LS-1 MAF in up pipe
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A partially open throttle does not pull air evenly thru the MAF and therefore makes the chip programming a handful.
Bruce spent a buncha time getting his to run right.
Its a great experimenter project, Bruces car runs very well set up that way (although he's on to the next project now). It is NOT a plug-and-play deal though.
Bob
Bruce spent a buncha time getting his to run right.
Its a great experimenter project, Bruces car runs very well set up that way (although he's on to the next project now). It is NOT a plug-and-play deal though.
Bob
Not quite that simple. As Bob stated. The partially open throttle body doesn't allow the air to flow smoothly over the elements (more than one). Sorta like turbulance, and causes from unusual symptoms.
Bruce can probably clerify, if he's around.
It does seem that most of them have been done by guys doing there own chips, there are some running, run of the mill chips by others that are getting along OK.
The only negative comment I've received so far was from a guy that tore his hood liner, he hadn't expected the .5" spacer to cause that. OK, there was the guy that tried doing it with the stock MAF, that was surprised when it blew apart.
BTW, the Extreme and 72s just took a few more PSI of Fuel Pressure, and it seems pretty good, from first reports. Again, it's blow thru.
More like projectS. LOL
Originally posted by V8KILLR
Why does it matter, maybe I'm just over looking something because I'm low of sleep, but
m dot in has to = m dot out
Jason , Well on cars that have a tip in stumble, seems like this mod would help the situation being as when you move the throttle slightly the air has to move through the up pipe, intercooler, turbo, hose on turbo inlet, then the MAF finally sees the change of air flow. Also the turbo would much rather have to blow through this restriction than to have to suck through it. I could see where cars with front mounts would really benefit from it. Just my thoughts.
Steve
Why does it matter, maybe I'm just over looking something because I'm low of sleep, but
m dot in has to = m dot out
Jason , Well on cars that have a tip in stumble, seems like this mod would help the situation being as when you move the throttle slightly the air has to move through the up pipe, intercooler, turbo, hose on turbo inlet, then the MAF finally sees the change of air flow. Also the turbo would much rather have to blow through this restriction than to have to suck through it. I could see where cars with front mounts would really benefit from it. Just my thoughts.
Steve
The advantages to the blow thru are.
It's less of a restriction, when in boost then a draw thru. Turbos make better pressure pumps then vac pumps.
The Lat MAFs have there own internal temp compensation, so the MAF readings reflect any heat saturation from prolonged staging, stop+go traffic etc etc. The more accurate the info the ecm has the better it's calculations.
There has been mention that for every 1% decrease in intake restriction there is a 2% increase in HP, all other things being equal.
Slightly better resolution of air consumption during throttle transistions. Since the air doesn't have to work back past the turbo to correct the MAF reading.
If your injector limited, and lose the restriction of the MAF being on the draw thru side, you might slow down a little. If on the other hand you have injector to spare, then you might be faster in blow thru.
It's something to experiment with.
Screen in, vane cut out seemed to be the best combo.. There MAY have been a slight amount of turbulence across the MAF, but it wan't enough to really worry about with my combo.. Again results may vary, yada yada.
Disadvantages,
Possible oil containation from a bad oil seal in turbo. Thou in about 10K miles of use, mine never showed any problems from any normal seepage.
There is an outside possiblity that on a really hot day with a heat soaked I/C you MIGHT reach the thermal correction limit of the MAF. But, again, nothing that I ever saw.
If I was to go back to a MAF, it would be blow thru.
It's less of a restriction, when in boost then a draw thru. Turbos make better pressure pumps then vac pumps.
The Lat MAFs have there own internal temp compensation, so the MAF readings reflect any heat saturation from prolonged staging, stop+go traffic etc etc. The more accurate the info the ecm has the better it's calculations.
There has been mention that for every 1% decrease in intake restriction there is a 2% increase in HP, all other things being equal.
Slightly better resolution of air consumption during throttle transistions. Since the air doesn't have to work back past the turbo to correct the MAF reading.
If your injector limited, and lose the restriction of the MAF being on the draw thru side, you might slow down a little. If on the other hand you have injector to spare, then you might be faster in blow thru.
It's something to experiment with.
Screen in, vane cut out seemed to be the best combo.. There MAY have been a slight amount of turbulence across the MAF, but it wan't enough to really worry about with my combo.. Again results may vary, yada yada.
Disadvantages,
Possible oil containation from a bad oil seal in turbo. Thou in about 10K miles of use, mine never showed any problems from any normal seepage.
There is an outside possiblity that on a really hot day with a heat soaked I/C you MIGHT reach the thermal correction limit of the MAF. But, again, nothing that I ever saw.
If I was to go back to a MAF, it would be blow thru.
The Radius Kid
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I tried it with a 3" Impy MAF and an off the shelf chip.
50# inj's,CAS V-1 and cold air kit and it seemed to work fine.
Isn't GM doing it that way these days?
I think the accuracy offered would tend to compensate for any chip tweaking that would be involved.
Correct me if I'm wrong here.
50# inj's,CAS V-1 and cold air kit and it seemed to work fine.
Isn't GM doing it that way these days?
I think the accuracy offered would tend to compensate for any chip tweaking that would be involved.
Correct me if I'm wrong here.
I have been running with a LT1 maf. 52# Siemens and Bob's Extender chip for a while, and found no problems with the blow through setup. Can't share a comparison, because when I switched over to the Trans+ LT1 setup I went directly to the up pipe setup.
Paul
Paul
Would this give any more horsepower? Or is it just for better drivability? This is an intresting post. My buddy has a blower on an lt-1 car, and his maf is after the supercharger. He was telling me that it corrects the air flow alot better after the supercharger.
Joe
Joe
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