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| | | |-+ Should I change gears, if so to what ratio??
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Author Topic: Should I change gears, if so to what ratio??  (Read 2218 times)
z-adamson
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« on: May 03, 2011, 11:31:42 pm »

I have been contemplating a gear ratio in the rear end for two reasons.

1) It is a fairly heavy vehicle and it will do light duty cargo hauling.

2) A numerically higher gear ratio would help ease the load on the engine and get the engine into the power band quicker upon take off which should in theory keep the engine further away from ping.

-5500-6000 pound vehicle
-1200 to 4500 rpm engine power band
-1800 rpm stall
-c6 trans with 2.72:1 1st, 1.54:1 2nd, 1:1 3rd
-28 inch tall tires

-I may haul an additional 700lbs or less.

-Currently installed are 3.55:1

Not sure what other info to include.

What gears would you suggest?

I was considering 4.10:1. I am not too concerned with trading off some freeway cruise speed. I don't mind getting into the slow lane and going the speed limit to keep the rpms down. I am not sure if this is going to be too low of a ratio though to the point of not being streetable given the wide ratio gears in the trans.


 
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dennis112
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« Reply #1 on: May 04, 2011, 07:30:41 am »

I would think that without an OD your 3.55 would work the best all around unless you are also storming mountains or doing lots of start/stop in-town driving.  

No doubt a 4.11 would help in the above 2 situations but do you really need it?

What is your hauling experience now?
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Dennis

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gmatt9858
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« Reply #2 on: May 04, 2011, 08:34:27 am »

4.10:1 = ~3000rpm @ 60mph. I've done this, it's OK around town but not much fun for long trips on the highway. My exhaust seemed to get resonant at that rpm, made me want another gear.
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68mustang405
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« Reply #3 on: May 04, 2011, 11:15:52 am »

Honestly man run what you have and see if it pings. We've talked about this before. Other members and myself had said they don't think it's going to ping at all. Gears are going to be at least 500-1000 to install. Save the money, then if it does ping you can change the gears then. Stop worring so much about the little things, try it, and see.  Good Luck!
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68 Mustang 310 twisted wedge 170, tfs1, weiand stealth, 1.6 rr t5 3.55s with a locker, a/c and all the creature comforts.

On a serious note.. wagon made 3000hp on the dyno
z-adamson
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« Reply #4 on: May 04, 2011, 02:11:37 pm »

Save the money, then if it does ping you can change the gears then. Stop worring so much about the little things, try it, and see.  Good Luck!

I do plan on giving it a try as is before the change, but in the event of a needed change I want some advice as to which way to go, hence the thread. I don't plan on changing the gears before hand. I have changed gears before and have no problem doing it again. Wear pattern, pinion preload, backlash, runout...not an problem. I have the tooling, the facility etc. The gears would set me back no more than couple hundered dollars, not worried about that. But at the same time, I would rather not go through the work if not needed, and save a couple hundred bucks to boot.

The little things that can get overlooked often make or brake a project in my experience. I tend to try not to leave stones unturned. Maybe I am worried about nothing, but if thats the case, then no harm done.

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68mustang405
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« Reply #5 on: May 04, 2011, 02:54:44 pm »

IMO gears are one of the bigger things compared to what you could be doing. An adequet cooling system, cooler thermostat, cool air intake charge, moderate timing, cooler plugs, are all "small" things that could be done compared to changing gears.
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68 Mustang 310 twisted wedge 170, tfs1, weiand stealth, 1.6 rr t5 3.55s with a locker, a/c and all the creature comforts.

On a serious note.. wagon made 3000hp on the dyno
289nate
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« Reply #6 on: May 04, 2011, 03:25:47 pm »

How tall is the tire again?  I believe the only way to know for sure is to drive it and see which direction you personally want to go.
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z-adamson
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« Reply #7 on: May 04, 2011, 04:24:57 pm »

How tall is the tire again?  I believe the only way to know for sure is to drive it and see which direction you personally want to go.

28" tall tires.
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David Claflin
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« Reply #8 on: May 04, 2011, 04:46:01 pm »

Any reason you couldn't do two things, like an AOD swap and 4:10 or 4:30 gears?? You never mentiioned vehicle or engine size so just throwing that out there....
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