moving dual afm's to top hoses?

ok im not sure about this but i have been thinking lately after reading much info on blow off valves and the problems venting to atmosphere creates with fuel air mixture and the problems this causes...im running dual afm's and i am thinking if they are moved to the top intake hoses before the plenum and then they can only read the air from after the valves...

Thoughts?

steve

 

I've had this idea for a loooong time, like situating the AFMs right before the TBs somehow. No idea if it is possible though.

At a glance I think there is only 2 hurdles, one being how to fit them in the Engine Bay and the other is whether or not they handle pressurized air (post-Turbo). Might be more hurdles, but eh, never really looked into it. Was more of a curiosity.

MoulaZX

 

Isn't this what Theo's HKS VPC unit thing does? Measures pressure in the plenum as opposed to sure coming in?

 

Not quite. What Martin has now is not a MAF, its a MAP. Different kind of sensor design to read Vacuum/Pressure directly off the Intake Manifold/Plenum. We're talking about just moving the existing MAF sensors the majority of us have back up closer to the Plenum.

MoulaZX

 

dont quote me on this, but im reasonably certain that afm's will not work on the pressurised side of the turbos.....

 

Yeah but the thought behind it is the same, correct? It will accomplish the same thing as far as I can tell, but I'm a turbo noob, so enlighten me

 

I don't think Dean meant the VPC moved the AFM's, but that it served the purpose required here. He's right too - a MAP sensor is the only way to do this I think.

 

Oh, if thats what you mean then yep. From what I understood from the OP he's trying to get similar effects of a MAP sensor but with the standard MAF. No more minor popping noises backing off from a hard acceleration if you left it in the same gear and decelerating. And no black smoke (unburnt fuel) being blown out the rear (usually for a split second though) also after backing off from a hard acceleration.

IMO both very minor inconvenience and neither would lead to any damage and as MagicMike said, not worth the immense hassle involved.

Martin mostly wants it so that he can run only the MAP sensor and ditch the MAF because eventually he wants to split the single intake under the nose panel and have it be a dual intake, with the intakes coming out from where the SMICs mount. Which is exactly what I was looking into before I gave up and with Selin + SMICs. I didn't like the idea of having a dual intake system behind already an already hot FMIC.

MoulaZX

 

Normal MAFs will be configured for reading near ambient air pressure, give or take normal variation. I dont know that they will be accurate with boost added. Also, they are set up to see near ambient air also, say at most ~50deg C. Placing them after a turbo, even with intercooling (unless u have water/meth spray) will result in higher temps, thus lowering the life span of the part...

im sure a MAFs could be designed to go after the turbos though, if there was a performance benefit

 

Actually this has been both done and discussed a few times.(tt.net i think)
The resolution on the mafs is the same and they work quite well on the pressure side,but what made it not really feasible was the fact that they pop around 17psi.the material just wont handle too much boost.

 

whe you say they 'pop', is it the surrounding plastics (tube, flanges, ect), or does the sensor itself fail?

 

Without a doubt it would be the sensor. It's just not what they're made to handle.