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Crawl Ratio ? 4x4 Calculators


MorganM
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http://www.oly4x4.com/4x4calculators.htm

 

Transmis Ratio: 3.307

TransCase Ratio: 1.592

Axle Ratio: 3.9

"Crawl" Ratio: 20.5325016

 

 

Seem's pretty wussy when I was talking to a guy yesterday about Land Cruisers while looking at some Subaru's he was trying to get rid off. He was boasting 300+ "crawl" ratio :slobber: Said it was more than you'd ever need but did it anyway :-p

 

What kind of #'s are you t-case mod duders pulling? Is this the only real viable way to improve our gearing? Honestly this was the first thing I noticed when I got out on some real trails in 4Lo after the lift and tires.... I wanted another Lo range !_!

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Lets see here, this is what I have with my dual transfercases....

 

Transmission Ratio: 3.954

First TransferCase reduction box Ratio: 2.28

Second TransferCase reduction box Ratio: 4.70Axle Ratio: 5.29

"Crawl" Ratio: 224 ish

Oh wait, you where talking Subies huh.... well my Subie is the same as yours mogan........ 20 ish : 1 .... :yuck:

 

Sure my Toyota seem's pretty low but there is still time I wish I had 300 ish. But the smaller the tire the less distance you are going to travel per revolution. But another way to look at it might to be to comapre actual feet travel per minute. This is an unfair example but it will give you the equation of rthe subies...... With 800 rpm * 36" tire * 3.14 / 12 in/ft / 224:1 = 33.6 feet per minute at idle. Now in a Subie at 800 rpm* 28" tire * 3.14 / 12 in/ft / 20.5:1 = 293.2 feet per minute at idle.

 

Anyways sorry for the rambling.... its just this 20 ish crawl ratio makes me laugh.....

 

 

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first gear is 3.5 something I believe on the 5spd

 

so mine is

 

first gear: 3.5 (ish)

low range: 1.592

second case: 2.1:1

final drive:3.9:1

 

=45.6:1 on 31" tires, which I am happy with. In double low I have enough control to navigate any situation I can think of on the island (mostly fitting in tight spots between trees, bedrock climbs, riverbeds, and dirt/gravel) Plus just running my second case in low gives me 29:1 which is great for mud or loose climbs cause it gives me speed and keeps me in the 3-5k powerband.

 

I guess thats 160ft/min.

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Interesting.

 

I used the calculator to figure out the difference in MPH if I changed the RX tranny to 3.9 from 3.7. At about 3000rpm in 1st, there is only a 1 MPH difference and at 4000rpm in 5th there is only a ~4 MPH difference. Makes me wonder if it is worth doing.

 

I think it would be better to have the 1.592 low range and keep the rest the same, 3.7. This would make for some great 0-60ish times with the turbo.

 

Jay

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