Fuel and Timing with Tunercta.
04-27-2004, 01:56 PM
#1
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Fuel and Timing with Tunercta.
I did a quick search, but only kept finding PE tables mentioned. PE stands for Power Enrichment right? I am still confused as to which tables to use to modify fuel. I have tunercat. I need help with some tuning questions, specifically for fuel and timing:
To play with timing, do I use the Main Spark and Extended Spark Advance Tables?
What tables do i use for fuel (Please try and reference the tables name on Tunercat)? People mention PE tables, but there isnt a table labeled like that on Tunercat.
Any other tables I need to look at when I do my dyno tune?
Thanks. Any help would be appreciated.
To play with timing, do I use the Main Spark and Extended Spark Advance Tables?
What tables do i use for fuel (Please try and reference the tables name on Tunercat)? People mention PE tables, but there isnt a table labeled like that on Tunercat.
Any other tables I need to look at when I do my dyno tune?
Thanks. Any help would be appreciated.
04-27-2004, 11:03 PM
#3
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Location: Three Oaks MI
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Fuel is %change toFuel/Air Ratio vs Cool.Temp at WOT
and
Fuel is %change toFuel/Air Ratio vs RPM at WOT.
There is a formula that you use to change the values in the tables to obtain something close to the desired AFR. Right now I don't have it to give you but I will try to post it for you.
and
Fuel is %change toFuel/Air Ratio vs RPM at WOT.
There is a formula that you use to change the values in the tables to obtain something close to the desired AFR. Right now I don't have it to give you but I will try to post it for you.
04-27-2004, 11:12 PM
#4
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That formula isn't perfect.. Because where my stock fueling tables were running the car at 11:1 by the formula, I have had to add 3 points of fuel so by the formula the car is running at like 8:1 or so.
The best way to work on the fueling is on a wideband.
The best way to work on the fueling is on a wideband.
04-27-2004, 11:14 PM
#5
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Air Fuel Ratio per Andrew =
(1 - ([# in Temp Table] + [# in RPM Table])/100)*14.7
A/F Ratio per Jody Shapiro =
14.7/(1+Number in the Cool temp .table/100+ number in the RPM table /100)
Using either formula:
If your car runs around 180 degrees use the value of 16 that is in the PE cool table alone and change the value in the RPM table to get to the AFR you think you want
Both formulas will give you roughly the same answer but I think Jody's is more accurate. Or so I've heard. Just remember that with these formulas, the PCM will think it's supplying the AFR that it calculates but in actuality that might not neccesarily be the case.
(1 - ([# in Temp Table] + [# in RPM Table])/100)*14.7
A/F Ratio per Jody Shapiro =
14.7/(1+Number in the Cool temp .table/100+ number in the RPM table /100)
Using either formula:
If your car runs around 180 degrees use the value of 16 that is in the PE cool table alone and change the value in the RPM table to get to the AFR you think you want
Both formulas will give you roughly the same answer but I think Jody's is more accurate. Or so I've heard. Just remember that with these formulas, the PCM will think it's supplying the AFR that it calculates but in actuality that might not neccesarily be the case.
04-28-2004, 07:31 AM
#6
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Originally posted by LWillmann
That formula isn't perfect.. Because where my stock fueling tables were running the car at 11:1 by the formula, I have had to add 3 points of fuel so by the formula the car is running at like 8:1 or so.
The best way to work on the fueling is on a wideband.
That formula isn't perfect.. Because where my stock fueling tables were running the car at 11:1 by the formula, I have had to add 3 points of fuel so by the formula the car is running at like 8:1 or so.
The best way to work on the fueling is on a wideband.
04-28-2004, 07:42 AM
#7
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Originally posted by s_willis
Fuel is %change toFuel/Air Ratio vs Cool.Temp at WOT
and
Fuel is %change toFuel/Air Ratio vs RPM at WOT.
There is a formula that you use to change the values in the tables to obtain something close to the desired AFR. Right now I don't have it to give you but I will try to post it for you.
Fuel is %change toFuel/Air Ratio vs Cool.Temp at WOT
and
Fuel is %change toFuel/Air Ratio vs RPM at WOT.
There is a formula that you use to change the values in the tables to obtain something close to the desired AFR. Right now I don't have it to give you but I will try to post it for you.
If I modify this, will it lean out on the dyno, or do i need to modify both % tables you listed? i know both tables are used in the equations you gave me, but technically i could leave one alone and just keep modifying the other until I hit the target AFR on the wideband?
Also, what does the Open loop AFR vs coolant vs map do. Does this table afftect WOT AFR? Does it affect part throttle?
Also, can you tune the AFR in using VE tables, and would this be a better way to go. Sorry for all the questions.
Last edited by RealQuick; 04-28-2004 at 07:57 AM.
04-28-2004, 08:53 AM
#8
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Ok, I would just work in the %changetofuel/Air Ratio vs RPM at WOT table.
It would probably be best to leave the coolant temp one alone and make the adjustments in the other.
Increasing the number will richen the car up and lowering it will lean it out.
My understanding is that the VE tables are only used in speed density mode.
The Open Loop AFR vs Coolant vs MAP is only used when the car is first started before it warms up and kicks over to closed loop. This is the table you use to lean up your initial startup mixture so it doesn't burn your eyes.
WOT isn't a true open loop mode, so that table isn't used during WOT.
It would probably be best to leave the coolant temp one alone and make the adjustments in the other.
Increasing the number will richen the car up and lowering it will lean it out.
My understanding is that the VE tables are only used in speed density mode.
The Open Loop AFR vs Coolant vs MAP is only used when the car is first started before it warms up and kicks over to closed loop. This is the table you use to lean up your initial startup mixture so it doesn't burn your eyes.
WOT isn't a true open loop mode, so that table isn't used during WOT.
04-28-2004, 09:25 AM
#9
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Originally posted by LWillmann
Ok, I would just work in the %changetofuel/Air Ratio vs RPM at WOT table.
It would probably be best to leave the coolant temp one alone and make the adjustments in the other.
Increasing the number will richen the car up and lowering it will lean it out.
My understanding is that the VE tables are only used in speed density mode.
The Open Loop AFR vs Coolant vs MAP is only used when the car is first started before it warms up and kicks over to closed loop. This is the table you use to lean up your initial startup mixture so it doesn't burn your eyes.
WOT isn't a true open loop mode, so that table isn't used during WOT.
Ok, I would just work in the %changetofuel/Air Ratio vs RPM at WOT table.
It would probably be best to leave the coolant temp one alone and make the adjustments in the other.
Increasing the number will richen the car up and lowering it will lean it out.
My understanding is that the VE tables are only used in speed density mode.
The Open Loop AFR vs Coolant vs MAP is only used when the car is first started before it warms up and kicks over to closed loop. This is the table you use to lean up your initial startup mixture so it doesn't burn your eyes.
WOT isn't a true open loop mode, so that table isn't used during WOT.
04-28-2004, 10:12 AM
#10
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Location: Middle Tennessee
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Assuming it's REAL knock, I'd make sure the AFR is right, and pull a couple of degrees of timing if needed.
I would think is 6 of one and 1/2 dozen of the other.
Power lost by proper fueling with too much timing vs power lost by timing with too much fuel
I'd get the fueling right, then work with the timing.
My car has knock retard no matter what I do, and I've verified that it's not real, so I've adjusted the max retard down, decreased the attack rate, and increased the decay rate to minimize it's effects.
I would think is 6 of one and 1/2 dozen of the other.
Power lost by proper fueling with too much timing vs power lost by timing with too much fuel
I'd get the fueling right, then work with the timing.
My car has knock retard no matter what I do, and I've verified that it's not real, so I've adjusted the max retard down, decreased the attack rate, and increased the decay rate to minimize it's effects.
04-28-2004, 10:47 AM
#11
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Originally posted by LWillmann
Assuming it's REAL knock, I'd make sure the AFR is right, and pull a couple of degrees of timing if needed.
I would think is 6 of one and 1/2 dozen of the other.
Power lost by proper fueling with too much timing vs power lost by timing with too much fuel
I'd get the fueling right, then work with the timing.
My car has knock retard no matter what I do, and I've verified that it's not real, so I've adjusted the max retard down, decreased the attack rate, and increased the decay rate to minimize it's effects.
Assuming it's REAL knock, I'd make sure the AFR is right, and pull a couple of degrees of timing if needed.
I would think is 6 of one and 1/2 dozen of the other.
Power lost by proper fueling with too much timing vs power lost by timing with too much fuel
I'd get the fueling right, then work with the timing.
My car has knock retard no matter what I do, and I've verified that it's not real, so I've adjusted the max retard down, decreased the attack rate, and increased the decay rate to minimize it's effects.
04-28-2004, 04:48 PM
#12
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VE tables are used on a MAF car. if you change thr VE tabbles you can see on datamaster at what map and rmp it affected. ive fixed my blms in several areas using the ve tables. after all the the VE tables are telling the pcm how effently the engine is using the fuel. if you tell the pcm that the engine is not that effiencent at 50kpa and 2000rpms it will add fuel, to compensate and vise versa.
but what i dont understand is how the 02s are used in combination with the VE tables.
but if you change them it will affect performance.
but what i dont understand is how the 02s are used in combination with the VE tables.
but if you change them it will affect performance.
04-29-2004, 02:55 PM
#13
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Location: Portland, Oregon
Posts: 72
Originally posted by 97Z-M6
VE tables are used on a MAF car. if you change thr VE tabbles you can see on datamaster at what map and rmp it affected. ive fixed my blms in several areas using the ve tables. after all the the VE tables are telling the pcm how effently the engine is using the fuel. if you tell the pcm that the engine is not that effiencent at 50kpa and 2000rpms it will add fuel, to compensate and vise versa.
but what i dont understand is how the 02s are used in combination with the VE tables.
but if you change them it will affect performance.
VE tables are used on a MAF car. if you change thr VE tabbles you can see on datamaster at what map and rmp it affected. ive fixed my blms in several areas using the ve tables. after all the the VE tables are telling the pcm how effently the engine is using the fuel. if you tell the pcm that the engine is not that effiencent at 50kpa and 2000rpms it will add fuel, to compensate and vise versa.
but what i dont understand is how the 02s are used in combination with the VE tables.
but if you change them it will affect performance.
My BLM's average low (123) but I've used BLM locker, and it has helped tremendously. Tuning A/F is done with the PE RPM table. Since BLMs read 128 at WOT, only the PE tables affect the a/f ratio. I've also set WOT to equal 0tps volts between 400 and 1200 rpms. The BLMs read 128 at idle, which has had the cumulative effect of making my average BLM numbers consistant at about 123-4.