Thread: maf and blow off valve location

I been going threw alot of pics lately and noticed maf and bov in intresting locations. On my car i have maf on intake pipe before turbo and bov very close to throttle body on cold side and then recircultated back into intake pipe between maf and turbo. From what i know this is the proper way because you want boosted air off the throttle plate as quickly as possible, and want recirculated air to pass threw the turbo so turbine keeps its rpm up. The air needs to be behind the maf so that your not loosing air out the system.

Pics i have seen have maf right before throtle body on cold pipe and bov on cold side. Why is it done this way or is my way incorrect?

Ummm... I'm trying to visualize this in my head, and it's not making much sense.

By hot pipe, are you referring to the compressor outlet (intercooler piping)?

You seem to be running a recirculated setup, in that the MAF is between the cone filter and the turbo inlet (Pre-turbo intake arm). This is fine. Then you would need the BOV on the cold side piping (after intercooler), before the TB (obviously, nowhere else to put it on the cold side). The bypass then recirculates the charge back into the system, between the MAF and Turbo inlet, which is proper.

The other way to run a setup, if you want an open atmosphere BOV setup, and don't want to run pig rich in between shifts/boost, would be to place the MAF between the TB and the intercooler, cold side. At the same time, you'd want the BOV between the MAF and the Compressor housing. Some place it on the hotside piping between the compressor and intercooler, where others place it between the intercooler and the MAF housing (preferred method, prevents any undue stress to diaphram/piston from excessive heat).

I hope what I stated here makes sense.

-TeK

when i said hot pipe i was thinking intake pipe before turbo. not hot pipe from turbo to intercooler. sorry for type o fixed post

There are many other reasons for recirculating your bov.
1. Keeps turbo spooling between shifts
2. Helps cool turbo with intercooled air
3 No backfire between shifs Keeps police off your back
If you have a car ran by a map sensor there is no real need to recirculate

I agree that there are many reasons that are beneficial, regarding a recirculated setup.

I for one, prefer a blow thru setup, as I like the ricetastic sound the BOV gives off

In all seriousness, though, my turbines are watercooled, so I'm not worried about them breathing hot air. Hell I live in El Paso, so intercooled air STILL isn't that cool. I never worry about backfire issues, either. That's all in the tune. If you run too rich, then of course you will have backfire issues. Running a proper blow thru setup will not have you running too rich.

Blow through FTW!

blow through you mean open atmosphere? I agree about the wooosh. I have a hks super sequential so i can run either way, but if im going to a track it recirculated. on the steets open atmosphere for sure.
backfire when shifting: exceptible, backfire while on the throttle:game over.

blow thru = compressed air going thru the maf, maf after the turbo

draw thru = uncompressed air going thru the maf, maf before the turbo.

I find that there are several benefits to having the maf after the turbo. My idle is smoother and lower, which is a common complaint among SR20 owners, esp. classics. I also find that I have less tuning issues since the recirc piping is gone. It's just one more place to have a leak to chase. I, like Tekkie, love the ricetastic whooosh that my type-RS emits upon shifting. I admit it, I'm a ricer, it's a beautiful sound! Also, I find that my tune is better overall. I don't know if it's an air turbulence thing or something, but my afr's are much smoother overall on the datalogger since going blow thru. less spikes and valleys to try to iron out. The one issue with a blow thru setup is that the maf can leak air thru the cap to the circuitry. I preempted this by coating the whole dumb thing with a thick layer of epoxy. In short, KD has it right: Blow thru FTW!

I think ill try your blow threw method . Will help my intake pipe layout significantly, especially cause i just bought a z32 maf and wont fit in current location. Im with you guys in lovin the ricetastic sound blasting out the hood of my car. I just never seen it done that way. So in a gtir manifold what would you do about the 1" to 1.5" pipe coming out the manifold. Was going to put my bov there, now i dont know.

you mean the turbo outlet? I made a custom pipe that has a couple of adapter sections that wraps around the turbo and drops right behind the radiator. The pipe ends up 2.5" shortly after the turbo. My bov is in the fender just after the air comes out of the FMIC. You do need to make sure that your MAF is as far as possible from any bends in either direction to reduce turbulence to a minimum. My setup is still kinda ghetto because I didn't want to make new pipes, but didn't have a good, solid section to cut out. So I have a short section at the TB, then the MAF, then a short section, then the fender section. Not pretty, but works very well.