2002snortbird

What are the pros/cons. Would it be better to tune down the values or have a screened maf to report the correct values?

WS6FirebirdTA00

iTrader: (33)

well i think i would get the maf sensor, cause well...i did,lol. its always best, in my opinion, to do it right and not trick the computer. plus having a descreened maf cant be good its there for a reason right?

J&JsTA

I think "the" most appropriate thing to do would be to put the stock MAF back on if that is what caused the LTFTs to go that high...they seem rather high for just a MAF.... any hints on how we got there <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Doc99SShome

I tend to agree with J&J.

Exactly what MAF are you using to get +20% LTFTs, and what other mods do you have???

NoGo

iTrader: (2)

I would tune out of it. Just make sure you know what you are doing first.

LTerms are just a number. Your car is always at the same A/F ratio as long as your not setting a Lean/Rich SES light (LTerms between +25 to -25).

2002snortbird

I think the ported maf, headers, and cam got the lterms out of wack. Nogo explain?? So your saying that the Lterms have no effect on a/f, if your not setting a code??? With positive lterms I'm running lean, and when I go WOT the computer will dump fuel, making me pig rich not?

2K T/A Driver

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by BudChevy8:
<strong> plus having a descreened maf cant be good its there for a reason right? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I think the '03 Z06's MAF is descreened. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

98TAauto

iTrader: (2)

results on my car:

Ported ends: +20% LTRIMS
Stock: -5%
SLP 85mm: +4%

Tim Sloper

Be careful with 02/03 Z06 MAFs. They are very suceptible to turbulence and can cause erratic MAF readings. This is particularly true of ZO6s that have gone to alternate intake setups. I would stick with an 01 Z06 MAF with a screen and alter the table appropriately.

Tim

NoGo

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2002snortbird:
<strong> I think the ported maf, headers, and cam got the lterms out of wack. Nogo explain?? So your saying that the Lterms have no effect on a/f, if your not setting a code??? With positive lterms I'm running lean, and when I go WOT the computer will dump fuel, making me pig rich not? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">As long as your car is running in closed loop after you start it up, it is always going to have a 14.8:1 a/f ratio, UNLESS you have pegged the LTerms, or are in WOT mode. With that in mind, then you should be able to shift your Lterms anywhere you want in-between -25% and +25% and not change the part-throttle running characteristics of the car.

Yes, the ideal place for LTerms is slightly negative so that the PCM doesn't dump fuel when it goes WOT.

IMO, if a ported MAF drives your LTerms that far positive, then you can either ****-can it or jump into the long laborous process of charting its frequency.

Charting the frequency of the MAF is basically determing how much air is actually entering your engine for the reported hz that your MAF is giving. If your exhaust isn't highly modified, then you can do this fairly accurately using your LTerms.

Ask Doc99SS how to do it. He lives for it.

There is another side effect of some ported MAF's though. If you intake tract does not function to straighten airflow on its own (ie you have a FIPK induction) then your ported MAF is going to give erratic readings at higher airflows. This will drive the a/f all over the place and ultimately costs power.

Good Luck,
Kevin

2K T/A Driver

I am currently having this problem and am trying to find the best way to mod the maf table.. I need to buy a stock maf and see what happens just for grins... My maf is descreened..

I have tried to find DocSS's method and have yet to find it on the boards...

Doc, HELP US! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

2002snortbird

thanks for the explaination Nogo, it makes sense. I think I'm going to try a screened 85mm maf and see what happens.

Slowhawk

iTrader: (12)

I've learned that 01 +02 LS1's hate descreened or ported ends on the MA.The few I've dealt with alway's go into the high+'s on L-terms.I had good results with my SLP screened MA.Before=L-terms +15-+20 After=+5