Merits of mechanical vs electronic

[JohnEd]

TomC,

Long ago I read a post where the Knut was discussing the merits of the "mechanical" engine VS the "electronic" versions.  His take on the subject was that the additional MPG that you get with an electronic was not worth the "Holy Crap" expenses associated with doing almost anything to the electronic that was associated with fuel.  Hearing some of the horror stories told by the likes of Ace and Sean, I tend to agree. I know that the ECM and associated parts in the DD electronic system are touted as being "Bullet Proof" and "reliable in the extreme" and then there are the Heart breaking (read wallet here) stories.   So "if" I am confronted with a decision....which one?  Don Fairchild, I am told, is running a "fresh" 8V92 coupled to a 740 and is getting 8.5 and better and is not driving for MPG.  Don't know what version of DD he is using but he built and tuned it personally.  So if all things are equal, what mpg could I expect from a mechanical, DDI, DD II, DD III and then  Series 60.  And what kind of improvement is anticipated from that 32,000 lb/sq inch common rail version running 17.5:1 CR?

Here is something that is really putting me off on this:  The MPG for a 4 cycle Cummins L10 or M11 electronic was supposed to be nearly double what a Mech 8V92 was capable of giving.  I am not offering this as my own personal lie but I believe that is what has gone around as "truth".  What has started to choke me up is the "impression" that the really new engines, newest 60's and the even newer generation stuff that you mentioned, are NOT getting better MPG but the same and WORSE.  Are they adding these levels of cost and sophistication just for smog reasons?  Doubt it, but I have been surprised more and more often of late.

Anybody else?

Thanks for your consideration,

John

[Blacksheep]

John since you mention my name I feel I must answer with utmost honesty! Regarding electronics over mechanical (which I have had both) let me say openly that in my opinion the largest problem with owning AND maintaining AND diagnosing ANY and ALL problems that may have in the past OR in the future, simply stem from lack of knowledge about the system/s. In other words, I was and am STILL somewhat stupid when it comes to what make these things tick but with each new problem that occurs, I learn more about them.
Let me also say, almost all cars and trucks on the road today are electronic! Yea they have the check engine light that tells you there is something not quite right! What do most people do? Yep, take it in to have it checked! With our b us, it is and has been most benificial to TRY and do the fix ourselves which means buying the necessary testing equipment to do so. Now here lies all this high dollar equipment and now you not only have to learn or teach yourself what's wrong with the issuse at hand, you have to learn and teach yourself how to use the equipment! Yea it takes a little time and MOST of the time, so far with me anyway, it has been really SIMPLE things like a 10 cent blown fuse!
As far as my opinion on fuel economy goes, I think a lot of it depends on HOW its driven, if your pulling anything, running flats or mountains! Bottom line is, I think the electronics can and WILL save you in the long run especially with a auto shut down feature!
Series 60's are a great motor for longevity but are they better on fuel? Hardly! I know of some that get around 4-5 where my bus averages 6-8! They pull, I don't or haven't yet! Both run mostly flat roads! One has his foot in it, I don't!
So you see, there are differences in everything!
My vote (at this time) is electronic. Now when I have a problem with it like last time, my vote may change!

Ace

[buswarrior]

The issue is whether the engine has been matched up to the proper gearing, not whether it is mechanical or electronic.

Drive your electronic fuel injected car in 3rd gear direct instead of 4th overdrive, and it'll get the same horrible fuel mileage that a 30 year old carburated version with a 3 speed transmission got.

And just try to get that old carburated one to pull the overdrive in your new car...

Won't work out too well.

What RPM is the engine intended to operate at for best economy and/or performance, and what are the implications of running it above or below those values?

Same with the heavy diesels. A Series 60 driving a HT740 through the old stock 3.7 differential is not going to show you much difference over the 8V71/8V92 that it replaced, as the fuel savings in the S60 is in running the revs much lower than those gears will allow. Now, go find a taller differential, and you'll start seeing some much better numbers.

The trick with the electronic engines/transmissions/suspensions/braking will be to religiously maintain the wiring and the grounds, beside having the scan tools. Creeping corrosion in the harnesses will be the devil busnuts will have to contend with in the coming years.

I'm a fan of the newest stuff I can get my hands on. EPA may see to it that the rest of us have no choice?

happy coaching!
buswarrior

[luvrbus]

JohnEd, BW has it right it is the gearing for the electronic 4 strokes example take series 50 (4 banger) run it with a 740 and 3.73 or a 3.36 and it will average around 7 running at 1800 rpm install a b500 6 speed it will go up to around 9. now figure the price and see if you can ever recoup that amount of cash on fuel savings.If you had somebody like Southern Oregon Diesel do the transplant he is going to be in the 30,000 range plus the b500 transmission.I run a 8v92 in my Eagle I average 7.5 in the northwest and I have a heavy foot going across Texas on 10 where the speed limit is 80 mph that is where I will be running with the big dogs.

Some info for you the 8v92 or the 6v92 DDEC are not a electronic injected engines they are a mechanical injected the DDEC just controls the amount of fuel to be injected it is the same engine as a mechanical 8v92 or 6v92 .I am very lucky I have 2 friends that tell me how to get the most from my 8v92  with the least amount of fuel and I love my engine.BTW Don Fairchild has a 6 speed Allison not a 4 speed 740 but he does not baby his 8v92 and tows a 6000# truck. The EGR 60 series engines get around 5 to 6 MPG at tops with a auto tranny I have friends that have them in their buses and are not happy campers after spending the big bucks for a swap       good luck

[belfert]

Why would anyone put an EGR Series 60 in as a transplant?  EGR just adds more complexity to make the EPA happy.

My bus weighs about 40,000lbs loaded for a trip and my factory installed S60 gets around 8 MPG traveling at 65 MPH from Minneapolis, MN to Reno, NV and back.  I do have an older Series 60 that is only 11.1L.

[luvrbus]

Belfert, it is tough to find a 12.7 L that is not a EGR engine they been around since 2002    good luck

[TomC]

John- first of all, Don Fairchilds bus has a DDEC 8V-92TA with an Allison B500 World electronic 6 spd in it (very rare).  That's why he can get over 8mpg with his big ol pickup truck in tow. 
With the merits of electronics capable of squeezing more mpg out of truck and bus engines over 1 million miles, I believe they are worth it for the present day trucks and for managing the VERY complicated smog control devices (the computers on the engines now have as much power as a lap top).  But for our use, I still think the good old mechanical engine and transmission is the way to go.  One failure of the electronics, and there goes all your money savings with fuel mileage.
Granted, since 1998 (the last year of really good mileage engines) the Diesel engines have been progressively going down in fuel mileage-until 2010.  As example, pre 1998 Series 60's with full aerodynamics and keeping the truck speed to 55 mph, they were seeing almost 10mpg on the flat with an 80,000lb truck.  Now the fuel mileage with the EGR and DPF equipped Series 60's is more like 6mpg.  The new DD15 is seeing more in the 7.5 mpg range when driven at 62mph.  With Urea reaction chamber added to the exhaust in 2010, we may see trucks getting over the 8mpg range again-and when you consider that the exhaust emission will be Nitrogen and water vapor-pretty cool.

So getting back to the fuel mileage differences.  Starting with a 8V-71N base; change that to a 8V-71TA or a 6V-92TA and you should see about a 1/2 to 1mpg change-and a huge difference in performance; go to a DDEC 8V-92TA or a mechanical 4 stroke engine-worth 1 mpg more.  Go to an electronic 4 stroke (without smog devices) and it should be worth another 1 mpg.  So while a 8V-71N bus might get 6mpg, you should see around 9mpg for a 4 stroke electronic engine (that's 50% better fuel mileage-huge!).  On my truck conversion with a Caterpillar 3406B 400hp mechanical engine and the Allison HT740, I'm hoping for 8-9mpg, compared to the 5-6.5 I'm getting with my 8V-71ATAAC engine with V730.  Good Luck, TomC

[JohnEd]

Tom,

Thank you very much.  You told me exactly what I wanted to know and was not smart enuf to form the question.  !998 is the latest engine I should be looking for.  A DD mech told me "82 or newer" for the engine block. etc.  Is that also correct?  82 to 98 is broad enuf to be doable.

One of the things that was bothering me was that I perceived the MPG going down and that seemed odd.  I remember when I was getting 17 to 19 MPG in mostly freeway driving.  Then they smoged everything all up and the same engine 5 years later barely got 12.  Infernal feduraly revonuern @#$#%)**& sweethearts is what they are.  Now I get 27MPG from a 300HP V8(alu block) automatic that is computer governed to 144 MPH.  I be happy camper grinnin.  Hopefully the D world will follow the cycle of the gas rigs.  Sounds like that may be what is starting to happen and it only took them 15-16 years.  If I were a trucker and my fuel costs were going up that much and fed reg was driving the whole thing....I would be livid as well.

From what you and others have said here and in other posts, I think any 2 stroke DD, 6 or 8 V 92, would be completely satisfactory.  As long as it were fresh, that is.

Much thanks to you and everybody. I am sure a lot of people are closer to a comfortable familiarization with the 2 strokes.  I feel that I am.  It is near certainty that when I buy my bus I will be joining the DD 2 stroke crowd.

Thank you all very much,

John

[edroelle]

Of the electronic engines, the DDEC III is the system that is preferred for reliability and economy.

Ed Roelle
Flint, MI

[buswarrior]

My DD buddy, apprenticed and worked at the big DD shop here for a decade before moving on to more lucrative pastures, second generation DD man, thinks that a 1997 DDEC III S60 is the best there was to date. He's not a fan of what has come along since, but is waiting patiently to see how DEF is going to work out. He isn't old enough yet to be close minded to the chance of something better coming along.

FWIW.

happy coaching!
buswarrior

[luvrbus]

I have to agree with him BW the 60 series 12.7 non EGR was a hard act to follow , but just not enough of those produced     good luck

[HB of CJ]

Doesn't matter if it would be electronic or mechancial.  The point is, whatever system you choose, you should first understand it, plus have the ability to fix it yourself.  Naturally there are practicalities and limits to this notion.

If you understand the newer electronic stuff...and can fix it yourself, then fine, go electronic.  However, if you can't fix the electronic stuff readily yourself, then it doesn't matter if you understand it or not.  See the total illogic here?

Again, we are talking here about practical limits.  If I had a mechanical 8V71N, I might be expected to know how to to reprime, set the valves, run the rack, etc..  All with lots of practice.  But, I may not be expected to know how to overhaul the thing.

Practically speaking again,  I couldn't carry all the necessary tools.  The practical line here is conducting ordinary repairs or adjustments yourself that could reasonable be expected to rarely occur while enjoying our Bus Conversions.

Joking here.   One large EMP bomb popped 1000 miles over Omaha Nebraska would probably fry most if not all electronics in most of North American including electronic diesels.  Oh well.  I would hope that is a very very low order of probablility event.

Keeping things KISS, an older, less complicated mechanical system might be the way to go if you can handle the increased maintenance.  Simple repairs are OK if you know the stuff.  With electronics, knowing and fixing may be separate issues.  HB of CJ

mechanical vs electronic Post