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Best Bang for the Buck? 3.73's or Underdrive Pulley

Old 05-03-2005, 09:06 PM
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Default Best Bang for the Buck? 3.73's or Underdrive Pulley

Trying to figure out which gives the best bang for the buck, either 3.73 gears or an Underdrive Pulley. I already have 3.23 gears that will soon be driven by a SY3500 converter. Right now I'm thinking the 3.73's are the winner.......

Thanks!

Adam
Old 05-03-2005, 09:11 PM
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3.73s would get my vote
Old 05-03-2005, 09:13 PM
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Same here...3.73s
Old 05-03-2005, 09:22 PM
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3.73s would be a MUCH better choice.
Old 05-03-2005, 11:21 PM
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Originally Posted by jdoyle
3.73s would get my vote
Old 05-03-2005, 11:36 PM
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I would bet this is going to be a unanimous agreement in favor of the 3.73's.
Old 05-04-2005, 04:25 AM
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Not unamimous my vote would sway on future mods, if you eventually plan on going cam I would vote pulley. Otherwise you will end up ditching the rear end anyway and just wasted money on the gears. my .02
Old 05-04-2005, 08:13 AM
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Don't waste the money on gears for the 10 bolt. Get a pulley and save for a 12 bolt with gears.
Old 05-04-2005, 08:46 AM
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all depends on what your plans are for...if you are almost done...get gears...if you plan on making 375+rwhp get a pulley...and then save for the 12-bolt like dmnspd said
Old 05-04-2005, 09:06 AM
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Pulley can lead to charging system flakiness and
I think they're not such a good idea for a street
car. Drag, sure, why not, as long as it charges at
idle. But you'll likely see drop-out at higher
accessory loads (hell, my stock alt sags in the
summer with the A/C and stero on).

SY3500 and 3.73s is supposed to be a sweet
combo. The low STR means you might actually
not break stuff. Kooky, huh?

Personally I'm happy with the 3.42s though that
step up is not really worth the cost from 3.23s.
Slightly used 3.42s are available real cheap. The
3.73s and up are not, so much.

The only reason I did it it was that I was putting
the T-2R chunk in, so the labor was already on
the plate, pretty much. T-2R has been a worthy
upgrade, you might want to think about what all
else you would want to be doing while you have
the guts out. How's your traction? One stripe or two?
Old 05-04-2005, 10:19 AM
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Originally Posted by jimmyblue
Pulley can lead to charging system flakiness and
I think they're not such a good idea for a street
car. Drag, sure, why not, as long as it charges at
idle. But you'll likely see drop-out at higher
accessory loads (hell, my stock alt sags in the
summer with the A/C and stero on).

SY3500 and 3.73s is supposed to be a sweet
combo. The low STR means you might actually
not break stuff. Kooky, huh?

Personally I'm happy with the 3.42s though that
step up is not really worth the cost from 3.23s.
Slightly used 3.42s are available real cheap. The
3.73s and up are not, so much.

The only reason I did it it was that I was putting
the T-2R chunk in, so the labor was already on
the plate, pretty much. T-2R has been a worthy
upgrade, you might want to think about what all
else you would want to be doing while you have
the guts out. How's your traction? One stripe or two?
you can always get an overdrive alt pulley with the underdrive crank...
Old 05-04-2005, 10:38 AM
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Originally Posted by jimmyblue
Pulley can lead to charging system flakiness and
I think they're not such a good idea for a street
car. Drag, sure, why not, as long as it charges at
idle. But you'll likely see drop-out at higher
accessory loads (hell, my stock alt sags in the
summer with the A/C and stero on).

SY3500 and 3.73s is supposed to be a sweet
combo. The low STR means you might actually
not break stuff. Kooky, huh?

Personally I'm happy with the 3.42s though that
step up is not really worth the cost from 3.23s.
Slightly used 3.42s are available real cheap. The
3.73s and up are not, so much.

The only reason I did it it was that I was putting
the T-2R chunk in, so the labor was already on
the plate, pretty much. T-2R has been a worthy
upgrade, you might want to think about what all
else you would want to be doing while you have
the guts out. How's your traction? One stripe or two?
Charging is fine on my Daily Driver with a underdrive pulley.
Old 05-04-2005, 01:11 PM
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QUOTE: you can always get an overdrive alt pulley with the underdrive crank...

Why add horsepower with the crank pulley, just to subtract it with the alternator pulley?
Old 05-04-2005, 01:22 PM
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Originally Posted by Redneck Z
QUOTE: you can always get an overdrive alt pulley with the underdrive crank...

Why add horsepower with the crank pulley, just to subtract it with the alternator pulley?
Net result should still be positive. Overdrive alt pulley shouldn't take much power.
Old 05-04-2005, 01:30 PM
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Ya... but 2 horsepower for all the time and money spent isn't worth it to me.
Old 05-04-2005, 01:46 PM
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Originally Posted by Redneck Z
Ya... but 2 horsepower for all the time and money spent isn't worth it to me.
I'll bet an underdrive crank and overdrive alt gives more than 2hp.
Old 05-04-2005, 03:04 PM
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it may subtract 2hp...if you don't want it then don't get it...but if you have charging issues then you will have 0 hp
Old 05-04-2005, 03:59 PM
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The HP loss at the alt will be minimal. Perhaps even a
net win, as you don't force the regulator to stuff more
current down the field winding (which it has to make,
itself). You trade rotor speed for field current and the
alt only takes what it needs. The power off the belt
is pretty much the same. Unlike the water pump
which has to stir fluid whether needed or not, and which
you might like to slow down (if you have a cooling
surplus).

I worked on tuning a truck with an underdrive pulley
recently and every time the e-fans kicked on the
line voltage at idle was dropping to 10.7V. Not healthy.
Old 05-04-2005, 05:05 PM
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Originally Posted by jimmyblue
The HP loss at the alt will be minimal. Perhaps even a
net win, as you don't force the regulator to stuff more
current down the field winding (which it has to make,
itself). You trade rotor speed for field current and the
alt only takes what it needs. The power off the belt
is pretty much the same. Unlike the water pump
which has to stir fluid whether needed or not, and which
you might like to slow down (if you have a cooling
surplus).

I worked on tuning a truck with an underdrive pulley
recently and every time the e-fans kicked on the
line voltage at idle was dropping to 10.7V. Not healthy.
so what you are saying is get an overdrive alt pulley along with the underdrive?
Old 05-04-2005, 05:08 PM
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Personally, I would either get just the crank pulley by itself, or not do anything at all.

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