliencurv]

Re: Psssssssssssssh

I don't get it.
The cars ECU reads and accounts for the metered air... not sure why you would add these?

okie i'll tell ya!

so firstly, it's not a bov. it's called a splitter. i hope i can write the reasoning behind the "scavenging" or syphoning properly to explain. so i'll try

ideally, you want a bov but you can really only have one on a MAP based ecu. when the pressure builds and the throttle plate closes, the air would is vented to atmosphere which actually spins the turbine faster as the pressure is released. that means no re-spool time between shifts

if you use a BOV in a MAF based system, the metered air is vented to atmosphere. that means the ecu expected air that isn't there. the ecu puts in fuel for that missing air, and voila: rich conditions. yuck.

soooo, the solution from manufacturers have always been to use recirculating valves on maf based systems. however, that's due to noise and simplicity.

let me draw the scenario of a recirculating valve... the air is pressurized between the turbo and engine... suddenly the throttle plate closes. a combination of boost spike and vacuum from the intake manifold opens the recirculated valve. that pressure is pushed into the intake. the intake already has moving air travelling towards the turbo. the pressurized air being forced into the intake goes right back out through the filter. that reverses the direction of air. it also causes a turbulance. like trying to breath towards the wind for the turbo.

so yes, your measured air gets put back in... but for a loss of performance.

now, with the splitter type setup... the valve (when open) has a large hole to the intake and a small hole to atmosphere. and here is key note: only the air that can fit in the intake will be put into the intake. the rest is vented.

the ammount that is vented is not enough for the ecu to recognize a rich condition.

so now you end up with the syphoning effect on the turbo AND you don't mess up the airflow of incoming air.

and yes, you get a little pssssh. but because it's only a few percent of the actual air, you can barely hear it

now between shifts, my turbines will maintain a higher speed then yours until you buy them also

[R-Audi]

Re: Psssssssssssssh

I think the question still exists.. the ECU is expecting the amount of air currently in the system, when you take any amount out, wouldnt it cause the car to run rich? There isnt any way of accurately measuring the amount lost or split, so unless you run and monitor a wideband aren't you basing everything on theory?

[aliencurv]

Re: Psssssssssssssh

I think the question still exists.. the ECU is expecting the amount of air currently in the system, when you take any amount out, wouldnt it cause the car to run rich? There isnt any way of accurately measuring the amount lost or split, so unless you run and monitor a wideband aren't you basing everything on theory?

you do lose air in a reciculate setup like u currently have. u just don't know it until u think about it.

the part about the air being forced back into the intake with the recirculate valve.. i said that it can only hold so much air. it's already full of air. so when the recirculate throws all that pressurized air back into the intake pipe, it goes out the filter into the atmosphere.

so what happens with the splitter, is that air doesn't go by out the filter. instead it goes out at the splitter.

[Snowcatxx87]

Re: Psssssssssssssh

Only if boost wasn't so expensive for my car :(

Nice engine bay man

[aliencurv]

Re: Psssssssssssssh

Only if boost wasn't so expensive for my car :(

Nice engine bay man

spanx dude!

[The_Jerbel]

Re: Psssssssssssssh

you do lose air in a reciculate setup like u currently have. u just don't know it until u think about it.

the part about the air being forced back into the intake with the recirculate valve.. i said that it can only hold so much air. it's already full of air. so when the recirculate throws all that pressurized air back into the intake pipe, it goes out the filter into the atmosphere.

so what happens with the splitter, is that air doesn't go by out the filter. instead it goes out at the splitter.

The only thing I see a problem with here, is that the pre-turbo intake tract doesn't contain pressurized air. The air flow from the MAF housing to the turbo inlet pipes (which is where the re-circulated air goes) is not compressed, but it is instead being sucked in by the turbochargers. The turbos suck in X volume of air per second, regardless of where it originates from. If air comes from the DV's, then less air must be sucked in through the MAF housing during that instant. When the DV's release pressurized air into the intake system, the vast majority of it will go into the turbo inlets, which will momentarily decrease the air flowing past the MAF sensor.

The direction of airflow is toward the turbo, so the pressurized air coming out of the DV's will mainly follow the path of least resistance, which is with the air flow. Sure, there will be a slight amount of air lost out the filter, but the majority of the re-circulated air will flow into the turbo, displacing the vacuum created in the MAF housing.

Releasing the charge air is certainly good for turbo spool, but pressurizing the intake tract allows the turbos to suck in intake air easier than if they had to do it by pressure differential force alone (as with a BOV or splitter).

It would be interesting to compare your car with another car running a similar setup to see if there is any difference in spool times.

[aliencurv]

Re: Psssssssssssssh

The only thing I see a problem with here, is that the pre-turbo intake tract doesn't contain pressurized air. The air flow from the MAF housing to the turbo inlet pipes (which is where the re-circulated air goes) is not compressed, but it is instead being sucked in by the turbochargers. The turbos suck in X volume of air per second, regardless of where it originates from. If air comes from the DV's, then less air must be sucked in through the MAF housing during that instant. When the DV's release pressurized air into the intake system, the vast majority of it will go into the turbo inlets, which will momentarily decrease the air flowing past the MAF sensor.

The direction of airflow is toward the turbo, so the pressurized air coming out of the DV's will mainly follow the path of least resistance, which is with the air flow. Sure, there will be a slight amount of air lost out the filter, but the majority of the re-circulated air will flow into the turbo, displacing the vacuum created in the MAF housing.

Releasing the charge air is certainly good for turbo spool, but pressurizing the intake tract allows the turbos to suck in intake air easier than if they had to do it by pressure differential force alone (as with a BOV or splitter).

It would be interesting to compare your car with another car running a similar setup to see if there is any difference in spool times.

what you just attempted to describe is perpetual motion. you can't use the energy of pressure from the air exiting the dv to spool the turbo lol. that's simple physics .. if you vent some of the air to atmosphere, you'll syphon air through the turbo.

pretend the air is water in your mind. that'll be easier to picture.

when the DV recirculates, it is pushing air into the intake. the path of less resistance is the air filter, not the turbo. so the air goes out the filter. some goes through the turbo, but only the ammount possible.

[Kor]

Re: Psssssssssssssh

This thread is wack. Good thing there's that fresh prince gif.

I gotta say that IMO Jordan is posting up the facts. There is no performance gain to a BOV. If you are venting metered air then you are running rich.

Probably will work fine on this car and you will get a nice sound, but it's not the optimal setup.

[The_Jerbel]

Re: Psssssssssssssh

The really simple version of the physics is like this:

The turbo has 3 forces acting on it: The exhaust flow through the turbine is positively affecting spool, the vacuum created in the intake piping is negatively affecting spool and is a negative force against the movement of the compressor, and the building charge air pressure is also a negative pressure and force.

Exhaust flow - spins turbo
Intake air vacuum + charge air pressure - work against the spinning turbo.

The less vacuum there is, and the less charge air pressure created, the easier the turbos can spool via the exhaust air flow. When the DV shoots charge air into the air intake, it is reducing both of those negative factors, which does nothing but encourage turbo spool.

This is not a description of perpetual motion since we are not relying on the recirculated air to spool the turbos in a continuum, only to decrease the resistance against the turbos spooling (hot exhaust gas flow has less resistance to overcome in order to spool the turbo).

[R-Audi]

Re: Psssssssssssssh

Either way I'd be up for some ECU-X comparison, although to be 100% fair it would be best to log DJ's car with and without the noise makers as opposed to adding another car in the mix.

[The_Jerbel]

Re: Psssssssssssssh

^ Yup, that's an even better idea than running against another car. Splitters vs. 710N, or something like that.

[aliencurv]

Re: Psssssssssssssh

This is not a description of perpetual motion since we are not relying on the recirculated air to spool the turbos in a continuum, only to decrease the resistance against the turbos spooling (hot exhaust gas flow has less resistance to overcome in order to spool the turbo).

that's the summary of everything you are saying. but it's incorrect. this is the easiest way i can explain it, but u gotta read until u understand:

a recirculate valve increases resistance because the high pressure is vented to a low pressure zone of the intake pipe. there is not enough airflow from the turbo, so the vented air gets pushed out the air filter. the vented air can not "spool" the turbo because that's energy acting apon itself from the pressure it had created.

the path of least resistance in the intake pipe is the air filter.

very simply, think of these fake numbers:

1) pressurized pipes have 25psi @ 4ft^2 volume
2) intake pipe (between filter and turbo) has 15psi @ 2ft^2 volume
3) atmosphere has 14psi @ infinite volume

if you have a divertor valve, the air in #1 will be released to #2. but there neither enough room in #2 and it's pressure is higher then #3. so the air vented to #2 will escape to #3, which is back out the filter to the atmosphere which is the lowest pressure zone.

~~~~~~~~~~~~~~~~~~~~~

now, if i share venting to the intake and atmosphere, then this is what happens... you get a "PROPER" syphoning/scavenging effect. the pressure gets vented "of what it can fit" into the intake. the rest gets put into the atmosphere.

by releasing the air into the path of least resistance without mucking up the airflow in the intake, you end up spooling the turbo. voila

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

i experienced the same concern as you guys when i was first explained. but after cam drew enough diagrams for me, i understood.

we learn new things everyday. and splitter divertor/bov valves are one of them. it's time to accept that guys .. and don't worry, they don't make a noise. they are SUPER quiet.

key summary: all that is happenin with a splitter valve is this: the air that normally gets pushed back out your air filter ANYWAY, is now being released to the atmopshere easier without mucking up the airflow direction in the intake. got it?