M.A.F.S.
03-05-2001, 06:43 PM
#1
Supporting Maxima.org Member
Thread Starter
Join Date: Aug 2000
Posts: 993
Stillen says the pulley that comes with the s/c maxs out the m.a.f.s., they had done testing on smaller pulleys, and different size diaphrams for the fmu, of course there was gain, but they were running dangerously lean, they found out that the mafs was maxed out with the standard size pulley. so they won't sell me a smaller pulley.
03-06-2001, 08:04 AM
#2
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Posts: n/a
What they mean is the voltage output of the MAF sensor is maxxed out with the pulley. You can physically flow more air through the sensor, but the additional air won't be sensed, and no additional fuel will be therefore added. You'll run lean.
Your options:
Call up a performance shop and ask their advice (I recommend because they'll have a lot more experience and can offer better advice that I)
But some things off the top of my head:
1) Install an aftermarket MAF sensor. Try http://www.splitsec.com, Split Second. They make high-flow MAF sensors. Looks like they'll be under $300.
2) Install something like the APEXi Super AFC air flow controller. You can adjust the fuel flows up to +/-50% to correspond with the altered mixture you'll get from the different MAF sensor.
Depending on how maxxed out the stock MAF will be...I'm guessing that it'll be fine up to ~5500 rpms, then will saturate...you may be able to get away with a Super AFC only. You could make adjustments past 5500 rpm to richen the fuel mixture. They fuel curve won't be optimized past 5500, though. Since you're making "blanket" changes past that rpm, the MAF sensor isn't providing any feedback to correct the fuel curve. If you tune it "perfectly" at, say, 55 degrees when you're flowing more air, when you start driving at 90 degrees (less air due to heat/lower air density), the car will be richer. This isn't bad for the car (within reason), but won't make optimum power. Still, I'd recommend if you did go the Super AFC-only route, that you either dyno on a cool day or have the dyno tuner purposely tune the car a little on the rich side past max-MAF rpm to be safe.
One more thing, I would definitely look into your injector pulsewidth also before you get the smaller pulley. If your injectors are near-capacity, that's another thing you'd need to upgrade...or increase the fuel pressure somehow.
Irregardless, I highly recommend you talk to a performance shop/installer/tuner before getting the pulley.
Your options:
Call up a performance shop and ask their advice (I recommend because they'll have a lot more experience and can offer better advice that I)
But some things off the top of my head:
1) Install an aftermarket MAF sensor. Try http://www.splitsec.com, Split Second. They make high-flow MAF sensors. Looks like they'll be under $300.
2) Install something like the APEXi Super AFC air flow controller. You can adjust the fuel flows up to +/-50% to correspond with the altered mixture you'll get from the different MAF sensor.
Depending on how maxxed out the stock MAF will be...I'm guessing that it'll be fine up to ~5500 rpms, then will saturate...you may be able to get away with a Super AFC only. You could make adjustments past 5500 rpm to richen the fuel mixture. They fuel curve won't be optimized past 5500, though. Since you're making "blanket" changes past that rpm, the MAF sensor isn't providing any feedback to correct the fuel curve. If you tune it "perfectly" at, say, 55 degrees when you're flowing more air, when you start driving at 90 degrees (less air due to heat/lower air density), the car will be richer. This isn't bad for the car (within reason), but won't make optimum power. Still, I'd recommend if you did go the Super AFC-only route, that you either dyno on a cool day or have the dyno tuner purposely tune the car a little on the rich side past max-MAF rpm to be safe.
One more thing, I would definitely look into your injector pulsewidth also before you get the smaller pulley. If your injectors are near-capacity, that's another thing you'd need to upgrade...or increase the fuel pressure somehow.
Irregardless, I highly recommend you talk to a performance shop/installer/tuner before getting the pulley.