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Author Topic: ddec 6v92  (Read 3529 times)
gladet1
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« on: November 19, 2008, 02:58:58 PM »

what does it take to use a 6v92 ddec in place of a 6v92 with mechanical governor ?
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luvrbus
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« Reply #1 on: November 19, 2008, 03:35:57 PM »

gladet, you will need the electronic foot pedal ,a wiring harness, a water sensor and some wiring diagrams for the coach and the ddec   good luck
« Last Edit: November 19, 2008, 03:40:06 PM by luvrbus » Logged
TomC
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« Reply #2 on: November 20, 2008, 12:17:52 AM »

It's not really worth the problems to convert to an electronic engine.  Now if you want to completely change out the 6v-92TA for say a Cummins ISM, then the conversion will be well worth the increase in power and fuel mileage.  The difference between a mechanical and electronic 6V-92TA maybe as much as one mile to the gallon.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
luvrbus
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« Reply #3 on: November 20, 2008, 05:01:47 AM »

TomC forgot to mention if you don't change transmissions and the gearing the ISM is not going to help all that much for the cash it is going to cost to do the conversion.keep your 2 stroke in tune and it wlll get about the same mileage and not knowing what model or make of bus you have the cost may be a major factor.I for one don't see spending large amounts of cash on a conversion that you will never get your investment back, just my thinking   

good luck
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uncle ned
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« Reply #4 on: November 20, 2008, 05:10:19 AM »




    Did any one ever do a conversion to save money.  The only reason is to brag about what i have.
and to lift the engine door and stand around and talk about.  that is a true bus nut.


uncle ned

talking from experience
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4104's forever
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TomC
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« Reply #5 on: November 20, 2008, 08:10:11 AM »

If you have a 6V-92TA and an Allison HT740 (or HT754CR 5spd) which are direct drive top gear transmissions, you can obtain a Cummins ISM with a 6 spd world transmission that has two overdrives and is not much longer then the HT transmission, then you'd have the correct gearing in place for great fuel mileage.
For instance, most buses have 3.73 gearing with 12R-22.5 tires (485rpm).  With the stock direct drive Allison, you get 1809rpm @ 60mph; 1959 @ 65; 2110 @ 70-which would be the advertised top speed.  With the World transmission, you get a .74 5th speed and a .64 6th speed overdrive.  So with the same 3.73 gearing, you'd have speeds in 5th gear of-1356 @ 60; 1469 @ 65; 1582 @ 70; 1695 @ 75; 1809 @ 80.  I doubt 6th could even be used, but here are the engine speeds for 6th gear- 1157 @ 60; 1254 @ 65; 1350 @ 70; 1447 @ 75; 1543 @ 80; 1640 @ 85.  The transmission probably wouldn't even shift into 6th until 75 or 80.

Some rough rules of thumb.  If you have an 8V-71 now, take your base mileage. If you change to a turbo 2 stroke engine, you can expect 1/2-1 more mile per gallon.  If you switch to an electronic 2 stroke or a mechanical 4 stroke, you could expect another mile per gallon.  If you switch to an electronic 4 stroke (older design) you could expect another 1-2 mpg.  If you switch to the newest 4 stroke Diesels now with common rail fuel injection (Cummins ISB, ISC, ISL @ 425hp and 1200 torque, Detroit Diesel DD13, DD15, International Maxxforce 13 liter) you could expect another 1-2 mpg more.  So switching realistically from a 8V-71 non turbo to a Cummins ISM with World transmission, if you now get 6mpg with the 8V-71 you could get in the 8-10 mpg with the Cummins ISM.

Just as a side note- we have a gentleman running his semi truck from Salt Lake City to Phoenix on a dedicated run with our new Freightliner Cascadia with the 455hp @ 1550 Detroit DD15.  He has progressive shifting programmed into the computer and a top speed of 62mph.  After the first 145,000 miles, his on board computer is reading a lifetime average of 7.6mpg!  With a low of 6.9 and a high of 7.9.  That's running always between 75,000 and 80,000lbs.  That's pretty good for this day and age of smog engines.  We expect that mileage to go up in 2010 when Urea injection in the exhaust is used, since Detroit will be able to back off the smog controls a bit on the engine.  We might see trucks carefully driven in the 8-10mpg range!  Pretty fuel efficient. Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #6 on: November 20, 2008, 04:23:47 PM »

I would prefer to get rid of the DDEC and run a mechanical engine. If I had a mechanical there is no way I would put in a DDEC.
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« Reply #7 on: November 20, 2008, 07:09:05 PM »

what does it take to use a 6v92 ddec in place of a 6v92 with mechanical governor ?

If you gotta ask, you probably don't want to go the DDEC route. 
Anyone that has access to a donor coach (or truck), and is knowledgeable about modern EFI automotive electrical systems could deal with the conversion.   
DDEC systems have benefits.  Mechanical systems have their benefits too.
I'd likely keep the MUI.  As has been stated, the gains of a DDEC system aren't worth the effort.
Unless you change out the transmission to an ATEC, you are going to have to create some interesting hardware. You'll have to mount a TPS (for DDEC) at the engine end of the throttle cable so the mechanical HT740 has some idea of throttle input. You cannot lose the accel cable/modulator cable and keep the HT740...and have it shift normally.   
If the DDEC ECM was married to an ATEC (bolt-in conversion from HT740 BTW), you're gonna have to divorce the transmission.   MORE expense.  MORE headaches. 
Be careful with DDEC bus engines... 6V92TA DDEC engines used in intracity bus environs were often set at 270 HP @ 1800 RPM.  These are not desirable limits for highway use.  Generally DD will charge $1 per HP to reprogram a DDEC II and up ECM.  DD don't do DDEC 1.   Don't make the mistake of getting involved with a DDEC 1 unit.   DDEC 1 units are the easiest to up the HP (replace EEPROM with truck unit), however they have miles of extra wiring, when compared to a DDEC II and up,  and remote mounted ECMs.  The old wiring is problematic at best.       
Good luck, JR

 
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

Ayn Rand
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« Reply #8 on: November 20, 2008, 07:27:29 PM »

tomc
"when Urea injection in the exhaust is used"

is that like peeing in or on the exhaust?  does that improve mileage or is it marginal since i'd have to stop the bus to walk back to the engine area?  Cheesy Cheesy
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Tom
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« Reply #9 on: November 20, 2008, 10:23:15 PM »

In between rest stops, you'd have the cleanest burning exhaust out there...TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
hargreaves
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« Reply #10 on: November 21, 2008, 06:52:05 PM »

This is  is  a very interesting thread. I am considering putting a B500 in my 102a3 with a 6V92 mechanical engine 300 hp . I have the adapter to attach to the throttle so the wtec knows when to shift the trans. my concern is the speeds of the engine in 5th and 6th gear. Assuming I have 3.73 gears ( I don't know what I have ) but the rpms mentioned seem to be close I will be lugging the engine will I not?  Don't want to waste my money buying a tranny that won't work.

Does anyone have this setup and if so how is it working?

Thanks Gerry.
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now as of Feb 2012 series 50 B400  . Sunshine Coast British Columbia
makemineatwostroke
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« Reply #11 on: November 21, 2008, 07:42:43 PM »

Gerry; your standard gear ratio to use the B500 needs to be in the 4.30 to 4.56 to use 6th gear save your money and keep the 740 if that is what you have and not planning a 4 stroke upgrade in the future

have a great evening
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NJT5047
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« Reply #12 on: November 21, 2008, 07:43:51 PM »

1/1 trans (HT740) with 6V92TA @ 2100 will give about 72 MPH with a 3:73, which is likely the diff ratio you have in your coach.  Tire size will vary the WFO speed a little.
Unlikely the B500 overdrive would be of much use.   A B500 is a nice shifting unit.  The overdrives can be electronically locked out.  Overdrive ratios are often factory programmed to function with specific engine/diff ratio/road speed  combinations.   Prior to buying, you may want to see how the transmission ECM is programmed.  
No matter how many gears you have, shifting to higher gears will not give more speed.   Two stroke engines are happiest at 1700 or 1800 cruising...about 65 MPH in your coach?   This will give you a little hill-climbing ability.  They don't tolerate 'lugging' at all.  
Unless you want to install a 4 stroke engine (or 8V92TA MUI or DDEC), IMHO, pass on the B500 conversion.
Very nice transmission, but the only gains will be a smoother shift.  
Changing out the diff would allow you to use the B500's potential, but how much you want to spend?  And, if you decide later to repower with a 4 stroke, you'll have to 'unwind' your diff mods.  
A significant downside is the cost of repairing B500s...should that become necessary.  A 6V92 clearly will not 'stress' a B500.
My dos centavos, JR


  
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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

Ayn Rand
hargreaves
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« Reply #13 on: November 22, 2008, 08:17:16 AM »

Thanks guys, you just saved me a lot of money, I currently have a 5spd standard. I will go to the 748 and stay away from the B500.  I am currently running approx. 1800 rpm at 65.  which would put me in the 3.73 range.

Gerry
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now as of Feb 2012 series 50 B400  . Sunshine Coast British Columbia
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« Reply #14 on: November 22, 2008, 11:03:16 AM »

Thanks guys, you just saved me a lot of money, I currently have a 5spd standard. I will go to the 748 and stay away from the B500.  I am currently running approx. 1800 rpm at 65.  which would put me in the 3.73 range.

Gerry

3:73 was standard issue for MCI/6V92TA.   
Save yourself some work (and bucks) and use an HT740 with an air shifter.  It'll be an easier install.  And immensly simpler to diagnose and repair should it cause issues.   
HT748s are electronic versions of HT740 transmissions.     
An HT740 is typically a lot less expensive to buy.  Both 748 and 740 are similar mechanically.    An HT748 would be a good choice if used with a compatible DDEC engine.     
JR   

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JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.

Ayn Rand
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« Reply #15 on: November 22, 2008, 09:54:47 PM »

A quick story about lugging engines.  When I had my Kenworth with the 8V-92TA, I was hauling beer and beverages in California and going over the Grape Vine either north or south everyday.  I wanted to get better fuel mileage (back then about 4.6).  Delaney and Ahlff told me to upshift at 1800 and down shift at 1400 and not use the splitter in the 13 speed.  Well, I left out of the Budweiser brewery with two other guys, one had a big cam 400 Cummins and the other a new Pete with a 6 and 4 trans with a 400 Caterpillar and we all weighed the same 80,000lbs. On the hills I just walked by them both, and they couldn't believe my Yamaha could pull so well. Running it down in the torque range is why it pulled so well.  On a DDEC 2 stroker, the torque is rated at 1300rpm, and I wouldn't be afraid of pulling it down that far.  If you have a non turbo with 60 injectors max, or a 92 series with no bigger than 90 injectors, pulling down to 1200 rpm won't hurt them-despite what is thought in the industry-I know I've done it with my first truck, and got 500,000 miles on my first overhaul.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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