I am building a twin turbo 98 GMC sbrc with ramjet intake. Would it be logical and or possible to run the stock MAF on the intake side of 1 turbo and rescale the MAF table.

 

Are you goingto run the stock 75mm MAFS or upgrade to the 1999 and newer 85mm MAFS. I got a 2001 ZO6 Vette 85mm mAFS for $42US shipped to my door.
Dont forget about the L31's stock rev limit of 5600 rpm. No one in North America has been able to raise it more than 200 rpm to 5800 rpm. I wanted to to a cam and head package on my truck, but Iwill use my larger injectors for a dry nitrous shot I think, just something that will keep my 350 below the unbeatable L31 Vortec 350 5800 rpm rev limiter.

I currently have a Marine Intake installed and am running 28.1 lb/hr fuel injectors. The stock L31 PCm will control any size fuel injector so long as it is high impedance and NOT the peak and hold style.

I think you could put the MAFS wherever you want.


Here is the GM/Mercruiser Vortec Marine iNtake manifold I am using, http://www.sfatek.com/images/efi.jpg

I like the Ramjet intake, but I like the marine intake due to the fact that the throttlebody is in the exact same position as the stock t-body is, this allows the use of the factory throttle and cruise control cables, along with stock air intakes (FIPK or equivalent).

Check this out, this guy has a Ramjet intake using 57 lb/hr injectors with a Procharger(Ithink). Hellbents from this site tuned that beast.

http://www.fullsizechevy.com/forums/...d.php?t=168474

The 2 BAR MAP sensor from any of the GM Supercharged 3.8L V6 engines will bolt right in for a 96-99 L31 application, the MAP even uses the same wiring.

I have Tunercat OBD2 for tuning my L31, Hellbents also used Tunercat OBD2 to tune that Ramjet Procharger truck. hellbents just tuned that truck in Speed density mode I think, you may not need the MAFS. I think you may pegthe stock 75 mm MAFS rather quickly, maybe look into that 85 mm unit.

Have fun
peace
Hog

 

Thanks. I just figured that the stock MAF on the inlet side of 1 turbo would not restrict flow. I also thought the trans needed MAF input for best operation. As a side note my 4l60e went KA-BOOM a couple months ago, so I upgraded it to a 4l80e... I am very happy with that swap project.

 

I would highly advise against taking maf readings of only one bank and trying to tune for that. In a perfect world you could scale it and make it work, but I'd put more money on it failing to accurately meter air than working properly. Minor variances in turbo and head flow could really easily upset your readings.

How much boost do you plan to run? You don't necessarily need a MAF sensor at all.
You could purchase the 2 bar map that Hog mentioned, rescale your VE table and then run Mafless and still have full control of your VE table in and out of boost.