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Discussion Starter · #23 ·
I’d like to get into the 30s. Haven’t played with any tweaks yet, and I’m also not sure my setup will allow it. Other than shifting through the gears quickly, I like it.
 

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DAVE DO YOU KNOW WHAT GEAR YOUR REAR Axle is .
... I HAD AN OLD 1982 OLD'S diesel & It got 32 mpg.
I Loved it but It'd not pass a freight train.
............
......& Again My 2000 24V is the worst I've ever dealt with .
 

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Getting a 4bt into the 30's MPG will be very difficult. We've only seen a very few who have achieved that. Vehicle will need to be light weight and aerodynamic. 25 MPG is a good average. You can't drive 65-70 on the interstate and expect 30 MPG. I read an article on a Dodge 5.9 dually where a magazine did a test to see how good they could get it. No ac on, windows rolled up, body seams taped, grille covered, outside mirrors removed, and tailgate down. No speed over 55 MPH and they managed to break the 30 MPG barrier. If you can drive and keep the engine speed in the 1600-1800 RPM range you might have a chance.
 

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Char good post.... That the 1st time I've anyone agree with me. Our diesels get much better mileage than Gas ride but ...Most won't get 30.
..... Back when I 1st joined this group. Mine wasn't even built yet. & Some cat on here was telling how he was getting in the low 30's. Come to find out after about 6 months .. His truck wasn't even built yet. His was just just B/S OR Speculation..
Funny He didn't stay on here long after the Guys found out his wasn't finished yet.
............ But my little gas Bronco got about 4 mpg on my farm. & It got very hot in about 20 minutes .
My Bronco with the 4BT Doesn't get hot & if it does I have an electric fan I can flip on & cool it down in about 2 minutes . FROM 205 Down to maybe 140. Then it'll take about 5 to 10 minutes to get back up to over 200.
I don't even run a fan blade on mine no room for it . Just the pulley & Belt .
..... But I feel I get about 11 mpg most of the time .. If I can get a little highway time it goes up to maybe 16. But Since I use mine 99% of the time on the farm . & in 4 wheel drive at 4 mile per hour or Idling looking at cows. I think my 10 or 11 is great It's more than twice my gas.
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................ I just wish I could improve this 24 V 2000 YEAR MODEL W/ Automatic trans.
 

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Discussion Starter · #27 ·
I don’t expect to get 30, especially at 70mph. I’m happy with the 25ish I get rolling 33” tires. I used to be happy with the 12mpg after my efi build, and I think once I change the differentials, I’ll have it dialed in. Thanks for the advice on the ratios. Tires have been changed since this photo.
131194
 

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Discussion Starter · #29 ·
I’ll definitely be changing the ratio, it won’t be for a couple months at least though. Summer trips and whatnot.
 

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Papitt, I've driven most varieties of gas engine vehicles since I was 8 years old. Back then it was the farm tractor. Feet couldn't quite reach the pedals on the cars and trucks. LOL. I've driven cars from 90HP to near 400 HP so I know all types of performance. Got into diesels in the 1970's. Considered a Dodge with the Mitsubishi 6 but that one was an absolute dog in performance. Looked at the diesel Scout, VW Rabbit, and Mercedes. My income couldn't quite afford that last one. Ended up with a Peugeot 504D which was a fine car. I learned with diesels just be patient and you'll get there just as fast as the guy with the jack rabbit starts. Never purchased another gas car or truck after 1979.
 

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Torch, I’ll be the guinea pig on this one, I just re-installed my 3rd member with 3:25’s going from 3:89s. I’m off this Saturday and my plan is to run it on the highway up a 7% grade (Cuesta Grade on the 101) and see how she does. A quick run into town to pick up my kid from school is all I’ve got so far, never saw 5th and the taller gears felt great.




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Discussion Starter · #33 ·
3.25’s? How does first gear feel? I don’t do any crawling so I’m not worried about that too much. Right now I feel like everything is almost one year off. I’m in 5th gear by the time I hit 45. What trans are you running?
 

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Papit yep it’s a 4bt. Torch I’m in the same boat as you not too much crawling at least not yet. I’m running an NV4500. If I decide I want to get more into crawling I’ll just drop the transfer case and go with a reduction gear set for the low range.



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Torch I originally had 4:11s(stock gear set open carrier) I was ripping through gears just to get to 45mph like you are. I then went to 3:89s with a truetrak just to be able to get up to speed on the freeway. I could get to 65-70 but it didn’t feel like the engine had much left if I wanted to pass or just cruise at 70. After a lot of consideration I just desided to jump to the 3:25s Instead of baby stepping down again to 3:75s or 3:55s(gears are expensive). The one drive I’ve done with the 3:25s so far I was really happy and it felt like I was actually able to utilize the torque and boost with the taller gears.


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1995 Bronco XLT, 4WD, 4BT-ZF5
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My Bronco has 3.55 gears and the 4bt easily pushes over 80mph and also plenty of grunt off the line. I definitely wouldn’t want 4.11 gears.
 

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My Bronco has 3.55 gears and the 4bt easily pushes over 80mph and also plenty of grunt off the line. I definitely wouldn’t want 4.11 gears.
My Bronco has 3.55 gears and the 4bt easily pushes over 80mph and also plenty of grunt off the line. I definitely wouldn’t want 4.11 gears.
the early bronco dana 30,s came with 3.50 as did the 9 inch.. as far as mixing 3.54 and 3.50 gears, not a problem at all..
 

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WOW are there at least 4 of us on here with 4BT's in our Early BRONCO.
... i DON'T BELIEVE THERE ARE THIS MANY ON THE classicbroncos.com & There are a lot more members over there .
I need to get all you Bronco Guys To where I know you in case any of us have questions.
 
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