downrated engines?

[heptofite]

I've noticed this, and was wondering, why do the > 350 superduty's and > 3500 dodge trucks have lower rated engines, even though it's the same displacement?

 

[mn_smokeater]

could be for durablity id assume an engine will last longer if its not cranked way up to what its cabable of?

 

[adsm08]

+1.

Entirely possible. And since the >35 class trucks have lighter suspensions and can't carry as much weight they don't generally need the full power the engine is capable of producing to do what the rest of the truck is capable of doing, so they de-tune it a bit to make it live longer.

Also makes it easier on the trans.

 

[mentalbreakdown00]

If you want all the power a ford can give you get a nav pack and the bracket that bolts it on top of then engine from international and all you need the along with the wiring harness is a hot and ground. It will have a lower hp rating, but won't rev higher than about 2500, but will destroy the trannies you put behind it. It's all in the programming.

 

[heptofite]

no, trucks bigger than 3500, not smaller, the 550's and 650's, they have about 50 hp and torque less, and i don't know why, the diesels that is.

 

[LearjetMinako]

They probably did it to lower the EGT on the diesels. So when hauling or towing that heavy load, the engine won't over heat the exhuast or itself.

I know on my dad's Cummins 160HP diesel usually runs between 300~600 *F without a load. But when he has the camper on the truck and boat towed behind. The EGT's screem to 1200*F. With a lighter right foot, he can keep it below 900*F.

 

[mentalbreakdown00]

What laret said, but I am talking about bigger ones. A nav. pack only comes on international trucks with a dt44E, it will cook what ever tranny you put behind it in a smaller than class 6 truck for the most part, but you can't rev it above 2500 rpm and it has sno balls

 

[adsm08]

Heh, I misread that. Math ain't one of my strong suits.

Yeah, probably to lower exhaust temps and save the trans. Under those loads the transmission is under enormous stress already, putting full engine power to it might blow it to bits.