ISX or DD15, which should I buy?

Over the 2 years I had my '12 Cascadia with the DD15, I averaged 7.2 running all 48, with an average of 35k in the box. Then again, I never ran over 62, and I didn't have to be the first truck to the top of (insert grade here).

 

I couldn't say, the only cascadias I have seen with cummins were 2010 and older. the cummins I drove was in a 2012 pete 587. I have heard that the cascadias do alright with cummins but the dd15 has them beat. its capable of 8-9 mpg, all depending on how you drive it and spec it. I average 7.75 but my ecm is slightly tuned to the power side, I lose fuel millage but get big turque gains at over 1400 rpms, makes up for the 10 speed tranny in the hills. 1200 to 1350 is fuel millage range.

 

All SCR engines have problems. I would count detroit as the best EPA2010 engine.

 

DD15, usually gets .2 mpg better then isx, just make sure if its used, check and see if its been repaired for and oil leaks and got any of the updated parts..

 

There is one number on the engine they can not lie about, that is the MM3 of fuel needed to make the advertised HP. It is on the EPA tag, look at the numbers on older units, of the same HP and torque range, it is amazing the differences.

 

I'm in a 2013 Cascadia with a DD15,.. on Flat Land it's a great engine and governed at 80mph it's getting around 6.5mpg average MPG,... but the thing doesn't climb hills.

I spent last week running in Colorado traveling east bound on I-70 was a joke, I call it "Drag N Fly" Drag slowly up the hills,..then Fly down the other side. By the time I got to Denver my average MPG was 4 MPG.

When I took it to Frieghtliner to get the engine HP turned up they said the installed "software package" would only allow on this truck a maximum of 475hp and 1650ft-lbs torque... no wonder they say the engine should last over 1,000,000 miles it still feels gutless turned up all the way. I don't get it my 2009 Freightliner Century Classic also had a DD15 but was pulling the SAME hills 10mph faster. I guess that 560hp and 1850ft-lbs torque (OLD DD15) vs the NEW DD15 which won't allow (because of the installed software package on this particular truck) anything more than 475hp and 1650 torque without voiding the warranty... must be the wave of the future. It's annoying.

I guess the moral of the story is,... never drive a 600hp truck with 2050 torque because it spoils you, you can leave the cruise control set most of the time and pull mountain passes only occasionally shifting gears. High horse power trucks are so much easier on the driver.

 

When you buy a truck with a low HP engine it is built different than a high HP engine it may have different kits turbo, many things, also the warrenty is a Lot cheaper.
To up the HP and torque you may need different hard parts in the engine, a different clutch, possibly a different transmission.
You have to know what you are buying and what you are going to use it for. I was involved with many units bought to run, east of the Rockies, then when they got sent over the mountains, they were all upset when it was explained what was needed to make the truck practical for use in the mountains. Do not blame the truck because it was not spec-ed out correctly

 

You should be able to uprate your engine, but you will have to pay for it, price should be $1000 to go from your standard rating to a performance rating...

 

Hi everyone. Anyone know if its true that the 2010 DD-15 came out defective? Any info on this subject would be great.

 

Any engine can go defective. As long I drove those DD15s, im impressed the way its running. Sadly my Cascadia is taken and replaced with 2014 prostar with Maxxforce 13 SCR.