MAF Swap Re-Tune?

[bhunter0830]

I apologize, let me elaborate some more. MAF question was based on the my summer DD. I have a LS6 block itching to have something done with it and a shell of a 2002 sitting in my storage unit. I obviously am not inclined enough to do a ProCharger by myself. However, If I have a shell and a block, something needs to be done with it right?

Thanks for the write up Jon. That definitely helps put into perspective what I am going to be looking forward to as far what I am going to need and where to start the process of building it up. Do you have an idea of the total cost of what you have into it? Just looking for an idea.

[35th-ANV-SS]

Orion is a more savy tuner than I am when it comes to computers, but to try and answer that question, your MAF also relies on your 02's for fuel trimming, so either way, your 02's are important. When the MAF fails, it relies on your VE tables (which is what an SD tune does/is), so either way you need those VE tables spot on, and you need properly functioning 02's. All the SD tune does is get rid of the middle man (the MAF).

What an MAF does do however is have the ability to make slight adjustments to incoming airflow, which helps in situations like changes in altitude, or mild bolt ons, etc...but that only goes so far.

Got it. Thanks for reiterating the above. It had been awhile since reading about that. That all makes perfect sense to me.

[35th-ANV-SS]

Do you have an idea of the total cost of what you have into it? Just looking for an idea.

I went a little beyond what the typical install calls for. I added a FMIC instead of the (2) smaller intercoolers that come with the kit, a methanol injection kit, gauges, and some other miscellaneous parts which I felt were a necessity. I know the exact amount I have in parts alone. Shoot me a PM if you want. It's pretty expensive...

[98TransAmWs-6]

FBJ - Correct me if I am wrong, but while removing the MAF for a Speed Density set-up is a good way to go, doesn't that also make the PCM rely a lot more on the O2 sensors for your A/F and any adjustments? What I mean is, if either one of your O2's get lazy, what is there to try to correct the A/F reading without the MAF? Nothing is my understanding. Which means you need to pay a lot more close attention to your upstream O2's. At least with a MAF, it's kind of having a fail-safe. No?

Speed Density also relies on your manifold absolute pressure sensor more heavily in addition to your upstream O2s. At least this is what Frost explained to me.

[bhunter0830]

Thanks to my quarterly bonus, I have an extra $12-14k that I have set aside for it. Wife knows about the block, but not the shell... Also doesn't know about the amount of my bonus, so that's also a bonus! I figure that'll at least get me rolling this year.

[pajeff02]

Adding to what FBJ posted, in speed density mode the PCM calculates air flow based upon the VE table, engine rpm, and the TPS and MAP sensor data. This is a substitute for the MAF which measures actual airflow and allows the PCM to compensate (as FBJ posted) better for variations. Measured airflow is more precise than estimated airflow, assuming everything is functioning properly.

[0rion]

FBJ - Correct me if I am wrong, but while removing the MAF for a Speed Density set-up is a good way to go, doesn't that also make the PCM rely a lot more on the O2 sensors for your A/F and any adjustments? What I mean is, if either one of your O2's get lazy, what is there to try to correct the A/F reading without the MAF? Nothing is my understanding. Which means you need to pay a lot more close attention to your upstream O2's. At least with a MAF, it's kind of having a fail-safe. No?

The MAF doesn't make corrections....it reads real time air. The O2's are where the corrections are made and they will be made with or without the MAF in place. Without the MAF the fueling calcs will be made using the VE table but as long as you're in closed loop the O2's will still try to maintain your commanded AFR. If you get a bad O2 it's going to act the same way regardless if you have a MAF or not. IMO there's no reason to get rid of the MAF unless you're heavily modded.....the MAF actually does a pretty good job but just like the VE table it's only as good as it's calibration. If you alter or change that MAF you should get tuned for it. Same with the VE table....if you get rid of the MAF you need a tune to correct that VE table for your mods. You do get a little better throttle response dumping the MAF and going SD but overall the MAF probably works just fine for the vast majority of people out there.

[bhunter0830]

From what it sounds like, since this one is not heavily modified, leave the MAF alone! There doesn't seem to be any real gains that wouldn't cause a head ache by making a change. Thanks for everyone's input! It's been a great help! Anyone looking for an SLP MAF, I'll make you a sweet deal!

[0rion]

From what it sounds like, since this one is not heavily modified, leave the MAF alone! There doesn't seem to be any real gains that wouldn't cause a head ache by making a change. Thanks for everyone's input! It's been a great help! Anyone looking for an SLP MAF, I'll make you a sweet deal!

You can run the slp maf....just get tuned for it. My advice would be to sell it & buy something a little more useful like sub frame connectors or something along those lines.

[bhunter0830]

You can run the slp maf....just get tuned for it. My advice would be to sell it & buy something a little more useful like sub frame connectors or something along those lines.

Sub frame connectors are waiting to be installed. Don't see enough supporting info to justify a retune. Might keep it for my project block, but will probably buy something better for that since it's a bare block build up. I have replace the LCA's and PHB and installing relocation hardware for the LCA's since I am lowering it. I also have a STB and am replacing the front suspension. The summer DD is about done unless there's something simple you can think of.