4.10s = As fast as a DCT?

[shakywarrior]

I've been thinking lately. I see many videos online of DCT (modded & unmodded) cars completely destroying 6MT cars in a 1/4, 40roll on, w/e straight line situation. That is because of the gearing, correct? Anyway, would "slapping" a 4.10 FD close the gaps I see? I understand the 6MT shift will still be slower but could the gap be closed at least...

[SVH]

Nope....

[doogee]

Originally Posted by shakywarrior

I've been thinking lately. I see many videos online of DCT (modded & unmodded) cars completely destroying 6MT cars in a 1/4, 40roll on, w/e straight line situation. That is because of the gearing, correct? Anyway, would "slapping" a 4.10 FD close the gaps I see? I understand the 6MT shift will still be slower but could the gap be closed at least...

Yeah the gearing has nothing to do with it. DCT is just far superior.

[Richbot]

I see a lot of vids of people who don't know what the hell they're doing with a shifter and clutch too. The big problem you can't overcome no matter what short of a new gearset in the 6MT is the 2-3 rev drop on the manual drops the car 600rpm further down than the DCT on 2-3 shifts (5500 rpm vs. 6100 rpm) and the DCT gear ratio spread is just a lot closer where it matters, though once you are doing 3-4 and 4-5 the 6MT starts to be geared just about perfectly for max accel, that 2-3 shift is a killer. But eventually if you keep going long enough the DCT will overheat or all the fluid will leak out, so there's that and if you are delimited the shorter 6MT top gear means you will eventually pass the DCT car after it shifts into the too-tall 7th at 174mph, right before you crash into a tree at north of 185 mph, assuming you haven't changed to the 4.10, in which case you'll run out of revs at 184

[Patrón]

i think it will help. i've seen e46m with manual vs smg and the manual with 4.10s was awesome. it's like a cheap supercharger.

[pbonsalb]

DCT will shift faster than a human. Cant beat that. Gearing could make a 6MT faster in a certain limited speed range, however. Expertly driven, a 6MT is very very close to a 7DCT in a straight line, but it takes much more work to drive a 6MT.

[shakywarrior]

Well I was doing some number crunching on the 4.10s vs 3.84 gears. So 40 roll with stock FD would be about 4700rpms (even though I feel like it's at 4500 everytime I'm at the strip for some reason...) while 4.10 FD I'd be at 5100rpms. That's pretty significant. Idk what rpms the DCT would be at @ 40 but I feel any pull about 5k is remarkably faster for the e92 since revs and power don't stop till 8500. Hopefully I can find someone with a DCT car I can do some real world testing with.

[Richbot]

DCT and 6MT are essentially identical through 1st-2nd gearing wise, the differences start on the 2-3 shift (and obviously DCT is going to make the 1-2 shift happen quicker too)

[Longboarder]

DCT may be tricky to launch sometimes. That's where a good 6MT driver can gain some advantage.

[bigjae1976]

So...you are going against a car that shifts faster. So you want to beat that car by adding more slower shifts in a given distance by lowering your final drive ratio?

That really doesn't make sense.

[shakywarrior]

Originally Posted by bigjae1976

So...you are going against a car that shifts faster. So you want to beat that car by adding more slower shifts in a given distance by lowering your final drive ratio?

That really doesn't make sense.

How is going from 3.84 to 4.10 lower.... Maybe u miss read.

[FogCityM3]

From an acceleration perspective from a dig, think the difference of 4.1 vs 3.85 would be negligible. On a track however, Turner Motorsport themselves say that going to a shorter ratio is one of the best things you can do to make an MT faster on the track to really take advantage of the gift of one of the widest power bands in existence. A lot of time is typically spent in 3rd gear, where on many tracks its a tough call to downshift into second. On long straights you pretty much have to shift in 4th anyway, so don't feel like you're really adding shifts at least on the tracks I go to..may actually subtract downshifts into 2nd. Adding more torque at the wheels at the bottom of the power band helps and the ability to tune to 8600 rpm also helps with the rpm drop. Also look at the M3 GT4 gearing: 4.1 rear diff. It's done for a reason, not to mention the benefits you get from earlier locking mechanisms and that 6th gear has a very hard time overcoming wind resistance and is basically unusable.

[pbonsalb]

I would do 8600 limiter if I changed to a 4.10.

[shakywarrior]

Originally Posted by FogCityM3

From an acceleration perspective from a dig, think the difference of 4.1 vs 3.85 would be negligible. On a track however, Turner Motorsport themselves say that going to a shorter ratio is one of the best things you can do to make an MT faster on the track to really take advantage of the gift of one of the widest power bands in existence. A lot of time is typically spent in 3rd gear, where on many tracks its a tough call to downshift into second. On long straights you pretty much have to shift in 4th anyway, so don't feel like you're really adding shifts at least on the tracks I go to..may actually subtract downshifts into 2nd. Adding more torque at the wheels at the bottom of the power band helps and the ability to tune to 8600 rpm also helps with the rpm drop. Also look at the M3 GT4 gearing: 4.1 rear diff. It's done for a reason, not to mention the benefits you get from earlier locking mechanisms and that 6th gear has a very hard time overcoming wind resistance and is basically unusable.

I feel ya. I'm talking about purely acceleration though. Wouldn't the gear drops change with the 4.1 change? Meaning we'd be higher in the powerband after every shift compared to 3.85.

[shakywarrior]

Originally Posted by pbonsalb

I would do 8600 limiter if I changed to a 4.10.

I have the 8600 rev limit. I love seeing the tac go well into the red.

[dparm]

Originally Posted by shakywarrior

I've been thinking lately. I see many videos online of DCT (modded & unmodded) cars completely destroying 6MT cars in a 1/4, 40roll on, w/e straight line situation. That is because of the gearing, correct? Anyway, would "slapping" a 4.10 FD close the gaps I see? I understand the 6MT shift will still be slower but could the gap be closed at least...

It also has to do with the fact that there is effectively no drop in power between shifts. Yes, a 4.10 final drive will improve acceleration, but it will not overcome the brief period of time when you are between gears, no matter how fast you can shift.

What is the reason for wanting the 4.10? Is it for stoplight racing? Are you going to take the car to the drag strip often? Do you track the car? One or more of these things? Knowing this will be the first step in deciding if you need to change the gearing (if at all) and by how much. Lego-building might not get you what you want, so help us understand the use cases.

[shakywarrior]

Originally Posted by dparm

It also has to do with the fact that there is effectively no drop in power between shifts. Yes, a 4.10 final drive will improve acceleration, but it will not overcome the brief period of time when you are between gears, no matter how fast you can shift.

What is the reason for wanting the 4.10? Is it for stoplight racing? Are you going to take the car to the drag strip often? Do you track the car? One or more of these things? Knowing this will be the first step in deciding if you need to change the gearing (if at all) and by how much. Lego-building might not get you what you want, so help us understand the use cases.

There's a 40 roll drag strip in my area. I would like to be as fast as the DCT cars and all other NA V8s in our HP range, 400-500 range. I really do think having the revs higher up with the 4.1 would help a lot. I do a lot of experimenting, and I've noticed, 50 roll with the rpms around 5500 is a PERFECT spot for this powerband. So my logic is, I want 5k or higher at 40mph because I feel it would increase acceleration.

[bigjae1976]

Originally Posted by shakywarrior

How is going from 3.84 to 4.10 lower.... Maybe u miss read.

Meant shorter. Doh!

[Dave07997S]

A set of 4.10 gears with a 8600rpm would be an awesome package, especially from a roll. Off the line you can leave to hard and just end up smoking 1st and 2nd gear.

I plan on doing this along with bumping up the rpm limit to 8600rpm once my warranty gets near the end. Then maybe a set of Shcrick bumpsticks to go along with it.



Dave

[shakywarrior]

Originally Posted by Dave07997S

A set of 4.10 gears with a 8600rpm would be an awesome package, especially from a roll. Off the line you can leave to hard and just end up smoking 1st and 2nd gear.

I plan on doing this along with bumping up the rpm limit to 8600rpm once my warranty gets near the end. Then maybe a set of Shcrick bumpsticks to go along with it.



Dave

Exactly my thoughts. I feel like the S65 would be monsterous from a roll with 4.1/8600. I never really do digs anyways.

[Richbot]

Running a 285/30-18 is nearly the same gearing advantage compared to the stock tires

[dparm]

Originally Posted by shakywarrior

There's a 40 roll drag strip in my area. I would like to be as fast as the DCT cars and all other NA V8s in our HP range, 400-500 range. I really do think having the revs higher up with the 4.1 would help a lot. I do a lot of experimenting, and I've noticed, 50 roll with the rpms around 5500 is a PERFECT spot for this powerband. So my logic is, I want 5k or higher at 40mph because I feel it would increase acceleration.

Okay, then you may want to start looking at generating thrust curves for the proposed gearing/tires/powerband, something I talk about in this old thread:

http://www.m3post.com/forums/showpos...0&postcount=39