bmanice

Generally speaking, when adding a blower or turbo to a motor, still using FI, would speed density or mass air be better, ive heard supporting sides of both.... but it seems to me after doing some reading on FI, that SD would be the choice here... ?

88blackgt

depends on how far you're wanting to go. when going large hp, its usually better to go to sd.

88BlueGT

reason?

shaners90lxhatch

I say MAF. MAF is more accurate period. When it comes to stoichiometry of a forced induction motor - very small inaccuracies can have very significant consequences. I am willing to bet that you will not find a speed density system on any factory turbo/supercharged vehicle after the mid to late 80's. MAF all the way. It can obviously be done with speed density but I think the benefits of a MAF controlled system are obvious.

88blackgt

with forced induction many people use sd, only w/ a gm map sensor. the system is slightly different from the stock sd system, but this allows you to tune based on boost. w/ a maf setup the tuner has no clue what the boost pressure is. and you say sd is more accurate, maybe without tuning, but when you are tuning the car you can get it just as accurate as a maf car.

86/02stang

As long as you get a good tune with the SD cars you will be fine. Alot of high HP cars use a variation of the SD computer.

shaners90lxhatch

I agree that a MAP sensor is necessary for the computer to know what the boost pressure is, but all the turbo engines I have ever come in contact with all have both a MAF and a MAP sensor. The presence of an MAP sensor does not necessarily mean that it is SD. The MAP in these systems are used to validate the MAF, calculate boost pressure and are used as a backup should the MAF signal be lost or out of range. They also provide a more accurate measurement of barometric pressure. I may be misunderstanding your point but I figured I would clarifiy myself for the same reason

88blackgt

ok there we go this is what i was going for. i thought you were trying to say JUST a MAF. there is a better thorough explanation

Black Snake

SD cars are tuned by Vacum so tunning it is easy MAF take a little more time with injector and Air calibrations, but as for SD drivabilty will suffer depending on how good ur tunner is