MAF question
MAF question I was wondering (being i am new to FI and all) about the MAF on turbo applications. Most turbo applications I have seen do not have the MAF in the piping. I hate to ask about this but I am new and am going turbo! 
FormerVendor
Joined: Dec 2001
Posts: 2,444
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From: WWW.SPEEDINC.COM
On anything other than low boost on a stock engine, removing the MAF sensor and converting to speed density is by far your best option.
It's all based on ones opinion, Some say MAF, others say Mafless, Some say they gained HP going to SD and drive ability improved, others say they switched to SD and did not gain anything. Mine with a MAF, 12lbs of boost = 648 RWHP on pump gas, No issues what so ever...
Speed density like hptuners setup have advantages ,some disadvantages too.
No maf is nice and clean looking.Also you get two PE tables which control WOT fueling. You can set the non boost one to say 12.8 thru the range. Then set the boost table to say 11.0 thru the range.
Now for sure you richen up when you want to and don't richen up when you don't want to.
With maf you are setting that one table so you are guessing when you are going to be in boost .You might think you are for example always in boost at 3000rpm but turbos spool up at different rpm in various gears.Higher up in 1st than 2nd..etc.
I would think this dual table also helps mileage as not running rich when don't have to/want to.And should help off boost driveability as being off boost you would not be at optimal afr.
One negative to Speed density at least the hptuner system is you lose misfire detection.This is handy to have .person could of course keep maf around or even in the car and then go back to maf and 1bar for misfire detection. Bit of pain but doable.
I found no big problems getting car to run on SD .It sounds daunting but isn't too bad really.
Now think past about that 650rwhp range the maf does pretty much become a limitation and you start to have to guess at fueling once it maxes out. I was /am planning to beyond the 650rwhp range on my build so for me the speed density mafless was
logical and pretty sure necessary.
No maf is nice and clean looking.Also you get two PE tables which control WOT fueling. You can set the non boost one to say 12.8 thru the range. Then set the boost table to say 11.0 thru the range.
Now for sure you richen up when you want to and don't richen up when you don't want to.
With maf you are setting that one table so you are guessing when you are going to be in boost .You might think you are for example always in boost at 3000rpm but turbos spool up at different rpm in various gears.Higher up in 1st than 2nd..etc.
I would think this dual table also helps mileage as not running rich when don't have to/want to.And should help off boost driveability as being off boost you would not be at optimal afr.
One negative to Speed density at least the hptuner system is you lose misfire detection.This is handy to have .person could of course keep maf around or even in the car and then go back to maf and 1bar for misfire detection. Bit of pain but doable.
I found no big problems getting car to run on SD .It sounds daunting but isn't too bad really.
Now think past about that 650rwhp range the maf does pretty much become a limitation and you start to have to guess at fueling once it maxes out. I was /am planning to beyond the 650rwhp range on my build so for me the speed density mafless was
logical and pretty sure necessary.
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You can accidentally turn off misfire detection (speed density or not).
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Verdad Gallardo Hmm.didn't turn it off and don't seem to see anything but zero now. I did change cam but should still see some would think. I thought misfire depends on the maf to work?
it would be great if it is still there. Maybe can pull off a plug and check.
I will be super happy if its still there it can be very handy. I tried to ask on hptuners board but couldn't get a simple yes or no answer from them. I did read about a few guys think said they had it still with sd but not sure if thats only with 1bar maybe not 2bar or 3bar?
The fueling is one good reason though to switch over.I don't want my afr to be too rich when not in boost.And I want it to be right at any boost level.
it would be great if it is still there. Maybe can pull off a plug and check.
I will be super happy if its still there it can be very handy. I tried to ask on hptuners board but couldn't get a simple yes or no answer from them. I did read about a few guys think said they had it still with sd but not sure if thats only with 1bar maybe not 2bar or 3bar?
The fueling is one good reason though to switch over.I don't want my afr to be too rich when not in boost.And I want it to be right at any boost level.
All I can say is that with my setup, running 2 bar, my A/F was flat as a board to the commanded range, and beyond 650 RWHP? Mine made 722 RWHP on the fast gas with app 14lbs of boost. I may try SD but to me I have one more tuning parameter with the maf. The only way for me to see SD vs MAF is to tune to MAF then right there on the Dyno go to SD and see what is really the advantage for me....