I own a 1989 D-350 Flat bed. Love it, Has the cummins engine. Auto trans 136,000 miles. I used it as a tow truck and a lawn service truck

Not really up on my turbochargers but an intercooler delivers cooler,denser air into the engine and off hand I don,t remember if that means more power or less exhaust gas temps while towing. All I know is non-intercooled isn't bad but intercooled is better. You should be able to find those answers on those sites I provided. I also owned a 4wd 1990 that had a v6 gas engine that was so under powered in a headwind it had a hard time doing 60mph:eek:.

Intercooling allows higher boost without destroying the engine through detonation so more power available.

I like these old dodges because they are nice and low. My 03 nearly takes a step ladder to enter.

it also results in more air (mass) entering the cylinder at a given boost pressure.

Isn't that what Tom said? That's how you get more boost/power then right?

- Peter.

We are in agreement!;)

Partially the same thing, I think Tom was saying that the cooler air is less prone to detonation so you can turn up the boost and get more maximum power. I was trying to say that the cooler air in more dense so you get more mass of air for any given boost level, which results in better efficiency at all boost and power levels. Both are good things.

Another aspect of intercooling, is that the inlet charge (air) is cooled. I know duh, and this gives a denser charge of air. It also helps to keep the top of the piston cooler. The air from the turbo picks up a lot of heat from the turbo and also by being compressed. Since the turbo is powered by the exhaust, the heat from the exhaust gets tranfers to an extent to the inlet air. All this heat is dumped onto the top of the piston. That is why diesels with turbos require/have piston oil cooling noozles. They sqirt some oil at the bottom of the piston to cool it. Some have a channel or port, that goes through the piston, that helps cool it better.
So, intercooling should help with longevity of your engine. Especially, since you will be in the desert. I have also heard simular clains as the one poster for the mpg of 91-93, at least the 93. I have also read some post on WVO forums. I think the earlier ones had a vane type pump. They are not recomemnded for WVO conversions, even by the WVO crowd.
Tom

Very true, in addition to detonation, the maximum boost is limited by the maximum exhaust gas temperature (hardware limitations); inter-cooling also helps this limitation.

Hmmm. Interesting stuff. I wonder if it were possible on a 92/93 with judicious use of such things as economy rear axel ratio and maybe a six speed manual tranny to get close to 30mpg highway.

- Peter.

Well sure, as long as you didn't want to pull or carry anything. The Rams (especially the old "square fronts") aren't actually designed for aerodynamics.

Yes I know. In normal use it would be way lower but I'm thinking specifically of what could be achieved in optimal conditoins simply heading down the highway.

- Peter.

True on a gasoline powered vehicle but Diesel engines don't have to worry about pre-ignition detonation since the incoming air isn't pre-charged with a fuel mixture.

Intercooling on a Diesel does permit more air/oxygen to enter the combustion chamber since cooler air is denser air. More oxygen means more fuel can be injected for more power.

I had an 89 W250 4WD with the Cummins engine for about 6 years before I upgraded to my current 98 Dodge/Cummins.

My 89 would get about 22mpg unloaded and around 15-17 towing, it was a great truck and in many respects it was superior to my 98. My 89 was sold to my cousin and is still in service with him at 212K if I recall correctly, the truck has only had routine maintenance over its lifetime.

I'd buy another one in a second.

Yea, what he said.
Truck still runs and looks great.
Rude and crude, but it makes no pretense to be anything other than what it is.

Jim

Seems like a stretch!;)