Anyone running a stock MAF on the "pressure" side of a high boost setup? I am thinking about trying this and would like to hear what experience others have had with this mod. I am trying to lower the inlet restriction on my Procharger F1 setup. When we completely disconnected the intake tubing and ran SD we saw a 4lb boost increase! And that's with a custom 4" rigid intake pipe.

Rich Krause

 

So far, everything is good. Im sure yo already will know this but you just have to worry about maxing out the maf now that your considering moving the maf to the pressure side.

 

I am going to do this in my setup (though still haven't gotten around to bolting it all up - have an every growing pile of parts in the closet ).

I have done this on a few other peoples FI setups, and honestly I like it better. I generally had an easier time getting a smooth/stable idle, and other readings seemed repeatable. It does change the response of the maf (calibration), so you will have to do a bit of re-tuning, but I think it is definitely worth it. As a bonus piping is now simplified as you can vent the BOV directly to the atmosphere.

I have *heard* (never seen) of problems with the plastic bodied MAF's at >15lbs of boost.



Really it should read the same on either side, as the sensor measures massflow. The change in positioning will effect the calibration of the sensor to a certain extent, but we are talking a small percentage here, not the difference between maxining out the MAF or not (which you should be on any decent FI setup ).

Chris

 

Thanks, Chris.

Yes, it's already maxed out.

Rich Krause

 

Chris, whatever happened to the Pro-M MAF and the voltage to frequency converter you were building?

 

I have only heard of it going on the intake side. That is alot of heat and air for a plastic MAF sensor to handle. If it is stock, I definately recommend putting it on the intake side of the charger, If it is aftermarket, then maybe you can get away with it going on the boost side of the charger. In any case, good luck!

T

 

I have a stock sensor in a metal housing.

Rich Krause

 

I have a Vortech with the Maf relocated up top and have had no problems. I am only running 5lbs boost right now but the MAF is almost maxed out. The only reason Vortech recomends putting it on the Intake side I think was for smog reasons, and a read an earlier post on the board that said ATI recommends putting the MAF topside as well. Personally I think you get a more accuarate reading up top as that is where they locate the stock ones.

 

I ran mine up to 18 psi on the pressure side. I was running the ATI twin intercoolers, and used an aluminum elbow (vortech) and had the MAF right at the end of that. I had absolutely no problems with it running there. Like I've stated times before, I haven't had any problems running it before or after the MAF with the BOV either venting metered or nonmetered air.

Bill

 

Still there - going to be on the pressure side actually have a tone of parts in my closet, just been so busy with school/work I haven't had a chance to put it all together (plus I still need to fab up the intercooler piping). I ended up scrapping the circuit with the V-F converter as it drifted to much vs. temperature (LJ and Harlan both warned me to watch out for that) - I now am using an avr Mega8 to sample the voltage and output the frequency - it's pretty accurate

Chris

 

Cool. Can't wait to see the results.

 

My MAF has been on the pressure side for a few thousand miles... no problems here.

 

Now that's how to do it

AVR have more than 8 bit resolution? Curious how the conversion granularity is.

either way, much better solution. My box from Pro-m was too sketchy for my taste, and when it crapped out i ditched their MAF for the current setup.

I've always run the MAF on the pressure side with great results.

 

Seems clear that there is no good reason not to go over to the pressure side with the MAF.

Thanks.

Rich Krause

 

The obvious reason for moving the MAF up to the pressurized side is of course to minimize the chance of an innacurate air flow reading. Since the MAF is right next to the intake manifold there is not much room for a leak. Other than that some people have had it help with surging, idle, etc.