MAF in 2bar SD OS

[dragracn]

I was just looking thru the different OS and in "2bar MAP - Speed Density" I see alot of MAF values still? Is it possible to run a MAF in that "2bar MAP - Speed Density" OS. I know if I run over 512gs it does no good, but its a low RPM motor that sees a high of about 400gs, I would like to have the added fueling options of that 2bar OS. This is a daily driver/tow vehicle with a single turbo, I would like to keep the MAF for the elevation changes and big temp changes. If I just change the OS to 2bar and leave my MAF is the computer going to read it and use it, or just be there giving useless numbers? I have researched and haven't found a yes or no answer, the threads turn into, "the MAF is useless after 512gs" and most seem to decide not to use it. Thanks for any info.

[RonSSnova]

If the MAF is in place now, maybe just try it? Set VE to disable at a convienient number. You will know pretty quick if it works.
I seem to remember though that hPT says Speed density only.

[dragracn]

Would like some help still please. I switched the OS to 2bar, installed 2bar map, changed PIDs in scanner to read 2bar map, I am seeing 2bar data in scanner. Can also see MAF data on scanner. I put a bad low spot in my Main VE table at cruise RPM to see if it was using just the VE table for fueling or both the MAF and VE. Sure enough it stumbled and went lean, changed the "MAF Airmass filt" from 4000rpm to 1000rpm and the stumble and lean spot went away. I assume this means it is using the MAF even in this 2bar OS? I have always been a bit confused as to what exactly that "MAF Airmass filt" does, can someone explain it to me?

So I start playing with PE and boost Enrichment settings, I can not get Boost enrichment to work under part throttle low boost, on the scanner I can see its commanding for 12.5afr (or what ever its set to) in low boost, low RPM, low TPS situations, but AFR stays at 14.7ish on my Wideband and I can see the narrowband O2s are still switching neutral. If I go over the PE TPS enable settings it will richen it to the PE settings not the boost settings. I tried making the PE setting less then the boost settings because I read the computer uses the richer of the two, then I even set the PE settings to 1.0 all across the range. I tried setting the "open loop STFT" to disable because I read it goes into open loop when in boost enrichment. I tried setting the "MAF Airmass filt" back to 4000rpm. I rewrote the computer thinking maybe it didn't go thru properly the first time? Still no enrichment in low boost, low rpm, low TPS condition, it commands it, but doesn't richen it. The narrow bands still are switching and it doesn't look like the Injector duty cycle trys to go up, but if I do have the PE set to richen it up, it will richen it and run at the commanded AFR if in the rite parameters for the normal PE table. I have been setting up the VE table in the new area that the 2bar OS has but have not got it all dialed in yet, is this part of my problem?

The truck is a 97 Chevy 1 ton dually 454 that I installed a turbo on and swapped over to a 411 computer from an 02 van. I had the computer flashed for stock 5.7 van settings, then adjusted all the parameters from there.

I have been running this setup for a year now in 1bar MAF OS, and really would like to keep it on MAF values for the different temps, altitude we see with the truck. Its or tow truck we use to tow a camper/boat/car trailer with and sees alot of different conditions. I was hoping to have the ability to run the boost enrichment in low RPM, TPS conditions we often see towing, very often can see 30-35% TPS at 2500 RPM, with 6-10lbs of boost. I have been trying to do it now with just the PE settings and obviously has worked, but wanted more control over fuel. Once I found out that I am pretty sure it is reading and using the MAF in the 2bar OS I got excited thinking I could get the best of both worlds, but now I cant seem to get the boost enrichment to work? I have got to be missing something simple?

Thanks in advanced for any help.

[JakeFusion]

I log my MAF in my scanner config. It still shows up. I've never tried to enable it...

[dragracn]

I knew I was just missing something simple. I assumed the boost enrichment worked off the MAP signal only, I had to set the TPS enable back to a low setting to get boost enrichment to work. Funny it was commanding it on the scanner but not allowing it to richen the AFR.

I still am not completely sure of what the "MAF Airmass filt" RPM does? Does it actually use the MAF readings to control fueling when this is set to a lower RPM, or does it just filter the VE table if it sees a bad spot with in the readings, acting a as fail safe for the VE table?

[GHuggins]

I knew I was just missing something simple. I assumed the boost enrichment worked off the MAP signal only, I had to set the TPS enable back to a low setting to get boost enrichment to work. Funny it was commanding it on the scanner but not allowing it to richen the AFR.

I still am not completely sure of what the "MAF Airmass filt" RPM does? Does it actually use the MAF readings to control fueling when this is set to a lower RPM, or does it just filter the VE table if it sees a bad spot with in the readings, acting a as fail safe for the VE table?

Now that's an interresting way of looking at it. Curious myself. What happens if you 0 out your MAF curve, does the filter still work?

[camarokid]

can you post your tune? a friend has a 411 pcm on his 454 one ton truck. it seems to pick up a lot of false knock. the timming table is much lower than the stock ecm was.

im also curious is the MAF can be made to work in 2bar. I have a LQ4 truck I pretty much only use for towing. ive just about got the custom jackshaft driven tvs2300 blower ready to go on.

[Ranger6202]

In my experience.....yes you can run it in maf on a 2bar os, I know the description say SD only, but mine worked when I disabled the VE and left the maf. Disable your VE and see. If you run into maxxing out your maf range, increase your maf housing size and then retune the maf curve frequencies to the new increased airflow values. Don't forget you want your maf post BOV or you'll go super rich when you shut 'er down if it were pre BOV. To get things up and running I had my maf on the suction of my turbo in which I stayed out of boost (avoiding blow off) just to make sure my new injectors and their values were going to work. I'm now 100% SD with an intake temp sensor threaded into the intake before the TB, but I plan on going to the ls3 slot maf post BOV someday soon while still using the 2bar os.

[dragracn]

can you post your tune? a friend has a 411 pcm on his 454 one ton truck. it seems to pick up a lot of false knock. the timming table is much lower than the stock ecm was.

im also curious is the MAF can be made to work in 2bar. I have a LQ4 truck I pretty much only use for towing. ive just about got the custom jackshaft driven tvs2300 blower ready to go on.

Mine picked up alot of Knock also when i first swapped the computer. I compared the knock sensor values to an 2002 8.1 and adjusted them. I'll see if I can get tune posted tomorrow. I have got it running pretty well but still think it was better with the MAF OS, it still needs work in 2bar SD OS.

[dragracn]

In my experience.....yes you can run it in maf on a 2bar os, I know the description say SD only, but mine worked when I disabled the VE and left the maf. Disable your VE and see. If you run into maxxing out your maf range, increase your maf housing size and then retune the maf curve frequencies to the new increased airflow values. Don't forget you want your maf post BOV or you'll go super rich when you shut 'er down if it were pre BOV. To get things up and running I had my maf on the suction of my turbo in which I stayed out of boost (avoiding blow off) just to make sure my new injectors and their values were going to work. I'm now 100% SD with an intake temp sensor threaded into the intake before the TB, but I plan on going to the ls3 slot maf post BOV someday soon while still using the 2bar os.

MAF is post blow off valve. they are about 6-8 inches from on another. IAT sensor is after MAF just before throttle body. I haven't maxed the MAF yet but am close 11,500ish.Hz I was going to try the slot style MAF if I do max it out. Wasn't sure if it would work with the older computer?

[camarokid]

Mine picked up alot of Knock also when i first swapped the computer. I compared the knock sensor values to an 2002 8.1 and adjusted them. I'll see if I can get tune posted tomorrow. I have got it running pretty well but still think it was better with the MAF OS, it still needs work in 2bar SD OS.

your using your stock 7.4L knock sensors? swaping to the 8.1L knock sensormay be a good idea.

the card type MAF should work fine