Constant Throttle = MASS MPG

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I had been anxiously awaiting trying my new throttle cable out and seeing what effect it had on my MPG.

I left Atlanta on Halloween at about 9:00am heading to La. I set my throttle cable to hold 60 MPH on level ground. I would hit hit about 70 MPH going down hills and slow to 50 climbing them. It took some discipline not to give any throttle as I slowed when climbing hills and more than one 18 wheeler got ****** at me.

I started to get real excited outside of Mobile because I had been 400 miles and my needle was dead on half a tank. I made it to my home town and the odometer showed 509. The odometer is right on the money less than 3/10ths off after 100 miles against mile markers.

I didnt diesel up then becuase I wanted the diesel to be cold because I didnt think I would get a true reading if it was hot from the trip. I was stunned to see the next morning that it only took 20 gallons. That comes out to 25. 5 MPG. That is crazy mileage for a 7100 lb truck. I told all my Uncles who have powerechokes and I know it made them sick.

I wish I had a reg crusie to see how much better my constant throttle would be than cruise but I dont; oh well. I am really proud of my truck I wish I didnt have to post my next post about it shuddering everytime I hit a bump.

That Cummins just purrs on the Highway gota love it.

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2001 ETH/DEE ST 4X4 SPACE SHUTTLE

 

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No surprise there, thats how I have been averaging 19mpg doing 75mph. I just allow a bit of leeway speed wise and the MPG climbs.

Crazy, isn't it?


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Y2K 2500 QC Sport 4x4 LWB
72 Dart 340
89 LeBaron GTC 2. 2 TI

 

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Cool... I wish I could keep my foot out of it like you #ad
I know the incredible mileage is in there, It just feels too good rolling on all that torque #ad
Good experiment!

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2001 HO 6 speed Regular Cab SLT 4x4 3. 54 anti spin 2500. Used for the daily grind and sneaking away to some secret Baja beaches toting a cabover

 

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You can adjust your speed #ad
I thought there is only two settings for the Go Pedal OFF & ON #ad


[This message has been edited by KWIKKURT (edited 11-06-2000). ]

 

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I tried much the same experiment with my cruise set at 65 though the flats of the plains on I-80. 758 miles from Cheyenne WY to Des Moines IW with one stop in the middle,still had a little less than a quarter tank to go. Put in 27 gallons in DM for a mpg of 28. 07. Speedo is right on,get this though,it's a AT 4x4!Of course it is a 12 valve!I think at 60 mph I could of got over 30 mpg!

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95' 25004X4,AT,Driftwood,Banks,Warn fender flairs and running boards(Play truck)95 3500,5 speed,driftwood,Banks&phscotty,34,000 GCVW apple and tractor hauler(work truck)

 

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Originally posted by illflem:
I tried much the same experiment with my cruise set at 65 though the flats of the plains on I-80. 758 miles from Cheyenne WY to Des Moines IW with one stop in the middle,still had a little less than a quarter tank to go. Put in 27 gallons in DM for a mpg of 28. 07. Speedo is right on,get this though,it's a AT 4x4!Of course it is a 12 valve!I think at 60 mph I could of got over 30 mpg!

The question is what kind of mileage would you have got if you werent using that inefficient cruise and instead a constant throttle control. You might have gotten 30 at a 65 setting on level ground

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2001 ETH/DEE ST 4X4 SPACE SHUTTLE

 

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jsonder,I'm sure you're right,maybe even get up to 35 mpg. Only problem is that I lack the patence to drop below the speed limit for even a minute. By watching the boost pressure with the CC on flat land you can see that the fueling is varieing all the time. I feel that the CC will get you better mileage than using your foot to control speed.

 

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Originally posted by illflem:
jsonder,I'm sure you're right,maybe even get up to 35 mpg. Only problem is that I lack the patence to drop below the speed limit for even a minute. By watching the boost pressure with the CC on flat land you can see that the fueling is varieing all the time. I feel that the CC will get you better mileage than using your foot to control speed.

I agree using your foot would be worse unless you were very very good at holding it constant then the next best would be CC and I beleive the very best would be a throttle cable like I used and incidentally now i am jealous of 12 valvers again although i lost tha jealousy for awhile when I got 25. 5 but I wonder what a 12 valve could do with a throttle cable at say 50 MPH. Do you think it could break 30?!?!?!? That would be awesome

 

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jponder,I think a 2wd 5 speed 12 valve with 3. 54 rear end,free flowing air filter,enlarged exaust with no cat or muffler,will get over 25mpg empty if you don't stomp on it or drive over 70. Add a throttle cable and you will probibly be good for at least 5 mpg,slow down to 50 maybe 5+ more. It would be interesting to see how many mpgs you could wring out of one of these rigs,I think 40 mpg is not out of the question though.

 

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Hi jponder! I stumbled on to this phenomenon quite by accident some months ago. My transmission and torque converter were going away quickly while pulling my race trailer, but I had to get through a few more weekends before I could get to Ted J's place for repairs. To minimize slippage, I would hold my throttle as constant as possible, maybe even letting out a little, so as to not have the transmission "kick down" to try and maitain speed. My mileage sky rocketed. I gained as much as 5 mpg while pulling my 8,000 lb trailer. That got me to wondering why someone doesn't invent a throttle control mode as well as cruise control. You're right, vehicles overtaking you aren't happy with your wide variations in speed up and down hills, but mpg is mpg!

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'99 Black QC Dually 3500, 3. 54, auto, K&N, VA Box, JRE 4" exhaust with 5" Monster tip, boost & EGT gauges on "A" pillar, silencer ring removed, Cragar Aluminum wheels, mud flaps all around, stainless bed rail guards, Pendaliner bed-liner, custom 12" truck box, Cobra 75WXST model remote CB, ProTorque Converter, Shift Kit, Pressure Lock & Transmission by Frank!

 

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illflem> okay i think we can get some insane mileage out of our rigs with slow constant throttle cruise but I think 40 is really stretching it but I wonder what a turbo Jetta which claims 50 MPG would do at 45 MPH and a constant throttle on the interstate would do. I really do want an old beat up 12 valver though. I hope I can just find one where the person doesnt know how special that baby is.

Megaram> you know I stumbled on this when I was a kid(37 now). I used to sell papers as aboy and i geuss it was in the 70s when we got hit with the embargo or whatever it was anyway our local editor was doing a story on how you save gas, His name was Bill Irwin and he was the editor of the Tangi Talk, anyway he said the maximum mileage you could get was by holding your throttle constant. He talked about how it was hard when he was on the interstate going 40 MPH up a hill but he said that it was true and you know what ! IT IS. IHis son was my best friend and I thought he was cool beans because when we would go sailing he would do this and we LIKED IT!!!!!

 

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Hey JPonder,

Where are you from? Sounds like you are a lost and lonesome Louisiana boy.

Interesting stuff on your truck and mpg. . With all the computerized gizmos people invent is seems like they could make a device that worked off of the TPS instead of the speedo. Also it would be nice in the stock design of the CC, if you could set a range of say +/- 3 mph before the fuel and boost would kick in or out. It would be even cooler if you had a key pad to adjust these to your personal taste. My CC is just to **** sensitive. **** when I run over an ant the turbo spools up.

Anyway, enough of this wishing for something I can't have. Got to go now and vote for Ole GW and cancel a vote for ***** (aarrgh, oops. ), I mean Gore.

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2001 ,2500 ST Light Driftwood QC,LB,ETH,6 speed,3. 54 LS, LT265/75R16, TrTGr, Smoothie, Step Sheilds, C. Crane Truck Antenna, Line-X bedliner and rocker panels.

[This message has been edited by Cocahoe (edited 11-07-2000). ]

 

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JPonder,this may be something for the injection pump experts to comment on but here goes. All my diesel tractors have basicly a thottle cable set up,you set the rpm and it stays there. I mean it really stays there,no matter if you're going up or down hill or pulling through hard ground. No electronics are involved,throttle position is fixed. Could it be an internal governor in the pump?That's what we need for great mpg.

 

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Nah, not gonna get 40 mpg. I plugged 0 mph into my handy-dandy gas mileage formula, mpg goes way up, but only to 36 mpg. Of course, you don't really have to drive 0 mph; all you have to do is go 45 mph with a 45 mph tailwind. #ad


But hey guys - gotta say this: The things that "**** off" the other drivers, could also result in road rage (with you as the victim), or even an accident. Please be careful!

 

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Cocahoe> I was born in The Baton Rouge general and went to school in Baton Rouge and also Amite. Amite is where all my family is. I was sitting in Tiger Stadium on sat and boy was it rockin. Alan Reagan was talking about have your throttle set electronically. A cruise that would let your mileage change X MPH beffore it kicked in would be cool. It would be a hybrid between pure constant throttle and constant velocity CC. I want Maximum mileage and dont mind going a liuttle slower so Constant throttle is good for me.

Ifflem> EXACTLY a throttle control from a tractor is exactly how out throttle control should work for maximum mileage. Wait a minute I just read your post again and you dont want to mantain contant RPM because then you will get engine breaking when going down a hill and your engine will add fuel climbing a hill this is the same as reg CC. You want to hold throttle in one position and let speed vary ovey terrain for max mileage. I geuus it is governed kinda like a lawn mower. I dont really know how though

 

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If I'm not mistaken, JCWhitney used to sell a mechanical "poor man's cruise control". It was just a cable lock that disconnected itself when you hit the brake. I have not seen it in the catalog in a while. I'd love to try one. I'm in flat country, it'd be perfect.

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'96 Regular Cab, 113. 5K, SLT 2WD auto 3. 54, Vista topper, Pillar-mounted Autometer Boost/Pyro, transmission temp and oil pressure guages under dash, starwheel spun

 

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I went to Baltimore last weekend. 340 miles round trip. 65-85 MPH. Many tolls, and people screwing up the cruise control.
It took 15 gallons. Thats 22. 6 MPG.
I fill out of 5 gal cans, so I know it may not be exact. Even figuring say... . 15. 5 gals, I still got just under 22 MPG !!!!
This isnt too bad concidering the tires are all but bald, and it was probibally further than it actually clocked on the odometer.
I'm real dam happy.

 

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Oh yea, FYI if you take a long trip, the fuel needle moves much slower. I think it has a damper built in. I've already gone 450 miles, and had 1/2 tank. LOL!! #ad
#ad

Another 150 miles down the road, and I had my fuel light on. #ad

Reason I think there is a damper (or some sort of buffer) in the tank is, if you fuel up with the engine running, it could be full, but it might not actually read full until you shut off the eng and re start.
Just my experience.....
illflem, what do you think you'd get if you got an OD unit, and propane??
28?????
I'm jealous!!!

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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. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 59,000 Mi as of 10/21/00.
NRA life member. High power/IDPA.

 

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patriot,a propane unit would probibly up your mpg a bit but I think your $ per mile would go up or remain the same. If you can get your desired highway speed at say 1600 rpm your fuel economy would have to go up. You could do it with a OD unit,3. 09 rearend or even bigger tires. These are the the types of mods,along with dropping some weight, I was thinking of when I said you might squeeze 40 out of a CTD. Other things you could do would be to lose the fan,AC,spare tire,one battery,rear bumper,trailer hitch and 20 gallons of fuel. All this is just in the quest for high mpg,I'm not saying it's practical,with these type of mods you wouldn't be able to tow anything and your truck would lose alot of it's zip. Same with a fixed throttle cable,it's not really practical and is downright dangerous.

 

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Yea, I'd love to get the OD. I saw on a post about a week ago, some guy with one, when he was going 75, the RPM was at 1600. #ad

I know the CTD will take it, but it hurts to hear it winding that high in the RPM's that long.
My class 8 never went over 2200 RPM's. Old habits die hard.
Money is tight now. It'll have to wait.