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View Full Version : attn:Gearheads- explain speed density



99WhiteBeast
07-29-2003, 11:00 PM
Can someone explain "speed density" vs MAF? I see this posted all the time and from what I gather the MAF talks to the PCM like in the GenII's(and those parameters can be controlled with a chip) but in the GenI's they use other things (intake vacuum, TPS...) that talks to the PCM but a chip won't get you much.

Why do some convert from speed density to MAF conversion?

I'm confused:confused:

L8 APEX
07-30-2003, 12:19 AM
Speed density is an early form of fuel injected computer control. The PCM runs on a basic fuel and timing map based on the intended original equipment demands. It does not learn or adapt to changes like a MAF system does. You have to tune it by tricking sensors or raising fuel pressure etc. It is harder to do cams and other mods on a speed desity motor. Basically the MAF cars know how much air/combustibles they are taking in and speed desity has no way of measuring that. SD cars ran better stock for stock than MAF cars because of a better tune from the factory. You want a MAF car to mod because they learn and adjust for cams, headers and such much easier than tricking a SD motor.

diablolightning
07-30-2003, 03:38 AM
Speed density is an early form of fuel injected computer control. The PCM runs on a basic fuel and timing map based on the intended original equipment demands. It does not learn or adapt to changes like a MAF system does. You have to tune it by tricking sensors or raising fuel pressure etc. It is harder to do cams and other mods on a speed desity motor. Basically the MAF cars know how much air/combustibles they are taking in and speed desity has no way of measuring that. SD cars ran better stock for stock than MAF cars because of a better tune from the factory. You want a MAF car to mod because they learn and adjust for cams, headers and such much easier than tricking a SD motor.

what terry said.
And also you get better gas milage with MAF since it ajusts the air/fuel/combustion etc. Speed density cars (some) fire all four injectors at once per side thus giving you bad gas milage:hammer:. MAF gives Better throttle response.
but the biggest are the mod opportunities with MAF. Usually w/ SD you can port/polish (stock) heads intake etc but no wild cams. Unless it is avery mild cam.
my friends stang was runnin I believe mid to low 12's with ported heads(e7)/intake and a 150 shot:burnout:
And before with stock(e6) heads he ran an 12.80 with a 100 shot.:burnout:

If done right very fast.:burnout:

Sixpipes
07-30-2003, 03:55 PM
Speed Density = The faster you go, the more stupid you become. :cool:

cpeapea
07-30-2003, 09:03 PM
cool!

99WhiteBeast
07-31-2003, 08:49 PM
So to convert to MAF you need a PRO-M and new PCM right?

L8 APEX
07-31-2003, 10:18 PM
So to convert to MAF you need a PRO-M and new PCM right?
Not necissarily all magazines sell the upgrade kit, Summit carries them also. This is for a Mustang no?

diablolightning
08-01-2003, 04:04 AM
I believe the mass air conversion runs you right around $700 for a truck. and cheaper for a stang. It all goes down to how fast with what mods.:evil
cause $700 is a lot of money. since it does save you a little gas eventialy:roll it would pay for itself.



It's a lot of money for me maybenot for you guys hugh.

George G.
08-01-2003, 10:43 AM
Hey Steve,

Before you go spending money on the mas air, I've actually read a lot of posts from NLOC where numerous people are making pretty good times(and power) while staying with speed density. Of course some are also using an EEC tuner and making their own changes. I can't remember what most people are using for cams but it can only be so much or you'll have trouble idling.

George G.
08-01-2003, 10:45 AM
So to convert to MAF you need a PRO-M and new PCM right?

The stock pcm is still used to control the transmission.

99WhiteBeast
08-01-2003, 06:05 PM
At this point I'm just learning about the Gen1 and don't intend to do much to it right now.

Thanks for all the info guys.