I built a supercharged 383 stroker with inner cooler for my 96 SS. I got a basic tune, then took it in to have it dyno tuned and they said my mass airflow sensor wasnt reading right. I replaced it and took it back and they said its still not right. They said it should be reading 12 g/s at idle and its only reading 6. Is there a difference between a lt1 and ls1 mass air flow sensor. I might have gotten one for a ls1-not sure. Just needing to know what I need to do to get this car done. Heres so more info on the motor.
Its a 383 stroker with the LT4 hot cam, 60 lbs injector with 255 intank pump ,trickflow heads, vortech supercharger w/innercooler and the mass airflow is stock and on the charged side of the tubing.

 

OK, but what is it doing, are they complaining about the fueling? What are the readings as the RPM goes up? is it just staying at the 6 gms

 

Can't wait to see the numbers on that build!

 

The MAF is the same for both. If the engine requires 12g/sec of air at idle and the MAF is only seeing 6 g/sec then the engine is getting some air that isn't being measured. Vaccum leak, leak between the MAF and TB etc.

 

They said its running lean. I will see if I can find a vacuum leak.

 

Theres no vacuum leaks. I found that if you unhook the charged side of the tubing going into the motor and just put a rubber boot and maf on it reads 12 g/s and the car runs great. Then when I hook up the charged side back up it drops down to 6 and doesnt run right. Could I need a bigger bypass valve.

 

Heres a picture of what my set up looks like.

 

I know this will sound crazy, but you should try it. Flip the MAF sensor 45 or 90 degrees at a time, and see if there's not a certain "clock" position it likes. Where it's at in that 180 degree bend in the intake pipe, could have a big impact on how the air is flowing across the hot wire, and in a certaiin position, it may not "see" alot of the air. I'ts worth a shot. Doesn;t cost anything. Flip it 90* and see what the scanner says. That don't work, flip it another 90 and see.

 

I only problem with doing that is the maf is welded to the elbow, but i was thinking the same thing that the air running past it is some how creating some kind of turbulence and messing up the readings.

 

Second option is to speed density tune it. It's quite a bit more involved, but if done right, will turn out much better than a MAF tune anyways.

 

What would I need to get to have it tuned this way.

 

A tuner that knows how to tune an LT1 in SD. You can also get a 2 bar MAP sensor and tune it 2 bar, but that's a little more complicated. You have to hack the injector flow rate and VE tables to make it work.

 

I'm guessing you have removed the screen, as well.? If so, put a screen back in your MAF and it should clean your signal up considerably.

 

The screen is still in there, it does it will all 3 maf sensors I have. Im going to look at the tubing elbow right before the map tomorrow. I think I need to remove more of the metal tubing going into the rubber boot. I think its directing the air more to one side then the other and maybe that will fix it.

 

Cleaning up the tubing didnt help, but by covering up half the bypass it runs and idles fine. Could the bypass be to big.

 

Bypass is probably too close to the MAF. Moving it farther away or having it stay closed on idle would be two ways to diminish the issue.

 

How would I get it to stay closed at idle.

 

Most of them have an adjustment nut on the top. Crank down on it until it just barely stays shut at idle.