BigToe wrote:
Whenever reading how so called "under powered" or "slow" the 7.3L is when towing, bear in mind the axle ratio the person with the opinion had.
For example, in this thread, we have on the one hand a poster who had a 3.73 ratio who complained of a lack of power on the grades with 12K of trailer. And on the other hand, we have a poster who is quite satisfied with his 7.3L at 22K gross who had a 4.10 rear end and who says "and we go and we go."
The rear end ratio makes a significant difference in the towing experience. The 7.3L engine was used in true medium duty applications with GVWRs at 33K Lbs. Not GCWRs... GVWRS. And the horsepower rating of those motors? 175HP to 230HP at the very top end of the line, for fire truck apparatus. The rear ends had deeper gearing. And the top speeds were governed at 65 to 70 mph.
Navistar warned that the use of exhaust brakes can create enough back pressure to float the valves, causing damage to the 7.3L engine. I don't doubt that several different style of exhaust brakes have been used on the 7.3L for years... including the Pac Brake, the BD Brake, and the Banks Brake, not to mention various electrical black box devices that use the 7.3L's own stock exhaust back pressure warm up valve already built into the turbo as an exhaust brake. Those who have used them judiciously have enjoyed them. But apparently International saw cases where their overuse led to engine damage, which is pretty hard to do on a 7.3L, compared to the more delicate diesels in Fords made since.
I don't have any power complaints on my stock 7.3L, but I have 4.88 rear gears. This gives me the use of all four forward speeds of the automatic transmission, even when towing, whereas if I had 3.73 gears, I'd be limited to locking out OD and using only 3 gears. On really steep grades (10%), like towing over the Teton pass in Wyoming, I of course had to drop it down to third, and then to second for the final climb, but I was able to climb part way in 4th, then about 3/4 of the way to the top in third, and just as EGT's started to climb from lugging, finish the last little bit in 2nd.
Which was perfect, because I wanted to be in 2nd at the very beginning of the descent on the other side, rather than downshifting later after allowing momentum to build with the trailer pushing from behind, like I've noticed some drivers do. Again, deep gearing helps in both directions when heavy.
It does not help fuel economy when empty though. Which is why 3.73 gears are so popular. The point is, I would pay attention to what rear gear people have when they talk about their satisfaction or lack thereof with the power they felt they had with the 7.3L. Having the same model year 7.3L as the OP, I think the power of the engine is quite adequate as is, but gear ratio is key.
Again his is a F250 SRW trying to tow 12K with 3:73 gears, isn't happening as great as some of you would like him to believe. ETG's are always going to be a factor that will hold that 7.3 back on long grades. I even went to the 6.0 intercooler, helped some, but I still had to get out of it on long grades to lower the ETG's.
It seems some of you are all hung up on the power of a 7.3, and forget he is overloading that F250.
