HUGE gains with MAF removed completely...
07-22-2006 | 08:54 PM
#31
Thread Starter
TECH Addict
Joined: Feb 2003
Posts: 2,864
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From: Geneseo, NY
RedHardSupra: WOW...an LS1Tech legend showing his face on PT.net, I'm humbled 
...thanks for the great info !!!
Kano: No...it developed a crack in it near the back I didn't know about and was causing me all kinds of tuning issues until I figured that out
dew: I've been dyncylair all along...just still had the MAF in place and was seeing the reading off of it (it'll still read with fail=0hz but the PCM ignores it and sets dtc...as long as the dtc's are set it's truly in SD mode)
...thanks for the great info !!!Kano: No...it developed a crack in it near the back I didn't know about and was causing me all kinds of tuning issues until I figured that out
dew: I've been dyncylair all along...just still had the MAF in place and was seeing the reading off of it (it'll still read with fail=0hz but the PCM ignores it and sets dtc...as long as the dtc's are set it's truly in SD mode)
07-22-2006 | 08:57 PM
#32
okay then. I am going out tomorrow and doing a tq log. Then if I can, I'll remove mine to compare. Obviously keeping an eye on my %error in the boost areas. Again, Very interesting.
07-23-2006 | 10:28 AM
#33
Well I tried removing the MAF from the air stream and had no positive results. Take a look here are the two logs. The top one is no MAF the bottom one is with it. These are both in SD of course.
07-24-2006 | 01:23 PM
#35
Originally Posted by Yelo
I've been running an SD tune with the MAF still place for quite a while now....late yesterday evening I removed the MAF completely from the intake tract but still left it plugged in and sitting near the filter to keep the IAT sensor sort of half-assed working.
All I can say is WOW !!!
Using the pid in HPTuners for delivered torque (which I know is not accurate...but it's at least consistant in its inaccuracy so it can be used to detect changes) I was never able to get above 345 ft/lbs with the MAF in place....in a direct comparison on the same road yesterday evening 15 minutes apart I went from 341ft/lbs @ 4400rpm with the MAF installed to 374ft/lbs @ 4400rpm with the MAF removed (in both cases the IAT was reading 121º)...that's just shy of a 10% gain in power !!!
I unfortunatly cannot see grams/cyl now because there is no MAF reading to derive that number from so I can't give you an actual airflow gain....but I CAN tell you that it pulls MUCH harder from 2800 rpm on up to the shift at 6000 than it EVER did before
I'm running a screened 85mm MAF (stock 6.0)....I'm absolutely stunned that it it's that much of a restriction on a baby-cammed 6.0, I can only imagine how bad it's got to be on guys running 224's and bigger. I'm considering a 235/239 .575 lift cam....trying to run that through the MAF would be pointless !!
All I can say is WOW !!!
Using the pid in HPTuners for delivered torque (which I know is not accurate...but it's at least consistant in its inaccuracy so it can be used to detect changes) I was never able to get above 345 ft/lbs with the MAF in place....in a direct comparison on the same road yesterday evening 15 minutes apart I went from 341ft/lbs @ 4400rpm with the MAF installed to 374ft/lbs @ 4400rpm with the MAF removed (in both cases the IAT was reading 121º)...that's just shy of a 10% gain in power !!!
I unfortunatly cannot see grams/cyl now because there is no MAF reading to derive that number from so I can't give you an actual airflow gain....but I CAN tell you that it pulls MUCH harder from 2800 rpm on up to the shift at 6000 than it EVER did before
I'm running a screened 85mm MAF (stock 6.0)....I'm absolutely stunned that it it's that much of a restriction on a baby-cammed 6.0, I can only imagine how bad it's got to be on guys running 224's and bigger. I'm considering a 235/239 .575 lift cam....trying to run that through the MAF would be pointless !!
I look at it like this the pcm uses alot of sensors to form calculations if I take
1*2=2 (the 1 and 2 represent sensor inputs) and I remove one of the inputs I get a zero or a default value it then makes
0*2=0
The maf still measures hz even when the fail code is set to 0, with the maf removed from the air tract and still reading an incorrect measurement this could account for those numbers being higher.
Not trying to be an ******* just objective
07-24-2006 | 01:51 PM
#36
Thread Starter
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Joined: Feb 2003
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From: Geneseo, NY
I guess it's possible that the wierd MAF readings caould have accounted for the increase in delivered torque (which I KNOW is not accurate...I was only using it for comparison) but if the fail is set to 0hz and the DTC's are set I was under the impression that the MAF was ignored and all fueling calculations were done via the VE table
I agree that dyno numbers or track time are the only way to be 100% certain that there was a gain...but since I really didn't feel like driving 2.5 hours to a dyno or track I was using what I had available.
How would you account for the trims going positive ??....positives trims indicate increased air-flow right ??
I agree that dyno numbers or track time are the only way to be 100% certain that there was a gain...but since I really didn't feel like driving 2.5 hours to a dyno or track I was using what I had available.
How would you account for the trims going positive ??....positives trims indicate increased air-flow right ??
07-24-2006 | 02:04 PM
#37
Originally Posted by Yelo
I guess it's possible that the wierd MAF readings caould have accounted for the increase in delivered torque (which I KNOW is not accurate...I was only using it for comparison) but if the fail is set to 0hz and the DTC's are set I was under the impression that the MAF was ignored and all fueling calculations were done via the VE table
I agree that dyno numbers or track time are the only way to be 100% certain that there was a gain...but since I really didn't feel like driving 2.5 hours to a dyno or track I was using what I had available.
How would you account for the trims going positive ??....positives trims indicate increased air-flow right ??
I agree that dyno numbers or track time are the only way to be 100% certain that there was a gain...but since I really didn't feel like driving 2.5 hours to a dyno or track I was using what I had available.
How would you account for the trims going positive ??....positives trims indicate increased air-flow right ??
Trims go positive when air gets hotter also (still researching this)
Last edited by 02sierraz71_5.3; 07-24-2006 at 02:11 PM.
07-24-2006 | 02:20 PM
#38
Originally Posted by joshluther
Well I tried removing the MAF from the air stream and had no positive results. Take a look here are the two logs. The top one is no MAF the bottom one is with it. These are both in SD of course.
