Alright, so I own a '93 z28, and the words 'speed density' keep popping up over time about them, and it is the reason that it was the fastest year lt1. But, after searching the forums (both with the search function and manually), as well as googling, wiki-ing, and all around trying to find what it means, I am stumped.

So, my question is this: WHAT IS SPEED DENSITY?!?!?!?11?2112???

P.S.
If I missed a topped thread that has it defined already, please don't flame, and point me in that direction.

 

who told you it was the fastest year lt1?

 

http://www.carcraft.com/techarticles...ion/index.html

Tells all about it and also compares it to MAF. It was at the top of the list when I googled "speed density".

 

well i thought it ment that the faster you go the more dense yu get...meaning you hit somthing harder and can move more mass with your force................thats what i learned in science class anyway...i think

 

uh, i beleave it's a sensor, that the MAF took the place of, i know my ION has a MAF(mass air flow) and a IAT(intake air temp) sensor, maybe it's s'pose to be "air density sensor" not a "speed density"

 

if you read it all, it states MAF is best, but the second best is Speed density. essentially, they are the same, the speed density uses RPMs and vaccum(kPa) to calculate how much air needs to be put into engine. i beleave a MAF uses air/fuel ratio to determine how much air is required.

honestly.. i dont know why any of it is required... lol. let the engine take in the amount of air it's displacement requires. carb FTW.

 

Trying to keep things simple. Speed density is fancy name for vacuum controlled operation. The MAP sensor measures the absolute pressure in the intake manifold, which is the opposite vacuum. The absolute pressure depends on engine load, throttle opening, engine speed, and some other variables. Based on the input from the MAP sensor, coolant temp, O2 sensor, throttle position sensor,the ECM searches several pre programmed tables and determines how much fuel the injectors should deliver, and what spark timing to command. A mass air system, which uses a MAF, actually measures the mass (weight) of the air entering the intake. The ECM/PCM uses the data from the MAF, and the other various sensors to look up the fuel and spark tables, and control fuel & timing.
Most newer engines are equipped with both MAP and MAF sensors. The MAP is used for starting and as a back up system should the MAF die, Once in closed loop the MAF is controlling.
Power wise, there is no difference. However; speed density sets a tight limit to how much the engine can be modified before a ECM tune is needed. The system cannot determine how much air the engine is taking in, based on absolute pressure, if the engine is modified. The mass air system is more lenient because the PCM knows exactly how much air is taken in, and as long as the tables are big enough it can continue to provide good engine management.

 

oh, he's good.[8D]

 

Thank you all very much.