Anyone go from SD back to MAF tune?
02-12-2020, 12:33 AM
#1
On The Tree
Thread Starter
Anyone go from SD back to MAF tune? Maybe I'm just getting bored with the snow and winter but..... been kinda thinking about going from SD tune back to MAF/SD tune like stock does it. I ended up not running WMI, which was a big reason I did SD originally, just made setting up the hardware easier. I don't have a huge cam or anything. Low speed driveability is good, maybe even a hair better than when I was MAF tuned, pre-SC....but honestly that could very well be because I never really bothered to get VE table dialed in that well.
I understand a good SD tune should account for temp/elevation changes no problem, but I really haven't got to put the elevation part to the test yet....but in theory MAF does this better and easier. Looks like I could easily weld on a MAF mount and run the LS3/7 MAF in the cold side pipe and even just use it's internal IAT sensor. I have read through all of the MAF / tune scaling stuff I would need to do and feel comfortable with that. Currently making around 700whp.
At the end of the day, both work, but I can't think of any good reason not to run the MAF anymore. Does high rpm low load condition with a centri blower cause weird MAF reading/airflow turbulence issues?
Just looking to see if anyone has any personal experience on the subject, thanks!
I understand a good SD tune should account for temp/elevation changes no problem, but I really haven't got to put the elevation part to the test yet....but in theory MAF does this better and easier. Looks like I could easily weld on a MAF mount and run the LS3/7 MAF in the cold side pipe and even just use it's internal IAT sensor. I have read through all of the MAF / tune scaling stuff I would need to do and feel comfortable with that. Currently making around 700whp.
At the end of the day, both work, but I can't think of any good reason not to run the MAF anymore. Does high rpm low load condition with a centri blower cause weird MAF reading/airflow turbulence issues?
Just looking to see if anyone has any personal experience on the subject, thanks!
02-12-2020, 01:08 AM
#2
Temp changes need to be properly accounted for with SD, but elevation sort of handles itself. The only thing that might be an issue with elevation and SD is idle or extremely low throttle positions at very high elevations. It really sounds like you are bored and want to tinker with the tune. Nothing wrong with that.
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jrob56 (02-26-2020)
02-12-2020, 10:20 AM
#5
On The Tree
Thread Starter
Temp changes need to be properly accounted for with SD, but elevation sort of handles itself. The only thing that might be an issue with elevation and SD is idle or extremely low throttle positions at very high elevations. It really sounds like you are bored and want to tinker with the tune. Nothing wrong with that.
And yeah I definitely like to tinker, this is my tinker/fun car. It runs very well now honestly, but I'm always looking to learn, experiment or try to make things better.
I think I see a small error in the procedure regarding the idle/CL mode stuff in the guide. Once I dig into it, if I find anything worth mentioning I'll definitely chime into the thread!
See above....car is running very well, I always ignore the "if it ain't broke don't fix it" throught process lol.
Honestly as I've gone through a few hardware changes or realize an issue with injector data/fix it etc, I've had to go back and re-do the VE table multiple times and it's just been a little time consuming on the street for me.
Big picture, it drives well and WOT fueling is good, but I feel like I'm stuck at the 90% point of where I'd like to be. Not quite as consistent as I'd like....but admittingly most would just turn on CL fueling and never look at a datalog again at this point lol.
MAF table I'm thinking will just be a lot more straightforward and hopefully more consistent. I understand I still need to maintain a correct VE table, but only below 4000rpm as I understand it, so that makes it a lot easier.
Or I'm just bored
Thanks for chiming in Greg, that's what I'm hoping for!
02-12-2020, 12:17 PM
#7
TECH Addict
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02-12-2020, 02:07 PM
#9
On The Tree
Thread Starter
Well, I was getting excited about this and about to order the parts, but then I realized that my cold side piping is 3.5", not 4.0" like I thought. So I am almost certain I'm not going to have enough Hz.
It's a C5 with A&A kit, there's really no easy way to convert the cold side pipe to 4" since there's a big long custom coupler off the intercooler that is 3.5" and pre-blower is out of the question too. Not going to put in some sort of janky transition pipe right at the MAF, would kind of invalidate the whole thing I think. A complete custom cold pipe might be the only real alternative, but not exactly a cheap or easy option.
It's starting to look like I can't easily make it work with my current config, bummer.
It's a C5 with A&A kit, there's really no easy way to convert the cold side pipe to 4" since there's a big long custom coupler off the intercooler that is 3.5" and pre-blower is out of the question too. Not going to put in some sort of janky transition pipe right at the MAF, would kind of invalidate the whole thing I think. A complete custom cold pipe might be the only real alternative, but not exactly a cheap or easy option.
It's starting to look like I can't easily make it work with my current config, bummer.
02-12-2020, 02:08 PM
#10
TECH Addict
i assumed it was a more tedious process that may require more/different calculations than one or the other alone. tools was meant as a generality; dyno, wideband, software, spreadsheets, expertise, etc
02-12-2020, 02:22 PM
#11
Well, I was getting excited about this and about to order the parts, but then I realized that my cold side piping is 3.5", not 4.0" like I thought. So I am almost certain I'm not going to have enough Hz.
It's a C5 with A&A kit, there's really no easy way to convert the cold side pipe to 4" since there's a big long custom coupler off the intercooler that is 3.5" and pre-blower is out of the question too. Not going to put in some sort of janky transition pipe right at the MAF, would kind of invalidate the whole thing I think. A complete custom cold pipe might be the only real alternative, but not exactly a cheap or easy option.
It's starting to look like I can't easily make it work with my current config, bummer.
It's a C5 with A&A kit, there's really no easy way to convert the cold side pipe to 4" since there's a big long custom coupler off the intercooler that is 3.5" and pre-blower is out of the question too. Not going to put in some sort of janky transition pipe right at the MAF, would kind of invalidate the whole thing I think. A complete custom cold pipe might be the only real alternative, but not exactly a cheap or easy option.
It's starting to look like I can't easily make it work with my current config, bummer.
Tuning a MAF transfer function with EFI Live/HPT that can log a digital wideband out is CAKE compared to tuning a VE table.
02-12-2020, 02:40 PM
#14
You would replace that coupler and pipe to the TB with a 4 inch pipe and the MAF. It's not janky because your TB is a 4 inch coupler anyways lol.
Tuning a MAF transfer function with EFI Live/HPT that can log a digital wideband out is CAKE compared to tuning a VE table.
Tuning a MAF transfer function with EFI Live/HPT that can log a digital wideband out is CAKE compared to tuning a VE table.
02-12-2020, 02:46 PM
#15
On The Tree
Thread Starter
best pnp option I’ve found so far, but it would only offer 3” before the transition. Better than the really compact MAF housings made by lingenfelter or Texas speed.
https://www.ebay.com/itm/4-0-OD-Slot...-/253108003593
Gonna have to pull out the tape measure tonight and figure this out.
02-12-2020, 02:52 PM
#16
TECH Addict
i have done sd only tunes in the past that were excellent and resulted in much much smoother afrs than my current professionally tuned e38 maf setup.
I have never tuned a maf/sd ecm so i was curious. I have always completely disabled one or the other.
02-12-2020, 02:57 PM
#18
im sure its not bad but the point was Greg's statement that one 'tuned properly' would be better than SD alone, and my question was what does it take to get a maf/sd tune better than sd only?
i have done sd only tunes in the past that were excellent and resulted in much much smoother afrs than my current professionally tuned e38 maf setup.
I have never tuned a maf/sd ecm so i was curious. I have always completely disabled one or the other.
i have done sd only tunes in the past that were excellent and resulted in much much smoother afrs than my current professionally tuned e38 maf setup.
I have never tuned a maf/sd ecm so i was curious. I have always completely disabled one or the other.
Doing a blended tune isn't difficult, you do exactly what it sounds like. Disable MAF, tune VE table. Then disable VE table, tune MAF. Turn both on and set the RPM threshold for airflow calc to the desired RPM. Above that RPM its strictly looking at the MAF for steady state airflow (WOT). You'll get better throttle transitioning and idle. Just takes longer and in most instances people are happy with a 95%. Shoot.....most people don't even get that close lol. The following users liked this post:
aaronc7 (02-12-2020)
02-12-2020, 03:02 PM
#19
Its not hard....its just more difficult than a MAF tune LOL.
Remember Greg does OEM calibration....that stuff has to be perfect Doing a blended tune isn't difficult, you do exactly what it sounds like. Disable MAF, tune VE table. Then disable VE table, tune MAF. Turn both on and set the RPM threshold for airflow calc to the desired RPM. Above that RPM its strictly looking at the MAF for steady state airflow (WOT). You'll get better throttle transitioning and idle. Just takes longer and in most instances people are happy with a 95%. Shoot.....most people don't even get that close lol.
Remember Greg does OEM calibration....that stuff has to be perfect
Doing a blended tune isn't difficult, you do exactly what it sounds like. Disable MAF, tune VE table. Then disable VE table, tune MAF. Turn both on and set the RPM threshold for airflow calc to the desired RPM. Above that RPM its strictly looking at the MAF for steady state airflow (WOT). You'll get better throttle transitioning and idle. Just takes longer and in most instances people are happy with a 95%. Shoot.....most people don't even get that close lol.