MAF or SD tune?

**mark21742** · 07-22-2008, 06:36 PM

I have an 04 a4 GTO with lt's, 3" true duals, p&p tb, cai, slp maf. and hptuners pro
I know I need to do a lot of tuning. I also now know I didn't need the slp maf, but at the time I saw "10-15 gain in hp" and bought it and sfter two years have no clue where my stock one is so I might as well use what I have
just for shits and giggles I unplugged the maf tonight (iat sensor is seperate from maf). now I should be running in speed density mode correct?
with the maf unplugged I'm getting 3 more miles to the gallon average and ALOT more power. is this because my maf table is so out of whack, and can I retune for it?
can I just remove the maf and leave the car in SD since it runs so much better?
what are your thoughts and what do yall recomend?
thank you guys!
P.S. frost its all your fault for getting thinking again lol

**0rion** · 07-23-2008, 08:18 PM

why not just tune for the maf? That's what I would do if I were in your shoes. Do some logging and use the maf histogram and tune for the maf.

**mark21742** · 07-24-2008, 01:50 AM

I was looking at the hptuners website and started getting a headache....so its not that bad once you actually start calibrating it?
do I log both ways, with and without the maf hookedup?

**foff667** · 07-24-2008, 03:28 PM

I always prefer to tune the VE table but then enable & tune the maf in the end so that way if the maf ever fails you won't have much of a problem even if you do pop a SES light & go into SD mode.

**0rion** · 07-24-2008, 03:57 PM

Originally Posted by mark21742

I was looking at the hptuners website and started getting a headache....so its not that bad once you actually start calibrating it?
do I log both ways, with and without the maf hookedup?

look in hptuners help menu under working with vcm editor>tuning how to section>user submitted>speed density.
That will give you a step by step on tuning the ve and maf.

**mark21742** · 07-24-2008, 05:13 PM

ok sounds good, im going to get into it in the morning after I get home from work and see if i can get anywhere.
Thank you guys!

**Frost** · 07-24-2008, 08:38 PM

The only reason it feels so much better is that MAF is making it so fat. A stock MAF will bring back a lot for you if you don't wanna tune.

**mark21742** · 07-24-2008, 10:28 PM

Originally Posted by Frost

The only reason it feels so much better is that MAF is making it so fat. A stock MAF will bring back a lot for you if you don't wanna tune.

ok let me ask this. would I get any performance gain at all with the slp maf tuned in over a stock maf? I'd like to learn more about tuning and get good at it so I can sqeeze every bit out of my setups

**Frost** · 07-25-2008, 04:08 PM

Maybe a couple in a larger-cube or ultra high revving setup. Nothing with stock internals.

They just aren't honest when they sell those things...

**Khaotic** · 07-25-2008, 04:19 PM

Originally Posted by mark21742

ok let me ask this. would I get any performance gain at all with the slp maf tuned in over a stock maf? I'd like to learn more about tuning and get good at it so I can sqeeze every bit out of my setups

Its a trial and error with the maf every engine is differant, Here is something to think about Most OEM mass airflow sensors are sized to be slightly smaller than the rest of the inlet plumbing in an effort to control velocity and increase accuracy. Stock maf are very accurate and typical the best to stay with as long as you dont go over 62 lbs min of airflow.

As you know more air and fuel is more power but takes time to recalibrate the maf to correct scale, But I agree with Frost go back with the maf you will have better results.

**mark21742** · 07-25-2008, 08:08 PM

Originally Posted by Frost

Maybe a couple in a larger-cube or ultra high revving setup. Nothing with stock internals.

They just aren't honest when they sell those things...

Yeah ive come to realize this...just wish I would have known before I spent the money on it.
But on the other hand we did alittle tuning tonight and got it alot closer than it was.....and what you said in another thread aout getting rid of torque management was right....It is adictive, I do like the just off idle chirp from the 1-2 shift and feels like I got ALOT of time back that I was losing between shifts.
All in all id say for to amatures we had a pretty good night tuning!

Im still gonna keep looking around for the stock MAF. I know its in a box in the garage somewhere.

**mark21742** · 07-25-2008, 08:13 PM

Originally Posted by Khaotic

Its a trial and error with the maf every engine is differant, Here is something to think about Most OEM mass airflow sensors are sized to be slightly smaller than the rest of the inlet plumbing in an effort to control velocity and increase accuracy. Stock maf are very accurate and typical the best to stay with as long as you dont go over 62 lbs min of airflow.

As you know more air and fuel is more power but takes time to recalibrate the maf to correct scale, But I agree with Frost go back with the maf you will have better results.

ok thanks for the velocity theory, I never thought about it from that aspect...its amazing how much Ive been learning lately, and to think a few months ago I thought I was pretty well versed in the automotive feild.....man was I wrong, the more I learn the more I realize I really havea long way to go lol