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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => The Highs (Raising/Lifts) => Topic started by: alabama87 on December 30, 2012, 11:18:16 am
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I have a rough country 4" Suspension lift with 35's. Gas mileage is really starting to hit my wallet on this daily driver and im wanting to go with 33's and get the wind resistance down on my truck. Anyone know if i can replace the 4" Blocks with 2" blocks and what other mods might be possible? Thanks in advance.
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How are you geared and what kind of mileage are you getting and what kind are you hoping for? 15-17mpg is about tops for a 4x4.
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How are you geared and what kind of mileage are you getting and what kind are you hoping for? 15-17mpg is about tops for a 4x4.
thanks for the reply. Ive got an 87 4wd with 3.08 gears. im getting around 8/9 mpg on the highway driving about 60mph. i watch my speed, takeoffs, and braking. i dont run the air/heat hardly at all. my tire pressure is spot on 35 psi which the tire calls for. i have a k&n air filter. ive ordered a throttle body spacer besides lowering the suspension lift with smaller tires, i dont know what else to do.
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i should also mention, ive recently done an oil change and a tune up. somewhat at a loss. sometimes, rarely, ill get 10mpg on the highway. it has to be the air resistance thats killing my mpg along with the tires.
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Re-gear your axles to something like a 3.73 or 4.10 and you should see more like 14mpg and you'll notice alot more get up an go if you put your foot in it.
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Your gears are killing your mileage with those 35's, as Da67goatman stated, change the gears. I would go with 4.10's with 35's, what transmission are you running?
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whats the cheapest route? regearing or lower the truck with smaller tires??? the tires are brand new, so i could probably trade them for some brand new 33's. just need to know if rough country will allow you to drop it two inches or if i would have to buy another kit.
also, im a newbie at this stuff. when you say regear, do you mean buy a whole new front and rear axle, or the gears in the existing axle can be replaced??? thanks again!
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oh, and i have a 700r4
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If you have the standard Rough Country lift it will have springs for the front and blocks for the rear, there is no way to lower the front without getting new springs (new kit)
Their 2" and 4" lifts are about the same cost (around $350). 33" tires are probably about $225 apiece, so $1000. so you are about $1400 in to go with lowering and new tires.
Regearing requires new gears front and rear. They are anywhere from $200-500, so lets say $300 for front and rear, plus an install kit at about $100, plus the cost to install it around $200-400 per axle. You're are at $1100 if you choose middle ground. These can be found cheaper, but your biggest cost is finding someone that has the tools to set one up and the cost to do so.
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thanks for all the info. well, i think i might sell my lift and tires. they are both brand new. i could probably just trade my tires and maybe sell my 4 inch for 200. so i might only have to pay a couple hundred to drop it. dont u think my mpg will go up drastically if i lower tires and lift two inches?
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No
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so if i only have 2 inches of lift and get some 33s, you dont think it will make a diff in mpg????? You think its all in the gears??? do u think a cold air intake or tb spacer will make a difference?
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No
As Capt said, you could go stock height and 30" tires and you might get 10 - 11 MPG. The lift, or wind resistance as you call it does not effect MPG as much as your high gears are.
Go online and do research by looking up gear ratios Verses MPG. You will find out the gear ratios has the most dramatic effect on miles per gallon.
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The spacer and a cold air kit isn't going to do anything. The engine is straining to turn those 35's, you need gears. and cold air kit isn't going to do you a bit of good...
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thanks for the info guys. ill look and switching gears. last thing, would manual hubs make a difference as opposed to my automatic hubs?
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No
As Capt said, you could go stock height and 30" tires and you might get 10 - 11 MPG. The lift, or wind resistance as you call it does not effect MPG as much as your high gears are.
Go online and do research by looking up gear ratios Verses MPG. You will find out the gear ratios has the most dramatic effect on miles per gallon.
why is 3.08 considered high? i would think this is considered low....
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Your right, got my verbiage backwards, it is low geared not high.
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thanks for the info guys. ill look and switching gears. last thing, would manual hubs make a difference as opposed to my automatic hubs?
These are not going to make a bit of diffrence on rather or not you get beter mpg..however if you ever actually use the truck for it's intended purpose and get it off road they would be the best low buck investment you could do to the front axle.
Not sure what other mods you have done to the truck but as earlier mentioned the cold air intake will help minimually but coupled with a better exhaust you can see good inprovements in power and economy. I used flowtech longtubes and my exhaust isn't as good as I want it or need it for now bit I can tell a huge diffrence in power and several mpg over stock. Granted I also have 3.73 gears but they were stock from the factory. Are you sure of the gears you say you have? I've got the same running gear as you should.
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well, it says on the original window sticker 3.08. with that being said, i guess i need to find out for sure. ill tell u this. i have a 45 degree angled driveway, and i cannot reverse up it without it bogging down. im thinkin its low geared. i have exhaust and headers and k and n, and other than that, nothin really. i realize these trucks arent made for mileage, but my gosh i shld be gettin more than 9.....
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Wow yea.. i haven't seen 9mpg in a while. When I first got this truck in '10 (for Free) it was getting just over 6mpg. I have changed the things I have told you about and then a few but I also have 3.73's and I average 14mpg except in the winter where it is more like 12. Not sure how mechanically inclined you are but a good dial indicator, magnetic base, and soem grease are enough to get the results you need to put the greas in yourself. The hardest and most annoying part of the corporate 10 bolts are the pinion crush sleves. You get one shot per sleve you buy. The sleves are for the pinion pree load and once you tighten the pionion nut on it you leave it. The best way to set one up is to pull your old bearings and use a carbide bit to grind the inside of the race so they fit snug but loose enough for you to slide off by hand. This will allow you to mock up as many times as you want/need to get the right amount of shims on the right sides for the best contact patch between the ring and pinion.
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thanks for all your effort but everything you just said might as well have been chinese. lol. im not too mechanically inclined. im gathering by greasing the ring and pinion, it may free the gears up and i might get a better ride???
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thanks for all your effort but everything you just said might as well have been chinese. lol. im not too mechanically inclined. im gathering by greasing the ring and pinion, it may free the gears up and i might get a better ride???
Not even close^.. so... if you go the best option to get the power and better mpg's yet ratain your clearance then just pay someone to do the gears.
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verify what ratio you have first. if you do only have 3.07 thats like having 2.54s with the 35s then pick some up from the junk yard. you want at least 3.73s i wouldnt go more than 4.10s
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im getting an avergae of 7.5 -8 with 4.10s 4inch lift and 35's. 350 stock plus headers. not meaning to steal his post or anything but can someone help me out here? my mileage is horrible.
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whats your trans?
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turbo 400