TooManyIDs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ChrisB:
<strong>If anyone who is experiencing this wants to, it would be interesting to play with the numbers in the COT table to see if you can stop it from occuring in your particular instance at WOT, but still leave functionality intact (this would be a boon for those people with CATS still)
Chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">First, I'll say we need to understand why COT is kicking in. That is a problem in itself.
Second, we need to understand the risk of deactivation. Melt down? Fire?

Last two dyno sessions:
First pull doesn't show any COT induced richness in either session.

Second session, second pull, saw a straight AF line (12.6:1). Still saw richness kicked in at high rpm, but the start point moved from 6,050 rpm to 6,350 rpm. Before the COT adjustment, AF ended up at 11:1 at 6,600 rpm. After the COT adjustment, AF ended up at 11.8:1.

Values used:
1st threshold from 830C to 890C
2nd threshold from 840C to 900C
3rd threshold from 850C to 910C
4th threshold 920C to 920C (no change)

Had scaled the MAF table by 122%, adjusted PE vs RPM table. Was up to 17.8rwhp, but have since gone back to stock programming. Odd smell of fuel (rich mixture) at WOT now gone. See other posts on this topic.

John B

iTrader: (10)

WicketMike, why are you changing your MAF tables when you have a stock MAF? You should make fuel changes first with the injectors.

WicketMike

iTrader: (13)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by John B:
<strong>WicketMike, why are you changing your MAF tables when you have a stock MAF? You should make fuel changes first with the injectors.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">messing with the MAF table is just like turning the base switch on a MAFT ,right?
i do have a stock MAF, but its descreened and i do have a lid and ported TB and functinal ram air hood.. and ive asked questions about changing fuel w/ my injectors, but people on here said not to touch it if i had stock injectors..

i did add 12% on the MAF table and it did take care of adding fuel at WOT

tuning the MAF table was wrong?

John B

iTrader: (10)

Since you have modified your MAF you did the right thing by changing it's parameters. Typically what I have seen is that if the intake tract is basically stock, then the injectors flow will richen or lean the A/F best because the factory has them set up to perform with a stock intake, cam, heads and exhaust system. Once you change these, then the A/F parameters can change. Typically the MAF can adjust for this on its own but not in all cases....I know it didn't for me!

WicketMike

iTrader: (13)

i put the COT to false and i sitll have to lean out my 02's alot, right now im running 112% MAF and 90% rpm vs. PE. w/ the mods in sig.

by leaning it out 10%, i did gain in the 1/4.. and even w/ 10% lean , it will still reading rich, i need to get to a dyno soon

WicketMike

iTrader: (13)

so should i put the MAF table back to stock and start over with the injectors?

John B

iTrader: (10)

What are your total motor modifications?

chuckster

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by John B:
<strong>Since you have modified your MAF you did the right thing by changing it's parameters. Typically what I have seen is that if the intake tract is basically stock, then the injectors flow will richen or lean the A/F best because the factory has them set up to perform with a stock intake, cam, heads and exhaust system. Once you change these, then the A/F parameters can change. Typically the MAF can adjust for this on its own but not in all cases....I know it didn't for me!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">John I have the same question...
I had Ported MAF ends with a MAFT set to BASE+10
I just put my Stock maf back on when I got LS1-Edit.. I changed the MAF table to 5% (just like a MAFT)
I have HEaders, Intake, Gutted cats and Exhaust
I want my LTFT's to stay negative.. Should I put my MAF table back to stock and bump the injectors?

John B

iTrader: (10)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">John I have the same question...I had ported MAF ends with a MAFT set to BASE+10
I just put my Stock maf back on when I got LS1-Edit.. I changed the MAF table to 5% (just like a MAFT)I have HEaders, Intake, Gutted cats and Exhaust I want my LTFT's to stay negative.. Should I put my MAF table back to stock and bump the injectors? </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If you have changed the amount of air entering your motor by modifying the MAF (either de-screening it, different ends or installing a larger one) than you need to compensate for this by inceasing the MAF table values accordingly. If you have a stock MAF, I would first change the injector tables with the stock MAF on to obtain the correct amount of fuel entering the motor. Once this is accomplished, put the ported MAF back on and recalibrate the MAF tables as required to obtain the correct zero WOT LTFT's.

There may be several ways to skin a cat here but you can see my final HP results in my signature below.

WicketMike

iTrader: (13)

i have functional ram air hood
air lid w/ k&n
descreened stock maf
smooth bellows
ported TB
asp underdrive pully
160stat
and thats it besides hooker LT's w/ no cats and a cutout

running 12.6 by the way <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
sorry, love saying that with the little mods i have and could be even faster with some better tuning and weather <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

John B

iTrader: (10)

Based on your track numbers WicketMike I would say that your tuning is pretty close! Just like I mentioned in my post above regarding MAF changes, since your have modified your intake tract, you need to change your MAF table anyway to compensate properly for this.

At this point you really need to understand what is happening on a wideband using the dyno. My 02 sensors show max power at optimum A/F in the 0.935 range for my particular application so you can't always use the 0.890-0.910 rule.

Keep an eye on total timing and KR too. Good luck!

Phil99vette

iTrader: (11)

I have LS1 edit with my 99 corvette. Where do you find the COT feature? I have looked on all of the menu's and cant seem to find it.
Phillip

WicketMike

iTrader: (13)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by phil97svt:
<strong>I have LS1 edit with my 99 corvette. Where do you find the COT feature? I have looked on all of the menu's and cant seem to find it.
Phillip</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">its in the Test Paramaters tab
do you have the updated ls1edit also?

DriveATransAm

my A/F is above 12 the for the average...it looks like its actually 13, dips down to like 12.8 at 6400. would this not benefit me then?

John B

iTrader: (10)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> my A/F is above 12 the for the average...it looks like its actually 13, dips down to like 12.8 at 6400. would this not benefit me then? </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">A dip from 13 to 12.8 should be corrected in the PE tables. The COT problem shows a massive sudden dip as indicated in my dyno graph.