4.10's vs 3.73's

joey50gt · 04-10-2001, 03:20 PM

is there really a big performance diffrence between 3.73's and 4.10's in an aod???
The only reason i ask is because i can get a new set of 3.73's for free from a friend of mine, but if the 4.10's are that much better than i will go ahead and buy them.
thanks for any answers

xspeed02 · 04-10-2001, 03:46 PM

I had a 3.73 in my Aod. I was extremely happy with the car. I think 4.10's might be a little steep for the Highway bro. I dunno though, depends how radical you wanna go and how much you care about gas mileage.

fiveohpatrol · 04-10-2001, 03:52 PM

both gears will have you smiling from ear to ear, but the decision lies in what kind of driving you do, if you think you can get good traction and dont do a whole lot of highway driving then the 4.10s are the way to go, my gears made me fall in love with my car all over again, but now i think that i should have went with the 4.10s

------------------
88 Notchback 5.0, 3.73's, Explorer intake, pulleys, Crane 1.7's, BBK headers, off-road H-pipe, flowmasters, subframe connectors, 65mm TB, shift kit, March ram air kit, motorsport wires, MSD coil, upper and lower control arms, 155lph fuel pump, cheap 2800 stall, Crane Adj.FPR, best time- 13.99@99.75, not yet tested times after rocker and intake install

jimberg · 04-10-2001, 07:15 PM

One of the mistakes people seem to make a lot with gear selection is that they don't realize that they're giving up something in return for more torque.

Gears are kind of like a lever. If you increase the length of the lever on the side of the fulcrum you apply power, you'll be able to move more weight with less effort but you won't move it as far.

With gears you are able to apply more power to the wheels, but your power band runs out quicker, limiting the speed at which you cross the finish line.

My guess would be that the optimal gear ratio would have you going through all the non-overdrive gears and having you cross the finish line just as you pass your peak horsepower. Too much gear will have you out of your powerband too fast and you'd be loping through the finish line and too little gear will have you starting slow and accelerating through the finish line, wasting power.

Oh, the performance difference between 3.73s and 4.10s would be less than the difference between 2.73s and 3.08s.

Whenever someone asks this question, and if someone is going to answer it correctly, the thing they need to know is where their powerband starts and ends.

I may not be exactly right about what's optimal, but I thought I'd throw that out there as a baseline for discussion and to get people thinking about what is optimal for a specific car rather than some guy with a stock engine asking someone with a race engine what they think of their 4.10s vs 3.73s.

I hope no one takes this message the wrong way. I'd just like to see a more thoughtful discussion on how to pick gears and not just apples telling oranges why they picked their gears.

BTW, I picked 3.55s since I already have tons of torque but want to keep my top end somewhat.

------------------
351W 89 Mustang GT Convertible

NOS_Notch · 04-10-2001, 08:56 PM

If your car is mostly stock it will be the difference from running a 14.80 w/ 3.73 to about 14.50-14.60 w/ the 4.10's.
My old AOD w/ 3.73's...i was dissapointed the day i drove it from the shop.
4.10 is optimum 1/4 mile gear for AOD or t-5 car.....r's about 5500 through the traps...
R's on the e-way..about 3 grand at 75
2 tenths is about 2 cars worths racing....

------------------
4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

FivepointOH · 04-11-2001, 12:00 AM

Go with the 4:10's... you might cross the traps a tad high at first but once you do more hp mods it will make up for it

------------------
92 AOD GT, K&N, ram air, pulleys, 2 ch. flowmasters, 4:10's, shift kit, 1 5/8 mac longtubes and offroad hpipe 14.249 @ 97.34 mph before the headers and hpipe

smokedchevy · 04-11-2001, 12:46 AM

I have a stock t-5 with 4:10s and p255 15 tires. I love them. The revs aren't that bad on the freeway and the acceleration is great. I go through the traps at around 5700 rpm(stock tach reading).

Mustangbelle306 · 04-11-2001, 07:23 PM

??? My car has 4.10s, and I lose all the time to cars with similar mods but with 3.73s. I just assumed my powerband was running out too quick, and that was a price I had to pay for good low end ooomph. But I see you all seem to be happy with the overall performance...am I missing something here???

------------------
Elisha (Mustang Chick Extraordinaire)
1994 GT/Saleen: Cartech intake,4.10s, full exhaust, pulleys, Compucar nitrous kit 125 shot
Sold the 1986 LX sedan

http://www.geocities.com/mustangbelle_306
AOL name: GT306Chick

smokedchevy · 04-12-2001, 01:27 AM

You're probably missing traction. The engine needs something to pull against.The acceleration I was refering to was 1/4 mile racing at the strip. With slicks and 4:10s, you'll eat most cars out of the hole and give you enough of a lead to win, even if you're a little down on power. On the street forget it. You won't get any kind of traction even with a stock engine. What kind of cars are beating you?

stanger8172 · 04-12-2001, 05:34 AM

Anyone want to get rid of their old 3:55's or 3:73's for an 8.8"? My '91 LX convertible still is wearing the turtle shell (2:73's). stanger8172@hotmail.com

Mach 1 · 04-12-2001, 07:41 AM

without question, 4.10's. I had them both, and the 4.10's were a MAJOR improvement over the 3.73's. Dont make the same mistake I did and have to change your gears twice. And this difference doesnt even compare to a 2.73 to 3.08 jump, dont know how anybody came up with that theory? They will work great with your motor from stock to mildy to more aggresively modified.

[This message has been edited by Mach 1 (edited 04-12-2001).]

jimberg · 04-12-2001, 09:21 AM

It's simple math, Mach 1. 3.08 / 2.73 is approx. 1.13 which is about a 13% difference. 4.10 / 3.73 is approx. 1.10 or a 10% difference. Maybe I'm wrong and you can explain the physics to me.

------------------
351W 89 Mustang GT Convertible

Mach 1 · 04-12-2001, 04:03 PM

1.13, 1.10? 13% and 10%? Ok, ive been out of school for a long time, but I dont see how u came up with these numbers? Maybe you can explain to me? The way i see it, there is a bigger difference between 3.73 and 4.10 than there is between 2.73 and 3.08.
And Im also judging by the seat of the pants feel. My change from 3.73 to 4.10 felt like a bigger difference than when I went from 2.73 to 3.73.
There are a lot of variables, like transmission gearing and such, and im speaking from my own experience. Just dont see how your making such a claim?

------------------
1993 GT/AOD
'93 Mustang GT

Mach 1 · 04-12-2001, 04:11 PM

ok, after smacking my calculator around,(piece of crap) I understand how u got your numbers. Maybe your right, maybe not. Im not going to expell a lot of energy on this, but again, judging from seat of the pants feel, I would disagree.

jimberg · 04-12-2001, 05:40 PM

I never said there was no seat-of-the-pants feel from going to 2.73s to 3.08s. I was just saying that going from 3.73s to 4.10s was just less significant as far the comparison. No one really ponders over whether to go to 3.08s from 2.73s, though.

How much did your e.t. change when you made the switch?

------------------
351W 89 Mustang GT Convertible

NOS_Notch · 04-12-2001, 06:21 PM

you are right in saying the % of gear change is more, but the reason (my opinion, which doesn't mean much) that there would be a bigger improvement going from 3.73-4.10 than 2.73-3.08 is because neither of the 2.73-3.08's are putting you in a good power band anyway. 3.73's are getting you close...4.10's are dropping you right in it...about 3 grand at the beginning of each gear....and through the traps at about 5500-5700.
Much more time in your power band will give you much more improvement in ET and MPH.....
But that's what i think....................

------------------
4.10's,long tubes & 75 shot...Goes 12.50's
Check it out at http://www.burnouts.webprovider.com

Mach 1 · 04-12-2001, 10:33 PM

I agree with NOS notch, and thats what I was trying to explain, I just was tired and couldnt put it into words.

Jimberg - you said "the performance difference" would be less...this is what I dont agree with. Bigger change in gear ratio or not, the performance difference is better in the higher range, not in the lower range..hope this clears thinks up.

------------------
1993 GT/AOD
'93 Mustang GT

[This message has been edited by Mach 1 (edited 04-12-2001).]

Mustangbelle306 · 04-13-2001, 04:29 PM

Quote:

Originally posted by smokedchevy:
You're probably missing traction. The engine needs something to pull against.The acceleration I was refering to was 1/4 mile racing at the strip. With slicks and 4:10s, you'll eat most cars out of the hole and give you enough of a lead to win, even if you're a little down on power. On the street forget it. You won't get any kind of traction even with a stock engine. What kind of cars are beating you?

Exactly. With my 4.10s and NOTHING ELSE, I mean even air silencer intact, my 94 GT ran a 14.01 @ 99. But on the street I lose to LT1's etc etc. Cars that I should be at least be close to are beating me by cars and I'm not a TERRIBLE driver. Not the best but not the worst either. Hmmm something to think about.

------------------
Elisha (Mustangbelle)
1994 GT: Cartech intake,4.10s, full exhaust, and pulleys.
Sold the 1986 LX sedan

http://www.geocities.com/mustangbelle_306
AOL name: GT306Chick

04-10-2001, 03:20 PM	#1
joey50gt Registered Member Join Date: Jan 2001 Location: hurst,texas,america Posts: 95	4.10's vs 3.73's is there really a big performance diffrence between 3.73's and 4.10's in an aod??? The only reason i ask is because i can get a new set of 3.73's for free from a friend of mine, but if the 4.10's are that much better than i will go ahead and buy them. thanks for any answers

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04-10-2001, 03:46 PM	#2
xspeed02 Registered Member Join Date: Nov 1998 Location: Kettering, Ohio Posts: 119	I had a 3.73 in my Aod. I was extremely happy with the car. I think 4.10's might be a little steep for the Highway bro. I dunno though, depends how radical you wanna go and how much you care about gas mileage.

04-10-2001, 03:52 PM	#3
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	both gears will have you smiling from ear to ear, but the decision lies in what kind of driving you do, if you think you can get good traction and dont do a whole lot of highway driving then the 4.10s are the way to go, my gears made me fall in love with my car all over again, but now i think that i should have went with the 4.10s ------------------ 88 Notchback 5.0, 3.73's, Explorer intake, pulleys, Crane 1.7's, BBK headers, off-road H-pipe, flowmasters, subframe connectors, 65mm TB, shift kit, March ram air kit, motorsport wires, MSD coil, upper and lower control arms, 155lph fuel pump, cheap 2800 stall, Crane Adj.FPR, best time- 13.99@99.75, not yet tested times after rocker and intake install

04-10-2001, 07:15 PM	#4
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	One of the mistakes people seem to make a lot with gear selection is that they don't realize that they're giving up something in return for more torque. Gears are kind of like a lever. If you increase the length of the lever on the side of the fulcrum you apply power, you'll be able to move more weight with less effort but you won't move it as far. With gears you are able to apply more power to the wheels, but your power band runs out quicker, limiting the speed at which you cross the finish line. My guess would be that the optimal gear ratio would have you going through all the non-overdrive gears and having you cross the finish line just as you pass your peak horsepower. Too much gear will have you out of your powerband too fast and you'd be loping through the finish line and too little gear will have you starting slow and accelerating through the finish line, wasting power. Oh, the performance difference between 3.73s and 4.10s would be less than the difference between 2.73s and 3.08s. Whenever someone asks this question, and if someone is going to answer it correctly, the thing they need to know is where their powerband starts and ends. I may not be exactly right about what's optimal, but I thought I'd throw that out there as a baseline for discussion and to get people thinking about what is optimal for a specific car rather than some guy with a stock engine asking someone with a race engine what they think of their 4.10s vs 3.73s. I hope no one takes this message the wrong way. I'd just like to see a more thoughtful discussion on how to pick gears and not just apples telling oranges why they picked their gears. BTW, I picked 3.55s since I already have tons of torque but want to keep my top end somewhat. ------------------ 351W 89 Mustang GT Convertible

04-10-2001, 08:56 PM	#5
NOS_Notch Registered Member Join Date: Sep 2000 Location: Fresno,CA. USA Posts: 384	If your car is mostly stock it will be the difference from running a 14.80 w/ 3.73 to about 14.50-14.60 w/ the 4.10's. My old AOD w/ 3.73's...i was dissapointed the day i drove it from the shop. 4.10 is optimum 1/4 mile gear for AOD or t-5 car.....r's about 5500 through the traps... R's on the e-way..about 3 grand at 75 2 tenths is about 2 cars worths racing.... ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.webprovider.com

04-11-2001, 12:00 AM	#6
FivepointOH Registered Member Join Date: Jan 1999 Location: Sugar Land, Tx USA Posts: 478	Go with the 4:10's... you might cross the traps a tad high at first but once you do more hp mods it will make up for it ------------------ 92 AOD GT, K&N, ram air, pulleys, 2 ch. flowmasters, 4:10's, shift kit, 1 5/8 mac longtubes and offroad hpipe 14.249 @ 97.34 mph before the headers and hpipe

04-11-2001, 12:46 AM	#7
smokedchevy Registered Member Join Date: Jun 2000 Location: ventura,CA Posts: 438	I have a stock t-5 with 4:10s and p255 15 tires. I love them. The revs aren't that bad on the freeway and the acceleration is great. I go through the traps at around 5700 rpm(stock tach reading).

04-11-2001, 07:23 PM	#8
Mustangbelle306 Yay for Chickys Join Date: Feb 2001 Posts: 1,532	??? My car has 4.10s, and I lose all the time to cars with similar mods but with 3.73s. I just assumed my powerband was running out too quick, and that was a price I had to pay for good low end ooomph. But I see you all seem to be happy with the overall performance...am I missing something here??? ------------------ Elisha (Mustang Chick Extraordinaire) 1994 GT/Saleen: Cartech intake,4.10s, full exhaust, pulleys, Compucar nitrous kit 125 shot Sold the 1986 LX sedan http://www.geocities.com/mustangbelle_306 AOL name: GT306Chick

04-12-2001, 01:27 AM	#9
smokedchevy Registered Member Join Date: Jun 2000 Location: ventura,CA Posts: 438	You're probably missing traction. The engine needs something to pull against.The acceleration I was refering to was 1/4 mile racing at the strip. With slicks and 4:10s, you'll eat most cars out of the hole and give you enough of a lead to win, even if you're a little down on power. On the street forget it. You won't get any kind of traction even with a stock engine. What kind of cars are beating you?

04-12-2001, 05:34 AM	#10
stanger8172 Registered Member Join Date: Nov 2000 Location: Milwaukee,Wisconsin Posts: 380	Anyone want to get rid of their old 3:55's or 3:73's for an 8.8"? My '91 LX convertible still is wearing the turtle shell (2:73's). stanger8172@hotmail.com

04-12-2001, 07:41 AM	#11
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	without question, 4.10's. I had them both, and the 4.10's were a MAJOR improvement over the 3.73's. Dont make the same mistake I did and have to change your gears twice. And this difference doesnt even compare to a 2.73 to 3.08 jump, dont know how anybody came up with that theory? They will work great with your motor from stock to mildy to more aggresively modified. [This message has been edited by Mach 1 (edited 04-12-2001).]

04-12-2001, 09:21 AM	#12
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	It's simple math, Mach 1. 3.08 / 2.73 is approx. 1.13 which is about a 13% difference. 4.10 / 3.73 is approx. 1.10 or a 10% difference. Maybe I'm wrong and you can explain the physics to me. ------------------ 351W 89 Mustang GT Convertible

04-12-2001, 04:03 PM	#13
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	1.13, 1.10? 13% and 10%? Ok, ive been out of school for a long time, but I dont see how u came up with these numbers? Maybe you can explain to me? The way i see it, there is a bigger difference between 3.73 and 4.10 than there is between 2.73 and 3.08. And Im also judging by the seat of the pants feel. My change from 3.73 to 4.10 felt like a bigger difference than when I went from 2.73 to 3.73. There are a lot of variables, like transmission gearing and such, and im speaking from my own experience. Just dont see how your making such a claim? ------------------ 1993 GT/AOD '93 Mustang GT

04-12-2001, 04:11 PM	#14
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	ok, after smacking my calculator around,(piece of crap) I understand how u got your numbers. Maybe your right, maybe not. Im not going to expell a lot of energy on this, but again, judging from seat of the pants feel, I would disagree.

04-12-2001, 05:40 PM	#15
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I never said there was no seat-of-the-pants feel from going to 2.73s to 3.08s. I was just saying that going from 3.73s to 4.10s was just less significant as far the comparison. No one really ponders over whether to go to 3.08s from 2.73s, though. How much did your e.t. change when you made the switch? ------------------ 351W 89 Mustang GT Convertible

04-12-2001, 06:21 PM	#16
NOS_Notch Registered Member Join Date: Sep 2000 Location: Fresno,CA. USA Posts: 384	you are right in saying the % of gear change is more, but the reason (my opinion, which doesn't mean much) that there would be a bigger improvement going from 3.73-4.10 than 2.73-3.08 is because neither of the 2.73-3.08's are putting you in a good power band anyway. 3.73's are getting you close...4.10's are dropping you right in it...about 3 grand at the beginning of each gear....and through the traps at about 5500-5700. Much more time in your power band will give you much more improvement in ET and MPH..... But that's what i think.................... ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.webprovider.com

04-12-2001, 10:33 PM	#17
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	I agree with NOS notch, and thats what I was trying to explain, I just was tired and couldnt put it into words. Jimberg - you said "the performance difference" would be less...this is what I dont agree with. Bigger change in gear ratio or not, the performance difference is better in the higher range, not in the lower range..hope this clears thinks up. ------------------ 1993 GT/AOD '93 Mustang GT [This message has been edited by Mach 1 (edited 04-12-2001).]