Can I run a turbo on my TPI with MAF? If so, how??

route the air into the MAF, then to the turbo, and then to the engine. or just build it to blow through the MAF because the sensor rate for the stock MAF gets exceeded pretty quick any ways and it will still work like normal.

I sudgest you talk with the guys @ Precision Turbo & Engine (219-996-7832). They sell aftermarket ECU's that will interface with the TPI EFI on our cars (direct plug and pray). I believe their ECU will also control the MAS. You'll prolly have to upgrade to a 76mm or even 80mm MAS.

WTF?

Dude, next time research your answers before you give bogus answers. There is only one MAF for TPI, always has only been one MAF for TPI and probably always WILL be one MAF for TPI. There is no upgrading. And even if you could, then you have to overcome the limits in the ECM. It only reads to a certain point then it wont register more air.

sounds like ford stuff.

ok well it was my understanding that with this aftermarket ECU --> the FAST system from Precision Turbo & Engine would control the MAS so it would no longer interface with the stock ECM. I also think it allows you to upgrade to a bigger MAF. But then again I haven't verified this ... just stuff I picked up from reading about aftermarket ECM solutions for turbo applications ... sorry for trying to help out.

No as far as I know the only one precision sells is the Speed Pro / FAST and I have it. If they sell something else, it is only useable for Fords or Buicks.

FAST/Speedpro has

ABSOLUTELY NO INPUT FOR A MASS AIRFLOW SENSOR

you either go speed density or alpha-n

alright sorry

Wrong. There is one MAF that is compatible with the standard TPI MAF - The Wells SU-145. Better airflow and same characteristics, but uses a honeycomb matrix instead of the hot-wire technology.....

but still doesn't overcome the limits of the ECM which i think the point guido was trying to make..

Thanks fly89.

there are some dudes (although a little impatient and cranky) over on the chip burning board (here at thirdgen) that have some pretty good ideas on how to overcome both the flow limitations but also the data limitations of our MAF's. most of it has to do with changing to a later GM computer and harness that has the ability to sense airflow above part throttle (big amounts of air).

Yes, the 255 gm/sec limitation in the computer is being worked on so it won't be a limitation any longer but they've been working on that for .... ever.

What exactly is alpha-n?

Basically figuring there are three main types of EFI metering; speed density (MAP), mass air (MAF), and Alpha-N (basic). It is EFI that is as close to mechanical as it can be. where load is not merely calculated but pre-figured or pre determined and fuel is delivered based on RPM vs. throttle angle with an O2 sometimes being called upon to smooth out the A/F ratio. It is often used in racing and in very radical motors where a vacuum signal is out of the question. the old analog holley projection is a form of alpha-N, and accel, speedpro, and a few other manufacturers offer the alpha-N option at the click of a mouse from the programming screen.

Thanks for the info. I think that's the reason a friend of mine can run his '89 IROC with stock ECM, no MAF, bigger injectors, 50psi, and N20. He has the stock chip but I think it's running in LHM which would put the ECM into Alpha-N. Very interesting.

Is the pre-determined tables for Alpha-N programmable so if a person wanted to intentionally run their 165 ecm in alpha-n mode they could and still program it to run properly? This would be very helpful for someone like myself that has the 165/MAF ecm and wants to use a turbo? Would I be better off running in Alpha-N or just running a turbo and maxing the MAF at 255 gm/sec. Swapping to SD is not an option for me.

alpha-n is the BIGGEST PITA to tune

basically you are ONLY tuning on TPS voltage/angle and RPM

it is extremely tough to tune and you just about need a dyno unless you have someone who has tuned alpha-n before

the maps are TOTALLY different

So what's going to be the disadvantage to maxing the MAF at 255 gm/sec other than the obvious? Also, if I were to install a turbo with the MAF, what exactly would need to be changed in the chip to compensate for the extra air from the turbo?

Blowing thru the stock MAF will generate about 6 ozs of plastic chips from the case blowing apart.

If you want to do a blow thru this is how to do it but you have to use a LT/LS1 type MAF. this happens to be an option on the 89 TTAs but none of the others.

http://www.gnttype.org/techarea/engine/mafrelocate.html

u mean that's not good for the engine?

Gee, it would be easy to quote you about quoting bad information. The ecm isn't the limit. The software will read to 255, that number isn't grams/sec unless you write the tables that way. Using a GM computer, and what was a 255 grm/sec limited system, I'm running a calibration that allows for 510 grams/sec..

Using a TPI ECM?? I've gotta see this to believe it. Sorry, I live in the Show Me State.

So if I can't blow the air through the MAF w/out destroying it then I should be able to get away with putting the MAF before the turbo and sucking the air through the MAF right? I know this will max the MAF due to the sofware limitation, since it's written as gm/sec in my calibration, but it's not like I have much other option at this point in time and I know there's at least 1 person on this board that's running a supercharger with MAF.