kc8ksg

Okay, I did a search to see how high I can run my EGT's without hurting anything, but didn't really find the answer I was looking for, my question is how high can I get my EGT's w/o hurting anything? When loaded or going up a steep hill with the hammer down I can get up to 1350-1400, but let off it pretty quick since I don't know what the limit is and keep it around 1200. I was just wondering how hard I can push it and what the time limits are ect... I know I need to get a BHAF, and bump my timing to get my EGT's down, but as for now I was just currious what the limits are.
BTW: it's a pre-turbo reading


Thanks
Chris

jeepsuck

im no expert, but i've asked this question before. keep sustained egt's below 1200. its okay to go past, but dont let it ride for long periods above 1200.

someone who knows better will give you a more difinitive answer.

Begle1

I believe that Cummins' are tested for a 100% duty cycle at 1250 F.

(I am not liable for any melting pistons that my faulty data may cause.)

(Nor should I be taken as an expert at all, or even somebody that knows anything about the subject.)

(So don't run at 1250 for a few hours until somebody else says it's okay.)

G1625S

1250 is the sustained pre-turbo number, but give yourself at least 75 degrees for probe/gauge error. I don't hold it over 1100 for long at all, but I'm a big wussy

Underpsi

I've had it well over 1500 for a couple seconds on more then one occaision but i don't reccomend it. From whats i've heard a quick burst at 1500 won't hurt anything and so far my truck seems fine (knock on wood)

rockjeep73

Heres the deal, 1250* max for sustained EGT's.

Now for short bursts, like 20 seconds or less, dont even look at the pyro!
No but seriously, high EGT's in short bursts, like 20 seconds or less, are not going to hurt anything.

FWIW, I drag race my truck quite often and I see about 1600 to 1650 at the end of the 1/4 everytime. With the old turbo I had seen temps as high as 1800* several times.

kc8ksg

Thanks for the replies ya'll that was basically what I was wanting to know, if I am pulling hard for a while I don't let it any higher than 1250, but the other day I was running it pretty hard and got it up to 1400 for a short period, and was curious if short periods like that would kill it and just wanted to know my limits, before it got expensive!!

Chris

wheelo90

I think aluminum melts at 1300*, I dont know.
But like the others say, short bursts should not hurt anything. But I know that it takes a faulty injector to burn through a piston(at least on the extremely older semis). And that aluminum does not melt as soon as it hits 1300* either, it takes some time at 1300* to melt it. Hope it helps,
Wheelo

BearKiller

I accidentally melted an aluminum pulley a couple days ago with a bottle/propane torch.

One second it was fine and the next it was boiling.

I didn't think a propane torch could get close to 1300*.

rockjeep73

If I recall correctly the pistons melt at something like 1375*

Boatnik

Correct but it does depend on the alloy. !270 dgrees will soften most aluminum.

texaspower19

im pretty sure propanes neutral flame temp is 4579 degees F

wannadiesel

Keep in mind a couple things: The piston only sees those temps for a small percentage of the whole cycle. Also the piston is oil cooled. EGT does not equal piston temp.

BC847

Unless, I'm mistaken, there's the question of Thermal Shock. Ultimately, one may risk a shorter than normally expected life span due to cracks developing from the exaggerated expansion/contraction rates. This may be further compounded when one considers that the metal conducts the heat at a given rate. One side gets really hot, expanding substantially as compared to the cooler side, that hasn't expanded as much. Something's gotta give.
Further, metallurgical data shows most metals present with markedly reduced strengths with elevated temps (outside of design).

It's always been my understanding that a well funded drag racer fully expects to hurt the engine at the end of a single pass. If not, he's not pushing it for all it's worth.



Hope this helps.

Bushy

A fairly knowledgeable guy in the sport once told me (ok, more than once cause I'm a slow learner ).....

1250*F- all day long....watch coolant temps due to heat saturation under sustained 100% duty cycle..
1350*F- 1 minute out of 5...allow good cooldown if you are pulling off to stop or park.
1500*F- Chernyobl any minute...just pray....

'Course that' the same guy who said I wuz on a first name basis with god cause I've run mine up into the 47-50psi range at a pegged 1800*F guage...too many times...Ahhhhhhh....run away......->>>>>

pb.....

edit: OH,...on the cooldown issue....it's also best let the temp "ease back" a bit slowly rather than just dropping you foot off the throttle and letting drop like a rock....radical/extreme cycling is just as bad as the deed itself...