99 Chevy 3500 HD (CK) 6.5 to dmax

gone from 9mpg to 12.5mpg avg... best i have seen is 14 when towing. thats the best i got with with no trailer nad the 6.5.
this heat wave as killed it down to about 10.5mpg.. looking at putting a bigger fuel cooler on the return line where majority of the fuel heat comes from.

only real issue i have was power supply to the lift pump asnd the fuel pump balance control module. it would through a p0087 low rail pressure code. got it fixed and put on a 2 micron fuel filter as well.
i have put in a 60gl saddle tank and removed the main tank.. then aux will be gone shortly.. PO welded the reciver hitch into the skid plate mount on the tank..
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malibu795 said:
dont forget about the 3000 or 4000 series allisons.
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We just discussed it :D 3000 series would be workable, although I think it's unnecessary in a pickup-sized vehicle. 4000 is far too large - although you don't have to worry about exceeding it's gross combined weight rating, since it doesn't have one. Allison lists the GCW for the 4000 series as "unlimited" :p
 
MaxPF said:
Heya Luke! Speaking of wretched excess, how is that project of yours coming along?
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Which one?!? LOL!

Actually what I'd really like to do is put an HT750 in my cabover, and put the 13spd double over from that in my superduty.........

Sent from my HTC Desire HD A9191 using Tapatalk 2
 
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any updates, pix of the saddle tank?? and one more thing are you using the 6.5 fan shroud, if not want to sell it I just broke the one I modified.. and HD shrouds are taller than regular ones... found out after I went and got one...
 
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6.5 shroud no i didnt use it.. i think its long gone to trash.. the HD radiators are ALOT bigger then the non HD trucks as well. the core is identical to the Dmax rad core.

did upgrade rear brake calipers.. wrecker package came with dual 2.6" piston vs the big single every one else got.. also replace the master cylinder had alot of sediment in the resivor cleaned it out.. wasnt sure if the lip seals on then MC were chewed up so i replaced it out of safe of mind and the system was open and the fluid was black...

caliper AZ part number C595 and will work for all 4 spots both the bleed hole and banjo bolt are M10x1.5. brake pads are the same F/R even though the rear rotor is .3" smaller diameter
MC is M2574 JF9 brake systems..
the regular 3500 ran JB8 disc/drum and a 1.25" bore ours is a disc/disc and a 1.574"(40mm) bore just be mindful..

on the saddle tank..i mounted it on the crossmembers between the frame rails right behind the cab. more then doubled my range went from then twin tank 22/18 and a useable ~30gl (280-330 miles)to ~55 useable and over 600 miles range
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been avg good 11.5-12mpg if i stay under 2400rpm/68mph brake upgrade is outstanding.. with just the dual piston in the back truck stops harder then the trailer with controller maxed out. front is getting the same calibers

manage to short the supply side to my 800w invertor. melted every 10ga ground from frame/body to bat and arc'd holes in both my fuel line and tranny line while going to the engine which has 2/0 cables to both bats. and natually it shorted before my 100a fuse :bang talking short 6" from the bat and fuse now was a 2" lead on it.. nice thing i was 10 mile form summit racing in akron. 275 tow bill and got myself up and running
coming up on 10,000 miles havent gotten custom ac lines to hook the condenser up yet.. then run the signal/control wire for then a/c relay through the HP/LP switches and a/c will be working
it is very nice to have a 600mile range
 
Nice mileage considering what you are towing,

I may want to add a fuse back by the battery's . Mine are in the side box on the bed, I used 175 amp to protect the alt and 150 for my grid heaters.

My a/c was done local, 200 for custom lines and I charged it. A bit of advice replace everything in the system. When you do it especially the evaporator in the dash and the accumilator.. Mine caused me fits as the fitting on the evaporator wouldn't seal to the new accumilator, Ranchu is a local auto a/c where house but they ship everywhere and even with a brand new factory compressor mine was less than a grand. That was replacing the whole system..

Thanks for the update and good luck..
 
found week link in drivetrain.. the flywheel became collateral damage though.. put in a new FW and allison flexplate
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well if your going to own it....then you can have it back!! lol

i havent have a single hiccup out of this 4l80E

borrowed a 04 CC 3500 dodge dually to finish delivery of the load.. ride quality about the same.. nose is really light when loaded nois raised when you acceled and drove badly when brakeing.. most like ball location mine is ~2" above the tires when loaded vs the 6-8 this dodge was..
, didnt pull grades or start out ro stop nearly as nice at mine does and got worse mpg.. on the DIC and the owner said hand cal is less then that!!! had 9,000lb of lumber on the trailer
 
posted a link to this over on 3500hd.com you may get some more questions, some good guys on there with alot of info..

just wondering how many miles you are up to with this combo?
 
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