1dirtyZ

iTrader: (1)

cool idea , keep us posted!

Patrick G

iTrader: (14)

I know it sounds crazy, but hear me out. 2.73 gears have quite a few advantages compared to 3.73 gears (which I have right now):

1. Strength. The 2.73 gears (in stock 10 bolt) are the beefiest things you can find. When running a lot of spray, that can come in handy.

2. Street Racing. With 3.73 gears, 1st gear is useless on the street, even with Nittos. With my Yank Super Thruster 3500 converter, I would be able to launch nearly with my foot to the floor and really take advantage of torque multiplication for a longer period of time with 2.73 gears. With 3.73 gears, I have to pedal the car at the launch. Can't go WOT until I'm on top of 1st gear (with Nittos on the street). I'm in 2nd gear at 35 mph in 2nd gear with 3.73s. I'd stay in 1st gear past 50 mph with 2.73s (and under WOT for a longer period of time).

3. Better passing gears on the street. Hear me out on this one. 2.73 cars have incredible passing gears (when coupled with loose converters). You can be driving 35-40 mph and still get a downshift to 1st gear. You can be driving on the highway at 70 mph and get a wicked downshift to 2nd...as a matter of fact, you can downshift to 2nd up to 85-90 mph.

4. Better launching with a power adder. Just ask "Just Me" Steve Harmon about this one. You can run a really big shot of nitrous out of the hole with less starting ratio (8.35 vs. 11.41). Higher starting ratios are better for running N/A, but lower are better for running Nitrous or forced induction.

5. Less need for sticky tires at the track. Nittos would be more than enough for mid 1.6 to low 1.7 60' times. You could get nearly as good a time on the street with less 1st gear starting ratio (like the 2.73s give you).

6. Fuel economy. 2.73 cars get fuel mileage nearly as good as as M6 cars with 3.42 gears. Longer engine life is an obvious plus. My fuel economy on the highway is around 20 mpgs with 3.73 gears. It would be over 25 mpg with 2.73s...maybe even 27+.

OK, to sum up, with my loose converter, I feel that I'd be losing around a tenth (max) at the track (considering the converter I'm running) on motor, but go faster on the spray (since N2O makes max hp and torque so low). Street racing will be a lot more deadly with a better, more usable 1st gear. Swapping 2.73s for 3.73s...crazy or genius?

RPM WS6

iTrader: (3)

Patrick, the downshift points are a really good point. I often wish that my car would automatically downshift to first at 35 for a really hard hit instead of the “dead spot”.

Micks SS

How will my stlt3200 feel if I go from 3:23 to 2:73

Micks SS

Corection!From 3:23 to 2:73?

IndyZ28

I know a guy that has a 2001 Z with the 2.73's and he is running 12.50's w/lid FRA and a bullet muffler off of the Y and on radials. He doesn't have a converter and this might not really apply to your app. but the 2.73's don't seem to be hurting him. Here is a link to the time and mod's - http://web.camaross.com/bb/Forum9/HTML/005606.html

My 98 S-10 SS had 3.08 7-5/8 10-bolt. Ring and pinion gears would be direct bolt in for F-bodies. My 86 Monte Carlo had 2.4x(it was 2.42 or .41 or something like that, can't remember exactly) in a 10-bolt with a 200-4R overdrive trans. Talk about top end with a built 350 and still decent gas mileage. I'm not sure if they were of the 7.5 or 7.625 size. I'll bet that they were the weaker 7.5 ones though.

Ragtop 99

iTrader: (7)

[quote]Originally posted by Patrick G:
<strong>I know it sounds crazy, but hear me out. 2.73 gears have quite a few advantages compared to 3.73 gears (which I have right now):

1. Strength. The 2.73 gears (in stock 10 bolt) are the beefiest things you can find. When running a lot of spray, that can come in handy.</strong><hr></blockquote>

agree

<strong> [quote]
2. Street Racing. With 3.73 gears, 1st gear is useless on the street, even with Nittos. With my Yank Super Thruster 3500 converter, I would be able to launch nearly with my foot to the floor and really take advantage of torque multiplication for a longer period of time with 2.73 gears. With 3.73 gears, I have to pedal the car at the launch. Can't go WOT until I'm on top of 1st gear (with Nittos on the street). I'm in 2nd gear at 35 mph in 2nd gear with 3.73s. I'd stay in 1st gear past 50 mph with 2.73s (and under WOT for a longer period of time).
</strong><hr></blockquote>

Disagree.
Torque to the tires is = engine torque * converter torque multiplication * gear ratio

What causes tires to break loose is too much torque. You are trading one variable for another, thus you gain nothing in total torque to the ground. However, I will agree that the 2.73 gears make it easier to drive at the limit as there is less pedalling and more mash and go.

<strong> [quote]
3. Better passing gears on the street. Hear me out on this one. 2.73 cars have incredible passing gears (when coupled with loose converters). You can be driving 35-40 mph and still get a downshift to 1st gear. You can be driving on the highway at 70 mph and get a wicked downshift to 2nd...as a matter of fact, you can downshift to 2nd up to 85-90 mph.
</strong><hr></blockquote>

Maybe. You have to look at all the variables including the start and stop speed for the race. Start the race at 45 - 55 mph and we both hit 2nd gear and my 3.73s will put 1/3 more torque to the ground and leave you in the dust.

<strong> [quote]
4. Better launching with a power adder. Just ask "Just Me" Steve Harmon about this one. You can run a really big shot of nitrous out of the hole with less starting ratio (8.35 vs. 11.41). Higher starting ratios are better for running N/A, but lower are better for running Nitrous or forced induction.
</strong><hr></blockquote>

Dunno. What if you have Ed wright add second gear start? That will give you shorter gearing, but is that too short or will it work?

<strong> [quote]
5. Less need for sticky tires at the track. Nittos would be more than enough for mid 1.6 to low 1.7 60' times. You could get nearly as good a time on the street with less 1st gear starting ratio (like the 2.73s give you).
</strong><hr></blockquote>

Disagree. This is the same point/counterpoint as #2. Torque is torque and the tires don't care how it got there.

<strong> [quote]
6. Fuel economy. 2.73 cars get fuel mileage nearly as good as as M6 cars with 3.42 gears. Longer engine life is an obvious plus. My fuel economy on the highway is around 20 mpgs with 3.73 gears. It would be over 25 mpg with 2.73s...maybe even 27+.
</strong><hr></blockquote>

Definite gain in fuel economy and reduced engine noise on the highway.

You'll give up .1 at the track, maybe even .15 and the car will feel looser around town, bit it will be eaiser for a stab and steer on the street.
...And I never doubt your genius <img src="gr_images/icons/wink.gif" border="0">

Patrick G

iTrader: (14)

Mick SS,

I have the equivalent converter in my Tahoe (Truck Thruster 3000 behind a 5.3 = Stealth Thruster 3200 behind a 5.7).The Tahoe has 30 inch tall tires and 3.42 gears which would compare to an F-Body with stock tires running equivalent to a 2.84 gear. Having said that, my Tahoe feels really nice with this converter (even with its 5400 lb race wieght), so I feel the Stealth Thruster 3200 would be excellent with 2.73 gear in an F-Body. You'll like the combination a lot.

Larry

iTrader: (4)

Here's my test results with 2.73 verses 3.42 gearing:

2.73
60' = 1.756
1/8 = 7.938 @ 87.21 mph
1/4 = 12.437 @ 108.76 mph

3.42
60' = 1.757
1/8 = 7.943 @ 86.48 mph
1/4 = 12.506 @ 109.10 mph

Barometer 29.97, 29.94; temperature 78, 81 and humidity 76, 80, respectively. Wish I had my 2.73 gear back in!

I did have a Vigilante #6 pump converter. Without the converter I am sure the 3.42 would have came out on top. But with the right converter, 2.73 is equal to the task!

Crazyquik

It makes plenty of sense to me, especially since that converter, even with 2.73s, shouldn't be that hard to live with. Probably extend tranny life as well.

Dave Carney

I think most people want whatever gear they don't have, ha... I have 2.73's and want 3.42s but I have no str....

BIGBOS

Would it be good in my case if I'm using this setup to run a 2.73 instead of a 3.73?

I will have a TH400
Moser 12-bolt (gear pending)
4400 converter

Patrick G

iTrader: (14)

BigBos,

A TH400 has a 2.48 1st gear ratio. That coupled with a 3.73 gear gives you a 9.25 starting ratio. A starting ratio of 10 is considered ideal for running N/A with a converter. A starting ratio of 8-9 is better with huge cubes or running a power adder (read traction limited).

If you ran a 2.73 gear, your starting ratio would only be 6.77...that's really low...even a Powerglide with a 1.76 1st gear has 7.22 starting ratio when coupled with a 4.10 gear.

With a TH400, to get a starting ratio of 10, the best gear ratio would be a 4.10 gear. To match the starting ratio of a 4L60E and a 2.73 gear (8.35 starting ratio), you would need around a 3.42 gear.

Incidently, the best gear to achieve a starting ratio of 10 with a 4L60E is a 3.23 gear...imagine that?!

WILWAXU

iTrader: (6)

[quote]Originally posted by Dave Carney:
<strong>I think most people want whatever gear they don't have, ha... I have 2.73's and want 3.42s but I have no str....</strong><hr></blockquote>

OMG! I can't imagine how loose that thing is! A SY with 2.73!!.. Maybe you an patrick can swap <img src="gr_images/icons/wink.gif" border="0"> Those 3.73's would work awesome with a SY-3500.

gwj

I never thought about the 2:73s being a good thing until I put the ST3500 in. It's nice to be able to kick back to 2nd @ highway speeds and hold it to 100 or so. In fact, I try to run from a roll as the street radials can not hold any kind of traction from a stop. Wish I could find a compromise between street radials and Nittos as I hate getting squirrly in the rain.

Micks SS

I say you should Go to the other side. The Dark Side! <img src="graemlins/gr_devil.gif" border="0" alt="[devil]" /> 4:10's!

mmiller

iTrader: (1)

I have an ST-3500 and I have the stock 3.23's in my car. At the track it hooks like a mother on ET Streets. I have cut a best 60 ft. of 1.57.

On the street, traction is marginal even with Nitto's. For street racing, ET Streets with VHT is the ticket (no pun intended, LOL).

Micks SS

I would think with 2.73 you will be moving the dead spot from 32 to 45.With 4.10's you should have no dead spots up to 110. I read that GM has a 5l80e a5. Not the truck allison. IS that true and will it fit an f-body?

Pro Stock John

iTrader: (34)

Big Daddy runs his Turbo Mustang with a powerglide and a small gear in the rear end. He also runs the car on drag radials. Car runs 9's.

But he also makes like 900hp.

Torque is torque.

Patrick has a lot of mods. He makes a lot of power.

I'd do a smaller gear but would never do 2.73's.

I did not like them on the street when I had them.

Steve Underwood

How do think 3.42's would be?