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This could be debated forever.

Even with the 265's and a 2.7 Toyota is only using 4.30's.

I would run 4.56 with 33's, and maybe 4.88's with 35's. Since when does altitude matter with an ECU and fuel injection?
 

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Discussion Starter · #22 ·
This could be debated forever.

Even with the 265's and a 2.7 Toyota is only using 4.30's.

I would run 4.56 with 33's, and maybe 4.88's with 35's. Since when does altitude matter with an ECU and fuel injection?
really? do you ever go 4 wheeling in the mountains? debating it with first hand knowlege and experience compared to charts, graphs and numbers found on the internet are 2 very different things.

Air Density decreases at a rate of 2.9% - 3.0% for each 1000 ft. of elevation above Sea Level.

Naturally Aspirated: Atmospheric Pressure 14.5 psi
Atmospheric Pressure @ 9000 feet = 10.5 psi
Pressure Loss = (14.5 - 10.5) = 4.0 (4.0/14.5) = 27.58 % @ 9,000 feet

without a forced air (turbo or charger) there is no way around this. the ecu does not magically make air denser, it measures volume.. the volume of air going into the engine is the same, the amount of useful molecules in that volume decreases as the elevation goes up.
 

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This could be debated forever.

Even with the 265's and a 2.7 Toyota is only using 4.30's.

I would run 4.56 with 33's, and maybe 4.88's with 35's. Since when does altitude matter with an ECU and fuel injection?
really? do you ever go 4 wheeling in the mountains?
X2 fuel injection is not the same as a supercharger. less air means less power no matter what. forced induction would make altitude a non-factor. but unless you are charged you loose roughly 50% of your engines performance by 10,000 ft.
 

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You guys are also posting data. Does altitude matter? On paper perhaps, but not anything you are going to feel in real world conditions. I have driven my truck at sea level, and at 12000+ ft, and it doesn't matter. I drove my truck to Phoenix and got the same mileage I get driving around CO.

I work in Vail, I am always driving at altitude. You are going to be rapped out at 4000 going down the highway, and getting like 10mpg. And if you are serious about low speed offroading, you ought to consider something like a dual case instead.

Define "losing 50% of your engines performance at 10000". If you are talking power, and mileage, that is bullshit.

PS. I just got 21mpg my last tank with a V6, driving up here in the mtns, and most of those miles were hauling 400lbs of building materials.
 

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Funny considering i just got 18 mpg out of my last tank of 1/2 highway and 1/2 town driving with 5.29's and bald ass 33x10.5 bfg alterrains. Yes is is high in the rpms on the highway, but you also use less throttle to do the same work. Throttle position plays a huge part in gas mileage.

That said, i would rather have the big tires on for long highway road trips. But with my Q78's which are a bit bigger than a 35 the gearing is about perfect on the highway. tire weight is another big factor is power and gear selection that the calculators dont show.
 

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To each his own I guess. I would rather cruise 2800-3000 down the highway. I like to do normal offroading, but I have never thought 1st gear in 4 low wasn't low enough. I am not into hardcore rock crawling though.

My buddy had 4.88's and 33's in his manual V6 and didn't like it.
 

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It does come down alot to how hard you push it off road. the harder you push the truck the more you will appreciate lower gearing.
 

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That ratio link posted above seems wrong. I will have to check again next time i drive the truck.



Altitude effects motor perfomence more then you would believe. N/A cars and trucks more then FI. I had a few friends running 13.0 in cali and come up here and are hitting 15.0 and slower.

I wish i could give a mpg rating for 5.29's and 33's but i cant. Im on 37's and at 72-73mph im at 3k I have had the truck over 100 with out hitting revlimiter or getting close. I have cruised to the springs from Ft. Collins running 95 about the whole way and still getting in the 20's If i drive nice with my 3rz im getting 27-32mpg to a tank. and to get really picky my truck is tall, Older and has more drag due to its square body, tires that stick out...all kinds of stuff.

Some people rather use the power of the motor to make them move and some like to gear down so the motor doesnt need to work as hard. I have duals and all that stuff and if your not going to wheel hard core trails its more of a problem then anyting. What gear to be in on what part of the trail and what rocks need what gears...lots of learning and headache when wheeling with guys that are not geared. I feel like im racing all over just being in normal low.
 

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To each his own I guess. I would rather cruise 2800-3000 down the highway. I like to do normal offroading, but I have never thought 1st gear in 4 low wasn't low enough. I am not into hardcore rock crawling though.

My buddy had 4.88's and 33's in his manual V6 and didn't like it.
Didn't like what, the RPM's? I cruise the highway doing 75 at 3100 rpm, it's not bad at all. I went from 4.10's to 4.88's. I travel back and forth to Steamboat quite a bit and was sick of always downshifting to 3rd to climb a hill. As for offroad, 4.88's are perfect for my tire size and the trails I like to wheel.
 

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I have 5.38 in my Tacoma and it's got about the same power as stock on 37's. And I live in Colorado. I wouldn't go over 4.88 with 33's. I had a 33's with 4.10 gears in my last truck and it was a dog. I know what that feels like having to downshift when you see a slight incline.

EDIT: Just saw the altitude thing. On paper it might be 50% less HP but it sure as hell didn't feel like it lost much driving several times accross Pikes Peak and Independance pass (over 14k ft and 12k ft)
 

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My friend with the 4.88's said it just reved too high going down the highway. I have read a ton of gearing discussions and data, and with a V6 and manual, seems like 4.56 or 4.88 is the norm. Just surprised you would need to jump from a 4.10 all the way to a 5.29 when only running a 33.
 

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My friend with the 4.88's said it just reved too high going down the highway. I have read a ton of gearing discussions and data, and with a V6 and manual, seems like 4.56 or 4.88 is the norm. Just surprised you would need to jump from a 4.10 all the way to a 5.29 when only running a 33.
4.56 is supposed to put you back at around stock powerband, and 4.88 is supposed to be for a little more low end. I had put a lot of research into it when I was about to regear my old Taco. This of course applies to a V6 5spd Tacoma that came stock with 4.10 gears and 30.5 inch tires. I guess if you get 5.29's and its too low you can alway go up to a 35" tire.
 

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My friend with the 4.88's said it just reved too high going down the highway. I have read a ton of gearing discussions and data, and with a V6 and manual, seems like 4.56 or 4.88 is the norm. Just surprised you would need to jump from a 4.10 all the way to a 5.29 when only running a 33.
You definately dont need to and 4.56 and 4.88 are the norm, but 5.29s are not unliveable either.
 

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i know this has been covered a billion times before but i cant find info regarding manual trannys only people with autos switching to 5.29 gears

i need to regear my truck, its got 33x10.5 tires, it weighs a TON (full skids, winch, bumpers, sliders, 2 batteries, aux 25gal tank, roof rack with 10+ gal of water on it, camper shell, sleeping platform, tools, spares etc..) i have a custom 9pack from alcan holding it up.

i live in aspen and generally drive up from my house.. air down in the driveway and go taylor, pearl etc. out to other places around here so i am generally at fairly high elevations

the truck is not a daily driver and lately i have been avoiding highways (last weekend i drove back from moab and it took 16 hours mostly dirt roads.

the info on running 5.29 gears that i have found has all been people with automatics. can anyone in the mountains (fairly high elevation) with a V6 manual and 33" tires let me know what its like? how bad is it on the highway? is mileage much worse? i know its pretty good to 70-75mph with an automatic and from what i have read it seems people with very heavy trucks get better mileage with the 5.29 gears with auto trannys.

what are the downsides with 5.29 gears? it seems like just about everything is better except for driving 75mph+ on the highway. i cant/shouldn't drive my truck much faster than 75 as it is, its tall, tippy and heavy and does not like to stop, but shifting into 3rd on the highway sucks and driving around feeling like the engine is bogged down all the time is not fun either so i gotta do something. from the limited amount i know about gears that i have learned in the past 2 weeks of reading i think i would be ok with either 5.29's or 4.88's but neither is really ideal, with the weight and elevation 5.29 might be better
What was your out come with your 5.29 re gear?
 
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