MAF or SD?
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From: Elkhart, IN, USA
Car: 77 K20 80 K2500 93 C2500 94 K1500
Engine: 350 350 454 350
Transmission: 350 465 80E 60E
Axle/Gears: 4.10 3.73 5.13 3.73
MAF or SD?
which will respond better to future mods and tuning? my LT1 is out of a '94 9C1 Caprice. which should it be, MAF or SD?
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Joined: Nov 2003
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From: Elkhart, IN, USA
Car: 77 K20 80 K2500 93 C2500 94 K1500
Engine: 350 350 454 350
Transmission: 350 465 80E 60E
Axle/Gears: 4.10 3.73 5.13 3.73
i take it that means that the MAF setup is more responsive to modifications?
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From: Oregon
Car: GM & Jaguar
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Transmission: Various
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I've been researching all this MAF vs. SD hubub for YEARS and have only just now come to a somewhat simple conclusion;
Come to think of it, I've only seen MAF LT1 motors (stock) - is there even such a thing as an LT1 that's SD? Up to '97 used MAF, and '98+ was LS1 
Unless you're talking about doing some funky retro-fit ECM swappin'...
Originally Posted by http://tpiparts.com
They each have their advantages and disadvantages over the other. Which one will suit your needs better depends on your specific application. Both have the potential to work equally well on stock engines, as well as on modified engines. However, MAP is much more sensitive to engine modifications (particularly cam and head changes). A heavily modified engine with a MAP system will not run well on a stock tune, but can run flawlessly with the proper tuning. A MAF setup on the other hand can run very well on a stock tune even with a heavily modified engine. There are gains with prom tuning, but it is not as critical as the MAP system. Parts are readily available for both, but there is a difference in cost for sensors between the two. A MAF sensor is significantly more expensive than a MAP sensor.
Unless you're talking about doing some funky retro-fit ECM swappin'... Can disconnect the wires for the LT1 MAF, then start the car and it should run in speed density.
Might have to have the pcm reprogammed though. I know there's an option to select in the bin file for a 94-95 to run in speed density.
Might have to have the pcm reprogammed though. I know there's an option to select in the bin file for a 94-95 to run in speed density.
Last edited by Firebat; Apr 19, 2006 at 12:32 PM.
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From: Ringgold, Ga/ Nashville, TN
Car: 1989 Chevrolet Camaro
Engine: LT1
Transmission: 700R4
Axle/Gears: 2000 rear, 3.73, auburn locker
Originally Posted by Firebat
Can disconnect the wires for the LT1 MAF, then start the car and it should run in speed density.
Might have to have the pcm reprogammed though. I know there's an option to select in the bin file for a 94-95 to run in speed density.
Might have to have the pcm reprogammed though. I know there's an option to select in the bin file for a 94-95 to run in speed density.
Originally Posted by Klortho
'93 models were SD
nope. unplug the MAF and start the car it defaults to speed density but will throw a code if not programmed right.
92-93 LT1s were speed density
92-93 LT1s were speed density
Last edited by Firebat; Apr 21, 2006 at 11:57 PM.
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From: Oregon
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Originally Posted by Firebat
92-93 LT1s were speed density
It's interesting to me that GM went from MAF to SD for TPI, then went from SD to MAF for LTx motors... notice the LSx or any other new GM setup utilizes MAF rather than SD
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From: Buckhannon, WV
Car: 84' Monte
Engine: 350
Transmission: 700-r4
Axle/Gears: ferd 9" posi 3.50 gears
Are you guys sure there is a map sensor with the LT1's????? There is a limp home mode that uses your TPS and rpm's to guestimate how much fuel to inject. It's not really speed density, and doesn't work all that well.
LS1's are both, they have a map and a maf sensor. The ecm uses one to check the other and switches back and forth depending on the driving situation.
LS1's are both, they have a map and a maf sensor. The ecm uses one to check the other and switches back and forth depending on the driving situation.
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From: Ringgold, Ga/ Nashville, TN
Car: 1989 Chevrolet Camaro
Engine: LT1
Transmission: 700R4
Axle/Gears: 2000 rear, 3.73, auburn locker
I thought that all MAF cars had to have the MAF sensor plugged in and working correctly to run right. I always thought if there was a problem, it would go into limp home mode and not run worth a crap. Wouldn't it do the same thing if you unplugged it?
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From: Buckhannon, WV
Car: 84' Monte
Engine: 350
Transmission: 700-r4
Axle/Gears: ferd 9" posi 3.50 gears
I admittedly haven't ever messed with LT1's, does this map sensor get referenced to the manifold, or is it open to the air? This could just be a barometer. The only reason I question this is that the fact that the LS1's used both SD and MAF was played up as the newest greatest way to run an engine. Not trying to step on toes, just clarify the info I have read. If it does in fact have a map sensor, then it could be tuned for SD only just like the LS1 ECM's.
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From: Kingston, Tn
Car: 1987 GTA
Engine: LT1
Transmission: T56
Axle/Gears: 9 bolt 3.70 posi
It's referenced to the manifold, thus the MAP. My Mustang has a BAP or Barometric Air Pressure sensor on it, but no MAP.
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From: South Florida
Car: 90' Trans Am
Engine: 94' LT1
Transmission: Built 700R4
I run a 94 LT1 with the ECM out of a 93 LT1, eleminating the need for the MAF and other sensors........runs fine....a lil rich but Ill have to look into that later.
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From: Timrå, Sweden
Car: 1984 Corvette
Engine: Turbo 350
Transmission: 4L80E with TCI T-Com
A MAF system has a air flow table that is calibrated to the MAF sensor. As long as you don't max out the MAF the engine knows how much air the engine uses and can calulate the amount of fuel needed.
Once you get to the point where you start to alter the calibration I think a MAP system is easier. The fuel table is like an excel sheet with engine RPM on one axis and engine vacuum on the other. If you have a vacuum(/boost) meter and a tachometer then you know the current operating point of the engine. If you want to add fuel you adjust that cell in the table.
Once you get to the point where you start to alter the calibration I think a MAP system is easier. The fuel table is like an excel sheet with engine RPM on one axis and engine vacuum on the other. If you have a vacuum(/boost) meter and a tachometer then you know the current operating point of the engine. If you want to add fuel you adjust that cell in the table.
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From: Kingston, Tn
Car: 1987 GTA
Engine: LT1
Transmission: T56
Axle/Gears: 9 bolt 3.70 posi
You can actually do that with the MAF LT1's JoBy since there are several fuel tables for both the MAP and MAF depending on throttle position, RPM etc etc.
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