I'll bet Ford is concerned about the amount of heat and potentially warped exhaust headers.

When the ECM senses a reduction in available oxygen as altitude increases, just give me enough forced air to (at least mostly) compensate under heavy load conditions such as towing my 9500 lb travel trailer through the Rockies. Not looking for full-time boost under light load conditions. Oh well, a man can dream! :rolleyes:

Nothing wrong with Dreaming..

what about nitrous oxide ... a high amount of oxygen in it :) even a 50hp add on.

I am totally confused, What is it you are trying to say?

6.7 is Turbocharged and doesn't over heat. You just need a cooling system designed for it.

Someone can chime in but I think that diesel turbo EGT are less than gas turbo EGT?

There are reports of 6.7's overheating in mountain climbs while towing and going into limp mode.

Gas EGT is indeed much higher than diesel.

But again, it's about how a total system package is designed. It's not that we could not have a small gas turbo SD engine, but it's cost would approach a diesel engine in terms of expensive components. A n/a gas motor that is large can achieve the same power levels, with less stress. But it's not nearly as fuel efficient.

diesel fuel is one of the most efficient choices; has about 30% more energy per pound than gasoline. If ONLY efficiency is your concern, then this makes the most sense.

Gas engines can make as much torque as a diesel via boost, if designed properly, but you'd end up costing nearly as much, and yet get less fuel economy.

Hence, a gas n/a motor that is large will give decent torque, but suffer in economy, but won't be too expensive to produce because it's not boosted.

Let's not forget that n/a diesel engines were pitifully low on power way back in the day. The old 6.9L and 7.3L IDI engines were very long lived, but ssssllloooooooooowwwwww when pulling a load. Boosting helps today's diesels, but we could get the same effect from a gas motor, but it would also cost nearly as much as a diesel today.

The "middle" choice is a large gas motor. You'll get good torque, but you'll suffer at the pump. The longevity is not necessarily a function of the topic of boost or not; that is only a part of it. Any well designed and made engine will last a long time.


If it were not for the complexity of today's diesel exhaust and emmisions treatments, I'd vote to have a small turbo-diesel as a choice; maybe a small inline 6 or small v-8 around 4.5L. The power it would put out would be a nice mid-line choice. But the complexity of that system today makes gas engines FAR, FAR more attractive to me. I'll take a big n/a v-8 on gas over a diesel today.

Keep in mind that turbo's are not 100% efficient...more like 80%. That means they burn more fuel to do the same job when at boost.

I owned a 1987 Grand National back in the day. It went through two turbos under warranty and then a third out of warranty. Add in the facts that turbo gas engines require cool damp air to run their best and I live in the Sonoran desert where even jet aircraft are grounded when it gets to > 115* F, I'd never buy another gasoline powered turbo charged vehicle again. I sold it in the third year of ownership.

They run well in places like the mountains in Colorado, Seattle, etc.

Here is an example of loaded MPG

Final answer: "Because 7.3"

Well . . . . that was 30 years ago . . . . . times have changed. Turbo's in the 80's were problematic.