Tunning Ported MAF Question?
Thread Starter
Launching!
Joined: Mar 2002
Posts: 229
Likes: 0
From: Amarillo
Tunning Ported MAF Question? I finally got the car to the track after I nstalled my C2 cam and Heads. The car went 12.92 @ 108. I'm running a ported MAF. So I've richened the MAF table up. However the car doesn't feel like its pulling on the top end. What all should I look at? My Ltrims are -3 & -4. My 02 are .87 to .88 no knock retard. The car pulled better with the granatilli MAF. Should I lean the Ltrims out a little?
Thanks for the help.
Thanks for the help.
Staging Lane
Joined: Jun 2002
Posts: 94
Likes: 0
From: Nowhere
Re: Tunning Ported MAF Question? The target for the LTRIM's is -2 or so. Damn, what elevation are you at? I trapped higher than that with a lid and cutout. I'm not trying to bust on ya, just need more info. The tuning all looks right. Don't know.
Re: Tunning Ported MAF Question? Chris,
Until you get rid of that ported MAF, your car is not going to run correctly. You are only registering 75% of the air that is actually entering the motor at the higher air velocities.
I looked at your A-tap file, and your very low airflow reading is goofing up the PCM's table references for timing / fuel / and god knows what else.
0.56 g/cyl at WOT is insane LOW. You are at the wrong spot on all of the PCM's tables.
Richening up your curve isn't going to cut it. With your MAF so far off, your car isn't running properly at WOT.
Until you get rid of that ported MAF, your car is not going to run correctly. You are only registering 75% of the air that is actually entering the motor at the higher air velocities.
I looked at your A-tap file, and your very low airflow reading is goofing up the PCM's table references for timing / fuel / and god knows what else.
0.56 g/cyl at WOT is insane LOW. You are at the wrong spot on all of the PCM's tables.
Richening up your curve isn't going to cut it. With your MAF so far off, your car isn't running properly at WOT.
Re: Tunning Ported MAF Question? Chris,
You will have to make some pretty dramatic changes to your MAF transfer function tables in order to get your ported MAF to work. I am currently in the middle of getting some correction factors calculated for your MAF compared to what my MAF (stock, untouched) reads.
I have a fully modded h/c vehicle though, so the curve may be about 5% off. It will still be a world closer than what your ported MAF is reading.
I will send you the excel file of a comparison between how your MAF is reading, and how a stock one normally reads.
Yours tapers off very sharply at 27 lb/min.
Proper corrections to your MAF Freq table should be able to compensate for this to a degree.
Know that the precision of your MAF is off as well though. The flow data that it reports back is not as consistant as a stock MAF.
You will have to make some pretty dramatic changes to your MAF transfer function tables in order to get your ported MAF to work. I am currently in the middle of getting some correction factors calculated for your MAF compared to what my MAF (stock, untouched) reads.
I have a fully modded h/c vehicle though, so the curve may be about 5% off. It will still be a world closer than what your ported MAF is reading.
I will send you the excel file of a comparison between how your MAF is reading, and how a stock one normally reads.
Yours tapers off very sharply at 27 lb/min.
Proper corrections to your MAF Freq table should be able to compensate for this to a degree.
Know that the precision of your MAF is off as well though. The flow data that it reports back is not as consistant as a stock MAF.
Re: Tunning Ported MAF Question? Okay, I finished you curve.
It looks like you were about 22% off in the upper ranges of the MAF.
I adjusted your curve so that it should read pretty close to what is actually flowing into your motor.
Before you hock your ported MAF, put this curve in and see how the car runs.
Your LTerms are going to be a little off, and your PE tables that you put in to richen the car up at WOT are going to have to be returned to normal. Buuut, your airflow should be reading correctly and you should get back your lost power as well as your timing.
You have mail <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ September 16, 2002, 05:15 PM: Message edited by: NoGo ]</small>
It looks like you were about 22% off in the upper ranges of the MAF.
I adjusted your curve so that it should read pretty close to what is actually flowing into your motor.
Before you hock your ported MAF, put this curve in and see how the car runs.
Your LTerms are going to be a little off, and your PE tables that you put in to richen the car up at WOT are going to have to be returned to normal. Buuut, your airflow should be reading correctly and you should get back your lost power as well as your timing.
You have mail <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ September 16, 2002, 05:15 PM: Message edited by: NoGo ]</small>
Thread Starter
Launching!
Joined: Mar 2002
Posts: 229
Likes: 0
From: Amarillo
Re: Tunning Ported MAF Question? Kevin, looking at the table you sen't me the numbers are close to the stock ones for my car. Will this show my Ltrims to be high since it is ported?
Give me a call to discuss.
I will pm you my cell number.
Thanks
Give me a call to discuss.
I will pm you my cell number.
Thanks
