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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Emcemv on January 17, 2016, 10:49:33 AM

Title: Fuel pressure
Post by: Emcemv on January 17, 2016, 10:49:33 AM
I'm adding a fuel pressure gauge on the filter housing at the output of the fuel pump, what is typical pressure? 8V92T from 2000, (Mechanical).
Title: Re: Fuel pressure
Post by: TomC on January 18, 2016, 12:00:59 AM
Rather than a fuel pressure gauge, a fuel restriction gauge is more helpful in telling you that the fuel filters are getting dirty. Good Luck, TomC
Title: Re: Fuel pressure
Post by: luvrbus on January 18, 2016, 02:06:25 AM
Bruce, they read between 50 and 70 lbs, after a new filter change take your reading at 2100 rpm use those numbers for your base.The Teltek fuel restriction gauge is a nice gauge it works off a vacuum sensor but a little pricey IMO @ 180 bucks it's pressure vs vacuum you get the same results    
Title: Re: Fuel pressure
Post by: Scott & Heather on January 18, 2016, 02:07:59 AM
While on the subject, Cliff remind me again how many GPH an electronic fuel pump would need to be rated for to feed these beasts?


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Title: Re: Fuel pressure
Post by: TomC on January 18, 2016, 04:38:19 AM
Scott-the fuel pumps on the 2 stroke engines are so reliable, Detroit used the same basic design on the Series 50 and 60. Electronic anything is not going to be as reliable as the mechanical one. Good Luck, TomC
Title: Re: Fuel pressure
Post by: Emcemv on January 24, 2016, 01:52:36 PM
Hey guys, thank you for all the replies, got a 100lb gauge and am going to install it once we have a break in the weather.  Tom and Clifford, thanks for the info on the fuel restriction gauge, maybe something to put on the wish list! I learn something with every question I ask on this forum.!
Title: Re: Fuel pressure
Post by: Iceni John on January 24, 2016, 07:19:21 PM
At 1100 RPM fast idle I have exactly 60 PSI fuel pressure from the spare port on the secondary filter's housing.   I just have a simple 100 PSI pressure gauge, not a restriction indicator, but it's better than nothing.

John
Title: Re: Fuel pressure
Post by: richardmc9 on January 26, 2016, 01:22:12 PM
what is the fuel consumption for a series 60 Vs 8v71T say at 65mph    Thanks Richard
Title: Re: Fuel pressure
Post by: TomC on January 26, 2016, 06:23:49 PM
Anywhere from 1-4mpg difference between the 8V-71T and Series 60. I get on average 6mpg with my 8V-71T and I weigh 31,000lbs.

The rule of thumb is-starting with a non turbo 2 stroke engine-change to a turbo'd 2 stroke and gain 1mpg. Change from a mechanical 2 stroke turbo to an electronic 2 stroke or a mechanical 4 stroke gain another 1mpg. Change to a Series 60 type get another 1mpg. Change to a common rail type engine, get at least 1-2mpg more. New trucks with the DD engines are regularly getting 8mpg with 80,000lb gross. Good luck, Tomc
Title: Re: Fuel pressure
Post by: luvrbus on January 27, 2016, 01:51:42 AM
All depends on the gearing you run a 60 series at 1800 rpm there is not much difference,you are comparing a 9L- 8V71 to a 12.7 or 14L series 60 there is no comparison IMO
Title: Re: Fuel pressure
Post by: brmax on January 27, 2016, 05:00:26 AM
Its a good question but probably have to throw another  acronym do dity in their like
GPH in work done so GPHWD, and I think this is a new one ;)

good day you all
Floyd
Title: Re: Fuel pressure
Post by: bevans6 on January 27, 2016, 05:22:06 AM
It's usually called fuel usage in  pounds per horsepower hour  (Lb/HP Hr).  The bottom line on the graphs in the attached brochure.

http://www.powerlinecomponents.com/literature/detroit_diesel/brochures/8v71t_automotive.pdf (http://www.powerlinecomponents.com/literature/detroit_diesel/brochures/8v71t_automotive.pdf)

The idea is that a job of work needs a certain amount of power, so the fewer pounds of fuel you use to get that power the better.  The curve on the graph is at rated HP RPM, so fuel efficiency at the maximum rated HP output at a given RPM, so this has little to do with how efficient an engine might be a partial power at an RPM like cruising down the road with the tunes on...

Brian
Title: Re: Fuel pressure
Post by: Lee Bradley on January 27, 2016, 05:52:30 AM
For very complete testing of fuel usage check the Nebraska tractor test.  They have been doing this almost since tractors were invented.


http://digitalcommons.unl.edu/tractormuseumlit/166/ (http://digitalcommons.unl.edu/tractormuseumlit/166/)
Title: Re: Fuel pressure
Post by: brmax on January 27, 2016, 05:54:38 AM
Good charts there Brian!
A little more humor than my other post heres a mention my brother has repeatedly said: you know when I do a lot of work I get rewarded with more mustard packs and crackers.
I complained I didn't get any pack at all  :(
Title: Re: Fuel pressure
Post by: luvrbus on January 27, 2016, 11:45:02 AM
Here is you a example the Eagle was 8v92TA powered with a 740 and weighed 36,000 ,the D I have weighs 45,000 lbs 45 ft long with the double overdrive B500 with a series 60 both averaged 7.5 mpg at the same mph,the 8v92 turning 1700 at 65 mph the series turning 1400 rpm at 65 mph