Today I tested the difference between SD and MAF mode both in open loop (Dyno inside)
05-23-2006, 05:00 AM
#41
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Originally Posted by Black02SS
I doubt it.
Glad to see youve stepped it up bro! 
05-25-2006, 06:57 PM
#42
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Originally Posted by txhorns281
This is where we start to get into trouble, using words like "feel." Most people can barely feel 20 horses, and b/w a good MAF or good VE table you're not going to have a 20 or even 10 horse disparity anywhere over the power band. "Feel" is such a subjective word, let's try to stay away from it since it holds no real evidence.
And with part throttle, how else would you measure it?
It FELT like I was missing 30 lb/ft of tq every time I hooked the MAF back up. Even my wife noticed how much quicker the car FELT at low rpms.
The most significant place was right at 2k rpms. In 2nd gear at 2k, I punch it in SD, the car pulls.
With the MAF hooked up, I punch it at 2k in 2nd gear, the car kinda goes, almost seems like it waits..... then pulls finally at about 3500 rpm.
I don't have a wideband, the only measurement I've got is fuel trims.
Fuel trims were all -2 to 0 in cruise/part throttle areas. The only difference in trims between MAF and mafless modes for me was this wierd QUADRANT effect.
See this thread...... http://www.hptuners.com/forum/showthread.php?t=5564
The last few posts have my log/tune and explain what's happening.
05-25-2006, 07:16 PM
#43
Originally Posted by silverTA2002
I don't have a wideband, the only measurement I've got is fuel trims.
Tune the car with a wideband and don't pay any attention to the ltft's. Then do the test and let us know what you think as I'll bet you will be suprised.
05-25-2006, 08:05 PM
#44
Originally Posted by Black02SS
That is your problem right there. You need a wideband as I'll put money down your fueling is all jacked up, causing the car to feel "soft".
Tune the car with a wideband and don't pay any attention to the ltft's. Then do the test and let us know what you think as I'll bet you will be suprised.
Tune the car with a wideband and don't pay any attention to the ltft's. Then do the test and let us know what you think as I'll bet you will be suprised.
05-26-2006, 07:45 AM
#47
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Originally Posted by silverTA2002
It FELT like I was missing 30 lb/ft of tq every time I hooked the MAF back up. Even my wife noticed how much quicker the car FELT at low rpms.
The most significant place was right at 2k rpms. In 2nd gear at 2k, I punch it in SD, the car pulls.
With the MAF hooked up, I punch it at 2k in 2nd gear, the car kinda goes, almost seems like it waits..... then pulls finally at about 3500 rpm.
The most significant place was right at 2k rpms. In 2nd gear at 2k, I punch it in SD, the car pulls.
With the MAF hooked up, I punch it at 2k in 2nd gear, the car kinda goes, almost seems like it waits..... then pulls finally at about 3500 rpm.
05-26-2006, 08:25 AM
#49
I think most of you guys are expecting the stock MAF tables to still be accurate on highly modified motors. This of course will not be the case. Intake mods change airflow characteristics. Heads, cam and exhaust mods change reversion. Not to mention it stands to reason that as VE table needs to be adjusted to correct fueling, the MAF would require the same changes.
If youre wondering why your car run so much slower with the MAF in place, its likely because of one of two reasons. First and foremost, your MAF simply isnt tuned accurately, which is throwing off your fueling / spark. Secondly, a stock MAF on a highly modified ls1 will be an intake restriction. Upgrade the MAF or port out the stocker and re-tune it.
If youre wondering why your car run so much slower with the MAF in place, its likely because of one of two reasons. First and foremost, your MAF simply isnt tuned accurately, which is throwing off your fueling / spark. Secondly, a stock MAF on a highly modified ls1 will be an intake restriction. Upgrade the MAF or port out the stocker and re-tune it.
05-26-2006, 09:35 AM
#52
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Originally Posted by Phil99vette
Have you guys ever logged the A/F into a VE table with the MAF enabled? Its pretty interesting to say the least.....
Mine was the same as the MAF table. They follow each other
05-26-2006, 09:48 AM
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Originally Posted by HumpinSS
Mine was the same as the MAF table. They follow each other
Of course there are slight variances b/w models, but it's like using F=M*A and then converting to figure out what someone weighs, or hopping on a scale and getting a readout. Both ways ought to be damn close, give or take a pound or two partially due to rounding, miscalibration, resolution loss or even crappy math! Yikes!
05-26-2006, 10:14 AM
#55
Originally Posted by txhorns281
I wish the search would fully work so that we could reference even more threads over a year ago that prove the SD vs MAF expectations. I think there are those of us out there that are almost blue in the face from screaming that there is little difference b/w the two for 99% of the setups out there.
Still on a stock descreened MAF here, still even on the stock VE table lol. MAF table is highly tweaked though, car drives like stock everywhere and 1.31 60's off the footbrake @ 3300lbs is acceptable IMO.
People still wont believe you, the MAF is evil and must be eliminated
05-31-2006, 04:58 PM
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DAMN 1.31 60's . hahahaha, the MAF. This reminds me of what a guy once was talkin to me about: You want have sex without a condom because it feels better but your afraid of the consequences...
well you want to take the MAF off cuz it FEELS better...and your
(*possibly) afraid of the consequences.
**I Will say that a tuned SD car would have no problems.
had to add that
well you want to take the MAF off cuz it FEELS better...and your
(*possibly) afraid of the consequences.
**I Will say that a tuned SD car would have no problems.
had to add that
06-01-2006, 06:22 PM
#57
Just put the MAF on my car and did 3 quick tunes (still have some issues but those are just the minor details). Bottom line is there isnt a damn bit of difference in how the car responds or anything. If I tap the throttle in 1st to about 25% it jumps and barks the tires just the same as it did in SD. WOT is a different story since I have about a 11:1 AFR right now lol.
The car also is not lean on start up like it was in SD, which is the whole reason I decided to attempt this. Thanks Steve for the MAF to try out lol
The car also is not lean on start up like it was in SD, which is the whole reason I decided to attempt this. Thanks Steve for the MAF to try out
lol
06-02-2006, 09:02 AM
#60
Originally Posted by HumpinSS
if there is its the tuner not the car