Apparently the MAF is a big restriction
Apparently the MAF is a big restriction Been running speed density for 2 years and i left the maf right where it was... I had a feeling the maf was chocking my engine... and i was right. I changed two things... one i took the torque management down to 50% (stock trans...) and pulled out my maf for a straight pipe...
anyways heres my track results.
Previous best before was a 7.62 @ 90.5 mph
With those changed i ran a time today of 7.39 @ 92.98mph and then backed it up with a 7.37 @ 92.02 mph.
So ~.25 tenths and 2.5mph is some nice free horsepower. the car has a 7.35 in it as shown in one of my 330' (was .025 faster) but i let out of the gas because i was bracket racing and didnt want to break out. DA was about 500 feet less then my previous best so that did help some. Anyways if your running speed density dont waste time like i did rip it out... lol.. cant wait to get on the dyno and see what it makes
anyways heres my track results.
Previous best before was a 7.62 @ 90.5 mph
With those changed i ran a time today of 7.39 @ 92.98mph and then backed it up with a 7.37 @ 92.02 mph.
So ~.25 tenths and 2.5mph is some nice free horsepower. the car has a 7.35 in it as shown in one of my 330' (was .025 faster) but i let out of the gas because i was bracket racing and didnt want to break out. DA was about 500 feet less then my previous best so that did help some. Anyways if your running speed density dont waste time like i did rip it out... lol.. cant wait to get on the dyno and see what it makes
then i guess you should have never switched to the 85mm maf? everything posted on the internet isnt always true. My exerience in removing the maf obviously was a restriction. I dont know if your being serious or sarcastic but ill take my findings over what someone says it should be good to. Been running speed density for 2 years and i left the maf right where it was... I had a feeling the maf was chocking my engine... and i was right. I changed two things... one i took the torque management down to 50% (stock trans...) and pulled out my maf for a straight pipe...
anyways heres my track results.
Previous best before was a 7.62 @ 90.5 mph
With those changed i ran a time today of 7.39 @ 92.98mph and then backed it up with a 7.37 @ 92.02 mph.
So ~.25 tenths and 2.5mph is some nice free horsepower. the car has a 7.35 in it as shown in one of my 330' (was .025 faster) but i let out of the gas because i was bracket racing and didnt want to break out. DA was about 500 feet less then my previous best so that did help some. Anyways if your running speed density dont waste time like i did rip it out... lol.. cant wait to get on the dyno and see what it makes
anyways heres my track results.
Previous best before was a 7.62 @ 90.5 mph
With those changed i ran a time today of 7.39 @ 92.98mph and then backed it up with a 7.37 @ 92.02 mph.
So ~.25 tenths and 2.5mph is some nice free horsepower. the car has a 7.35 in it as shown in one of my 330' (was .025 faster) but i let out of the gas because i was bracket racing and didnt want to break out. DA was about 500 feet less then my previous best so that did help some. Anyways if your running speed density dont waste time like i did rip it out... lol.. cant wait to get on the dyno and see what it makes
then i guess you should have never switched to the 85mm maf? everything posted on the internet isnt always true. My exerience in removing the maf obviously was a restriction. I dont know if your being serious or sarcastic but ill take my findings over what someone says it should be good to. Get all the info straight first before you make a commentA stock MAF is 74mm.. and an 85mm MAF is is jsut that 85mm.. Even then I still don't see an 85mm MAF being your restriction.
Maybe when you ran your previous times you were hotter weather (+DA) and when you ran this time you ran in little cooler weather (prolly still had a +DA but was lower)
FWIW, I too run an 85mm MAF.. I ran an 11.8 @ 119 with a larger cam then you and have no problems at all...........
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No where in your original post did you state it was an 85mm MAF that you were talking about Get all the info straight first before you make a comment
A stock MAF is 74mm.. and an 85mm MAF is is jsut that 85mm.. Even then I still don't see an 85mm MAF being your restriction.
Maybe when you ran your previous times you were hotter weather (+DA) and when you ran this time you ran in little cooler weather (prolly still had a +DA but was lower)
FWIW, I too run an 85mm MAF.. I ran an 11.8 @ 119 with a larger cam then you and have no problems at all...........
Get all the info straight first before you make a commentA stock MAF is 74mm.. and an 85mm MAF is is jsut that 85mm.. Even then I still don't see an 85mm MAF being your restriction.
Maybe when you ran your previous times you were hotter weather (+DA) and when you ran this time you ran in little cooler weather (prolly still had a +DA but was lower)
FWIW, I too run an 85mm MAF.. I ran an 11.8 @ 119 with a larger cam then you and have no problems at all...........
Also about torque management i didnt remove torque management completely i just cut it in half. One shift isnt going to drop me 3 tenths. And besides torque management doesnt account for higher map readings after removing the maf. The DA was a little better by 500 feet, nothing special. Map readings without the maf were 99-98 all the way to redline. With maf they started at 98 at low rpm ending up at 95 at redline. Thats pulling vacuum and restricting power.
Look im not here to argue what the stock maf will support for power. I removed and gained times and am just reporting my findings. I know removing it helped. The map told me so.
Last edited by got-a-ls1; Sep 12, 2010 at 08:38 PM.
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Verdad Gallardo about the weather my neighbor has a 5.79 dead consistent bracket racing car (consistent to .01). His times did not change at all compared to when he ran a month ago (which is when i ran the 7.62) so the air wasnt magical. Results speak for themselves.
The OP is correct you will gain higher map readings without the maf, running on speed density is been proven to make more power and better throttle responce. The gains from removing the maf being 74 mm with ls6 intake or 85mm with fast 90/90 is that air is not restricted by something in its path on its way to the TB. That is how you get a higher reading on you map readings . more air+fuel=more power.
Last edited by 01SS99red; Sep 12, 2010 at 08:43 PM.
The OP is correct you will gain higher map readings without the maf, running on speed density is been proven to make more power and better throttle responce. The gains from removing the maf being 74 mm with ls6 intake or 85mm with fast 90/90 is that air is not restricted by something in its path on its way to the TB. That is how you get a higher reading on you map readings . more air+fuel=more power.
Easiest thing to do is put it back in line, log the MAP sensor data, take it out, re-log.
Do a key on engine off with the scanner running, see what the kPa is for that day first.
Compare the kPa drop difference. That will tell you if there was really a restriction. Maybe the SD tune was just better than the other tune, maybe the MAF wasn't tuned correctly. Either way, if you had the 74 mm MAF it was probably a restriction.
Do a key on engine off with the scanner running, see what the kPa is for that day first.
Compare the kPa drop difference. That will tell you if there was really a restriction. Maybe the SD tune was just better than the other tune, maybe the MAF wasn't tuned correctly. Either way, if you had the 74 mm MAF it was probably a restriction.
i have always been running speed density since i first put in my 220 cam 3 years ago. I always heard the maf wouldnt hold you back until 500 rwhp, which is why i just left it inactive in the intake tract. When i swapped cams i didnt get the results i wanted so i thought it may infact be a restriction.
69lt1bird i already checked the map readings under wot before and after. At WOT now my map is a constant 99-98 before it would start 99-98 at low rpms and end up at 96-95 at high rpms.
69lt1bird i already checked the map readings under wot before and after. At WOT now my map is a constant 99-98 before it would start 99-98 at low rpms and end up at 96-95 at high rpms.
Interesting. I'm looking at my logs (85mm MAF, 90MM TB, FAST90) and I'm also seeing 95-96 with one or two 97's. Maybe I'll try the SD tune again sans MAF.
More interesting notes. I just looked at logs from 2007 when I was running an LS6 intake, stock TB and a 2002 Z06 85mm MAF and they all show 98-99.
I know I'm getting 4.63v at WOT and HPTuners shows 100% tps so not sure what to make of this new data.
More interesting notes. I just looked at logs from 2007 when I was running an LS6 intake, stock TB and a 2002 Z06 85mm MAF and they all show 98-99.
I know I'm getting 4.63v at WOT and HPTuners shows 100% tps so not sure what to make of this new data.
Last edited by Viper; Sep 13, 2010 at 04:39 PM.
So I decided to switch to cattless mids (from kooks catted mids), and ditch my maf. I got a piece of thin wall 4" od tube to put in place of the maf. I have been being easy on the car with the new rear but decided today to go wot in third just to see what the effect was...I was shocked.
I was almost 10% leaner for the short amount of time I stayed in it...lol. Something was holding me back, and I would say it was the maf.
Anyone else have a similar experience?
I was almost 10% leaner for the short amount of time I stayed in it...lol. Something was holding me back, and I would say it was the maf.
Anyone else have a similar experience?
Interesting. I'm looking at my logs (85mm MAF, 90MM TB, FAST90) and I'm also seeing 95-96 with one or two 97's. Maybe I'll try the SD tune again sans MAF.
More interesting notes. I just looked at logs from 2007 when I was running an LS6 intake, stock TB and a 2002 Z06 85mm MAF and they all show 98-99.
I know I'm getting 4.63v at WOT and HPTuners shows 100% tps so not sure what to make of this new data.
More interesting notes. I just looked at logs from 2007 when I was running an LS6 intake, stock TB and a 2002 Z06 85mm MAF and they all show 98-99.
I know I'm getting 4.63v at WOT and HPTuners shows 100% tps so not sure what to make of this new data.
Here in Southern Michigan I may see 98 kPa on one day and only only drop to 96 at WOT, others days I may see higher or lower. The barometric pressure changes the readings.
To the OP, if you have a 78 mm stock MAF than you should absolutely see a gain.