Cat advice

mpg guesstimate 5.0-5.9 depending on which model, they run hotter than the old 3406E but about the same as the twin turbo acerts, problems are usually it will have a slight miss around 1400rpm, thats the most common I can think of. how many miles are on it and what type of hauling you gonna do. I f I was looking I would step back to a 2002 or 2003 with the pre-mbn engine serial number, just my .02 as a former driver and now diesel mechanic.

 

I've got the same serial# motor 475hp with a fuel temp wire, same rears, and a 13 speed with 11r22.5's I average 5.6 mpg in a t600. I wouldnt have this motor in any truck without a 13 or 18 speed. The best rpm range to work in is 1400-1600 and up. It would be a lousy motor to work with if I didnt have the ability to split gears. I agree with previous poster try to find an '03 or older truck with the 6NZ serial# engine if you can. MBN is not all bad I seem to have a good one but you never know what youre going to get. Lot's of people say youre lucky to get anything better than 4.5mpg out of an MBN...

 

The cam needs to be changed along with a ECM and oxycats. You can run a 6nz ECM file but still won't do much better on millage with the mbn cam. 16.6:1 vs 16:1 compression on 6nz and older, being a 435 might be higher not sure but they run hot exhaust temps. 1100+ seems to be the norm, this results in early head gasket failure, they're known for it. First thing to do is dump the mufflers to get egt down. Mine would see 1200* bobtailing with a head wind when stock. Right now I have a million on it and all I've done is one of the injectors I bought from haney. Getting ready for a small overhaul now.

It's also seen 300k miles of 1000hp duty so I'm pleased with mine, stock it got anywhere from 3.7-4.3mpg, now all I do is run I5 western states, 55mph limit but heavy and see 6.1-6.6mpg with lots of big hills.

 

The MBN can be made to run much better with an ECM reflash to a 6NZ or 7CZ file............PM me if interested in doing this. You can get good mileage and power out of them doing this.

 

Mine still got horrible millage with the ECM I got from you running the west coast and back. Local I did ok, west coast I saw 4.7 at best. When I swapped cams that's when millage picked up big time right away.

 

I don't use the program that was in that ECM............I bought that ECM used and already programmed and I sold it to you for what I paid for it. At that time I didn't have the software to reflash ECM's. The cam change makes a great difference in fuel mileage, but most refuse to change it because of labor costs.

 

Yeah I know you didn't flash it, just saying it didn't help much. I actually think that this program is hurting millage. Especially the 6999 trim codes, it's like pouring water out of a bucket between 5232. And if you want any sort of jakes don't go with a B manifold and big turbo. I've learned that this big power thing is fun but not worth it in the end. Lose so much response from the engine and most of the Jake, in my case it just makes noise and won't hold at all. Went from building 20psi to 5-6psi with Jake. I'm going back to stock with a flash, running these grades out west it takes forever when you have to drop down at 20mph.

 

5232 is easier on fuel mileage. I try to stay with stock trim codes, unless someone has already played with them or the owner wants to change them. I don't use the MI Turbo stage 5 turbo any longer.........I use a Perkins Industrial engine turbo off a 1000hp generator......it responds much faster and moves 25% more air. Boost went up.........throttle response went up........fuel mileage went up..........power went up..........it doesn't smoke as much, and the jake works a little better. I use a PDI extrude honed manifold also........after some flow testing on 4 different manifolds.....this was the best one as of today.......I haven't gotten my hands on the new manifold of Full Tilts yet, but they flow test the ports....not the plenum or the manifold as an assembly through the plenum to turbo entry

 

any numbers on this turbo?