cummins2014 wrote:
Highbeam wrote:
For the OP, if he is still watching. Don't do it. 12k behind your (same as mine) truck is too much for our passes. Blewett pass is tough with even 7500# trailer.
Mine is 7.3, 2000, Ford AIS intake, 4" exhaust, tuner, trans cooler etc. I overtemp on EGT before I run out of "power" meaning I have to back off to 50 mph instead of 60 to keep it from melting down with only a tall TT.
Been saying it along. That 7.3 just can't handle that 12K in the mountains, period. ETG's are the enemy .
Or EGT's as the case may be. But it does
not make logical sense that a larger displacement diesel engine
must run out of "ability" sooner than smaller counterparts. If the EGT registers too high on the 7.3L, then something must simply be wrong with the tune. And the correct tune is a simple, basic principle; always matching enough air with fuel during the powerband.
So I think WTP-GC may have pinned it down. Many Programmers deliver too much fuel, not enough air; i.e. faulty tuning. It seems probable that if a 5.9 Cummins and 7.3L International had the same identical turbo, that the larger displacement 7.3 might suffer from too little "air feed delivery"; i.e. too much displacement space to fill in comparison. In other words the undersized 7.3 factory turbo cannot efficiently supply enough air to properly match increased fuel delivery on the large displacement 7.3.
A small turbo logically cannot flow as much exhaust, and will merely struggle to spin faster to reduce the resulting backed-up high exhaust pressure feed. High pressure up-pipe intake translates to high EGT heat just by reason of thermodynamics, since the up-pipe exhaust gas cannot expand as fast to achieve cooling. Voila, high exhaust temps. The physics law is that all gas cools as it expands, or is allowed to expand anyway.
If the 7.3L is pushed much beyond the factory turbo, it seems to suffer. OTOH, my understanding is that if the 7.3 is truly turbo'd enough, say 800HP+, the factory rods are the weak point. But somewhere there must be a reasonable compromise, a correct tune, that makes the 7.3 a top notch towing engine, able to meet modern demands for towing overkill.
I'm all about fuel economy. I was pretty happy with the stock powerband on my 2000. And for the record, my initial interest was in an even lower HP, low mile '95 Dodge with a 5.9L, manual tranny, std cab and 8' bed. My buddy unexpectedly traded it for about half the $ I paid for the F-250 crew. Ya sleep, ya weep.
Wes
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