D-train-13k Posted December 15, 2011 Report Share Posted December 15, 2011 hey guys i have a ford f150. its a 4.2 v6 so there are not many performance options out there for me. standard gears are 3.55 i have the truck lifted with 33'' inch tires on it. plus the shit load of soundsystem equipment. its lacking in low end power. i dont normally speed or drive over 80 on the interstate. so what im asking is. what would give me a good boost without absolutely destroying mpg. and id rather not be doing 3500 rpm at 70 mph i thinking that larger gears would help my mpg making it easier to move the tires. but would a 3.9 or 4.10 gear be better. i can also go to about a 4.56 gear. there are some in between as well. thanks guys. Quote The IrishmanCheck out my build hereXL 4th order wall build logIn Progress:alpine cda HU4th order Bandpass2xl 15's1- ab 400.1 (gonna be two hopefully)4- Crescendo 8's2- xts crecendo supertweeters 2 sq super tweetsMb quart 4.125Mechman 270a alt1- xs D27003- xs XP3000 4- odessey pc1700seller feed back threadhttp://www.stevemeadedesigns.com/board/topic/136418-d-train-13k/ Link to comment Share on other sites More sharing options...
SS4Luck Posted December 15, 2011 Report Share Posted December 15, 2011 If youve got a taller tire the effect of a rear gear change isnt as big of a deal on your MPG because your going back closer to a stock ratio. I ran a 29" tire on my camaro with 4.56s and got better mpg than the stock 26" tire and 3.42 gearing. Find a ford forum and see what guys are doing gear wise for 33s to get a little of the low end back. Im sure a 3.90 with the autio would be plenty Quote lol or you can just start hooking shit up together and blow up speakers and your amp Link to comment Share on other sites More sharing options...
D-train-13k Posted December 15, 2011 Author Report Share Posted December 15, 2011 If youve got a taller tire the effect of a rear gear change isnt as big of a deal on your MPG because your going back closer to a stock ratio. I ran a 29" tire on my camaro with 4.56s and got better mpg than the stock 26" tire and 3.42 gearing. Find a ford forum and see what guys are doing gear wise for 33s to get a little of the low end back. Im sure a 3.90 with the autio would be plenty yeah im leaning towards the 3.90 but the 4.2 only has 150 to 200 ftlbs of torque so maybe the 4.10 would work better. because i will be having 2 xls and a wall in my truck daily. as well as any other stuff that goes in the bed. Quote The IrishmanCheck out my build hereXL 4th order wall build logIn Progress:alpine cda HU4th order Bandpass2xl 15's1- ab 400.1 (gonna be two hopefully)4- Crescendo 8's2- xts crecendo supertweeters 2 sq super tweetsMb quart 4.125Mechman 270a alt1- xs D27003- xs XP3000 4- odessey pc1700seller feed back threadhttp://www.stevemeadedesigns.com/board/topic/136418-d-train-13k/ Link to comment Share on other sites More sharing options...
bass_stalker Posted December 15, 2011 Report Share Posted December 15, 2011 I'm assuming you have a model that can be tuned with a tuner? if i recall right you can alter the shift points and that might help you with mileage and what not, just besure to save your stock tune so you can revert if you need to Quote JEEP BUILD PROJECT ANTIBLING.2000 jeep Cherokee.HEADUNITAlpine Cda-9886SUBSTAGE1 acendent 18" audio mayhem motor with a TI basket and tantric parts1 prototype DAT hellfire 1000.1HIGHSStockELECTRICALdb link 0 gaugeKnuconceptz Kolossus 4 gauge1 xs power d3400 under hoodBig 3 upgradeold fourwheeler build The only way to delete your SMD account is for you crawl to steve meades door step on your knees and pleade for his forgiveness and acceptance to be released...He will either grant your wishes.....or choke you with a large piece of 0 gauge and electrocute you by hooking up a solid gold DC 12k at 0.000001 ohm and 10000 volts to your eye sockets and blow your head apart You guys act like you have never clogged a toilet and ran around the bathroom frantically hoping it don't overflow. Link to comment Share on other sites More sharing options...
POPLERO Posted December 15, 2011 Report Share Posted December 15, 2011 I would say 410s would be a good choice but you would get higher rpms while cruising on interstate and such I bielive.. Quote 2008 TBSS Black Granite Alpine CDA-117 Clarion EQS746 AudioQue Supertweets @ dash Alpine DDT-s30 @ b pillars Alpine SPR-60c @ front doors Alpine SPR-60 @ rear doors Alpine PDX-f4 Second Skin DampPro KNUkonceptz Wiring DCpower 270amp alt Optima YT underhood *temp Two15DCxls Hifonics bxi2610 *temp saz4500 and 4 xp3000s coming soon. Link to comment Share on other sites More sharing options...
chernenburn Posted December 15, 2011 Report Share Posted December 15, 2011 If you run a higher numeric ratio i.e. 4.10:1 vs 3.55 then you will have less of a tendency to ruin your rear end while you are running big tires. It will take the extra load off associated with running a larger diameter tire which intern lowers the numeric ratio. The bearings are what will typically fail, and the 4.2 doesn't exactly have the stoutest rear end. . Whatever you can get with a higher ratio for your rear end housing will help with reliability. I rebuilt the rear end on a 4.2 with big tires that only had 20k on it. Do the math and see what ratio will bring you back to stock driveshaft revolution speed per mph with your 33's. The 4.2 pistons have a long stroke so your not gonna want to spin alot of rpm's as long stroke=lower rpm capability due to a higher piston speed, so in short your engine's most efficient rpm will likely be low. I can't tell you what that is. x senior master ford driveline specialist Quote Link to comment Share on other sites More sharing options...
D-train-13k Posted December 15, 2011 Author Report Share Posted December 15, 2011 yeah i know rpms will get higher at interstate speeds. but i cant afford a tuner right now. but regearing is a cheaper option without changing the computer and screwing everything up Quote The IrishmanCheck out my build hereXL 4th order wall build logIn Progress:alpine cda HU4th order Bandpass2xl 15's1- ab 400.1 (gonna be two hopefully)4- Crescendo 8's2- xts crecendo supertweeters 2 sq super tweetsMb quart 4.125Mechman 270a alt1- xs D27003- xs XP3000 4- odessey pc1700seller feed back threadhttp://www.stevemeadedesigns.com/board/topic/136418-d-train-13k/ Link to comment Share on other sites More sharing options...
D-train-13k Posted December 15, 2011 Author Report Share Posted December 15, 2011 If you run a higher numeric ratio i.e. 4.10:1 vs 3.55 then you will have less of a tendency to ruin your rear end while you are running big tires. It will take the extra load off associated with running a larger diameter tire which intern lowers the numeric ratio. The bearings are what will typically fail, and the 4.2 doesn't exactly have the stoutest rear end. . Whatever you can get with a higher ratio for your rear end housing will help with reliability. I rebuilt the rear end on a 4.2 with big tires that only had 20k on it. Do the math and see what ratio will bring you back to stock driveshaft revolution speed per mph with your 33's. The 4.2 pistons have a long stroke so your not gonna want to spin alot of rpm's as long stroke=lower rpm capability due to a higher piston speed, so in short your engine's most efficient rpm will likely be low. I can't tell you what that is. x senior master ford driveline specialist yeah when i regear im going to replace the bearings. basically rebuild the whole thing. and im sure the rear end on my truck is going to get worse over time. ive only had the tires on for a year or so. but i baby the truck. i cant afford to dog it. i dont go mudding anymore. just trails. Quote The IrishmanCheck out my build hereXL 4th order wall build logIn Progress:alpine cda HU4th order Bandpass2xl 15's1- ab 400.1 (gonna be two hopefully)4- Crescendo 8's2- xts crecendo supertweeters 2 sq super tweetsMb quart 4.125Mechman 270a alt1- xs D27003- xs XP3000 4- odessey pc1700seller feed back threadhttp://www.stevemeadedesigns.com/board/topic/136418-d-train-13k/ Link to comment Share on other sites More sharing options...
chernenburn Posted December 15, 2011 Report Share Posted December 15, 2011 if you don't dog it you'll be fine the 1 I rebuilt was for a 16 year old kid it probably his first truck so of course it was getting thrashed on Quote Link to comment Share on other sites More sharing options...
chernenburn Posted December 15, 2011 Report Share Posted December 15, 2011 what was your factory tire size Quote Link to comment Share on other sites More sharing options...
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