EGT Question

[thechevyhdman]

Ok this may be simple for someone to answer. Ive been paying attention to my EGT guage alot and have noticed a few things that I have been wondering about. When I am towing and pulling a hill, And I pull the hill with no downshifts etc. I notice my EGTs go alot higher(1100) than If I pulled the same hill goosed the gas a bit more to downshift and ran up the hill that way(850). Why is that? Just a stupid question I was wondering about. Sorry for my lameness.......Its even worse considering the fact im not out on a frday night :( :( , But then again I dont want my Dr. to get drunk off the fumes coming out of my body at 730am tommorrow :D :D

[mguebert]

I may be way off base here, but I think it is because when you pull the hill in the higher gear your rpms are lower and therefore are not moving as much air through the motor raising the fuel/air ratio and making for higher egt.

[ 05-17-2003: Message edited by: mguebert ]</p>

[mackin]

It's called lugging ..... Opposite of chugging ..... Which is what happens at Maggie's .... ;)

Not good when excessive .... Dito .... :eek:

Lower RPM'S under load will yield higher EGT'S .....


Mac :D :D :D

[GMCTRUCK]

Actually lugging is not the opposite of chugging because you're still chugging the fuel (like Maggie's) just at a low rpm so you're not chugging the air. Unlike gassers diesels run hot rich and cool lean. At a higher rpm you're running about the same amount of fuel but, you're also pumping more air through cooling things down and being more efficient. Next time you're coasting down the road downshift a gear of two and watch how fast your egts drop. Sort of the same idea. Like good ole Mac said lugging isn't doing your engine any good. For that matter chugging at Maggie's can't be too good either. ;) BTW Mack, I was in your neighborhood yesterday at your buddy Jannety's. I swear I saw a parking spot reserved for you and a big smiling picture of you on his wall. :D :D Nice to see he's finally started on his dyno shop. It's gonna be nice driving only 20 minutes to spin the rollers.

[ 05-17-2003: Message edited by: GMCTRUCK ]</p>

[Lone Eagle]

I bought a diesel to be able to run in OD while towing. The Allison knows when to shift to protect the engine. 1100 is a good combustion temp for a diesel. Later! Lone Eagle :D

[ 05-17-2003: Message edited by: Lone Eagle ]</p>

[mark45678]

any time you run at or over 1250*f for more then a few seconds you run the risk of melt down! most pistons will melt around 1300~1380*f....true thy are oil cooled but that only helps for so long...... ever had a 2 stroke melt down? same deal just no oil to cool it off! ;)