WHY UPGRADE 6V92T DETROIT TO L10 CUMMINS?

[Mex-Busnut]

Dear Friends,

I am beginning to see a number of used buses (early 1990's) for sale down here (central old Mexico) that have had the 6V92T engine replaced with an L10 Cummins. Can anybody give me some info on differences in fuel ecconomy, longevity, performance, running costs, etc.?

So sorry to ask so many questions.

Dr. Steve, central old Mexico

[TomC]

They're both about the same power, but the Cummins L10 will get about 1mpg better then the 6V-92TA.  If the 6V-92TA was a DDEC, the mpg would be the same as a mechanically controlled 4 stroke.  Make the 4 stroke electronically controlled and 1 more mpg.

New engines now are in a class all by themselves.  The new DD15 from Detroit with DEF (Diesel Exhaust Fluid [Urea]) with an 80,000lb truck driven around 60mph are regularly seeing 8mpg.  On a bus that would translate to about a 15mpg bus. Good Luck, TomC

[Tom Y]

15MPG from a DD15? Seems hard to believe. Dr. S. When I start my L10 in a campground I do not smoke anyone out. No oil leaking. I would have put a 6/92 in mine if the tranny would have fit. So I can't compare the two. I do like the L10 I have.  Tom Y

[twocnusa]

I have a 6v-92ta in my flx. what is the hp of the L10, and the size. will it fit in the same place?  Why am i even asking this, this sounds like a major job both  in $$$ and time. but it would keep care of the oily mess in the back of the bus and the toad.  thanks, ron

[twocnusa]

Tom C, just re-read your post. can u tell me more about the DD-15?  Tom Y, what is your mpg with the l-10 in your bus?  thanks, ron

[luvrbus]

Main reason for the swap is parts from a DD have gone through the roof 500 bucks for a cylinder kit,and you can buy a L-10 for 1000 bucks if you shop.
I know a guy in Vegas that bought 10 for 500 bucks each upgrade I would not call it a upgrade more like a swap. 
Tom Y is always talking about smoke on startup and leaks on a DD it doesn't happen on a 2 stroke that has been maintained at least on the ones I have owned over the years nothing smokes as bad a old 855 Cummins on start up kinda like the ice cream thing 


good luck

[cody]

I would find it hard to rationalize changing a running 6V92 to anything to gain in fuel mileage, it would take forever to make up the difference, if i had one that was beyond repair then I'd give it some thought tho, but first I think I would have a large white planter in the yard for a long time, or maybe a guest house lol.

[poppi]

I would say more an option from the factory than a swap. In a lot of set-ups to convert from DD to Cummins
also requires a different transmission.

Skip

[buswarrior]

The DD15 propaganda:

http://www.detroitdiesel.com/engines/dd15/

5% better fuel economy than the 2007 S60, which was the best to date, and a target engine for bus nuts to swap.

Depending on application, wondrous things are possible with a dedicated flat run, geared specifically for that route, light loading, small frontal area/lower roof line, aero devices and a little slower running.

And, of course, a driver fully committed to fuel economy, not self gratification by way of the fuel pedal.

happy coaching!
buswarrior

[Tom Y]

Ron, I am at 9.5 MPG and8.5 Mpg towing a Wrangler. I have a 5C so not big bus, 26,000 lbs.

Luvrbus, I am not putting down the DDs. Not sure what always talking about leaks and smokeing is. I have not made many comments about this. But I have seen a few Detroits putting smoke out.  Tom Y 

[Mex-Busnut]

Thanks to all for your replies.

Mr. Tom Y:

What kind of tranny  do you have in that bus? And rear end gearing?

[Tom Y]

I have the 740 Allison and 3.36 or 3.38 gears. Wish I had a 6 speed Allison. Not sure if would help my MPG. I keep looking and thinking, but have not bought one. I had hoped for over 10 MPG. 1 trip may have been 9.6 or 9.7 would have to look at the book. I had bought a 6V92T with a 748 for my bus. If the 748 would have fit I would be driving a 6/92.  Tom Y

[TomC]

The big reason the Detroit DD15 and DD16 gets better fuel mileage then any other Diesel on the road is because of the turbo compounder.  The turbocharger is a simple turbo (no waste gate or variable ratio).  Then after the exhaust exits the turbo, it enters the turbo compounder that looks like a half of a turbo that is gear driven back into the engine.  Like our 2 stroke engines, the DD series once again have rear gear train.  Hence the turbo compounder  works on the rear gear train of the engine.  What it does is recoup wasted exhaust gases that would normally just go out the tail pipe and turn it into up to 50hp extra (usually on a full throttle hill climb).  This isn't new-piston aircraft engines had this feature around WWII.  The unique thing is, that no other Diesel manufacturer has the turbo compounder, so Detroit is once again at the front of the line with fuel mileage.  Course, this is with an engine that also incorporates a Diesel catalyst, particulate filter, and Selective Catalyst Reduction using Diesel Exhaust Fluid (Urea) injected into the exhaust stream to just about eliminate Nitrous Oxides (the stuff that makes the brown air).  The bad part, trying to retrofit one of these engines into a bus would be a massive job.  The DD engines are a bit heavier then the Series 60, plus having two exhaust treatment mufflers, plus a 20gal or so Urea tank.  On a new bus-it will work well if designed in.  Good Luck, TomC