Ltrims and Ign. Advance ....Quick Question
Ltrims and Ign. Advance ....Quick Question I have two quick questions for any of you guys.
First Question... Will adjusting the base setting of a MAFT to +15% rich result in a decrease in timing at WOT, given that the +15% is thrown in to bring LTrims to right around 0(+/- 3%)?
Now for the background on the vehicle in question...
2000 C5 Hardtop. Ran fine, MAFT set at 0/0 with o2 around .890-.910. Only mod at that time was a Donaldson in place of the airbox, air bridge, and a corsa.
After adding the LS6 Intake and SLP 85mm MAF, the LTrims shot up to around 22, after a decent amount of learning time. I ended up setting the base to +15% and managed to bring the LTrims down to right around -3 to +3. Logged a WOT run(+0) O2s were up around .930-.940 and timing was down an average of 4 deg.
Second question... Would setting the WOT to a -% to bring down the O2s to closer to .880 result in additional timing?
If leaning it out at WOT will NOT result in additional timing, my best bet should probably be to re-install the stock MAF. The loss in timing is probably greater that any sort of benifit I gain by going to a larger MAF.(?)
Thanks,
First Question... Will adjusting the base setting of a MAFT to +15% rich result in a decrease in timing at WOT, given that the +15% is thrown in to bring LTrims to right around 0(+/- 3%)?
Now for the background on the vehicle in question...
2000 C5 Hardtop. Ran fine, MAFT set at 0/0 with o2 around .890-.910. Only mod at that time was a Donaldson in place of the airbox, air bridge, and a corsa.
After adding the LS6 Intake and SLP 85mm MAF, the LTrims shot up to around 22, after a decent amount of learning time. I ended up setting the base to +15% and managed to bring the LTrims down to right around -3 to +3. Logged a WOT run(+0) O2s were up around .930-.940 and timing was down an average of 4 deg.
Second question... Would setting the WOT to a -% to bring down the O2s to closer to .880 result in additional timing?
If leaning it out at WOT will NOT result in additional timing, my best bet should probably be to re-install the stock MAF. The loss in timing is probably greater that any sort of benifit I gain by going to a larger MAF.(?)
Thanks,
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Re: Ltrims and Ign. Advance ....Quick Question Anytime you are fighting a lean condition and attempt to solve that by fooling the PCM to go richer the MAFT is fooling the PCM by changing the true MAF freq value.
The more load the engine thinks it is in ( by adding more gas (richer) the more timing it will pull out.
Consider for easy math, MAF functions to 10,000 Hz, you translate the MAF signal by lets say 10%.
10% then means 9,000 Hz.
The PCM believes the amount of grams/cyc is reduced by that much and consider that torque output is directly related to MAF values, thus the end result is less timing and less torque,
Add the fact the 3rd party MAF may also be skewing the MAF signal cause the vendor mucked with it and the LS6 intake has a bit longer runners, thus with that lean of a condition and forcing 10 - 15% richer, you loose.
Now if your lets say 20% lean and you go with SVO 30 injectors which are about 30% larger,
-30richer + 20leaner = -10 rich end result.
Now with a MAFT your dialing in to go leaner, means less engine load which means higher timing and higher torque.
Until LS1edit the MAFT was the only game in town to do on the spot partial tuning but the best path now is to go with LS1edit and tune it the right way, better gains long term, but if sticking with the MAFT, maintain the PCM relearning process and dial LTFTs to around zero and only then fine tune usig WOT switch on MAFT.
IMHO, best is run as lean as you can without effecting knock that would offset gains with retarding of timing so I rather be a few % lean then rich for part throttle LTFTs.
Use knock and WOT timing as your guide marks to know when to cease going any leaner.
The more load the engine thinks it is in ( by adding more gas (richer) the more timing it will pull out.
Consider for easy math, MAF functions to 10,000 Hz, you translate the MAF signal by lets say 10%.
10% then means 9,000 Hz.
The PCM believes the amount of grams/cyc is reduced by that much and consider that torque output is directly related to MAF values, thus the end result is less timing and less torque,
Add the fact the 3rd party MAF may also be skewing the MAF signal cause the vendor mucked with it and the LS6 intake has a bit longer runners, thus with that lean of a condition and forcing 10 - 15% richer, you loose.
Now if your lets say 20% lean and you go with SVO 30 injectors which are about 30% larger,
-30richer + 20leaner = -10 rich end result.
Now with a MAFT your dialing in to go leaner, means less engine load which means higher timing and higher torque.
Until LS1edit the MAFT was the only game in town to do on the spot partial tuning but the best path now is to go with LS1edit and tune it the right way, better gains long term, but if sticking with the MAFT, maintain the PCM relearning process and dial LTFTs to around zero and only then fine tune usig WOT switch on MAFT.
IMHO, best is run as lean as you can without effecting knock that would offset gains with retarding of timing so I rather be a few % lean then rich for part throttle LTFTs.
Use knock and WOT timing as your guide marks to know when to cease going any leaner.
Re: Ltrims and Ign. Advance ....Quick Question Team ZR-1,
Thank you very much. That is exactly the type of info I was looking for. I'm still a little undecided on if I'll keep the SLP MAF in it or not, but I'll do some more testing on it.
I will knock the base down to +10 and give it plenty of miles to learn, then tweak the WOT setting and see what the timing looks like. Going from the +15, with 0 LTrims, to +10 shouldnt really bring up the LTrims too much, probably less than 10. If its very close to the stock average timing, I'll keep it in there, but if I'm off by more than a degree(average timing), I'll probably pull it and install the stock MAF. Stock average timing was around 28.5 from 3k-6.2k
Thanks again,
Thank you very much. That is exactly the type of info I was looking for. I'm still a little undecided on if I'll keep the SLP MAF in it or not, but I'll do some more testing on it.
I will knock the base down to +10 and give it plenty of miles to learn, then tweak the WOT setting and see what the timing looks like. Going from the +15, with 0 LTrims, to +10 shouldnt really bring up the LTrims too much, probably less than 10. If its very close to the stock average timing, I'll keep it in there, but if I'm off by more than a degree(average timing), I'll probably pull it and install the stock MAF. Stock average timing was around 28.5 from 3k-6.2k
Thanks again,
Re: Ltrims and Ign. Advance ....Quick Question </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Team ZR-1:
<strong>Anytime you are fighting a lean condition and attempt to solve that by fooling the PCM to go richer the MAFT is fooling the PCM by changing the true MAF freq value.
The more load the engine thinks it is in ( by adding more gas (richer) the more timing it will pull out.
Consider for easy math, MAF functions to 10,000 Hz, you translate the MAF signal by lets say 10%.
10% then means 9,000 Hz.
The PCM believes the amount of grams/cyc is reduced by that much and consider that torque output is directly related to MAF values, thus the end result is less timing and less torque,
Add the fact the 3rd party MAF may also be skewing the MAF signal cause the vendor mucked with it and the LS6 intake has a bit longer runners, thus with that lean of a condition and forcing 10 - 15% richer, you loose.
Now if your lets say 20% lean and you go with SVO 30 injectors which are about 30% larger,
-30richer + 20leaner = -10 rich end result.
Now with a MAFT your dialing in to go leaner, means less engine load which means higher timing and higher torque.
Until LS1edit the MAFT was the only game in town to do on the spot partial tuning but the best path now is to go with LS1edit and tune it the right way, better gains long term, but if sticking with the MAFT, maintain the PCM relearning process and dial LTFTs to around zero and only then fine tune usig WOT switch on MAFT.
IMHO, best is run as lean as you can without effecting knock that would offset gains with retarding of timing so I rather be a few % lean then rich for part throttle LTFTs.
Use knock and WOT timing as your guide marks to know when to cease going any leaner.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Very interesting, if this is true that means that I am kinda going about my tuning sort of backwards <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" />
I have Ed Wrights tuning and I added a ported stock MAF along with a MAFT after I had him tune it, therefore it's not accounted for with his tuning. I monitored my LTrims and as of right now I have mt base at +20 and my WOT at +6. My LTrims are averaging around +5% on my part throttle fuel cells and I thought I had everything tuned OK until I saw this. I am seing no KR at WOT and I am seeing a solid 28 degrees of timing at WOT from around 5,200 rpm's all the way to 6,200 or so.
So, from what I understand of your post, I am actually causing my PCM to see more load by using my MAFT to adjust for my lean condition. I wonder if I would be better off to just put my stock, unported MAF back on and set my MAFT back somewhere towards 0/0???? Either that or I could send my PCM back to Ed (which I have to do anyway to have the EGR and AIR codes deleted) and have him account for my ported MAF.
What do you think??
Thanks
Paul
<small>[ June 28, 2002, 05:27 PM: Message edited by: JR HAWK 9 ]</small>
<strong>Anytime you are fighting a lean condition and attempt to solve that by fooling the PCM to go richer the MAFT is fooling the PCM by changing the true MAF freq value.
The more load the engine thinks it is in ( by adding more gas (richer) the more timing it will pull out.
Consider for easy math, MAF functions to 10,000 Hz, you translate the MAF signal by lets say 10%.
10% then means 9,000 Hz.
The PCM believes the amount of grams/cyc is reduced by that much and consider that torque output is directly related to MAF values, thus the end result is less timing and less torque,
Add the fact the 3rd party MAF may also be skewing the MAF signal cause the vendor mucked with it and the LS6 intake has a bit longer runners, thus with that lean of a condition and forcing 10 - 15% richer, you loose.
Now if your lets say 20% lean and you go with SVO 30 injectors which are about 30% larger,
-30richer + 20leaner = -10 rich end result.
Now with a MAFT your dialing in to go leaner, means less engine load which means higher timing and higher torque.
Until LS1edit the MAFT was the only game in town to do on the spot partial tuning but the best path now is to go with LS1edit and tune it the right way, better gains long term, but if sticking with the MAFT, maintain the PCM relearning process and dial LTFTs to around zero and only then fine tune usig WOT switch on MAFT.
IMHO, best is run as lean as you can without effecting knock that would offset gains with retarding of timing so I rather be a few % lean then rich for part throttle LTFTs.
Use knock and WOT timing as your guide marks to know when to cease going any leaner.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Very interesting, if this is true that means that I am kinda going about my tuning sort of backwards <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" />
I have Ed Wrights tuning and I added a ported stock MAF along with a MAFT after I had him tune it, therefore it's not accounted for with his tuning. I monitored my LTrims and as of right now I have mt base at +20 and my WOT at +6. My LTrims are averaging around +5% on my part throttle fuel cells and I thought I had everything tuned OK until I saw this. I am seing no KR at WOT and I am seeing a solid 28 degrees of timing at WOT from around 5,200 rpm's all the way to 6,200 or so.
So, from what I understand of your post, I am actually causing my PCM to see more load by using my MAFT to adjust for my lean condition. I wonder if I would be better off to just put my stock, unported MAF back on and set my MAFT back somewhere towards 0/0???? Either that or I could send my PCM back to Ed (which I have to do anyway to have the EGR and AIR codes deleted) and have him account for my ported MAF.
What do you think??
Thanks
Paul
<small>[ June 28, 2002, 05:27 PM: Message edited by: JR HAWK 9 ]</small>
