Possible to run MAF/SD Tune
For the newb here, it sounds like I can run the MAF until max and then use the COS to run the boost timing/pe tables in boost? If so, what codes need to be turned off or what is the correct setup procedure for this? Right now I believe that I have to set the MAF limit below the stock max threshhold, then what...?
TECH Fanatic
Joined: Aug 2005
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From: Sunny London, UK
Originally Posted by Gordy M
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
Yes I think the E38/E40? has a 2bar SD capability built in as you say. Even the latest ECM's still have an SD mode. It just doesn't have a VE table. Ask RedHardSupra, he has been messing with the simultaneous equations required to derive the constants and filter values used to calculate SD values on the fly by the newer ECM's
Originally Posted by 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!?
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!?
That's what I thought from second 1. That's why I posted what I did. Maybe he can't get the set-up perfect. Maybe that is why he wants it. No harm.
Originally Posted by Earl H
For the newb here, it sounds like I can run the MAF until max and then use the COS to run the boost timing/pe tables in boost? If so, what codes need to be turned off or what is the correct setup procedure for this? Right now I believe that I have to set the MAF limit below the stock max threshhold, then what...?
Can't mix SD and MAF control together. I've run both ways before. If you're out of time and are COMFORTABLE with rpm vs PE, keep the maf tune and adjust the rpm vs PE for wot.....be very careful because if you don't understand how to "crutch" the pe table you will go Boom. I ran +700rwhp this way...not the way to do it but it "works". Changed over to sd and never looked back...much more accurate way to tune...part throttle is great.
Originally Posted by dc_justin
If you want to stick with the MAF and utilize the 2 bar functionality, you'll want to set the MAF up to fail just before you cross into boost.
Oh yeah, I use EFILive.
Last edited by Earl H; May 8, 2007 at 09:21 AM.
Originally Posted by Earl H
I am setting this up now. I have reduced the MAF threshold from 15500 to 11500 under the assumption that once it hits 11500 (far before the 15500 max) the PCM will default to the Boost VE and Boost Timing Tables and once those have been maxed out it will default to PE tables. Have I set this up correctly or are there more tables that will need adjustment?
Oh yeah, I use EFILive.
Oh yeah, I use EFILive.
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Verdad Gallardo What I don't understand is if everyone says the MAF has absolutely nothing to do with 1bar, 2bar, 3bar, etc, it only reads airflow why does the 2bar OS care where/when the maf fails and goes into SD and then decides what part of the VE table to use?
I still dont understand why not just go with a 3barOS and be done?
yes, MAF has nothing to do with pressure. if the MAF tables were internally bigger by only 2 bits, MAF could measure 2048g/sec, which is like 44psi on 7L motor spinning to 7000rpm...drooling yet?
yes, MAF has nothing to do with pressure. if the MAF tables were internally bigger by only 2 bits, MAF could measure 2048g/sec, which is like 44psi on 7L motor spinning to 7000rpm...drooling yet?
Originally Posted by Holty
What I don't understand is if everyone says the MAF has absolutely nothing to do with 1bar, 2bar, 3bar, etc, it only reads airflow why does the 2bar OS care where/when the maf fails and goes into SD and then decides what part of the VE table to use?
Originally Posted by dc_justin
I'd be VERY careful trying to do that. Every time I've run into someone who has attempted that (myself included) the result is that once you cross into boost, the MAF is ignored, the boost VE table is ignored, and fueling and timing reference comes from the 105kPa value of the VE table only. This occurs both with EFILive and HPTuners' custom operating systems. If you want to stick with the MAF and utilize the 2 bar functionality, you'll want to set the MAF up to fail just before you cross into boost.
Originally Posted by Frost
But it doesn't "unfail" itself once it is marked out as failed.... so it only works until the first time you floor it and then after you shut the car off and back on it will do it again for 1 cycle...
Originally Posted by dc_justin
Not according to Rick@Synergy. I have yet to test this myself. It's on my list of to-do's.
Originally Posted by 12secSS
As Frost said, and according to the team at HPT, it is not possible. Once the MAF fails it is hard coded that it won't come back on until the ECM can run an initial start up test on the all sensors.
For the sake of testing, I'll increase the MAF calibration by 20% across the board, disable Closed loop, set commanded AFR to 15:1 and set the MAF fail rate to few hundred hz above idle. Should see a very distinct change in O2 sensor values (WB is not installed at this time). EFILive COS5 based on 12212156 OS.
Justin
First, I tried the code turn off thing this morning, no worky. You turn those maf codes off and that PCM is looking for that MAF. It wouldn't run. Seems to me those codes need to be set and visible to an emission station for me to stay in SD succesfully.
Second, I tried what your are talking about dc_justin, just my own way, I added 30% to MAF past 8800 hertz and set fail rate to 8300hertz (to see if it didn't fail, it go pig rich after 8800hertz). Then added tons of fuel in the off idle areas to see the SD rich hit if it did fail (and to see if it stayed failed). Sure this caused for a rich MAF/VE blend, so I leaned out the MAF off idle areas as well. It failed like it was supposed to and that whole drive cycle it never went rich in the off idle areas. So to me, it worked. BUT, I know more than left that member and his vehicle and he called and said it isn't working now. It is fine until he "gets" into it. And when he does, it stays pig rich until he restarts. So, I have no luck with it either. I have tried this on my truck a few times unsuccessfully as well.
Second, I tried what your are talking about dc_justin, just my own way, I added 30% to MAF past 8800 hertz and set fail rate to 8300hertz (to see if it didn't fail, it go pig rich after 8800hertz). Then added tons of fuel in the off idle areas to see the SD rich hit if it did fail (and to see if it stayed failed). Sure this caused for a rich MAF/VE blend, so I leaned out the MAF off idle areas as well. It failed like it was supposed to and that whole drive cycle it never went rich in the off idle areas. So to me, it worked. BUT, I know more than left that member and his vehicle and he called and said it isn't working now. It is fine until he "gets" into it. And when he does, it stays pig rich until he restarts. So, I have no luck with it either. I have tried this on my truck a few times unsuccessfully as well.
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Joined: Nov 2001
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From: Bellevue, Wa
Interesting thread.
I have been running Maf with my 2bar for months now.
I set the MAF to fail at 7000hz (according to my logging this is the point where my car crosses over to boost) and then the 2bar takes it from there.
As for the MAF not renabling after the first time I go into boost, thats what I find interesting. I guess I could do an experiment to see but this whole time I sure thought the MAF was working. The car certainly behaves differently than when I tried to do 100% SD. It's alot more consistant in the non boost areas.
I have been running Maf with my 2bar for months now.
I set the MAF to fail at 7000hz (according to my logging this is the point where my car crosses over to boost) and then the 2bar takes it from there.
As for the MAF not renabling after the first time I go into boost, thats what I find interesting. I guess I could do an experiment to see but this whole time I sure thought the MAF was working. The car certainly behaves differently than when I tried to do 100% SD. It's alot more consistant in the non boost areas.
Originally Posted by Blackbird
Interesting thread.
I have been running Maf with my 2bar for months now.
I set the MAF to fail at 7000hz (according to my logging this is the point where my car crosses over to boost) and then the 2bar takes it from there.
As for the MAF not renabling after the first time I go into boost, thats what I find interesting. I guess I could do an experiment to see but this whole time I sure thought the MAF was working. The car certainly behaves differently than when I tried to do 100% SD. It's alot more consistant in the non boost areas.
I have been running Maf with my 2bar for months now.
I set the MAF to fail at 7000hz (according to my logging this is the point where my car crosses over to boost) and then the 2bar takes it from there.
As for the MAF not renabling after the first time I go into boost, thats what I find interesting. I guess I could do an experiment to see but this whole time I sure thought the MAF was working. The car certainly behaves differently than when I tried to do 100% SD. It's alot more consistant in the non boost areas.
EFIL or HPT's 2-bar OS?