Thinking of doing some EGT measurments at each primary- thermocouple people inside
10-24-2006, 10:33 AM
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Thinking of doing some EGT measurments at each primary- thermocouple people inside Manifolds are cheap enough, $10 a pair.
I want to drill and tap them them for thermocouples and check out the EGT's at each primary. I'm interested because, beleive it or not, using a radar heat gun, my #7 cylinder is the coolest behind the #1 cylinder (prob due to fan air flow).
Id really like to see the EGT's of each cylinder under part throttle cruise. I dont expect the EGT to be that high under part throttle, but I really dont know what to expect. Gears are tall so RPM is low and there are some decent hills around here. Its also almost 6000lbs so.. yeah, there is some load there.
If I can get this going, Id definately get an HP tuner and go to town to get the best MPG 6.0 out there
...actually its just an engineer's curriousity and the benifits wont come near the cost.
I want to drill and tap them them for thermocouples and check out the EGT's at each primary. I'm interested because, beleive it or not, using a radar heat gun, my #7 cylinder is the coolest behind the #1 cylinder (prob due to fan air flow).
Id really like to see the EGT's of each cylinder under part throttle cruise. I dont expect the EGT to be that high under part throttle, but I really dont know what to expect. Gears are tall so RPM is low and there are some decent hills around here. Its also almost 6000lbs so.. yeah, there is some load there.
If I can get this going, Id definately get an HP tuner and go to town to get the best MPG 6.0 out there
...actually its just an engineer's curriousity and the benifits wont come near the cost.
10-24-2006, 02:34 PM
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Originally Posted by ArcticZ28
How do you plan on getting better gas mileage? Are you planning on enriching the AFR to get cooler cylinder temps? If not, how so? Just curious.
10-24-2006, 06:09 PM
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What question do you have?
http://www.omega.com/
There are some usb based type k loggers that you could use. My question for you is this: The highest egt is at stoich. Your ecu under closed loop will maintain stoich as an average read by your O2 sensor in the collected exhaust. How will you know if one cylinder is rich or lean and how will you adjust it? Colder than stoich could fall on either side.
http://www.omega.com/
There are some usb based type k loggers that you could use. My question for you is this: The highest egt is at stoich. Your ecu under closed loop will maintain stoich as an average read by your O2 sensor in the collected exhaust. How will you know if one cylinder is rich or lean and how will you adjust it? Colder than stoich could fall on either side.
10-24-2006, 06:12 PM
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Originally Posted by andereck
What question do you have?
http://www.omega.com/
There are some usb based type k loggers that you could use. My question for you is this: The highest egt is at stoich. Your ecu under closed loop will maintain stoich as an average read by your O2 sensor in the collected exhaust. How will you know if one cylinder is rich or lean and how will you adjust it? Colder than stoich could fall on either side.
http://www.omega.com/
There are some usb based type k loggers that you could use. My question for you is this: The highest egt is at stoich. Your ecu under closed loop will maintain stoich as an average read by your O2 sensor in the collected exhaust. How will you know if one cylinder is rich or lean and how will you adjust it? Colder than stoich could fall on either side.
10-24-2006, 07:35 PM
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Why don't you get an LM-1 or LC-1 and program the analog outputs to fool your computer into running leaner? You could bump up the AFR by .2 or so and do a drive cycle and check mileage and driveability. Rinse and repeat.
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10-24-2006, 11:38 PM
#11
When you're running lean, don't you get hot spots on your plugs though? That, to me, means it's running hotter. Also, by that statement, wouldn't that mean running richer would cause higher EGT's because more fuel is burning, when actually there is too much to be efficiently burned causing leftover to cool the EGT's?
10-24-2006, 11:55 PM
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Originally Posted by ArcticZ28
Also, by that statement, wouldn't that mean running richer would cause higher EGT's because more fuel is burning, when actually there is too much to be efficiently burned causing leftover to cool the EGT's?
10-25-2006, 12:05 AM
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Before the wide scale adoption of wide bands many people relied on realtime egt gauges or logging to tune by. Hopefully they weren't tuning from stoich but a point much richer than stoich. They would often tune "up" to an abitrary reading knowing that as the temperature rose they were progressively getting leaner. Most tuners would have a mental cutoff point that they would not try to exceed. As stoich, whether they knew it or not, is the temperature ceiling the tune wouldn't progress to the tipover point where it would once again start to fall as it got leaner unless there was some kind of fuel system failure. We in the automotive performance world don't operate our engines at high load near stoich on purpose, though pilots often do. Pilots with fuel trim control often operate the engine to maximum egt and then trim the fuel richer or leaner so the cylinder head temp is within a certain range so as not to overheat the engine or detonate. They can trim the engine for maximum economy while still mantaining a particular airspeed.
10-25-2006, 03:19 AM
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I have always wanted to do this on an Ls1....Tuning each cylinder via EGT would allow for greater efficency....how much? Probably not much at all. It would certainly help in an N2O application however.
10-25-2006, 07:31 AM
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14.7 is just an emissions number. My friend runs 17.5:1 in his car and gets spectacular milage.
The reason leaner = melted pistons is because the slower burn gives the piston more time to absorb the heat, even if the max temp is lower.
The reason leaner = melted pistons is because the slower burn gives the piston more time to absorb the heat, even if the max temp is lower.
10-27-2006, 10:42 AM
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An interesting idea Trey, I am also curious to see some data from it. I would be leary of running a 6000 lb truck @ 17:1 though. I am going to run the IR thermo on each cylinder of our boosted formula SAE engine once we finish tuning.
