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Go | New | Find | Notify | Tools | Reply | |
| EGT reading ?'s | Login/Join |
| DRR Pro |
I have several questions about EGT readings. When installing a temp probe where is it best located on the header tube? When putting the probe into the tube, how far is the tip inserted into the tube? With methanol and MFI what maximum temperature readings are you looking to achieve or avoid? Will these maximum temperatures be different for 1/8 mile vs 1/4 mile? | ||
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| DRR Sportsman |
Whew! let me get in here quick before the thread is bombed with "EGT is no good". 1. Install 2-3" from cylinder head. 2. Depth 1/2 of tube diameter. 3. Peak temps for 1/8 = 950-1100, 1/4 1050-1200 4. Make sure the peak is not a momentary flash after you lift (look at you unit last 2 seconds down the track during time shots). And just to stir the pot  - usually when EGT frustrates a racer it's more because of the handheld instrument. 8 EGT's in a data logger - pretty strong tool. | |||
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DRR Top Comp |
Treed .Because pretty much 100% adree with Greg. also amazed no negative post on egt's yet. They are a tool and must be used as such and correctly. America home of free. Brought to you by 2nd amendment. | |||
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DRR Pro |
naturally greg nailed it honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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DRR S/Pro |
Agree with everything Greg said except I would not go more than 2 inches from the head. I have all 8 on mine, blown TD, I tune by the spark plug but always look at the EGT in relation. 8 is great when you have a dead hole, makes it quick and easy to find the dead one. | |||
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| DRR Pro |
Thanks Greg. I’m switching from Enderle to Rons nozzles in a different size and just need to make sure I’m not too lean starting out. Once I get in a safe temp zone I’ll tune with mph. For me this will be 1 probe and a hand held and use my phone to record during the run. I’ve also been told that overly rich can increase EGT temps as well. Not sure how true this is. I can’t use plug color as I run a primer plus the majority of the time I’m not on the racing surface. Here’s the set that are still in the engine I’m replacing now. Over 500 runs on these and car still runs the same ET / MPH numbers from last 4 years.  | |||
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| DRR S/Pro |
I would imagine it's true. If it's rich enough that some unspent fuel is exiting the combustion chamber it would likely flash when it hits that hot header. I bought a motorcycle that had been sitting for sometime and passages of the carburetors were clogged shut. Had to run with the choke (fuel enrichment) partially on to get it home. It blued the chrome heat shield from fuel burning in the header pipe. Illegitimi non carborundum | |||
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DRR Sportsman |
I had mine in #6, installed as written above. Maybe it was reading the flash but my car liked the following numbers: Gas carb = 1400*+ 1/4 Alcohol carb = 1300-1350* 1/4 Alcohol injection (Ron's) = 1250-1290* 1/4 If I tried to get them in closer to the targets above it would make huge swings in ET with the weather. 72 Nova "Hooptie" | |||
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| DRR Pro |
those plugs are some ugly **** for a race engine honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Pro |
^^^^^^^^ Good info, Thanks Tom ! | |||
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| DRR Sportsman |
I have one EGT in cyl 3. I’ve found that the optimum number depends on finish line RPM in my case. When I had a tighter converter in the EGT would be 1115-1120 going through just shy of 7500. Looser converter I’m going through at 7650 and the EGT is 1175. 555, 7.4x dragster, Terminator 1/2 pump 39 nozzle 76 pill in good air, 80 pill in summer. Last race of the year in good air I richened it up to a 70 pill to see what it would do and the EGT came down to around 1130, car was about .03 and 1.5 mph slower. | |||
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| DRR Trophy |
Not enough timing advance will have the fuel still burning going out the pipe and give a higher EGT number. Try another degree or two and see if the temperature comes down. | |||
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| DRR Top Comp |
For What its worth. My normal tunning numbers are 1050 1/4 and if going low et same if running 1/8 only. Yes timing,cam and if rich can raise numbers.Rich because of fuel burning in pipe and timing same thing. Use EGT to compare cylinder to cylinder until get good plug reading then use to compare and as tuning point. JMO America home of free. Brought to you by 2nd amendment. | |||
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| DRR Sportsman |
I run 38-40 degrees of timing with the EGT's I posted above. 72 Nova "Hooptie" | |||
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DRR S/Pro |
Bottom line here is that there really isn't a definite right or wrong number, and also a high number which would usually indicate dangerously lean, could be caused by being too fat. Since you aren't running some oddball combination, why not get some advice from the experts, go a few steps fatter for a safety margin, and let the timeslip tell you which way to go from there? Tony Leonard | |||
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| DRR Pro |
I’ve talked with James Monroe (Killer Rons) and he gave me the base line. Turned out that both nozzles although different in manufacture and size are so close that going back to the original pill is what it needs for a starting point. Once the correct pill is determined, I would like to try incrementally moving my timing up to as high as 40* to see what the results are. I always hear from others that 34* tops with methanol, but believe this is not always true. I’m at 36* now. Here’s an impressive SBC THREAD that I have followed since 4-2017 that has me wondering what effect this would have on my engine. I want to be able to monitor the EGT to make sure I’m not moving into harms way when changing timing. Timing is something I can quickly change with Grid when testing. | |||
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| DRR S/Pro |
I'm inclined to think the timeslip will tell you that it isn't optimal before you get into something so far off that it would actually be harmful. This is assuming you are moving in small steps such as 2* timing or 4 pill sizes. Tony Leonard | |||
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| DRR Pro |
For anyone that logs EGT with MFI , do you experience any Flash after you lift in your EGT chart? | |||
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| DRR Elite |
I don't, but I do use some amount of smoothing on my data. Some of it may depend on what you do with fuel in high vacuum situations like lifting off the throttle. I am starting to pull a little more gradually. So I may start seeing a little climb. If I do, I will stop pulling fuel. Whoops. I read efi. I never saw it with mfi. Foxtrot Juliet Bravo | |||
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| DRR Elite |
My combo has always liked 36 degrees. Even with some pretty major changes, I end up back there. Foxtrot Juliet Bravo | |||
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