4.10's vs 3.73's

Discussion in 'SN95 4.6L Mustang Tech' started by 04gtdrop, Jul 13, 2005.


  1. 04gtdrop

    04gtdrop New Member

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    Ok, I have gotten a lot of good info on here from you guys :nice: . I think that I am going to go with a set of gears and have the shop tune for my gears with the Xcal so I will just do both at the same time. Instead of having to tune it twice (saves time and $$$ obviously).

    Now since I am limited on funds I think I will have to sit on my 500 that I have and wait till next month and I can get say another 4-500 and just do them then. Man that’s going to be hard, but will be well worth it.

    My question to you guys is; should I do 4.10’s or 3.73’s? :shrug: From most of the threads I have read I know you all say 4.10, but why? Is there really that big of a difference from 3.73 to 4.10? Also I do a good amount of freeway driving and I don’t know if I would want to be having high RPM’s while doing 70-80 mph. And when you’re in first gear with a set of 4.10’s vs. 3.73’s do you have to shift really quick? I saw the video that was a sticky and it seemed like he was in 1st for barley a second then had to shift to 2nd quickly. I guess I am just trying to achieve a good balance of a fast stang with a daily driver that will last.

    Last question, I am still thinking about doing a NOS setup like a 75 shot :D . Do you think that it would be too much to have a 75 shot with a set of gears? And if so should I just wait and have the shop dyno tune it all at once?
     
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  2. Pittsas

    Pittsas New Member

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    I've said it before and I'll say it again if you can't decide on 3.73 and 4.10 then just split the different and get a 3.90 Pro 5.0 makes a set and stangnet sells em
     
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  3. helty

    helty some Ukrainian's enjoying a handjob via my credit

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  4. BooWFO

    BooWFO New Member

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    I assume you have an 04 5spd. If so 4.10's on the highway no biggie, 3k is 90mph. I knocked down over 23mpg on a road trip with mine turning 80 the whole way. Since you have 3.27 from the factory your not gonna really notice the jump to 3.73. Heck I kinda think I should have gone 4.30's but I do wanna go with a KB (if fundage allows). 75hp shot heck once I get everything in 100hp shot on 4.10's. I know someone who is hitting 100hp (I think it's more) with 4.30's. Also how soon do you plan on doing the N2o if it's only a month or 2 you might wanna wait do the gears, tune, and n2o at same time. Then you'll really feel the change in the car.
     
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  5. 04gtdrop

    04gtdrop New Member

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    ok, yeah if i dont do the NOS, then i could have the gears and xcal done in about 1 month when i get paid. if i decided to go with the NOS setup then sept the 9th is when i could do the NOS, Xcal and gears in one shot. too many damn bills. but i would wait to do 1 tune and save the $$$. i guess i'm just wondering if its worth it to wait on the NOS. becuase either way i am going to do the gears now, ya know?

    and booWFO, yes it is a 5-spd. sorry, should have put that.

    helty, i saw the video of the sticky with the 4.10's and i'm still "iffy" i dunno, i am really torn. I guess i'm not TOO worried about gas, i mean heck its already 2.50-2.75 per gallon. i'm a little more worried about the high RPM's cuse i do like 70-85 on the freeway most of the time. and about 40% of my driving is freeway.

    i had a 95 gt with o/r h-pipe and 40 series flows and when i went on a road trip i had a horrible drone, man i got back from SF and my ears rang for like another hour or so.
    i'm just wanting to know what the 4.10's are like on the freeway and long trips ya know?
     
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  6. helty

    helty some Ukrainian's enjoying a handjob via my credit

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    i know what you mean. i drove from little rock to harrisburg pa and back with SLP Loudmouths. really no drone, but after a while even the sweetest exhaust note gets to you. especially 17hrs. but i still say 4.10's. if not, 3.90s.
     
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  7. twogts4us

    twogts4us Advanced Member

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    4.10s definitely. Trust me, we have both and I wish I would have listen to my heart (instead of my tuner) and got the 4.10s like I wanted.
    3.73s help and are nice. 4.10s totally wake it up and are perfect for the mod motor mustang.
     
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  8. AtlanticGT

    AtlanticGT New Member

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    According to the questions I've asked there's nobody that can show that a 4.10 gear is any better than a 3.73 for these cars besides the seat of the pants feel.

    I've asked around every forum and not once did anyone post actual track results.
     
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  9. csledd

    csledd Official Ovary Punching Member
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    That's probably because nobody has put 3.73's in their car, taken it to the track and ran, removed the 3.73s and put in 4.10s, and then ran at the track again. The reason for this is because it's mathmatically proven that 4.10s are better.. this is the best paragraph I've read about it..

    "Gears mulitply your engine's torque to get the car up to speed easier. Without gears to mulitply the engines torque, you will never be able to get your car to take off from a stoplight. Gears are numbered as a ratio, for example 3.27:1. This means that the drive gear (pinion gear) must rotate 3.27 times for the driven gear (ring gear) to rotate once. Let's look at some math to better illustrate this. A stock Mustang GT weighs in at about 3500lbs, its engine has a horsepower rating of 225hp and a torque rating of say 300 lb./ft of torque. Without gears your engine only making 225hp and 300lb./ft of torque will have to try to move a 3500lb mass. That simply isn't gonna happen. Now lets see what gears can do for us. Your typical Mustang has a first gear ratio of about 3.3:1 (in the 96-up cars.) So by taking it's torque of 300*3.3, you now have 990lb/ft of torque to help your car take off. That's still not enough to make for trouble free take-off's. Now take that number and use rear-end geras of say 3.27:1 to mulitply that onto the wheels you now have 3237lb/ft of torque to accelerate you. While this is a healthy number, its still less than your car weighs. Let's see what happens when we install say 4.30:1 gears to the car with 3.27's 300*3.3*4.30=4257lb/ft of torque! That's over 1000 lb/ft of torque, 1020lb/ft to be exact that will help your car off the line. This means less bogging, and a car that is extremely fun to drive. By this example, you can see the advantage of a numerically higher gear ratio."
     
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  10. AtlanticGT

    AtlanticGT New Member

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    In that case, why bother with the 4.10's? Why not go 4.30 or 4.56?

    Perhaps you can explain why a close friend of mine, ran slower with a 4.56 over a 4.10 gear?
     
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  11. csledd

    csledd Official Ovary Punching Member
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    cuz 4.30 or 4.56 is not always practical in driving situations.

    and as far as your friend goes.. it's hard to say without seeing all his numbers.. there's too many things that can effect it.
     
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  12. spikeGT_99

    spikeGT_99 New Member

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    :stupid:
    ive asked the same thing, although i am under no illusion that 3.73s are quicker than 4.10s, im not sure the rewards are worth the sacrifices 2500+ on the highway for hours at a time will get very old very quick
     
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  13. merc123

    merc123 Active Member

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  14. jocko

    jocko Member

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    im pretty sure your friend with the 4.56 gears went slower at the track cause when you run gears that high you need taller tires so you don't redline before the traps,ask him and you'll see,i just installed my drag radials today and got 4.10's in today and im going to try and do them tomorrow if im not that busy at the shop,i won't update cause everyone and they're mamas here have 4.10's and like them so i did not hesitate to buy mine.
     
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  15. flashstang04

    flashstang04 New Member

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    read this, one of the best gear write-ups around from stangnet.



    gears
     
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  16. 04gtdrop

    04gtdrop New Member

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    flashstang04 thanks for the link....
     
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  17. 04gtdrop

    04gtdrop New Member

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    hey guys, i was looking at stuff online and i was wondering, can i buy just the "ring and pinion" or do i need more than this? i.e. crush sleeve, bearings etc etc....
     
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  18. merc123

    merc123 Active Member

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    You'll probably need a bearing kit. If I remeber correctly, my FRPP kit came with a crush sleve but needed replacement bearings. They had to beat my pinion and they said it was ruined when they took it out.
     
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  19. Johnson505

    Johnson505 Member

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    04gtdrop,

    I went through the same thing when I was deciding. After the 4:10 videos were posted I was sold. I would recommend a short throw shifter if you don't already have one. My wife describes my car as scary fast now and it is stock other than the 4:10s. Mine is not a daily driver, but I do go down the interstate alot when I drive it. The rpm's and the flow 50s don't bother me. I would buy some good quality bearings just in case the installer needs them. You can always take them back if you don't use them. Be sure to do your research on a installer. The first guy screwed mine up. My gears whined all the time and there was a terrible hissing noise coming from the rear of the car. The second guy got them right, but had to replace the gears that I just had installed and all my bearings on a car that only had 10,000 miles on it. We can't figure out how the first caused so much damage. After the second install there is a faint whine between 65 & 70mph and I can't hear that when the top is down. The only negative I have heard about 4:10 gears and up are they are more likely to have some whine in them than a 3:73 or lower. Good luck with what ever you decide.
     
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  20. jimfitzgerald

    jimfitzgerald New Member

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    The answer to this question is not going to change, I don't care how many times it is asked. :bang:
     
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