does anyone have one?
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Joined: Jan 2007
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From: shawnee KS
I have done everything short of buying aftermarket risers and/or manifolds to beg this Bronco to get better than 9 mpg. I bought an 84 for parts and put the motor out of it into it now and I'm getting 13 mpg with twice as much power (also all emissions removed). I drove the Bronco one day on that tank of fuel, and also tweeked and tuned on it all week too, so 13 is kind of a rough figure. I now have it tuned where I am happy with it, and I'm hoping for 15 mpg but I'd be happy with 14. What are you fellas getting out of yours? I figure the truck weighs around 46 to 4700 pounds and I am running 31x10.50x15's that aren't really aggressive. Thanks for any input. At 60 miles round trip to work daily, 9 was killin me, 13 is a good start, but I'd really like to see better. Oh by the way, it is a 4 spd OD manual tranny.
I'll have the Roast Duck
Joined: Jul 2002
Posts: 9,622
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From: Northshore, MN
I got mine off of a mid seventies pickup. But going non egr, means to switch to a non advance distr. (well, technically you don't have to, but you'll get a miss on accel.)
I get 13 mpg in my '79 bronco with 300, C6, np203 fulltime 4x4, 3.50 gears, 31" tires, and going no faster than 60 mph....oh, and a leaking gas tank.
I get 13 mpg in my '79 bronco with 300, C6, np203 fulltime 4x4, 3.50 gears, 31" tires, and going no faster than 60 mph....oh, and a leaking gas tank.
Last edited by havi; Sep 28, 2007 at 09:01 PM.
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Posting Guru
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From: shawnee KS
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I'll have the Roast Duck
Joined: Jul 2002
Posts: 9,622
Likes: 110
From: Northshore, MN
Well, my 300 is an '86 with the original intake, '89 efi exhaust, walker downpipe, duraspark dist. and ignition, and '78 yf carb and spacer.
the spacer is a simple piece of aluminum with the hole in the center, and the 2 bolt holes.
the spacer is a simple piece of aluminum with the hole in the center, and the 2 bolt holes.
Last edited by havi; Sep 28, 2007 at 09:50 PM.
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Joined: Jan 2007
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From: shawnee KS
I wondered if a guy couldn't just make that riser with a chunk of aluminum, but wasn't sure how to do the intake hole shape wise. Straight bore, some sort of taper, hourglass maybe? I'm pretty good at wrenchin on stuff but I think that may be a little above my capabilities.
What is different about the efi exhaust, and is the walker downpipe any different than the stock one was? I don't mean to be a pain but it sounds to me as if you've been through it and know quite a bit about it.
What is different about the efi exhaust, and is the walker downpipe any different than the stock one was? I don't mean to be a pain but it sounds to me as if you've been through it and know quite a bit about it.
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Joined: Jan 2007
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From: shawnee KS
Thanks a million havi- I'm takin the 84 to the scrapyard in the morning, then doing a little gradework in the uniloader, then I'll start reseaching this. I really think I can beat 15mpg with this motor, it just may take me awhile, and probly some money.
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Joined: Nov 2004
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From: sunny fla sometimes windy
What gear ratio are you running, If the motor isn't in it's sweet spot, you will get crappy mileage!! That motor should get way better than that I get16-17 with a 302,auto,3:73 gears and 33x12.50 tires!! And that is not driving gingerly, Actually measure your tire diameter the sidewall isn't always correct!! And changing to carb on a Fi vehicle either by swapping in a older motor or swapping intake is a Federal thing
If D.O.T. was to pull you over you will get screwed!! And yes they will pull over passenger vehicles, I know someone whose diesel truck smoked alot because he had
mods and it really was burning too rich, The dot guy ran his fuel to see if it was off road fuel he was burning!!
If D.O.T. was to pull you over you will get screwed!! And yes they will pull over passenger vehicles, I know someone whose diesel truck smoked alot because he had
mods and it really was burning too rich, The dot guy ran his fuel to see if it was off road fuel he was burning!!