Stone0fFire

the largest (somewhat) compatible MAF i know of is the 85mm.
and even then, there is crap in the middle of it that doesnt help flow.

so how can a 90mm TB flow more than a 78mm TB
when they are both restricted by a 85mm MAF with junk in the middle?

have people tested the difference?
is it worth it?

is it possible to run without the MAF or use something else?

LSONE

iTrader: (1)

you can run a speed density tune without a maf, though i dont know anything about its drivability etc.

Another_User

SD mode=awesome. I have been arguing that same point for a long time. The worst part is, even if you had a 90mm MAF, it would still be a restriction with a 90mm TB. Plus all the 90mm TBs have a lot of issues. I have been running SD for awhile with no problems on my car. Excellent flow in the intake.

smokin' joe 00 ss

I'm really interested in this SD tune what's it take to go this route?

Another_User

Unplug and remove your MAF (store for later use), replace with a 3.5" OD X 3.5" long tube. I have a polished 1/8" thick aluminum pipe that I made. Very snazzy...and it draws attention to the fact that there is no MAF. Then you need to start leaning out your VE table using HP Tuners. You can do this based on your fuel trims. We have some posts in the PCM section on how to do this. I ended up with a better idle, better throttle response, and more power. But like some people say...it's not for everyone. It does not negatively affect driveability, and I actually get better fuel economy now.

leaftye

Another_User, can you confirm if altitude changes will mess with a speed density tune? I've seen a lot about it, but don't really understand it, and am barely grasping tuning now. I want to know because over the course of a year and with my road trips, altitudes can change from +10K to sea level, and from near 0 degrees to over 100 degrees. FWIW, I did search for altitude+speed+density.

Another_User

Good question. I think the computer would compensate. I have not changed elevation (that I have noticed anyways). I know that before you start your car it reads your MAP to compensate for altitude. I don't see a fuel table that changes based on that though. I am taking a guess here, but once your car has started it would actually compensate automatically. The fueling table would be accurate because it is based on MAP, which would actually change where on the table you idled at and everything. The engines "VE" would not change, you would just fall in the lower part of the VE table, which is less efficient. Any takers want to give us the real scoop?

leaftye

I suppose I can try it, but it'll take me a few weeks tho....I have to mail my cable back to HPTuners to swap for the wideband cable...and need a wideband too.

Another_User

The thing to remember is that your fuel trims still work, and it will still go into closed loop. The PCM will adjust for minor changes. The only thing you need to worry about once you have your table dialed in, is maxing out your fuel trims AFTER modifications like a different cam. Otherwise, once it is dialed in you shoudl be fine.