Bad millage
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Junior User
Joined: Jun 1999
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From: San Ysidro
Bad millage
Hi, i have a 87 bronco 302 2 barel carb , and c6
trans, and am concern that it just give about 9.5 MPG on city or highway,no matter if i drive fast or slow it still 9.5, and the engine have headers, no cat,flowmaster muffler,edelbrock crome air filter, 265/60 r15 tires on 8 inch wells, but still that bad MPG, before i have this engine i have a 4.9 L6 but that one does about 10.5 what's low for that engine either,does any body have any idea what could be wrong? i now a big truck have to sucks gas but i read about guy's having 11-13 MPG on the same engine or even more...please HELP!!
trans, and am concern that it just give about 9.5 MPG on city or highway,no matter if i drive fast or slow it still 9.5, and the engine have headers, no cat,flowmaster muffler,edelbrock crome air filter, 265/60 r15 tires on 8 inch wells, but still that bad MPG, before i have this engine i have a 4.9 L6 but that one does about 10.5 what's low for that engine either,does any body have any idea what could be wrong? i now a big truck have to sucks gas but i read about guy's having 11-13 MPG on the same engine or even more...please HELP!!
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From: saramento usa
Bad millage
I don't know what's wrong, but I used to get 17-21 mpg with my 300 I6 (21 was pretty rare, but 17 was common). I now get 10-11 around town with my brand new 351W (seems I've always got my foot in it) and 14 on the highway. What gears are you running in the tail (I have some wimpy 2.73s, great for mileage though).
Don't know what to say,
Slik
Don't know what to say,
Slik
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Bad millage
Slik
You must have either an 8.8" or 9" Ford rear axle. As far as I know they didn't even have an option of 2.73:1 ratio. But if they did,you are deffinitely not getting close to what your optimum performance should(or could)be. You should only be turning about 1900 RPM at 70 MPH without OD. Time for a gear ratio change if you want to really enjoy that Cherry engine set up.
Jeff
You must have either an 8.8" or 9" Ford rear axle. As far as I know they didn't even have an option of 2.73:1 ratio. But if they did,you are deffinitely not getting close to what your optimum performance should(or could)be. You should only be turning about 1900 RPM at 70 MPH without OD. Time for a gear ratio change if you want to really enjoy that Cherry engine set up.
Jeff
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From: saramento usa
Bad millage
Jeff,
Yeah, I am enjoying the mileage, but I'm up over 2 grand at 75 mph. I have a 9" and it is stamped 2.73. I have a major redo on the front of the engine, then paint, then wheels, then rear gear. Probably a 2 year project.
Slik
Yeah, I am enjoying the mileage, but I'm up over 2 grand at 75 mph. I have a 9" and it is stamped 2.73. I have a major redo on the front of the engine, then paint, then wheels, then rear gear. Probably a 2 year project.
Slik
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From: saramento usa
Bad millage
Check the metal tag located on the front, passenger side of the rear axle. There should be two rows of numbers/letters that will tell you the size, ratio, manufacturer and date of manufacture. Give us the numbers if you can't figure the code out and we will let you know what you have.
Slik
Slik
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Bad millage
>I don't know what's wrong, but I
>used to get 17-21 mpg with
>my 300 I6 (21 was pretty
>rare, but 17 was common).
>I now get 10-11 around town
>with my brand new 351W (seems
>I've always got my foot in
>it) and 14 on the highway.
> What gears are you running
>in the tail (I have some
>wimpy 2.73s, great for mileage though).
>
>Don't know what to say,
>Slik
Hey Slik,
I know what you mean about keeping your foot in it! Did you ever get rid of your pinging? I had a funny noise on acceleration and turned out to be the air cleaner, I ran a piece of hi-temp tape around the filter leaving about 4" exposed, now I hear the motor. Did you do any carb. work? (Jets, metering rods etc.) I've been going richer on both jets and rods and it keeps gettin better but not perfect because of the a/c, hard to get a even idle without a selinoid. (gonna git one though) My mileage is not good cause I have a foot problem
When I pulled my fuel tanks to check out the socks I took em off and now when my rear tank gets about 1/2 full she runs out of gas, I reckon the socks must hold some gas in the line. Whada think?
Moe
>used to get 17-21 mpg with
>my 300 I6 (21 was pretty
>rare, but 17 was common).
>I now get 10-11 around town
>with my brand new 351W (seems
>I've always got my foot in
>it) and 14 on the highway.
> What gears are you running
>in the tail (I have some
>wimpy 2.73s, great for mileage though).
>
>Don't know what to say,
>Slik
Hey Slik,
I know what you mean about keeping your foot in it! Did you ever get rid of your pinging? I had a funny noise on acceleration and turned out to be the air cleaner, I ran a piece of hi-temp tape around the filter leaving about 4" exposed, now I hear the motor. Did you do any carb. work? (Jets, metering rods etc.) I've been going richer on both jets and rods and it keeps gettin better but not perfect because of the a/c, hard to get a even idle without a selinoid. (gonna git one though) My mileage is not good cause I have a foot problem
When I pulled my fuel tanks to check out the socks I took em off and now when my rear tank gets about 1/2 full she runs out of gas, I reckon the socks must hold some gas in the line. Whada think?Moe
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Junior User
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Bad millage
>Slik You must have either
>an 8.8" or 9" Ford rear
>axle. As far as I know
>they didn't even have an option
>of 2.73:1 ratio. But if they
>did,you are deffinitely not getting close
>to what your optimum performance should(or
>could)be. You should only be turning
>about 1900 RPM at 70 MPH
>without OD. Time for a gear
>ratio change if you want to
>really enjoy that Cherry engine set
>up. Jeff
Hey Jeff,
I have a 3-sp. auto., C4 I think, that came with my 300/6 and I'm using it with my new 302HO. I.m turning about 3000rpm @ 75mph. I've been told I have a 3.05 rear end. What should I change to get 1900rpm @ 70mph? I'm on the freeway 90% of the time and she's suckin alot of gas. I really don't want a dog of the line though.......Just turned 1800mi.
Thanks,
Moe
>an 8.8" or 9" Ford rear
>axle. As far as I know
>they didn't even have an option
>of 2.73:1 ratio. But if they
>did,you are deffinitely not getting close
>to what your optimum performance should(or
>could)be. You should only be turning
>about 1900 RPM at 70 MPH
>without OD. Time for a gear
>ratio change if you want to
>really enjoy that Cherry engine set
>up. Jeff
Hey Jeff,
I have a 3-sp. auto., C4 I think, that came with my 300/6 and I'm using it with my new 302HO. I.m turning about 3000rpm @ 75mph. I've been told I have a 3.05 rear end. What should I change to get 1900rpm @ 70mph? I'm on the freeway 90% of the time and she's suckin alot of gas. I really don't want a dog of the line though.......Just turned 1800mi.
Thanks,
Moe
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Bad millage
Moe,
When I calculated Slik's RPMs I was basing it on an assumption of a 30" tire(which is about a P265R 15).The actual calculation is 1987 RPMs at 65 MPH with a 30" tire and 2.73:1 gears. For your truck without overdrive at 1:1 in your top gear,and 3.07:1 gear ratio and 30" tires,you should only be turning 2235 RPMs at 65 MPH. If we multiply 65 MPH by 15% it = 75 MPH/so if we multiply 2235 RPMs by 15% it = 2570 RPMs at 75 MPH. If you are turning 3000 RPMs at 75 you must be running about a 28" tire or even a little smaller. To lower your RPMs you can increase you tire size or lower your gear ratio. It will make your truck work harder though,especialy pulling a grade with a load. The way you are set up now,you are actualy sitting right in the middle of my charts for "Highway Driving/Good Fuel Economy". you could actualy get more performance out of it(at the loss of fuel economy)by going to 3.55:1 gears with your present tire size. I really need to know what size tires you are running or planning on running to calculate a propper Ring and pinion change,(if any).
Jeff
When I calculated Slik's RPMs I was basing it on an assumption of a 30" tire(which is about a P265R 15).The actual calculation is 1987 RPMs at 65 MPH with a 30" tire and 2.73:1 gears. For your truck without overdrive at 1:1 in your top gear,and 3.07:1 gear ratio and 30" tires,you should only be turning 2235 RPMs at 65 MPH. If we multiply 65 MPH by 15% it = 75 MPH/so if we multiply 2235 RPMs by 15% it = 2570 RPMs at 75 MPH. If you are turning 3000 RPMs at 75 you must be running about a 28" tire or even a little smaller. To lower your RPMs you can increase you tire size or lower your gear ratio. It will make your truck work harder though,especialy pulling a grade with a load. The way you are set up now,you are actualy sitting right in the middle of my charts for "Highway Driving/Good Fuel Economy". you could actualy get more performance out of it(at the loss of fuel economy)by going to 3.55:1 gears with your present tire size. I really need to know what size tires you are running or planning on running to calculate a propper Ring and pinion change,(if any).
Jeff
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From: saramento usa
Bad millage
Well, it's better. I took it to the beach a couple of weeks ago; was 100 out and nearly 200 miles. I ran about 75 most of the way and the temp gauge ran about in the middle. I had the A/C full blast so I guess it was OK, except when I nail the foot to the floor to pass someone, it started pinging. Otherwise it seemed strong and run good. I haven't played with the jets, but I've been following your thread and I think I will try to run a little richer and see what happens. My truck's been on the lamb since I broke an altenator bolt off with the end stuck in the head. I finally said I'm going to fix this right and ordered a whole new bracket set from ZOOPS. It should correct all my accessory alignment problems and look great to boot.
Keep me posted on your jetting!!
I don't know about the tanks; never dared to work on 'em after seeing all the posts. Maybe Phillip G. would have some insight on those things.
Slik
Keep me posted on your jetting!!
I don't know about the tanks; never dared to work on 'em after seeing all the posts. Maybe Phillip G. would have some insight on those things.
Slik
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Bad millage
Moe,
You guys have it made with your 302s,when my rear tank gets to 1/2 on the gauge Ive got about 60 miles left,and its reading fine, 9 gallons at 7 MPG = 63 miles,( I have to run premium fuel).Unless you have a Company Gas Card,or deep,deep pockets you deffinitely dont want to run a supercharged 460 4x4 with 4.10 gears and 36" tires.And being a glutton for punishment Im installing 4.56:1 gears when the Dana 60 swap is performed.It deffinitely moves through the mud though.One of the venders at a Mud Bogg has a picture of it on his web site at www.buffalomilke.com in the testomonials.It was a 1st place win(4th one this summer),in Modified V-8/Stock Wheel Base.
You guys have it made with your 302s,when my rear tank gets to 1/2 on the gauge Ive got about 60 miles left,and its reading fine, 9 gallons at 7 MPG = 63 miles,( I have to run premium fuel).Unless you have a Company Gas Card,or deep,deep pockets you deffinitely dont want to run a supercharged 460 4x4 with 4.10 gears and 36" tires.And being a glutton for punishment Im installing 4.56:1 gears when the Dana 60 swap is performed.It deffinitely moves through the mud though.One of the venders at a Mud Bogg has a picture of it on his web site at www.buffalomilke.com in the testomonials.It was a 1st place win(4th one this summer),in Modified V-8/Stock Wheel Base.
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From: saramento usa
Bad millage
Nice lookin' truck (should've cut the driver out of the pic, though). No, really it looks great and congrats on your wins!!!! I think I'll just sit and watch with my mild-mannered 2WD.
Slik
Slik
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Posts: 2,719
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From: Lee's Summit MO
Bad millage
>Nice lookin' truck (should've cut the driver
>out of the pic, though).
>No, really it looks great and
>congrats on your wins!!!! I
>think I'll just sit and watch
>with my mild-mannered 2WD.
>Slik
Jeff, I like your truck! What kind of tires are those? They look like 35" SuperSwamper TSl's.
>out of the pic, though).
>No, really it looks great and
>congrats on your wins!!!! I
>think I'll just sit and watch
>with my mild-mannered 2WD.
>Slik
Jeff, I like your truck! What kind of tires are those? They look like 35" SuperSwamper TSl's.
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Bad millage
Pastmaster,
They are 36 x 12.5 16s Superswamper Radial TSL,on Superior 16 x 10 Tri Bar Wheels. I also run a set of 38.5 x 11 16s Interco Boggers on 16 x 8 Alcoa Challengers(Mickey Thompson) with Champion Bead locks(for the drier Mud Pits).I usualy run about 15 PSI in the swampers and 18 - 20 with the boggers. Neither one are that great on the HWY but the Swampers are the better of the two.I also run the Swampers on my Jeep they are pretty good on the HWY with the lighter weight.
They are 36 x 12.5 16s Superswamper Radial TSL,on Superior 16 x 10 Tri Bar Wheels. I also run a set of 38.5 x 11 16s Interco Boggers on 16 x 8 Alcoa Challengers(Mickey Thompson) with Champion Bead locks(for the drier Mud Pits).I usualy run about 15 PSI in the swampers and 18 - 20 with the boggers. Neither one are that great on the HWY but the Swampers are the better of the two.I also run the Swampers on my Jeep they are pretty good on the HWY with the lighter weight.