Barry Grant EGT

Old 01-20-2008, 12:13 PM
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BEAST477
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Default Barry Grant EGT

I am running extremely high egts 1800-2000 degrees checked plugs even had deads off pistons looked fine. Have jetted up consideribly but no help. Any ideas ? Have not called Barry Grant yet. Thanks.
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Old 01-20-2008, 01:28 PM
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johnracer
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What has your et & mph done as you've jetted up? What do the plugs look like? May have a bad egt probe. I've seen that lead people astray. That's one reason why I don't rely on egt numbers for tuning. ET's and speed don't lie.....
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Old 01-20-2008, 02:08 PM
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IT was pretty obvious that it was too rich when I jetted up. If I remember right all my times were slower. It's been awhile as I'm up here in Michigan and my local track is under a foot of snow. I was just wondering if anyone else has had this problem. Also a buddy of mine has the same unit and his also reads very high.Thanks
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Old 01-20-2008, 02:43 PM
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The motor could be so rich that the fuel is burning in the header, causing false high readings.
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Old 01-20-2008, 03:15 PM
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Yep, absolutely! That's the problem with egt's. Higher temps don't necessarily mean lean mixtures. There are no all encompassing "perfect" egt numbers. Every engine is different. My suggestion is to tune it old school. Check plugs after every run. Look at your timeslip, especially MPH. Tune it to make it run it's best, then turn on you egt and record the numbers. That's the number you want. It's your's and your's alone and will be of no use to your buddy. When I first got one I was told the number to shoot for was around 1350 on gas, normally aspirated. After leaning the crap out of it and loseing 2 tenths, I got there. Turns out mine ran best at around 1225-1250......anyway, lean it back to where you started, then lean it a little more and see what happens.
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Old 01-20-2008, 03:36 PM
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A little story for ya. A buddy of mine bought a 522 RM engine this last spring. We installed it and decided to run it on a chassis dyno to nail down the tune up, so we could start sorting the suspension when we hit the track. The dyno operator insisted on running the car, and on the first pull he aborted at 6800rpm because the a/f ratio was very high (19:1). Really freaked the guy out. The car has an egt on it and it was also high, so we fattened it up 4-steps all around. Now bear in mind, the engine was dyno'd at RM in Texas. We're at 5000ft in Colorado. Next pull, operator aborted at 7000rpm. The a/f ratio and egt were unchanged, and it made considerably less power. My buddy and talked it over and pulled a plug. Black and sooty. We decided to lean it 6-steps and try again. We could hear the operator and his helpers talking about how we wer gonna burn it up. Next pull the operator was VERY apprehensive about nailing the throttle, but we finally convinced him to do it. The egt's came down to 1300 degrees but the a/f ratio stayed at 19:1. Picked up about 60 hp. Obviously an instrumentation problem.....
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Old 01-20-2008, 10:29 PM
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Could be egt placement ? or bad probe ?

Tell us what your combo is and what size/jets are in the carb ?

where do you race at in mich ?
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Old 01-21-2008, 06:22 PM
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I origanally installed them at 4" from head as per BG instructions was told that was to far and tried them at 1.5". My combo is a 477 BBC ,13.5:1 comp, Merlin iron heads ,1050 Ken Jones Dominator, jetted 96's all around. I run at US 131 in Martin,MI. Thanks for all the responses.
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Old 01-21-2008, 09:01 PM
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jmarksdragster
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96's sounds a little fat for a 1050.
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Old 01-21-2008, 11:21 PM
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hammertime
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Originally Posted by BEAST477
I origanally installed them at 4" from head as per BG instructions was told that was to far and tried them at 1.5". My combo is a 477 BBC ,13.5:1 comp, Merlin iron heads ,1050 Ken Jones Dominator, jetted 96's all around. I run at US 131 in Martin,MI. Thanks for all the responses.
What exactly did the plugs look like ? a 1050 with that jet should be plenty rich enough. What kind of timing ? I've had very similar combo but alum heads.

I also race at 131 here and there, maybe I have seen your car before ?
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