Will 3.73's turn my AODE vert into a slug?

DarkMesa8

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I'm downgrading from 4.10's in my 1995 GT AODE Vert in order to attain higher mph in the quarter mile. I originally was going to go with 3.55's, but that recieved much backlash from friends and experts. I am now considering 3.73's.

The AODE has a 3000 stall convert, and a Transgo shift kit. The motor is armed with aluminum heads, Cobra intake, custom cam. It will be recieving a 150 shot on the track with 26 inch Mickey Thompson ET streets.

According to calculations, 3.73 gears with 26 inch tall tires will allow me to go 5500 rpms in 3rd (1:1) at 114 mph. That is nearly perfect for my goal.

On the street, however, will 3.73's turn the convertible into a slug on wheels with a ragtop? I want to still fend off cars all motor, will the new gears severely hinder that?
 
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Killercanary

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I disagree. Going from 4.10's to 3.73's is a drop in gear ratio of .37. That's a sizeable decrease, especially when you concider there is only a difference of .47 when going from 3.08's to 3.55's Have you concidered going to a 28" high ET street? It'd be about the same price as getting new gears + install, and if it doesn't work out, you could easily sell them and then swap the gears. That's what I would do if it were me.
 

94GTLaserRC

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Killercanary said:
I disagree. Going from 4.10's to 3.73's is a drop in gear ratio of .37. That's a sizeable decrease, especially when you concider there is only a difference of .47 when going from 3.08's to 3.55's Have you concidered going to a 28" high ET street? It'd be about the same price as getting new gears + install, and if it doesn't work out, you could easily sell them and then swap the gears. That's what I would do if it were me.
Gotta differ with you on this. You have to go by proportion, NOT the ACTUAL gear drop.

You can say .37 is almost the same as .47.. BUT if you go by percentage:

when you go from 3.08 to 3.55 that is a .47/3.08 = 15.3% change.

When you drop from 4.10 to 3.73 ,that is a .37/4.10 = 9% drop

The change from 3.08 to 3.55 is (15.3-9)/9 or 6.3/9 or 70% more of a change than going from 4.10 to 3.73 (trust me, the math is accurate)

If you use the .37 and .47 number only, the difference "seems" like (.47-.37)/.37 or .1/.37 or 27% greater of a change.

So you see, the change from 3.08 to 3.55 is much more different than going from 4.10's to 3.73.

BOTTOM LINE IS: With a converter, shift kit, and your other mods, you will do just fine, whether or not you feel a difference.

RC
 

Killercanary

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RC, I'm a pretty smart guy but I have no idea what your trying to say in your post??? Either way you look at it, a rear gear ratio multiplies torque in direct proportion to what it sees at coming in through the DS. To make this REALLY simple, lets use my peak RWTQ number and assume the tranny is in 4th gear (1:1 ratio) and we hold the rpms steady at my peak TQ. If you multiply 3.08 times 327ftlbs and subtract it from 3.55 times 327ftlbs you come up with 153.69ftlbs of torque difference. If you do the same for 3.73 vs 4.10 you get 120.99ftlbs. The is you subtract 120.99ftlbs from 153.69ftlbs you come up with a difference of only 32.7ftlbs between the two. That's pretty close, enough so that you butt will not be able to tell much of a difference in terms of the amount of change felt by going from 3.08-3.55 versus 3.73 to 4.10. My entire point for making the above post was to illustrate that most people view going from 3.73 to 4.10's is only a swap to one range lower of avail. gears (excluding the 3.90's) but they miss the point that its a pretty sizeable one. I have re-read your post like three times and have no idea what your trying to illustrate. Can you ellaborate?
 

jmuva44

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I think RCs idea is close. However I think that comparing the percentage difference of four different gears doesnt tell you much. Lets say I had an income of $100,000 last month and take a 50% cut to $50,000 this month. You had an income of $1 million last month and took a pay cut of 10% this month. My percentage difference may be more but I only lost $50,000. You only took a 10% pay cut but you lost $100,000. This is where I think his reasoning becomes confusing. Maybe I'm just lost.
 

DarkMesa8

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One thing that was brought to my attention is the ever present converter slip in automatics. Calculating that in, 3.73's wouldn't even let me trap higher than 120mph. That's no room to grow, so I went with the 3.55's. They're in the car right now, and whoever said the stall convert would save me was right. That convertible is NO slug, even with 3.55's. Yes, I could tell the difference right away, but the nitrous should give plenty of torque to compensate for the lost gear.

Now, the track should tell me if it was truly worth it.
 

94GTLaserRC

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Killercanary said:
RC, I'm not a very smart guy..........Can you ellaborate?
Sure Paul, Anything for you! :rlaugh: :nice:

Basically to feel a difference in something (or notice), it is based on the change versus what youre use to, or the %. (like the post below yours).

Like the Pro athelete dudes being fined $5k. Since they make $5 mil per year, that is only 1/10 of one percent, but $5,000 is a lot of dough!

If I make 100 grand a year, that $5 is 5% to me, so I will "feel" the effects.

The numerical change in the gear will be felt if it is a BIG ENOUGH change compared to what youre use to feeling.

So.. (if the gears existed) you would "feel" more of a change going from 3.0 to 3.5 gears than you would from 3.5 to 4.0., since the PERCENTAGE is greater.


Sorry to confuse anyone, but as mentioned above, 3.73 will be :nice: with a good tranny setup.!

RC