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Old 12-02-2016, 07:05 AM   #16 (permalink)
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Join Date: Dec 2014
Location: Butte, Montana
Posts: 714

little jona - '91 Dodge D 250 first gen cummins LE
Team Streamliner
90 day: 23.4 mpg (US)

Little Jona airo modded - '91 Dodge RAM 3/4 TON D 250 2×4 AUTO
Team Cummins
90 day: 18.5 mpg (US)

The Salted Hound Jenny. - '87 Dodge Ram 50/D-50 5sp 4X4
90 day: 20.24 mpg (US)

Jona Allison aero - '91 Dodge Ram D-250 Le
90 day: 21.86 mpg (US)
Thanks: 206
Thanked 416 Times in 269 Posts
Install an EGT (ehxsost gas temperature) gage with a "fast response "prob . Then apply target Egt technique similar todriving with a Vacuum gage except yout target is the lowest temperature to maintain speed instead of the highest Vacuum . For my 1st gen cummins its about 500°f on flats 600 Med grade 700f heavy and 800 for major aka 7%and up ,all at 65-60mph (my trans will not hold OD above 800° below 60mph).
Some times on a grade as the rpm drop the EGT will rise 50-100°f with no change in throttle. in theas situations back off the throttle and maintain your EGT set point . I recommend the "fast response " because with my truck the needle moves at the same speed and ratio as my foot.
Just reducing the pressure but not the position will sometimes result in a 25-50°drop and will cause acceleration. Dont understand the physics behind it ,but it works.
I think the region should show up on the EGT gageas well .
1st gen cummins 91.5 dodge d250 ,HX35W/12/6 QSV
ehxsost manafulld wrap, Aero Tonto
best tank: distance 649gps mi 24.04 mpg 27.011usg
Best mpg : 31.32mpg 100mi 3.193 USG 5/2/20

'83 GMC S-15 Jimmy 2door 2wd O/D auto 3.73R&P
'79 Chevy K20 4X4 350ci 400hp msd custom th400 /np205. 7.5-new 14mpg modded befor modding was a thing
87' Hyundai Excel
83 ranger w/87 2.9 L FI2wd auto 18mpg on the floor
04 Mitsubishi Gallant 2.4L auto 26mpg
06 Subaru Forrester XT(WRX PACKAGE) MT AWD Turbocharged 18 plying dirty best of 26mpg@70mph
95Chevy Blazer 4x4 auto 14-18mpg
04 Chevy Blazer 4x4 auto 16-22mpg

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