Switching from mass air to speed density?Problems?

[LS1nterceptor]

I know a real knowledgeable guy around here who does all his own work on his cars, everything from fabricating custom parts to engine swaps into one-off vehicles, all the way to custom tuning.

He was telling me that among the regular things he could do for me like removing the SES light, changing the rev limiter, etc, he could also convert my car to speed density. Which is what he runs on all of his LS1 cars. He says he loves it and it allows him greater flexibility in tuning. He said his cars respond better run a lot better without the mass air when he makes performance changes like putting his cam in. He said that if he did the change he could put it right back if I didn't like it.

My question is, what problems could this cause? Has anyone done this? Did it work out? Is it more trouble than it's worth? Is it worth trying?

Since I won't have a laptop with all of the tuning software with me constantly like he does, I'm worried that the car won't be able to adjust to slight variations in conditions and will require constant tuning.

What do y'all think?

[Frost]

it definitely has it's place but you haven't described your setup at all, so it'd be kind of hard to say..

[Doc99SS]

I do not understand why people want to give up on the MAF/MAP PCMs that the factory provides, especially Closed Loop. The 4th gen cars have very large MAFs as compared to the 3rd gen cars. The 3rd gen MAFs are good for about 450 Hp. The 100mm MAFs that we can buy for our 4th gen cars must be good for 600+ Hp!!! In my opinion, a good CL MAF/MAP tune will outperform all other tunes over time. The best OLSD tune is good for maybe 2 months where I live, and you cant change your altitude by more than about 500ft.

[Frost]

I do not understand why people want to give up on the MAF/MAP PCMs that the factory provides, especially Closed Loop. The 4th gen cars have very large MAFs as compared to the 3rd gen cars. The 3rd gen MAFs are good for about 450 Hp. The 100mm MAFs that we can buy for our 4th gen cars must be good for 600+ Hp!!! In my opinion, a good CL MAF/MAP tune will outperform all other tunes over time. The best OLSD tune is good for maybe 2 months where I live, and you cant change your altitude by more than about 500ft.

He didn't say OLSD, he just said SD. CLSD is quite useful, and there are a few advantages in some situations to be had with it. Large cammed setups can have reversion issues from time to time that SD is impervious to. The factory and replacement MAFs that people use on these cars always seem to wander off cal-wise over time. I can tune a car with a clean MAF and the same car with the MAF clean 2 years later is off a half-point at WOT. NO MAFs work to anywhere near 600hp for GenIII hardware; the limit is the MAF's table's ceiling of 512g/sec. In fact, most of the larger (ie 85mm MAFs) run out EARLIER than the OEM units. The idea that the altitude fluctuation should bother an SD car is a wive's tale unless someone has butchered up, incorrectly setup, or not finished the needed tuning on the PCM. SD is based around the MAP sensor; which can certainly differentiate minute pressure changes, this is it's base purpose in fact. Another thing that many people like about SD is MAF fueling is inherently slow with changes, ESPECIALLY at low airflow. Look at it from an operational standpoint. The MAF heats a wire, which must be cooled by incoming air in order to "see" the air whereas the SD setup simply looks up fueling based on RPM and manifold pressure. This gives the SD setup a bit more snap that is real and can be felt. It doesn't mean higher peak numbers, just a bit more snappy. The cars I tune in SD NEVER need touching up unless they change something with their setup.

/end 2cents