4.56 gears question

so after finding out that my car has 4.56 gears in it (i just got it),
i did some online research. i found out that those gears are mostly for
big 4x4 trucks. having a 91 mustang gt 5.0 with 17 inch rims, is it
monitarily worth it to buy the 3.73 gears i hear so much about? and
what is the big difference? i am no expert on cars. the only thing that
i have noticed is that it is slightly annoying to drive, as i have to
switch gears often. Very often. what does this all mean for a normal
joe?

You bought a car that turns 3600 rpm at 60 mph in direct and, at todays gas
prices, you are wondering if 3.73s are worth the plunge? Your engine rpm
will drop to 2900ish in direct (4th in a stick - 3rd in an auto) and your
gas savings will likely pay for the gearset in the first year...


"oneadvent" > wrote in message
oups.com...
> so after finding out that my car has 4.56 gears in it (i just got it),
> i did some online research. i found out that those gears are mostly for
> big 4x4 trucks. having a 91 mustang gt 5.0 with 17 inch rims, is it
> monitarily worth it to buy the 3.73 gears i hear so much about? and
> what is the big difference? i am no expert on cars. the only thing that
> i have noticed is that it is slightly annoying to drive, as i have to
> switch gears often. Very often. what does this all mean for a normal
> joe?
>

The 4.56 (revolutions of your driveshaft) to 1 (revolution of your rear
axel) rear end gear ratio is low and in a Mustang are for short quick 1/8 or
1/4 mile drag racing type application. With these gears there will be few
street cars that can beat you from zero to sixty, but they will have a
higher top speed.

Basically the lower your final gear ratio (4.56 being a very low street gear
ratio), the quicker your car will get up to (a lower) top speed. This also
translates into higher engine RPM's at highway speeds, and generally a drop
in fuel economy.

If you bought this car for a daily driver, it will be quick, but not too
economical. :-)

If you are going to spend the $500-$2000 dollars to have the rear gears
changed for fuel economy reasons, 3.73/1 gears aren't considered a very high
(read economical) gear ratio. 3.50 and lower gears (4.11-4.56 the higher
the number the lower the gear ratio) are generally thought of as low gears.

Something in the 3.00-3.08-3.25 range would make more sense if you are
thinking of making kind of change for fuel economy reasons.



"oneadvent" > wrote in message
oups.com...
> so after finding out that my car has 4.56 gears in it (i just got it),
> i did some online research. i found out that those gears are mostly for
> big 4x4 trucks. having a 91 mustang gt 5.0 with 17 inch rims, is it
> monitarily worth it to buy the 3.73 gears i hear so much about? and
> what is the big difference? i am no expert on cars. the only thing that
> i have noticed is that it is slightly annoying to drive, as i have to
> switch gears often. Very often. what does this all mean for a normal
> joe?
>

i was planning to take a long trip. from pensacola to missouri. having
an average RPM of 3k(a guess) would that be a safe trip, or should i
use another vehicle. overheating is not an issue as it runs at a cool
120 ' f. so i guess i am asking if it is rough on the gears to go that
long that fast?

oneadvent wrote:
> i was planning to take a long trip. from pensacola to missouri. having
> an average RPM of 3k(a guess) would that be a safe trip, or should i
> use another vehicle. overheating is not an issue as it runs at a cool
> 120 ' f. so i guess i am asking if it is rough on the gears to go that
> long that fast?

I would suggest considering 3.55's. I have them on my '89 LX and they
are a good compromise between performance and economy. Also, 4.56 gears
on a trip that long will drive you insane from the engine screaming and
into the poor house due to low gas mileage.

oneadvent wrote:
> i was planning to take a long trip. from pensacola to missouri. having
> an average RPM of 3k(a guess) would that be a safe trip, or should i
> use another vehicle. overheating is not an issue as it runs at a cool
> 120 ' f. so i guess i am asking if it is rough on the gears to go that
> long that fast?
>

Not real good for a small block, but if it's running at 3K you'll
get about 30 miles and turn around.

--

I used to have abs. Now, I've just got ab.
One big ol' Ab. - BigSkiff www.titanspot.com

Pyongyang sounds more like the sound effect an ACME catapult makes
as it goes off at precisely the wrong moment for Wile E. Coyote. -
Cadbury Moose

"WindsorFox[SS]" > wrote in message
news:H0Uxg.104307$IZ2.74046@dukeread07...
> oneadvent wrote:
>> i was planning to take a long trip. from pensacola to missouri. having
>> an average RPM of 3k(a guess) would that be a safe trip, or should i
>> use another vehicle. overheating is not an issue as it runs at a cool
>> 120 ' f. so i guess i am asking if it is rough on the gears to go that
>> long that fast?
>>
>
> Not real good for a small block, but if it's running at 3K you'll get
> about 30 miles and turn around.


Why would 3000 RPM be "not real good for a small block"???
That small block Ford V-8 engine should be able to run at 3000 RPM non stop,
tank after tank of gas with absolutely zero negative results...



>
> --
>
> I used to have abs. Now, I've just got ab.
> One big ol' Ab. - BigSkiff www.titanspot.com
>
> Pyongyang sounds more like the sound effect an ACME catapult makes
> as it goes off at precisely the wrong moment for Wile E. Coyote. - Cadbury
> Moose

look gas shouldn't even be that bad. from here to missouri it is about
1.3k miles, going the long way. so you gotta think even at 20 miles to
the gallon, i will only need 65 gallons. that would be less that 200
dollars in gas. and i would have a car there. so even worst possible
situation, it wouldn't be that bad. i would think that the engine
should run stronger than 3k. without problems, why shouldn't it?

Your car will have zero problems going to Missouri with the 4.56 gears. You
will use more gas than with 3.27 gears or there abouts. Let us know what
kind of mileage you get on the trip.

I have a Sunbeam Tiger that the previous owner replaced the stock rear end
gears (2.88) with 3.36 gears.
My car runs 3500 rpm at 70 mph.
I don't have overdrive gears in the trans and the wheels are 205/60-13's
(only 23 inches in diameter).
I have driven on long trips (San Diego to San Francisco) with the tach
sitting at 4000 rpm (80 mph). The engine is completely happy. It just
sucks gas. 16 mpg tops.

"oneadvent" > wrote in message
ps.com...
> look gas shouldn't even be that bad. from here to missouri it is about
> 1.3k miles, going the long way. so you gotta think even at 20 miles to
> the gallon, i will only need 65 gallons. that would be less that 200
> dollars in gas. and i would have a car there. so even worst possible
> situation, it wouldn't be that bad. i would think that the engine
> should run stronger than 3k. without problems, why shouldn't it?
>

i will post the gas mileage, but the trip is not until december. i
don't think it will be a problem. i think that i will get better gas
mileage than that. it gets about 190 miles for 27.50 at 2.98 per
gallon. thats right at 21 mpg. i would hope i did better on the long
run. i can have it in neutral some of the way. i am glad that it not
bad on the gears.