Quote:
Originally Posted by firebird_1252
wow.. i always was told detroits liked more rpm. good to know! great advice copperhead.
I do step it up on the RPM's under a hard, long pull. But for regular cruising, Series 60's do exceptional in the range I mentioned. You just have to figure out what rear will give you the road speed you are wanting to run and keep the RPM's in that range. Once mine starts to move below 1300 on a hill, I usually split down and get the RPM's back up. If I am close to the top of the hill and about ready to go over, I will sometimes just let it pull at 1250 - 1300. Just have to use a little common sense. I hardly ever take the engine over 1600 for anything except maybe engine braking on a downgrade. And since i have the splits of an 18, most of my shifts up occur at the 1500 - 1550 range. Sometimes a tad higher on a real hard pull.
The earlier Series 60 engines did do quite well running a little higher. But the DDEC IV ('98) and newer engines do quite well running below 1500. Whether it be the 12.7 or the 14L. Now, I would also recommend to take the time and consider a higher flowing exhaust manifold, turbo, and mufflers to make this all come together. Before I dropped in the engine in this glider, we put on a Bully Dog ported/polished/coated exhaust manifold and got rid of the wastegate turbo and put on a larger non-wastegated Borg Warner turbo. We also removed the OEM mufflers off the stacks and put on Walker Megaflow's. I believe these mods did much to improve the overall performance of the engine at the RPM range I have been running it at.