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Does anyone have good support as to what is considered safe max EGT's? I have seen my EGT's go as high at 1380 when doing a quick run at stage five with the Edge. Towing I try to keep below 1100. How high have some gotten? Resulting problems? My own personal set up is a 4 inch ATS exhaust with no cats. I wonder how much higher temps the California trucks with the stock cat and muffler get.


Thanks
Edited by: hasselbach
 

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My 2cents: For a sustained run, 1350* F would be the most I'd want to go. For something like a 1/4 mile pass, 1500*-1650* F would be acceptable.
 

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The standard answer has always been 1250 degrees if you are measuring the temperature before the turbo. From what I have been hearing lately, that number appears to be low. I have heard from more than a few people who hit 1500 and some hitting 1800 degrees without meltdown. I personally have my Attitude set at 1400 degrees to cut the fuel back. You do not want to hold these numbers for long periods of time, but a quarter mile should not hurt.

Huck
 

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In a quarter mile run I doubt you are going to get it hot enough long enough to hurt it. As guys running over 500hp are pegging there gauges for most of the run. Now when towing a trailer you dont want to see over 1300degrees pre-turbo. I have seen 1300 post turbo on mine no problem, but still dont like it.
 

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Stock 2001 Duramax loaded to 21,000 lbs combined pulling on 85* day in local mountains saw a max of 1350 pre turbo. The max number I like to see is 1300*, but it does show what GM let's it go to in some conditions. There was no cat or EGR for 2001 and I have not repeated the test yet on a EGR equipped truck.
 

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If measured pre-turbo the max safe limit is generally 1300 degrees. Measured post-turbo, the max safe limit is generally 900 degrees.
 

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Does anyone think there is a difference in EGT limmits between a water cooled turbo and a (standard) non-water cooled turbo? Most of the info we have is on the LB7 set-up and not the LLY Garret 9 vein VV turbo.
I wonder if the VV Turbo eats the heat or pumps it up?





Burner-------------->
 

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The limits may not be determined by the turbo, but rather by the ability for the piston crowns to dissipate the heat. There is a jet that sprays oil on the underside of each piston - sprays into a channel cast in the crown. This cools the crown. At some point, it cannot do so. Watch your oil pressure on a long pull with temps in the 1200 range - it will drop as it thins.


The water only cools the turbo bearing - the real issue is the turnbine wheel and the housing (much like a jet engine). I have heard that at 1300, the turbine housing is translucent. On a long pull, I'll bet the turbine can withstand more heat than the pistons.
 

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I would think it's all about time. There is a guy on TDR saying he has made over 100 passes pushing 1500 degrees w/ no problems. Just because your EGT says 1500 doesn't mean your aluminum is melting...You could probably hit 2000 degrees for a very short period of time with no problems. I would be more worried about long 1300-1400 degree pulls up mountains.


Here's the real question. Can you sustain high enough heat in the quarter mile long enough to metldown. Has anyone out there ever killed one in the quarter (Duramax)?
 

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Even if you see 1500* + egt temp during the 1/4 mile the aluminum still needs time to heat up. You are measuring exhaust(air) temp, not the temp of metal around it. Yes aluminum does heat up quickly but not fast enough for it to melt in less than 15sec.
 

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Aluminum does heat up quickly but as long as coolant is present it cannot melt. Spikes of 1700-1800 are common. The LLY turbo may be more suseptable to heat than the LB7 since it's not water cooled.
 

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1bad01 said:
I see almost 1500 to the 1/8 mile. Does anyone else get that high to the 1/8th?




I finished moving my thermocouple to the exhaust tip... i got tired of hearing *tinK* (pegged needle) on a given Q/M run


So far the mod works well, i never see over 500F!
 

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My autometer stops at 1600* and i've often taken it until the needle is back to the 6 oc'clock position. if they gauge sweep were accurate it would be about 1900*...
 
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