Ltrims positive= reduced timing?
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Joined: Dec 2001
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From: new england
Ltrims positive= reduced timing? I installed ported Maf ends and drove car 30+ miles, L- trims were +8% and +10%, so i added
+ 10% base on translator. Drove it again and
atapped found only 23* of timing wot. Is this because it takes many miles to adjust and timing will come back? I have LS1edit and we added 5*, but it was 26* stock so why am i only 23* with no knock retard? LS1 edit does show up on Atap right? I should be seeing 31* right?
+ 10% base on translator. Drove it again and
atapped found only 23* of timing wot. Is this because it takes many miles to adjust and timing will come back? I have LS1edit and we added 5*, but it was 26* stock so why am i only 23* with no knock retard? LS1 edit does show up on Atap right? I should be seeing 31* right?
Staging Lane
Joined: Jan 2002
Posts: 54
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From: Houston
Re: Ltrims positive= reduced timing? Positive L trims indicate the MAF sensor is reading less airflow than it should, causing the engine to run leaner, hence the addition of more fuel. In the timing table, timing is a function of airflow (g/cylinder) and RPM. As airflow increases, timing decreases for a given RPM. Porting the MAF then should yield increased timing due to the lower g/cyl airflow. Check your timing table with LS1 Edit and run a log of MAF flow, timing, KR, and RPM and compare against the table. Hope this helps,
Paul J.
Paul J.
Re: Ltrims positive= reduced timing? you can also set your timing tables so it wont drop below 26 but im not a expert on how to do that....
ive seen a few cars loosing timing when they edit there MAF above 5%
i have mine edited at 104% and still have 26degrees of timing at WOT.
thats another reason i ditched the ported ends... with the cam I was 20+, with stock ends I was -4,and with SLP 85MM ends I was from +1 to +5
hope this helps any
ive seen a few cars loosing timing when they edit there MAF above 5%
i have mine edited at 104% and still have 26degrees of timing at WOT.
thats another reason i ditched the ported ends... with the cam I was 20+, with stock ends I was -4,and with SLP 85MM ends I was from +1 to +5
hope this helps any
Teching In
Joined: Aug 2002
Posts: 44
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From: Dearborn, Michigan
Re: Ltrims positive= reduced timing? PaulJ gave an excellent description of what is going on.
As far as the timing is concerned: if the adjustment with the MAFT has the reported air dead on the money, then the 23* might be the appropriate timing (however it may be a little conservative due to GM approach). There is an issue with how effecient the cylinders are being filled. A more effecient head design will require less timng to make the same or more HP. In GMHTP, they said that LS6 heads require less timing than stock LS1 heads because these heads are more effecient.
LS1derful: If you have LS1Edit, why dont you get rid of the MAFT? With LS1Edit, you can do what the MAFT does and get any timing you want. Also, is the timing you report at WOT??? I assume that it was. I have a '99 SS with heads/cam/exhaust/intake mods,, I used to use a MAFT but once I got LS1Edit, I sold the MAFT.
After making a change to the PCM, either with a MAFT or LS1Edit, it is always a good idea to drive the car around for at least 15 to 20 minutes trying to visit each and every fuel cell. This is hard to do, but a slow acceleration from idle up to highway speeds has worked good for me. Then after the relearning is over, take new logging sessions, and determine what your latest changes have resulted in.
As far as the timing is concerned: if the adjustment with the MAFT has the reported air dead on the money, then the 23* might be the appropriate timing (however it may be a little conservative due to GM approach). There is an issue with how effecient the cylinders are being filled. A more effecient head design will require less timng to make the same or more HP. In GMHTP, they said that LS6 heads require less timing than stock LS1 heads because these heads are more effecient.
LS1derful: If you have LS1Edit, why dont you get rid of the MAFT? With LS1Edit, you can do what the MAFT does and get any timing you want. Also, is the timing you report at WOT??? I assume that it was. I have a '99 SS with heads/cam/exhaust/intake mods,, I used to use a MAFT but once I got LS1Edit, I sold the MAFT.
After making a change to the PCM, either with a MAFT or LS1Edit, it is always a good idea to drive the car around for at least 15 to 20 minutes trying to visit each and every fuel cell. This is hard to do, but a slow acceleration from idle up to highway speeds has worked good for me. Then after the relearning is over, take new logging sessions, and determine what your latest changes have resulted in.
Re: Ltrims positive= reduced timing? I did the Edit in the car.We just started with some added timing and idle adjustments since the weather sucks here to fully tune the car.There are 3 of us with Edited 01 Cars.The other 2 cars are showing full timing,1 is 30 degrees at 6500 and mine is 28 degrees at 6500.Which is exactly what I set them for.
I'm thinking since the adding of the ported ends that the computer sensed something wrong and pulled the timing(ie different timing table)
Now I believe that a stock MA with screen or SLP MA is the best to run on a 01 car when you are tuning in Edit <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> A ported TB will take some time to get right.
I'm thinking since the adding of the ported ends that the computer sensed something wrong and pulled the timing(ie different timing table)
Now I believe that a stock MA with screen or SLP MA is the best to run on a 01 car when you are tuning in Edit <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> A ported TB will take some time to get right.
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From: new england
Re: Ltrims positive= reduced timing? Doc99SS, i kept Translator for minor weather tuning changes that i would like to keep simple. I agree with your thinking, but i added timing to my programming when i was seeing 25 to 26* stock. My question was if maf tuning changes were keeping max timing from occurring while it learned.
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From: Plainville,MA
Re: Ltrims positive= reduced timing? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong> Bob yes! 7:30 at your house! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">See U then pal! <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
<strong> Bob yes! 7:30 at your house! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">See U then pal! <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Re: Ltrims positive= reduced timing? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong> I installed ported Maf ends and drove car 30+ miles, L- trims were +8% and +10%, so i added
+ 10% base on translator. Drove it again and
atapped found only 23* of timing wot. Is this because it takes many miles to adjust and timing will come back? I have LS1edit and we added 5*, but it was 26* stock so why am i only 23* with no knock retard? LS1 edit does show up on Atap right? I should be seeing 31* right? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Paul J hit the nail on the head.
With a ported MAF, and MAFT to boot, your timing table is not getting referenced as it normally would. You need to determine first where your timing table is getting referenced prior to making adjustments to the timing table.
Log on A-tap (or whatever you have), MAF, RPM, Ignition Advance, Knock Retard, IAT.
Run the following equation on your data. Make sure you convert your MAF to grams per second first.
g/cyl = 15 * MAF (g/sec) / RPM
This will tell you what g/cyl and RPM your car is referencing timing at. Check your actual recorded timing with your 'look-up' timing on the timing table that you have programmed. Are they the same?
Good Luck,
Kevin
<strong> I installed ported Maf ends and drove car 30+ miles, L- trims were +8% and +10%, so i added
+ 10% base on translator. Drove it again and
atapped found only 23* of timing wot. Is this because it takes many miles to adjust and timing will come back? I have LS1edit and we added 5*, but it was 26* stock so why am i only 23* with no knock retard? LS1 edit does show up on Atap right? I should be seeing 31* right? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Paul J hit the nail on the head.
With a ported MAF, and MAFT to boot, your timing table is not getting referenced as it normally would. You need to determine first where your timing table is getting referenced prior to making adjustments to the timing table.
Log on A-tap (or whatever you have), MAF, RPM, Ignition Advance, Knock Retard, IAT.
Run the following equation on your data. Make sure you convert your MAF to grams per second first.
g/cyl = 15 * MAF (g/sec) / RPM
This will tell you what g/cyl and RPM your car is referencing timing at. Check your actual recorded timing with your 'look-up' timing on the timing table that you have programmed. Are they the same?
Good Luck,
Kevin
Re: Ltrims positive= reduced timing? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong> Doc99SS, i kept Translator for minor weather tuning changes that i would like to keep simple. I agree with your thinking, but i added timing to my programming when i was seeing 25 to 26* stock. My question was if maf tuning changes were keeping max timing from occurring while it learned. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Your timing doesn't learn nearly as quickly as your LTerms. In fact, it takes alot of KR (from what I have seen) to make any semi-permenant adjustments to your timing if any.
Your timing isn't like the LTerms. Immediatly after you program, you should be seeing the values that you programmed in......considering of coarse that you programmed your values in the right spot on the table.
<strong> Doc99SS, i kept Translator for minor weather tuning changes that i would like to keep simple. I agree with your thinking, but i added timing to my programming when i was seeing 25 to 26* stock. My question was if maf tuning changes were keeping max timing from occurring while it learned. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Your timing doesn't learn nearly as quickly as your LTerms. In fact, it takes alot of KR (from what I have seen) to make any semi-permenant adjustments to your timing if any.
Your timing isn't like the LTerms. Immediatly after you program, you should be seeing the values that you programmed in......considering of coarse that you programmed your values in the right spot on the table.