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that-son

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so i was a little disappointed to find i only got 15mpg ( mostly city) when i filled up the truck.  that was after changing my driving habits.  used to shift gears right at 3500 rpm but now do it before 3000 rpm.  i thought it was a little better than the 12 i used to get but still...  anyway, i still haven't taken care of the spinning speedometer issue plus the 235 75r15 is not the stock tire size  so i thought maybe the odometer was off.  followed my wife around town the other day and sure enough the odometer was consistently off by 28%!  point a to b... reads more by 28%... point b to c...  point c to d...  you get the picture.  total distance traveled... also 28% more.  so after doing a little math i came up with 20.34 mpg.  not bad for a 33 yr. old truck! 

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Where do you think we should shift for best mpg's Mike?

 

is there a formula to figure out when to best shift? 

 

forgot to mention, that mpg figure was before timing was fianlly properly adjusted.  i'm hoping i'll do even better now.

 

still haven't had it smogged though cause now i need new spark plug wires.  was gonna take it the other day but stuff kept breaking.  fianlly got it all good to go when it started missing.  tracked it down to the intake wire for cylinder 1.  oh well.

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hey justin theres some factors to take in consideration for shifting for the best mpgs, like are you running a stock or after market carb, diff gear ratios, tire/rim size, electric or manual fan clutch, proper timing, proper engine temp. things like that. i know some of the things listed may not seem like it but every little detail counts

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If you want good mileage, your going to have to drive under 60mph, and your going to have to drive like you have a glass of water on your console that is filled to near the top, and you cannot spill a drop, like when your driving a limo, you should not even be able to feel shifting gears.

You also need to be driving way ahead of yourself, if you see a light turning red, you let off the gas and coast till you get the green light again, if you have to touch the brakes, you fail.

Getting really good mileage is an art, and don't expect to get anywhere fast, I will kick your ass in a hundred mile trip time wise, as I can't drive 55mph, I will likely get there an half an hour ahead of you, but I will only get 27-29mpg in the diesel, the question is, what is your time worth.

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I tried driving 65 mph in my 2008 f350 king cab long bed 4wd diesel truck and only improved mileage less than 1 mpg 

truck likes to cruise between 70 and 80 doesent downshift on hills like when driving 60 to 65 but pulls 4 to 5 lbs of boost constantly 

if I pull a hard hill the boost will sometimes go up to 40lbs regardless of my pedal position, it takes what it needs 

 

in my 510 Rebello built L20b pumped to a 2150 with dual dcoe 40mm webers I get around 17 up or down a bit depending on my foot and yes the carbs are tuned a bit rich 

in my 73 1200 coupe stock a12 with a 3236 weber gets around 25 no matter how I drive it and up to 30 when the wife drives it 

my 05 350z gets 17 to 20 around town and havent done long freeway trips yet to see 

BUT ITS HARD TO DRIVE IT WITH A NICE FOOT 

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is there a formula to figure out when to best shift? 

 

 

 

Not really. You still have to share the road with others and can't hold them up. Drive in the slow lane or keep left when possible. Just going slightly above the speed limit can work wonders for mileage. If alone on the highway you could go slightly slower but this has it's own dangers from speeders over taking you if you don't watch out for them.  No sudden speed changes. You don't want to lug the motor when up shifting. My L20B pulls really well if the shift is followed by 1,800 RPMs in the next gear. Try not to excede 2,500 in any gear. The Z 24 has an abundance of torque so use it. This is again subject to holding up others who want to go faster. My 710 gave about 30 MPG US last year going to Canby but this was staying at the speed limit and only on one tank (which is hard to do when having fun driving) the other tanks wer inhigh 20s.

 

As wayno said... every time you touch the brake you are throwing away the gas you used to get to the speed you are at. Anticipate... watch ahead... don't follow so closely... really? what's the rush anyway?... don't get mad or anxious... leave sooner.

 

Empty out the bed of junk. EVERYTHING uses gas to accelerate up to speed. How many times has that lawnmower in the back been to town and back????

Check the tire pressure and run as close to safe maximum

Alignment?

Gas leak? Carb working? engine in tune?

Make one trip count.

Don't 'warm up motor' Start, put on seat belt and drive.

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I understand why you say don't warm up the engine Dmike, as it is burning gas, but I have found that every engine I ever owned lasted way longer if it was warmed up before driving.

I had one car that I pumped the gas once and started it, it went to fast idle and ran fine if I did not touch the gas, if I touched the gas pedal before it was warmed up it would inevitably die, and then it would not start again no matter how long I turned it over, I would have to let it sit for half an hour and then hit the gas once and it would start up, now once warmed up I could hit the pedal and it would idle fine.

That engine never burnt a quart of oil the whole time I owned it, the oil stayed a golden color even after one time I put 6000 miles on it in less than 2 months, normally I changed it every 3000 miles, but at 6000 miles it needed a quart of oil, but I changed the oil instead.

Now the reason I said all this was because I put over 100,000 miles on that engine in less than 5 years, and I never added a quart of oil to it the whole time I owned it, but I had to wait till it was warmed up before driving it, or I would not be driving it at all, I learned real quick to not touch that pedal till it was warmed up.

I believe that engines last longer if warmed up before driving them.

BTW, I beat the shit out of that engine after it was broke in, the only thing that ever happened was that I lost the timing belt at about 80,000 miles, but I guess they were known for loosing them at about that mileage.

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Wayno I think they come from the factory ready to drive. If they all stalled when you touch the gas they wouldn't sell or be kept. I start my 710 and it goes to slightly fast idle and I back out and drive one block to a stop sign. Pulls away perfectly and drives for 4 or 5 blocks to a stop at the highway. Drives smooth and pulls evenly and firm in all gears.

 

I agree the wear once warm is almost zero so I never 'give'er' until warmed up. It warms up quicker when driven. Way quicker. It's a personal preference to warm it up sitting or driving it, but I expect the gas engine to be ready when I am. I have had poorly set up carbs and chokes that were balky and rough until warmed up but this isn't the case here. My 710 automatic is the same. Fire up and put in gear step on gas and it drives away smoothly.

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I have an 86 2WD King Cab Z24 5 speed Weber DGEV 32/36 with a little over 300,000 miles on it that gets a constant 28 MPG in town and constant 30 MPG on the highway at 85 MPH.  I drive it like I stole it!  LOL

 

I ordered my Weber from Peirce Manifolds.  Deleted all the smog except EGR.  Running Distributor vacuum from the carb port and also still have the charcoal canister in place.

 

The thing I found out after running the Weber for a while was that I needed to use the stock fuel return "Y" (Metal piping).  The return side of this pipe is restricted (metered orifice) to cause a steady fuel pressure at the carb.  I am running the little rectangular air filter.  I deleted the A B valves and also the 3 port vacuum switch on the intake manifold.  My truck was California emissioned from the factory.

 

I also had to install a throttle return spring to get the carb to idle back when letting off the throttle.  I can set the idle as low as I want now but I set it to about 750 in the winter and 900 in summer when running the AC.

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I have an 86 2WD King Cab Z24 5 speed Weber DGEV 32/36 with a little over 300,000 miles on it that gets a constant 28 MPG in town and constant 30 MPG on the highway at 85 MPH.  I drive it like I stole it!  LOL

 

I ordered my Weber from Peirce Manifolds.  Deleted all the smog except EGR.  Running Distributor vacuum from the carb port and also still have the charcoal canister in place.

 

The thing I found out after running the Weber for a while was that I needed to use the stock fuel return "Y" (Metal piping).  The return side of this pipe is restricted (metered orifice) to cause a steady fuel pressure at the carb.  I am running the little rectangular air filter.  I deleted the A B valves and also the 3 port vacuum switch on the intake manifold.  My truck was California emissioned from the factory.

 

I also had to install a throttle return spring to get the carb to idle back when letting off the throttle.  I can set the idle as low as I want now but I set it to about 750 in the winter and 900 in summer when running the AC.

I'm jealous of your gas mileage! I was feeling good about getting my l20b up to 23mpg, but 30? Nice work. 

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how about a tutorial on rejetting?  or is that part of rebuilding the carburetor?

 

i remember posting on an older thread about carbs from national...  maybe i forgot to hit the post button. 

 

i'm actually excited to install this new speedometer cable i ordered.  will have to look for that post about calibrating or regearing when i get the package.  the mpg's i posted were all pre-tune up.  so we'll see how i do now that it's running properly...

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oh, and i am familiar with the finer points of hypermiling.  my bumper sticker says... i may be slow but i'm ahead of you.  kidding... there's no sticker on the bumper.  it's on the gate!

 

the only thing in my bed is some 50' of nylon rope.  let's keep it clean people.

 

i do need a bumper and i think i'm inspired by 84720fourwheel's post.  might even throw in a hitch receiver in there.  oh and a diy roll bar.  we'll see...

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A tip for mounting the bumper, cut the ends at an angle so you can access the bolts, I'll get some pics for you. If you choose to do it how I did, you will need to wire up some new reverse lights or cut a few holes in the bumper to accommodate the OEM ones. I just got some stick on LEDs but they don't work too well. They light up everything at knee level, and not the ground behind me.

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