Re: [AMC-list] 196/t96/od gear ratios

[Wrambler <wrambler242@xxxxxxxxxxx>]

I agree as you and Ken say, anything under 2000 seems to get the engine out of its torque sweet spot.
You will see less fuel economy, UNLESS, you live in flatland areas, then you can get by with lower rpms.

All the O/D'd 4.0Ls I have had over the years are geared to cruise at highway speeds at about 21-2200rpm and do real well.
My American gets fantastic MPG for the type vehicle it is.

Mark Price
Morgantown, WV 26508
1969 AMC Rambler, 4.0L, EFI, T-5
2004 Grand Cherokee Laredo, 4.7L, Quadratrac II
"I realize that death is inevitable.
I just don't want to be around when it happens!"

----- Original Message -----
From: "Frank Swygert" <farna@xxxxxxx>
To: amc-list@xxxxxxxxxxxx
Sent: Friday, April 24, 2009 5:51:17 PM GMT -05:00 US/Canada Eastern
Subject: Re: [AMC-list] 196/t96/od gear ratios

I'm back after being without internet for about three days! Luckily I had plenty work to do on the house and didn't really miss it. An ad-ware program on my daughter's computer hijacked my router somehow, changing the IP addresses -- never heard of that, neither did the IT guys from my provider who came out for three hours this morning to track it down. Daughter is always loading/trying something new...

A 3.78 gear was used in 63 Americans with OD and the OHV engine, and the 63 Classic w/OD (which was the 196 OHV -- no L-head in Classic!). That should be great, but note that the Classic came with a shorter 14" tire stock. Still, should be good with the 15" wheels (which were optional). 4.10's were optional. As long as you're not towing it should be fine, and if towing just lock it out of OD.  

You want to maintain AT LEAST 2000 rpm when cruising. The engine will still happily pull at less, but it will take more fuel since it's pulling harder than it needs to. It seems all the AMC sixes, even the 4.0L, were cammed and geared to cruise in the 2000-2500 range. Kick a 4.0L over 2500 and the fuel curve gets richer. Run it below 2000 and the gas mileage goes down, but it's more than happy to pull without lugging though. 

------------
Date: Wed, 22 Apr 2009 23:07:50 -0700
From: tom jennings <tomj@xxxxxxx>

That axle/trans (3.77, OD) combo is *perfect* for that car and motor. 60mph
all day long with no stress, can get up to 70, 75 but I never hold that
speed. Out of OD, 50 mph is pushing it, but around town it's great.

I'm running 215/60-R15 tires front and rear. !!#!@!~~ spreadsheet program is
crashing else I'd give you numbers.

A spreadsheet that calcs all that crap is at
http://wps.com/AMC/axle-ratio-tire-MPH.xls



On Wed, Apr 22, 2009 at 21:55, d stohler <das24rules@xxxxxxxxx> wrote:


> >
> > so, im about ready to drop this new t96/od in casper. i have the 3.77 rear
> > gear in it now. my 62 tsm says od cars were equipped with a 4.10 rear gear.
> > and that the od is a .30% reduction. i beleive that would make it a .70 gear
> > ratio? if i am doing my math right, not sure if i am, that would make the
> > 4.10 gear as if it were a 2.87 rear gear. if i stay with my 3.77 gear, would
> > be like having a 2.64 gear. with the tires i have on it, (245-45-17)
> > cruising at 60 would be about 2100 rpm or so. with the 4.10 gear, would put
> > it about 2250. either one of those beats 3000 to do 60mph. so, what gear
> > would probably work best for this motor to cruise down the freeway? anyone
> > have any ideas with different gears with their od? im wondering if that 2100
> > is to low for this small motor, but then again, it does have alot of torque
> > in the lower rpms. im not sure exactly where the sweeter spot is for this
> > motor. anyone with an idea or advice?
> >
-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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