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Old 03-08-2015, 10:23 PM   #41
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I'd just like to point out that all other things being equal, simply increasing the available fuel flow should not affect your vehicle's fuel economy.

A diesel-engined bus driving at a steady 50mph on flat ground with full throttle applied at 1600rpm should burn the same fuel as a diesel-engined bus driving at a steady 50mph on flat ground with partial throttle applied at 1600rpm. The only difference between these two vehicles is the position of the fuel pedal. The fuel flow at those two pedal positions is exactly the same because the power demands of the engine are exactly the same, which is only that power required to propel the two vehicles at the same speed on identical terrain. Because diesel engines lack a throttle plate (as is found on all gasoline engines) the amount of air inducted into the engine and expelled out of it is dictated only by the speed of the engine.

I understand that some previous comments have indicated increases in fuel economy after turning up the available fuel flow. Unless this has been confirmed with an actual flow meter or meticulous record-keeping (including average speed, head/tailwinds, fuel consumed, temperature, altitude, etc), there is no way to differentiate between facts and anecdotal evidence. Even over the course of a 5000-mile journey, a few extra miles-per-gallon could be easily explained by a hundred other factors, not the least of which is a slightly reduced average speed—the single biggest factor in a vehicle's average fuel economy.

This is not to say the aforementioned vehicles will perform the same at their respective maximum fuel flow rates. The bus that cruises at partial throttle will have a much higher upper threshold when it comes to maximum power available, and this can be very handy when needed for passing or climbing in the mountains. For normal cruise, on the other hand, there should be no difference.

The moral of this (already too long) story: If you want to save fuel, slow down.
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Old 03-14-2015, 01:16 PM   #42
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The tranny has had a blocker plate on the shifter it's entire life? I keep wanting to take it off but drive neutral reverse. drive should be all ranges? The man at the bus barn told me to change the rear gear's or they would burn up if i adjusted the governor's. I can quote the tag on the rear end but it doesn't tell me the gearing I guess I need to jack it up and count the rotation's? The rear tag I can give you part#,serial# and model 16-s if any of that keep's me from jacking this up on a gravel drive or an asphalt road that couldn't handle changing my work truck tire without the jack sinking?
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Old 03-14-2015, 07:50 PM   #43
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big block of wood under jack stops that
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Old 05-11-2015, 08:06 PM   #44
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For those of you with the Bosch MW pump(most 84-92 DT360, 466, Cummins 8.3, Ford 6.6 & 7.. This is the real fuel rate adjustment where the 10 & 14mm nuts are. Back off both nuts to the end of the stud.
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Old 05-11-2015, 10:16 PM   #45
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Quote:
Originally Posted by nevrenufhp View Post
For those of you with the Bosch MW pump(most 84-92 DT360, 466, Cummins 8.3, Ford 6.6 & 7.. This is the real fuel rate adjustment where the 10 & 14mm nuts are. Back off both nuts to the end of the stud.



I will be calling you soon. I am in Texas right now picking up a 95 International with a DT408. Maybe I can bribe you into working some magic on my pump.
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Old 05-11-2015, 10:50 PM   #46
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I will be calling you soon. I am in Texas right now picking up a 95 International with a DT408. Maybe I can bribe you into working some magic on my pump.
No problem, young lad.
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Old 05-20-2015, 07:27 PM   #47
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Great thread and info here. All the geocities links don't work though. Does the link that nvrenufhp mentioned replace all of them?

I saw mention of the AT545 and what it could handle. Here is a spec sheet. There are a few more models mentioned at the bottom of the page including the MT643.

http://ketechnical.com/linked/alliso...__brochure.pdf
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Old 05-20-2015, 09:50 PM   #48
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Quote:
Originally Posted by Jolly Roger View Post
The rear tag I can give you part#,serial# and model 16-s if any of that keep's me from jacking this up on a gravel drive or an asphalt road that couldn't handle changing my work truck tire without the jack sinking?

You can look up eaton #'s here.
http://www.midwesttruck.com/pdf/HD_DIFFTRANS.pdf
That 16-s maybe 16 1/2"?

The AT545 you probably need to find an allison shop. They can check if it's locked out of 4th.
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Old 05-20-2015, 11:05 PM   #49
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Originally Posted by SassyLass View Post
Great thread and info here. All the geocities links don't work though. Does the link that nvrenufhp mentioned replace all of them?

I saw mention of the AT545 and what it could handle. Here is a spec sheet. There are a few more models mentioned at the bottom of the page including the MT643.

http://ketechnical.com/linked/alliso...__brochure.pdf
Yes, correct, the Geocities site was my first how to site, and is no longer in service. I moved to freewebs several years ago. That pump picture a few days ago is the latest addition.
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Old 02-10-2016, 04:02 PM   #50
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so my bus has a DT 360 navistar w a 545 allison transmission, the sticker on my rear end shows ratio 5.11 my top speed is about 60 at about 2900 rpm What are my options for increasing speeds about 10 miles per hour. I've read about hurting the overall engine performance so looking for a little help.
Thanks
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Old 02-10-2016, 05:58 PM   #51
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Not familiar with that particular engine, but most diesels have a fuel screw somewhere on the injector system that can be turned up. It will add a few ponies without having much effect on MPG. The next item is the turbo. An upgrade there can again gain HP with very little MPG effect. Larger injectors will add still more but will reduce MPG somewhat. As long as none of these moves are too radical, they can collectively yield a pretty impressive increase in performance.

But...keep in mind the Allison 500 series are only good to about 250 HP. Any more and the engine will eat it. Likewise the torque and vehicle weight. See the specs below.

That's on the engine side.

Then there is gearing and tire size. Larger diameter tires will increase MPH at any given RPM.

Gearing, both in the tranny final output and the rear end can give you several more MPH. But here too there are limits. Gearing that is too tall or tires that are too big will require a significant increase in torque to gain any benefit. There are also aftermarket overdrive units that can put a few more MPH on the speedo.

A good place to compare these numbers is on the calculator at the bottom of the page.

Nearly all diesel engines can be easily tweaked to gain HP, just don't go overboard without updating all the other systems...including brakes. Remember they were matched to the other specs as well.

Allison 545 Specs:
ALLISON AT 545 TRANSMISSION SPECIFICATION - Topic

Gearing Calculator:
Engine RPM Calculator
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Old 02-10-2016, 07:36 PM   #52
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Quote:
Originally Posted by Pablo View Post
so my bus has a DT 360 navistar w a 545 allison transmission, the sticker on my rear end shows ratio 5.11 my top speed is about 60 at about 2900 rpm What are my options for increasing speeds about 10 miles per hour. I've read about hurting the overall engine performance so looking for a little help.
Thanks
Go with a higher rear axle ratio or larger tires if possible.
I'm damned impressed you do 60 with that setup!
My tops is 63ish.
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Old 03-09-2016, 09:59 PM   #53
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Tango, Eastcoast.
Sorry for the delay I've been out of reach. I appreciate all your words of advice. Tango you went all out, I appreciate that, and thanks for the links as well.
EastCoast it is a 47 passenger if that helps.
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Old 03-09-2016, 10:20 PM   #54
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There are some gradability charts online that let you know how much HP and Torque you need to go certain speeds with a certain amount of weight.

The charts go up exponentially the faster you want to go up a hill.

What I do know is the single most limiting factor on any bus is the frontal area. Pushing air out of the way is the hardest thing any bus has to do. Reducing your drag can also help you get down the road--perhaps not a lot faster but at the same speed you will use less fuel.

I own two different Avion travel trailers. One is a 26' tandem axle that weighs under 5,000 lbs. fully loaded. The other is a 34.5' tri-axle that weighs right at 7,000 lbs. fully loaded. I have towed both with two different tow vehicles enough to know their differences. Yes the bigger one slows me down faster and longer on hills. But the really odd thing is with both tow vehicles I get the same fuel mileage towing either trailer. The only thing that makes a real difference in fuel mileage is speed. The difference between averaging 65 MPH and 55 MPH is about 1.5-2 MPG. One tow vehicle is a 1965 IHC D1200 Travelall Custom 4x4 with an SV304 V-8 and 4-speed. The other tow vehicle is a 1993 Chevy K2500 Suburban Silverado with a 5.7L and 4L60E.
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