Earl H

iTrader: (1)

Is it possible to run the car off MAF until the car reaches boost and then run SD (2 bar) under boost? The premise is to get stock-like driveability/fuel economy off boost and the ability to control fuel and timing under varying boost curves. If this is possible, how do I accomplish this. I currently use EFILive.

ZL1Killa

iTrader: (17)

with efi live i believe there is a 2 bar custom OS that you can do the MAf and then have another table throw in your desired fuel or what not

Doc

iTrader: (9)

I'm sorry but I don't get the premise of your question? A really good SD tune wouldn't /shouldn't require the MAF.

Earl H

iTrader: (1)

I'm looking to run the MAF until it is maxed out. Once that that happens (under boost), it references the other tables to handle timing and fueling (ignoring the MAF).

2002_Z28_Six_Speed

iTrader: (19)

Wouldn't a SD tune be imperfect under some weather conditions? The MAF allows for more variablity so isnt his question valid?

ringram

Rubbish. Both SD and MAF use IAT to help determine airflow. And by nature SD measures pressure, so what weather issues arnt dealt with?
Its just with SD there are more tables and cells affecting the tune so guys who find it hard to get out of bed just tune the single column of MAF values and say "SD is no good".
When in fact as Doc and others have mentioned there is no problems running SD all the time, throttle response is improved because the MAF is actually inaccurate at low airflows and is blended with SD until 4000rpm anyway.

I vote drop the MAF altogether and learn the way of the SD for your app.

Afterall millions of efi Hemi engines cant be wrong. They are SD from factory!

Earl H

iTrader: (1)

Well, I'd still like to know if its possible.

ringram

.. not that Im aware. You could set the maf fail freq, but once it failed it would be out of the picture there on in, it would not re-enable.

Why not try SD for a while and see what you think. You can always go back to Maf if you dont work it out.

qqwqeqwrqwqtq

I don't know the answer to your question, but as others have said, a good SD tune will have stock-like driveability/fuel economy. (Actually better driveability than with the MAF)

gametech

iTrader: (1)

All I can say is ringram and INTND8 are absoolutely right, even if my spelling is a bit off. The only reason to have a maf is as a failsafe if your other sensors go out.

2002_Z28_Six_Speed

iTrader: (19)

The MAF can't be completely junk or less it wouldn't be used is all I am saying. He is asking if he can keep it NOT how good it is.

SD only is not superior for the non tuner. With SD you can't adapt. The car is set at WOT. With MAF it can sense the incoming air charge and adapt slightly at WOT.

I am sure that is all he wants.

Maybe you could hook some normally closed mirco switch on the gas petal. That would cut the MAF at WOT. Surely would go back to SD.

12secSS

iTrader: (30)

Once the MAF is failed the GM code reverts to SD, the only way to bring back the MAF into fueling is to turn the car off and back on again or clear the code. What you are asking is not at all possible with a gen3/4 ECM!

ringram

The MAF is an easy way out. As you say it adapts, thats why its there. Its a bandaid to fix the basetune which from factory isnt 100% anyway. Its also easier to tune as its a single column of numbers. Its less responsive from idle and it cant see more than 512g/sec of air.

Bottom line is if you want the best throttle response and no upper limit then go SD. If you want an easy to maintain tune with the same pk power as SD (assuming you are under the MAF limit) then go MAF. MAF is best for people who dont tune as it adapts to small changes without needing another expensive tune. Guess why the factory uses it!

If you have a tune tool and/or are interested in the best driving experience then SD is for you. Yes you need to tweak the tune for that new manifold, or exhaust, but you want the best performance anyway dont you? Otherwise why did you modify your car in the first place!?

Earl H

iTrader: (1)

When the MAF maxes out, doesn't it go into PE to control fueling? then defaults back to the MAF once airflow drops below the limit?


Guys, I'm not looking to debate which is better. SD probably is. Problem is, I've got a track day in a little while. I have a limited amount of time and wanted to get the tune nailed to the best of my ability with my current contraints.

ringram

Depends if you have triggered PE mode with the TPS and MAP trigger points etc

But in general yes you are right. However PE with no MAF is based on the VE table, which finished at 1Bar so if you want to fuel accurately you need a 2bar+ OS with an accurate VE to take over when the MAF runs out of steam. Otherwise you just make an educated guess as to how much fuel you need past that point and throw the same amount in irrespective of what it actually needs.

Once you get your head around the VE table and SD its easy. If you insist on using the MAF you are stuck with it and using PE to throw a random amount of fuel in to bandaid it. But loads of other guys do it that way with good results, its just not the best way IMO.

dewmanshu

iTrader: (4)

Interesting, ever time I bring this up I get bashed too. I prefer SD for every reason ringram has exclaimed, however in Maryland I need that MAF enabled to pass inspection, SD and maf code go together ASAIK and you can't pass emissions with the code set. Sure, when inspection comes around I could just reenable the MAF and go through all of the drivecycles again, but...would be nice to make it so the MAF(or lack there of) played nicely with the custom 2bar OS. Any idea how to be SD without a MAF code? That's #1, #2 is rick@synergy has a truck member tuned to be maf/sd combo. I have tried it plenty of times and fail each time. I made the MAF table really rich just to see once it failed if it would go rich once I went below the fail hertz again. It did the first time I tried it, but haven't been able to get it to do it again.

RedHardSupra

iTrader: (1)

i think you can just disable MAF codes so they dont throw any codes and drive in SD. just make sure all the readiness codes get set properly before you go.

dewmanshu

iTrader: (4)

really? i've asked this question before and never heard that. Shweet if so, I'll try that without the maf plugged in as soon as I get home. I am so "old skool" on the SD, i just figured you have to force a maf code as well to be in it.

dc_justin

iTrader: (13)

Yep, or just set the codes to Non-Emissions, either way will work.

Justin

Gordy M

iTrader: (2)

If you could adapt a C6 Z06 PCM to your car you would be OK, it has 2 bar MAF built in. So it can be done, but can the 512K PCM have enough calibration. By the way, rumor is the Corvettee SS will be 2 bar and no SD, all MAF