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      05-11-2009, 11:22 PM   #1
KiokenM3
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how would a 4.10 FD affect 1/4 mile times?

i have a e92 m3 and im just wondering how a 4.10 FD would affect 1/4 performance. dinan says its like a 6% increase but would it hurt or improve 1/4 mile times?
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      05-12-2009, 06:17 AM   #2
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I think it would help as long as you can get through the 1/4 mile without an extra shift. I'm going for this mod soon. It's not a drastic change but it should be a nice one. What I like about it is that it is a 6% increase in torque over the entire RPM band with no questions. Not like some of the engine mods that only improve at high RPM and are still questionable due to their testing strategies.
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      05-12-2009, 06:27 AM   #3
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I'm thinking it would improve times if it's a DCT. How much does a new FD cost?
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      05-12-2009, 06:49 AM   #4
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it would be too low for DCT
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      05-12-2009, 09:33 AM   #5
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any idea what gear i should be in at the end of a 1/4? i think i might be at the top of 3rd. if i end in 4th gear, then the 4.10 should help.
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      05-12-2009, 09:54 AM   #6
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At least as far as MPH go, a E92 M3 with a 4.10 and OEM 18" wheels and tires will just hit 100mph at the top of 3rd, and be pushing 135ish at the top of 4th.

A shorter final drive will always help with overall acceleration, and the nice thing about the 4.10 is that you still run out of gear at about 180mph- more than most M3 owners will ever need.
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      05-12-2009, 10:03 AM   #7
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I think the 4.10 gears would be a good mod. The M3 GT4 is running them from the factory, btw.

As far as 1/4 mile gains, who knows. Probably a modest gain since it's not a big jump. The toughest part would be maintaining traction in 1st gear since that can already be a challenge with the stock gears.

Last edited by FStop7; 05-13-2009 at 09:48 AM.
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      05-12-2009, 10:57 AM   #8
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Wouldn't traction be better with lower gears? Since the wheels will be spinning slightly slower when making the same power?
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      05-12-2009, 11:05 AM   #9
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A shorter final drive like a 4.10 would make getting traction more difficult, as power at the ground would be improved. Technically a taller ratio like a 3.43 would improve traction, but only by hurting overall acceleration.

I personally don't follow the logic of getting taller gears to improve traction. Turbo guys do this in the US all the time. What good is having a high horsepower car if you're going to diminish acceleration by running a numerically lower gear ratio?
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      05-12-2009, 11:10 AM   #10
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The problem I find with a higher gear is once you lose traction and start spinning the wheels and the faster they are spinning the less chance you have at regaining traction. So the lower gear will actually slow the acceleration of the wheel down, yet increase torque at the same time.
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      05-12-2009, 11:18 AM   #11
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Quote:
Originally Posted by J08M3 View Post
The problem I find with a higher gear is once you lose traction and start spinning the wheels and the faster they are spinning the less chance you have at regaining traction.
A 3plate diff with variable ramps (30/90) will help in this. I have it because it was installed by DiffOnline when they did my 3.62, should work great with the 4.10 MT. It really is almost night and day difference between the stock diff. Although, I do drive without traction control most of the time.
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      05-12-2009, 11:25 AM   #12
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If you can get the car to hook up 4.10's could be worth .25 sec in the 1/4mile with 1-2mph gain in trap speed.

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      05-12-2009, 11:27 AM   #13
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Quote:
Originally Posted by Ilia@IND View Post
A shorter final drive like a 4.10 would make getting traction more difficult, as power at the ground would be improved. Technically a taller ratio like a 3.43 would improve traction, but only by hurting overall acceleration.

I personally don't follow the logic of getting taller gears to improve traction. Turbo guys do this in the US all the time. What good is having a high horsepower car if you're going to diminish acceleration by running a numerically lower gear ratio?
Turbo cars make so much more torque they can pull the taller gear (lower numerical) and if you blow off the tires and get back on the throttle you could also be dealing with turbo lag. So sometimes it's better to trade off a little on torque multiplication to getting the car to stick. Also, the 997TT is quicker than the manual car for alot of the same reasons.

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      05-12-2009, 01:15 PM   #14
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Quote:
Originally Posted by Dave07997S View Post
If you can get the car to hook up 4.10's could be worth .25 sec in the 1/4mile with 1-2mph gain in trap speed.

Dave

actually i have a set of DR that im running on some stock 18's. so hooking up shouldnt be a problem, i just didnt wanna add another shift in the 1/4, because that would hurt my times. so since i should be in 4th at the end of the 1/4, the 4.10 should only improve my times since im not adding another shift. 4.10 it is. im gonna do it
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      05-12-2009, 09:14 PM   #15
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Quote:
Originally Posted by KiokenM3 View Post
actually i have a set of DR that im running on some stock 18's. so hooking up shouldnt be a problem, i just didnt wanna add another shift in the 1/4, because that would hurt my times. so since i should be in 4th at the end of the 1/4, the 4.10 should only improve my times since im not adding another shift. 4.10 it is. im gonna do it
If ur running DR it should only help, I had them on my E46 and it was harder to hook but it made a big difference through the over all powerband. On a 6mt it wont make as big a difference because they are already 3.82s i believe where as E46 M3 was 3.62 but def. make a difference. I got my fastest 1/4 mile times on my E46 M3 with the 4.10s.
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      05-12-2009, 11:39 PM   #16
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Quote:
Originally Posted by niterider View Post
If ur running DR it should only help, I had them on my E46 and it was harder to hook but it made a big difference through the over all powerband. On a 6mt it wont make as big a difference because they are already 3.82s i believe where as E46 M3 was 3.62 but def. make a difference. I got my fastest 1/4 mile times on my E46 M3 with the 4.10s.
nice
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      05-13-2009, 03:29 AM   #17
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3rd Gear with the stock FD maxes out around 107MPH, given the better traps are generally around 110MPH+, I'd say the 4.10 FD won't make any negative impact on a good run and should in theory be slightly faster assuming you can manage the extra torque to the wheels in 1st gear...
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      05-13-2009, 06:20 AM   #18
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Quote:
Originally Posted by mixja View Post
3rd Gear with the stock FD maxes out around 107MPH, given the better traps are generally around 110MPH+, I'd say the 4.10 FD won't make any negative impact on a good run and should in theory be slightly faster assuming you can manage the extra torque to the wheels in 1st gear...
Hopefully fatter rear tires can help balance this out
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      05-13-2009, 09:04 AM   #19
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Hopefully fatter rear tires can help balance this out

im gonna be running a 265 mickey thompson et street radial.
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      05-13-2009, 09:18 AM   #20
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      05-13-2009, 09:46 AM   #21
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Quote:
Originally Posted by J08M3 View Post
Wouldn't traction be better with lower gears? Since the wheels will be spinning slightly slower when making the same power?
numerically higher = shorter (which is often referred to as 'lower') gear ratio. Shorter ratio, higher torque multiplication.
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      05-13-2009, 09:49 AM   #22
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Quote:
Originally Posted by FStop7 View Post
numerically higher = shorter (which is often referred to as 'lower') gear ratio. Shorter ratio, higher torque multiplication.
Yes I know that hence the slower spinning wheels
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