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Old 07-25-2011, 08:44 PM   #37 (permalink)
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FORDF250HDXLT's Avatar
Join Date: May 2011
Location: ME
Posts: 16

chip truck - '93 ford F250HD DUALLY CONVERSION XLT
90 day: 12.89 mpg (US)

log truck - '93 Ford F-450/F-Superduty XLT
90 day: 9.17 mpg (US)
Thanks: 35
Thanked 6 Times in 3 Posts
Originally Posted by Milwaukee View Post
Found you from FTE.

Well my thought with idi 7.3L I used to own 87 F250 6.9L they are alike.

They get horrible mileage when it cold so you could try running little hotter thermostat like powerstroke 7.3L come with 203oF

They don't like run low rpm work. Mine get worse mileage if I have rpm around 1300-1600. Try run at 1700-2000 rpm it should improve.

City mile is BIGGEST KILLER. I try coast much I can in high traffic in city. It get 18-20 in warmer weather. In winter it 14-15.

I got much better mileage if I put about 2-3 gallons of used clean oil in tank. I did put oil in there first then go to diesel refill then reset mile. After that I refill with straight diesel. I saw 21 mpg city but it was slightly running hotter.

What psi you running on tires?

Have you thought of rewire switch to torque convertor to stay LOCK while you cruise 45 mph but turn off so it let rpm drop to idle while you coast.

My 00 F350 if I keep overdrive off I can let rpm drop to 600-700 while coast 25 to 55 mph. If I let overdrive ON it annoy it keep Lock torque convertor too early when you are try to coast it act like brake.
well,i have electric engine fans,and try to run around 210-220 degrees normally.
i run around 1400 rpm mostly @ 45MPH.
in order to get higher rpms,id need to go faster (wouldn't help because im pushing a large dump bed.speed is my killer) or id need to lock out over drive and just run third gear all the time.
im not interested in going backwards.
i feel the lower the rpms,the better the FE with the diesel.
but,what the heck,i'll go ahead and try a tank without using OD have me curious enough to try it,but it wont be until 10 more tanks or so,as i want to see what the newly installed air dam yields over the course of the next 10,without any changes.i'll trying running your rpms on a tank,but im very,very skeptical.
when i do,i'll reply back here (could be a month or so.)

im running max tire pressure in all 6 tires.

i have thought about putting the torque convertor on a switch,so that i could lock it up sooner.but as is,it locks up at 32-35 mph.not sure id want to mess around trying to lock it any sooner due to the truck weighing in at over 8,000lbs empty.
that said,
the TC does disengage when you let off the throttle to coast to a stop,and locks back up when you just touch the fuel again.
when i let off to come to a stop,she drops right off well below 1k rpm at 45 mph.

Originally Posted by Milwaukee View Post
Forgot to list.

I believe that injector pump still pump fuel if you off pedal.

I would put shift in neutral when stoplight so it coast like 1-2 miles from 45 mph to 25 mph. Let rpm at idle.

That how I got 20 mpg in city. I have hard time believe those people say they only get 10-16 mpg out IDI with 5 speed.

Have you try coast? Like you drive 45 mph and there stop sign or light change red then try coast to avoid use sudden brake.

Example bad driver waste gas. Light change RED or stop sign but driver still drive 45 mph until it 40 feet close then SLAM BRAKE HARDER. No coast.
this truck weighs too much,and pushes too much air to be able to coast 1-2 miles.
if im going 45 mph,and let it coast to a stop,on the flat it would probably only go a 1/4 mile until stopping on its own.thats probably being kind too.

when im sitting at a stoplight and the light just turned red,i often do slip her in N rather than keeping it in drive sometimes.
if i know i'll be stopping at a light or sign,sometimes i will slip in N before getting there too.

10-16 mpg for a SRW stock pickup going over the flat road for an hour or more at a time at a pretty constant speed, out on the flat,could be kinda low.but you need to remember im;
b.large frontal area dump body
c.weigh in at 8100 lbs when empty(full of fuel and tools-no passengers though),and this truck isn't for running empty. often i'm carrying a couple ton or more in the bed,and towing another ton as well.
d.never out on the flat interstate.i drive hilly back curvy roads in rural Maine.if it's not that,then im in the city,which yields even lower FE.
so under these conditions,10-16 is actually better IMHO than a pickup running empty out on the flat interstate pushing 20 mpgs empty.

when looking at my FE,you need think,large wind pushing dump bed,12-16k gross averages on rural hilly roads with various alternating speeds of 25 MPH zones through 45 MPH zones (occasionally 55's but those are our larger roads.i like to be on those when possible.those help a lot,and i still try to stick to 45 when i have the time too.) along with that 14+ lifetime FE.
taking everything into account,you can see this to be not too shabby.
also im non turbocharged still..........but this will change at some point.

I drive so slow and easy,Id put granny to sleep.

Last edited by FORDF250HDXLT; 07-25-2011 at 08:56 PM..
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