MAF.... blow through or pull from??
MAF.... blow through or pull from?? do you want to blow through it or pull through it. which is better and does it really make a differecne. just wondering what you guys thought and what you guys are doing
I'd think blow through is better becasue it will give a better representation of the air thats going into the motor. The compressor will change the air a little bit, but it's probably negligable. I dont think the MAF itself would care, as long as air is going through in the right direction.
depends on the maf style, there are benefits to both systems.
Most of my expierence is with ford tonsil style maf's and it is no question that a drawthrough setup is far easier to tune than a blowthrough setup.
The GM is not a tonsil style maf, so it does not seem to be as far off using it in blowthrough. Given the chance, I am still going to go with a drawthrouh on my car, eventhough a blowthrough does offer some nice advantages (blowing off air before it goes to the intercooler, keeping the aircharge temps lower)
Ryan
Most of my expierence is with ford tonsil style maf's and it is no question that a drawthrough setup is far easier to tune than a blowthrough setup.
The GM is not a tonsil style maf, so it does not seem to be as far off using it in blowthrough. Given the chance, I am still going to go with a drawthrouh on my car, eventhough a blowthrough does offer some nice advantages (blowing off air before it goes to the intercooler, keeping the aircharge temps lower)
Ryan
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Joined: Nov 2001
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From: Raleigh, NC
With the Procharger, I can unequivocally say that pull-thru is easier to tune and idles much better without the hunting and surging. I've swapped back and forth over and over again. Trust me on this... it is true. 
Also, you can tame LTFT's without adjusting the IFR's or MAF or whatever else you alter to make them zero/negative quite as much. Check your LTFT's, swap to before the blower, and check it again. I've done this over and over. The MAF does not read correct with blow-thru on the Procharger setup. I don't remember the particulars, but it has something to do with the way hoses are routed that alter the PCV circulation or something along that line. It makes the system think there is a slight vacuum leak, and LTFT's will go positive trying to add fuel.
That being said, the boost doesn't seem to come on as strong and quite as high. It may be due to the restriction this presents at the inlet of the blower... my guess.
Also, you can tame LTFT's without adjusting the IFR's or MAF or whatever else you alter to make them zero/negative quite as much. Check your LTFT's, swap to before the blower, and check it again. I've done this over and over. The MAF does not read correct with blow-thru on the Procharger setup. I don't remember the particulars, but it has something to do with the way hoses are routed that alter the PCV circulation or something along that line. It makes the system think there is a slight vacuum leak, and LTFT's will go positive trying to add fuel.
That being said, the boost doesn't seem to come on as strong and quite as high. It may be due to the restriction this presents at the inlet of the blower... my guess.
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Joined: Nov 2001
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From: Raleigh, NC
BTW... I solved the slight drop in boost issue by putting on a bigger filter and a bigger MAF without a screen.
Also, in the default MAF location, use a MAF with a screen and a MAF without a screen. You will see the same surging issues I described at idle. The biggest deal for me with the MAf location was the LTFT issue. I hated having to manipulate tables to drop nearly +10 LTFT's.
In the AFTER blower position, as long as you keep the MAF screened, you should not have a big surge/hunt at idle.
Also, in the default MAF location, use a MAF with a screen and a MAF without a screen. You will see the same surging issues I described at idle. The biggest deal for me with the MAf location was the LTFT issue. I hated having to manipulate tables to drop nearly +10 LTFT's.
In the AFTER blower position, as long as you keep the MAF screened, you should not have a big surge/hunt at idle.
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Originally Posted by onfire
All LPE TT's are blow through..........reduces the maf as a restriction.
Ryan
