A friend has been asking me for a long time what he should get. MAF or Speed Density, I know both have pros and cons, but could someone just lay down the law so I can print it out for him. Were any 4th gens Speed Density? I know that which one you go w/ really depends on application, but he's into AutoXing almost as much as I am, so I imagine that's what he'll be doing w/ it. Thanks.

Anthony
Former owner of(she's dead now, or I'd still have her.)

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87 Camaro LT
350, A4.Comp Cams 268H, Edelbrock Preformer intake, Hedman Headers and y-pipe, gutted cat, No AIR/smog pump. 14x3" Open element K&N, Q-jet w/ D hanger and DA rods, adjusted AV spring tension and quick can.

 

The 90-92 speed density cars were rated faster than the 87-92 MAF cars, and stock I believe they were a tenth and a MPH faster, but its a toss up which one is better. Some people like MAF, some people like MAP. The MAP system is not as sensitive to mods as some people like to say it is...
Only the 92-93 LT1's are speed density. 94+ have a MAF and a MAP sensor.
Oh, and in case you dont know, MAP = Speed Density. They both mean the same system. MAF system is just called MAF.

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1991 Camaro Z28
5.7L 5-Speed
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
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[This message has been edited by Kevin91Z (edited July 30, 2000).]

 

Thanks, I was looking for something a little more descriptive.. I knew that stuff already.. maybe I'll go buy one of those books.. but then I'd have to think and read.. Thanks tho.

Anthony

 

Well, let me see if I can help a little bit:

Speed Density: This system uses the MAP (Manifold Absolute Pressure) sensor to measure the load the engine is under. The sensor then communicates this information to the ECM which will alter the air/fuel mixture according to the load.

Mass Air: This system use the MAF (Mass Air Flow) sensor to measure the amount of air being drawn into the engine. This is done by measuring the voltage drop of a heated wire that is held in the air stream.

The speed density system is less restrictive since there is no MAF wire or protective screens that the air must flow through. But unlike MAF, speed density does not actually measure the amount of air flowing into the engine, in makes a guess (albeit a good one) as to how much is being flowed based on pre-programmed tables in the ECM. These tables are set up knowing how much air the engine flows and what kind of load it's under. This also means that speed density systems are not flexible. Since they calculate the air flowing into the engine instead of measuring it, they cannot adapt to major mods like cams and better flowing heads. New chips will be needed with reprogrammed tables. I've heard that some race teams prefer the speed density b/c it can flow more and they have the capability to reprogram chips on the spot, so it's not such a big deal to them like it would be to us.

Mass air on the other hand can better adapt itself to changes in the air flow of an engine. Since it measure the air flowing into the engine, it will simply communicate to the ECM that more air is being flowed when better flowing heads/cams are installed, leading the ECM to automatically adapt and provide more fuel. In my opinion, the MAF meters are not that restrictive anyway, especially if you get an aftermarket one that flows better than stock. Frankly, I personally would prefer a mass air system b/c of it's adaptability so I don't need to worry about messing with chips when I make major engine changes.

I hope this helped

Jason



[This message has been edited by 89BlwnRs (edited July 30, 2000).]

 

The biggest problem with the MAF sensor is that it can flow more air thru it than it can report to the ECM. Also, the best year for the MAF system is 89. 85-88 all have the 9th injector and varying levels of programming in the chip that make it less than desireable. You can convert an 85-88 system to 89 fairly easily. 90-92 speed density were all the same.