Electronic engines and ten speed manual transmissions -- Thread #2

[Bob Belter]

Ahoy, BusConverters,                  10/21/08

Lottsa interest in these engine swaps, so I'll start a second thread, giving a bit of 'swap' background.

First, these modern electronic control engines have had a change to EGR (exhaust gas recirculation) in maybe 2003.  Now, even more 'stuff' is going onto the current new engines.  Others more knowledgeable can comment on their suitability, but you know that they are not being made more simple. Your call on what engine you want. 
For you who are going for the Autoshift, make sure that you get EVERYTHING!!!!!  One of our posters did just that, bought the entire front of the truck, and did well.  Perhaps he will expand on this note.  A friend bought a crashed truck, Cat 3126B, with the cab missing.  Turns out the computer to control the Allison World trans (3060?) was missing.  He is running now, but recovery was a remarkable and costly flail.

Transmissions:  The old Allison 740/750 series is very robust, but terribly inefficient.  I cannot imagine installing a modern and efficient engine, and then coupling it to that fugitive from an archeological site. The modern Allison World transmission is very good, quite efficient, and quite costly.  With the discs/plates/stuff it cannot compete with a gear shifted transmission for mileage.  These 'crash-box' trannys are NOT easy to live with.  People hear me shift mine sometimes and wonder how I ever landed a jet on an aircraft carrier.
Eaton Fuller, and ZF both now have automated geared transmissions which give away nothing in terms of efficiency.  Some of them are 'two pedal' systems with an automated clutch.  (I believe there was a big patent lawsuit of some sort).  A colleague and I have developed a (proprietary) application for big trucks, and have learned that only about 10% of the new trucks being built are NOT equipped with an automated transmission.  Surprised me!  I guess that others are also troubled by the crash box.

Suffice to say that I would install an Autoshift if I could.   My Cummins M-11 does NOT have the SAE J1939 protocol connector, so I cannot install an Autoshift.  It was 'new', and now with ~~42,000 miles is perfect, so I'm living with the crash box with a pretty successful 'work around'.
Enjoy  /s/  Bob

[Brian Diehl]

Yep, buying the whole front end of the truck was the way to go!  I got everything I needed at one time and saved a bunch of money in the process.  Those little odds and ends can $100 you to death!  I really like the ISM for it's power to weight to durability ratio.  I think it is an excellent motor for the job and believe you me those 1450 ft/lbs of torque make a huge difference.  The torque curve is very flat with 1450 from 1250 rpms all the way up to 1500.  I can lope along at 1150 rpms in 10th gear doing around 58mph or so.   I've increased my average mileage from the old worn out 6v92 by over 40% and let me tell you that is definitely nice!  I've not come close to Bob's fuel mileage, but the old 96A3 is no where near as aerodynamic as the eagle is.  My best mileage has been 10.0 mpg.  The last few fill ups have been 9.4 or 9.6 mpg, still not too shabby.

Here is my web page with details of the swap:  http://home.earthlink.net/~diehls0792_1/BusSection10.html

[makemineatwostroke]

Electronic engines are great but if you don't have the capabilities like some to do the swap it's not worth it I have a 60s with the Cat CX35 8 speed fully automatic in my Eagle and the way I figure it with the milage I drive every year by  2021 it will pay for it's self and with the price of buses with electronic engines and transmissions being so low now I would buy a later model bus a friend  bought a H3-40 Mon in Vegas for $23,500 with the 60s and b500 Allision , needs body work but not bad        have a great day

[Sojourner]

Thank you all for more update. 

Sojourn for Christ, Gerald

[TomC]

Granted the Allison/ZF planetary transmission with torque converter will not get the same mileage as a geared transmission, just because of the 20hp or so of drag the clutch packs make.  But-the performance from 0-40mph is second to none.  That's why the vast majority of trash trucks, and buses have Allison type transmissions in them.  Plus, they shift like a car (whereas an automated geared transmission still feels like a manual transmission shifting-although a bit faster shifting).
Don't discount the HT740 or HT754CR as a viable transmission-they are extremely reliable.  Most fuel mileage problems are a combination result of drivers that just plainly floor the gas pedal all the time and less than fuel efficient gearing on the bus.  On my truck conversion with the Caterpillar 3406B mechanically injected 400hp, I am going to use the HT740.  With my current gearing of 3.55 and 11R-24.5 rubber (478rpm), that will give me 1555rpm @ 55, 1696rpm @ 60, 1838rpm @ 65, and a 2100rpm top speed of just under 75mph.  The gearing on the HT740 and the 6spd World transmission are just about identical for the first 4 gears.  But the World transmission has a .74 and .64 overdrive.  With our light weight buses (as compared to an 18 wheeler) we can re-gear them with the larger engines being installed to compensate for the lack of overdrives on the HT740.  For instance, if I changed to a 3.08, that would give me 1350 @ 55, 1472 @ 60, 1595 @ 65, 1717 @ 70, 1840 @ 75, and a top speed of 86mph at 2100.  With my truck conversion pulling a 10,000lb boat, I figure on a maximum of 50,000lb overall.  With 3.08's my startability will still be 27.1% gradability (Freightliner wants 16% startability for on road trucks, and 25% of on/off road).

If any of you want to fool around with startability, the method is- first take the maximum you think your rig will weigh including pulling any kind of trailer and multiply that by 10.8 and put it into storage.  Then take the torque rating of your engine X first gear ratio X torque converter ratio (if you have an Allison-usually 2 would be good; 2.5 for V730s) X rear end ratio X tire revs per mile and divide that by the figure in memory, and that's your startability in percentage grade.  Good Luck, TomC