Turbo MAF or MAFLESS
10-12-2011, 10:59 PM
#1
Turbo MAF or MAFLESS Seems like most people who turbo ditch the MAF. I was looking for threads to decide what to do on my setup (T72 magnum 5.3L stock with a 4l80e) and it seems like all the threads are older 2005 ish. From what I have seen ditching it would get me 2 PE tables, but I don`t really see any good reason to get rid of it unless I was going to exceed the 512 g/sec hardcode limit. Since this is more of a daily driver kinda build I`m considering keeping it. Any thoughts?
10-13-2011, 06:51 AM
#6
I can only think of 2 legitimate reasons not to go MAF:
Anybody else care to add legitimate reasons?
Regards,
Kurt
- 512g/sec hard limit (All the workarounds have compromises)
- Packaging (esp w/ twin turbos). Keep in mind the recommendations for proximity to bends & moving parts.
Anybody else care to add legitimate reasons?
Regards,
Kurt
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10-13-2011, 07:25 PM
#9
Older cars, SD was the easiest as the MAF limitations in G/sec and the frequency in HZ would both be maxed out.
Newer cars have higher G/Sec limitations, larger maf housings ( card slot style) and higher frequency plateaus, so using MAF in those cars is desired. ( Read 08+ LS3 vette/camaro, LS9)
Newer cars have higher G/Sec limitations, larger maf housings ( card slot style) and higher frequency plateaus, so using MAF in those cars is desired. ( Read 08+ LS3 vette/camaro, LS9)
10-13-2011, 07:45 PM
#10
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When you eliminate the MAF, do you just program the PCM to run only on MAP and IAT and just turn off the MAF option? I am building from the ground up and have no intentions on running a MAF, but I don't know how EFI Live or HP tuners works just yet.
10-13-2011, 10:35 PM
#13
Yes, but the processor still has MAF limitations within it. Stock 75/85mm MAFs will max out ~ 550-600 rwhp. Add a 100mm/card style maf, and itll bump up that limitation to ~700 rwhp.
LS3s are not nearing that limit. We have seen 1000+ through the MAF and still had both g/sec left as well as a thousand+ Hz.
LS3s are not nearing that limit. We have seen 1000+ through the MAF and still had both g/sec left as well as a thousand+ Hz.
10-13-2011, 10:38 PM
#14
I am running the older red/blue PCM and the MAF would have to be fairly close to a turn. I have to make a tight 90 into the turbo and I was going to put the filter on soon after it so the MAF would have to be fairly close to the 90 or filter.
What HP level does the 512 g/sec hard limit start to come into play at?
What HP level does the 512 g/sec hard limit start to come into play at?
10-13-2011, 11:14 PM
#15
you can get into some tomfoolery with Injector size, so you can keep the g/sec low. If you have a bigger injector, say, 50% larger than stock, pull 50% out of the Maf transfer table. This will bring your actual fueling closer to correct. Since we can alter the IFR table, this allows us to play with the MAF table so its closer to where we need it to be. keep an eye on your timing table as well, because this will have to be scaled 50% too.
Its a bit of wackey work, but you can skin the cat that way. On the new PCMs, we have a hardcoded limit of 63lb/hr for the IFR table. We then have to scale the MAF back. see here- http://www.injectordynamics.com/SteckScale.pdf
Dsteck frequents these forums, we can thank him for that article.
Best thing to do is start off slow, and see where you end up, if you have to use the MAF.
Louis
Its a bit of wackey work, but you can skin the cat that way. On the new PCMs, we have a hardcoded limit of 63lb/hr for the IFR table. We then have to scale the MAF back. see here- http://www.injectordynamics.com/SteckScale.pdf
Dsteck frequents these forums, we can thank him for that article.
Best thing to do is start off slow, and see where you end up, if you have to use the MAF.
Louis
10-14-2011, 08:14 AM
#16
On The Tree
you can get into some tomfoolery with Injector size, so you can keep the g/sec low. If you have a bigger injector, say, 50% larger than stock, pull 50% out of the Maf transfer table. This will bring your actual fueling closer to correct. Since we can alter the IFR table, this allows us to play with the MAF table so its closer to where we need it to be. keep an eye on your timing table as well, because this will have to be scaled 50% too.
10-14-2011, 09:42 AM
#18
On The Tree
The nice thing about a MAF system is it can account for changes in the system after it's been calibrated. MAP always assumes the same VE and then calculates fueling accordingly. If you remove some backpressure on a MAP car it will lean out if you don't retune it. If you do the same on a MAF car A/F won't budge with the same cal.
