Modifications to increase MPG

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As the cost of diesel continues to rise for no good reason, the idea of squeezing every mile out of every gallon is getting high on my list of stuff to think about.

Does anyone have any ideas about how to increase MPG?

Besides a 'free breathing' intake and exhaust, any other suggestions.



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Gregor Switca
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Torque is a beautiful thing

 

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No stomping on the pedal and keeping it under 2000 rpm will do more good than any mod.

 

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Amen Bill,

Works for me, but sure isn't as much fun!

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

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I wasn't very happy with the mileage or power of my '97. In Feb. we took a trip to Southern Texas pulling an enclosed Harley trailer 70 miles per hour. I got an average of 12. 5 m. p. g. With help from this board, I added gauges and a TST torque plate. Wow! I've picked up a TON of power and gained a good 2 to 3 miles per gallon! THANKS TST!!!
My truck is a '97 dually with 5 speed, 3:54s, long box, club cab, sun visor, cab ext, 4WD, and bug deflectors so needless to say, it's not the most aerodynamic.

 

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Switca, if you read issue 29, it says that most mods will inc. your MPG so long as you drive it like you want MPG's.
I'd suggest to adjust the AFC to an "economy setting" to help. (if it's still stock, it's OK) I "fueled" mine up, but it hurt MPG's, so I came to a setting closer to stock. I now have very little smoke upon acceleration, good acceleration, and decent MPG's.
Oh yea, propane is supposed to help, but I don't know if it's worth it after the cost of the kit, and price of the propane itself.
It's a good enough excuse to BOMB though... .

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. 55,000 Mi as of 8/21/00.
NRA life member. High power/IDPA.

[This message has been edited by The patriot (edited 09-22-2000). ]

 

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Patriot:

I just joind TDR and I'm waiting for my first issue. I'll look into getting issue 29. Sounds like required reading.

"AFC to an 'economy setting'"

What's AFC? Like I said, I'm new here.

 

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What year is your truck? I'm only familiar with the 94-98 12 valve.
Kind of hard to describe here, but here goes:
On top of your fuel pump is a round plug with an 8mm hex head hole. Inside is a spring and screw arrangement. (kind of like a drum brake adjustment) If you get a screwdriver in there, and turn the screw towards the engine, it lessens the delay of fuel to the engine. (more fuel faster) This would be the adjustment for more power. It really doesnt affect the power per say, just the delay of delivery. Result will be less turbo lag, and if turned enough, smoke!
Turn it away from the eng. will be less power etc.
If the seal is not broke, I wouldnt mess with it, at least until you make other mods.
I have adjusted this for more MPG's, but WAS IT A DOG !!! I did get better mpg, but it ran like a Yugo.
Modest application of the right foot is your best MPG modification.

[This message has been edited by The patriot (edited 09-22-2000). ]

 

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Thanks Patriot.

The truck is a 96 4x4 regualr cab, with an automatic. Yeah, I know. I wanted a 5 speed, but wha are you gonna do.

I think I'll leave the AFC alone. If I wanted Yugo performance, I could got a Yugo, saved myself piles of $ and kept most of my driveway open.

Is there a dictionary or glossary at this site? I need to learn a whole new vocabluary.

[This message has been edited by Switca (edited 09-23-2000). ]

 

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Switca,what you need is a Dodge service manual,I think there is an order form with a 800 # in the back of your owners manual. As Joe G. says"they're a good deal at twice the price. "Even if you don't do your own work you can find out what certain repairs may involve so you won't be taken for a ride. Their also great for proper terminology for ordering parts or just understanding what's being said here.

 

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Ya can also check out the classified area, and probibally save about $50. 00.
Good luck with the new ride.

 

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I think if you keep your tires inflated close to the max, you get a little less rolling resistance. I've heard that the less aggressive type treads (hiway as opposed to mudders) get better mileage.
And if you clean that extra 1500 pounds of junk out of the back, it's bound to help.

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"Roadrunner"-96 4X4 club cab-12v-auto-3. 54 gears-Amsoil bypass filter - all Amsoil fluids-trans filter-britebox-shelfit-DeeZee boards-Rhino liner-Rancho 5 speed shocks-Hellwig rear antisway & overload springs-Warn 12000 lb. winch-dual redtop optimas-combo gauge and trans. temp gauge in pillar mount-255/85R16 Kelly MSR tires-custom pinstriping- Walker muffler-Cummins mudflaps-Tuff Country control arms-2" coil spacers

 

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gulp

 

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Clean fuel makes big difference. Add additives to keep it clean.
Get timing checked out
Check and adjust valves.
Install k/n air filter or any other performance filter will do. Free up your exhaust. Remember easy in easy out.
I usually will hit 400 miles on 1/2 a tank. Have pushed 750 miles with fuel light on and close to running out of fuel.

 

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Jeff H 750 miles on a tank of fuel???? Man i need to drive in your town i posted 12-14 mpg in the city i also have K&N - automatic with 3. 54 gears what is your secret??

[This message has been edited by RedNut (edited 09-25-2000). ]

 

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Mine hits 400 at the half-tank mark, but I've never pushed it,(no pun intended), beyond about 600 miles. #ad
Got a little nervous, then. I average 19. 8 on the last 3 tanks.

Funny thing about mileage in my truck: Drove round trip to San Antonio, (400 miles or so), at EXACTLY 70mph. Felt S-L-O-W! Only got 20. 5 mpg. Pretty close to my mileage on my commute, 80 mile RT, 75%highway traffic, 25% stop and go. Go figure. Sure don't act like my gasser. The gasser will darn near double it's mileage on a long 70mph trip. Not griping, just an observation. :d

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'96 Regular Cab, 110K, SLT, auto, 3. 54, Vista topper, Pillar-mounted Autometer Boost/Pyro, starwheel spun

 

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Originally posted by Jeff H:
Clean fuel makes big difference. Add additives to keep it clean.
Get timing checked out
Check and adjust valves.
Install k/n air filter or any other performance filter will do. Free up your exhaust.

Just had timing and valves adjusted.

NEVER use fuel from a gas station. Always go truck stops (except the one that sells Texacrap).

Been using Redline Diesel Catalyst in the VW since day 1. Both vehicles will switch to Amsoil conditioner and cetane boost when the Redline runs out.

Installed an Amsoil air cleaner, may go to a K&N. They flow better.

Short on cash, could not afford a 4" exhaust. I'll drop note to Santa Clause.



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Gregor Switca
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96 2500 4x4 auto SLT.
Torque is a beautiful thing

 

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I wonder if Jim G has an advantage over the 5 speeds. The auto transmission has a taller OD than the 5 speeds, I think. With 3:54, 245x75's, 70mph, 5th gear, I'm @ 2100rpm or so. I understand the auto OD is bunches lower rpm than that. #ad
These Cummins grunters are happily making max torque below 2k rpm, so no wonder the taller OD makes better mpg turning slower. #ad


As for the lower rolling resistance tires, I haven't seen it yet. I swapped out the 245x75's for 235x85's. Smaller contact patch with mother earth. #ad
70mph is now @ 2k rpm & the mileage is the same. 100 or so lower in rpm & skinnier tires didn't help. #ad
The speedo reads around 67mph or so when the beast is pushing air @ 70.

If I put the speedo back @ 70, the tach is back around 2100 rpm & the mileage drops about . 5 to 1 mpg. I chalk it up to wind resistance. With these tires & the speedo @ 70, I'm probably pushing air @ 74mph or so. Wind resistance wins.



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Money Sink - 96, 5 speed, Injectors, TST #11/280 slid to 340 position.
4" CAT back & CATless, 4" chrome turn down straight out back.
Stand back & listen to the turbo whine :-}~
ISSPRO Pillar, Delvac 1 & Amsiol, K&N, Monicas silencer ring removed, Exhaust brake, Mag-Hytec, 3:54, 235s.
HX35s days are numbered, HX40-16 is here.
Un-Bombed = Boring

 

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Switca,could it be your cats pluged up?Your truck's old enough and probibly has enough miles for this to be a problem if the cat hasn't been removed.

 

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illflem:

The cat is still there. Time and money were both short, so I replaced the muffler and tail pipe (both were shot, held together with wire, no duct tape) so I could get it registered. Best of all, the idiots at DMV never even looked muffler or tail pipe.

Is it effecting mileage? Not sure. Still working on that first tank of fuel. Is it clogged? I dont know. It's a little too late to get rid of it right now. But come spring time...