[schneid4323]

Auto has a better diff for acceleration

[hotrod182]

Originally Posted by Kenny H

When I say track I meant drag strip, not auto cross etc....


And Fbody guys have mullets, not Mustang guys. Of course I have had 2 of them previously as well but I can't do the mullet thing....:-)

Is your 04 GTO stock running a 13.5sec qtr a 5.7L? What do the 6.0L GTOs run stock?

[bnj]

Originally Posted by schneid4323

Auto has a better diff for acceleration

Manual has better gear ratios.

[Walked U]

Originally Posted by hotrod182

Is your 04 GTO stock running a 13.5sec qtr a 5.7L? What do the 6.0L GTOs run stock?

My buddy ran 13.6@106 bone stock with stock tires. At LACR also.

So I guess you can say thats about a 13.4-13.3 @ 107ish at sea level.

Oh thats with a 6mt.

Driver mod.

http://www.dragtimes.com/Pontiac--GT...l?resultpage=3

look for the 05+, those are the ls2's (6.0L)

[Driver72]

Originally Posted by GraphiteBrawler

I only wish the 335 came with SMG as an option when I got mine

Why SMG kinda stinks.
Audi/VW's DSG is way better and BMW's own steptronic is way smoother.
There's a reason BMW is dumping the SMG and so many manufacturers are copying Audi/VW's DSG.

Oh and CDV delete or not, I'd say 9 times out of 10 the autos will be faster.
It'll take a perfect launch and super fast manual driver to beat the autos in a drag and then it won't be by much.
The manuals hold the advantage as speeds climb over 100 mph (4th-6th gear).

[Driver72]

Originally Posted by bnj

Manual has better gear ratios.

The individual gear ratios on the auto and manual are virtually identical.
But the auto has a lower (higher numerical) final drive ratio for more aggressive acceleration.

[bnj]

Originally Posted by Driver72

The individual gear ratios on the auto and manual are virtually identical.
But the auto has a lower (higher numerical) final drive ratio for more aggressive acceleration.

When you multiply the diff. ratio x gear ratios, you see that successive ratios are close to each other with MT, whereas AT successive ratios are far from each other.

So, what do you mean by aggressive?

[Mr. 5]

Originally Posted by l4wr3nc3

Thats the stupidest thing i ever heard. I guess you should tell all the e46 m3 smg's to gtfo the track. Oh and the auto 911 turbos should probably not even bother with track as well huh.

I completely agree with you. Most track cars these days are track cars.

[Insider]

Originally Posted by leftcoastman

Some of you may say that going into manual mode will prevent kickdowns, but what if your last paddle induced shift was a few linked turns ago and now the car is back in auto mode?

When I put it in 3rd, damnit, I want it to stay there until I tell it otherwise!

Why do you think the car would be back in auto mode? Once you use the paddles in SD, it stays in manual mode forever until you put it back in Drive or shut of the car.

[Driver72]

Originally Posted by bnj

When you multiply the diff. ratio x gear ratios, you see that successive ratios are close to each other with MT, whereas AT successive ratios are far from each other.

So, what do you mean by aggressive?

They might be "closer" but they are not as aggressive.
The higher the number the better for acceleration.
The lower the number the better for cruising and gas mileage.
Only 5th and 6th gear is more aggressive overall in the manual than the auto.

For instance in the manual 1st gear is 4.06 with a final drive of 3.08
In the auto 1st gear is 4.17 with a final drive of 3.46

This more aggressive gearing in the auto makes up for the 5-10 rwhp the auto losses in extra drivetrain loss. And the speeds of the auto shifts also help as it shifts faster than any human can in a manual.

[bnj]

Ok, I did not understand what you meant by aggressive. I would say AT gearing is shorter (gears 1-4). MT gearing is close-ratio and damn more aggressive from 70mph to 180mph.

[Driver72]

Originally Posted by bnj

Ok, I did not understand what you meant by aggressive. I would say AT gearing is shorter (gears 1-4). MT gearing is close-ratio and damn more aggressive from 70mph to 180mph.

Well, I wouldn't say the manual's gearing is "damn more aggressive".
But more like, "teeny tiny bit" more aggressive in 5th and a "bit" more aggressive in 6th.
5th gear in the manual is basically identical to 5th in the auto.
5th Gear ratio x final drive ratio = 3.08 in the manual and 3.01 in auto.
And 6th gear is an overdrive gear. Manual's is 2.679 and auto is 2.387

Top of 4th is like 120 mph.
As I said before, a rolling race from 100-150 (top speed) the manual will take the auto by a bit, but anything below that it's the autos advantage, and not many races start at about 100 mph.

[bnj]

Originally Posted by Driver72

Well, I wouldn't say the manual's gearing is "damn more aggressive".
But more like, "teeny tiny bit" more aggressive in 5th and a "bit" more aggressive in 6th.
5th gear in the manual is basically identical to 5th in the auto.
5th Gear ratio x final drive ratio = 3.08 in the manual and 3.01 in auto.
And 6th gear is an overdrive gear. Manual's is 2.679 and auto is 2.387

You wouldn't say that because you don't understand what I mean by "aggressive". What I mean by that is that the car puts a lot of power down, whereas you mean by "aggressive" that a certain gear is shorter. In AT the gears are further from each other meaning that a gear shift puts you down on the rev range where there is less power. Closer ratio MT puts you less down to the point with nice hp to begin with the new gear. So you end up putting more power down with MT.

Originally Posted by Driver72

Top of 4th is like 120 mph.
As I said before, a rolling race from 100-150 (top speed) the manual will take the auto by a bit, but anything below that it's the autos advantage, and not many races start at about 100 mph.

"Top of 4th is like 120mph" doesn't mean anything. You can take whatever speed (rolling start, not from 0mph) and close ratio MT tranny is more likely to have a good gear for the starting speed. And when the race is on, the gears being closer to each other keeps MT using the highest power rpm-range only, whereas at each shift AT falls further down in the revs (and power).

I'm not saying that AT wouldn't be fast. It is especcially since the gear changes are fast independent of a driver. But I would say that AT tranny has short gearing (1-4), not aggressive, because AT gears are far from each other putting less power down on average.

[Insider]

Originally Posted by bnj

You wouldn't say that because you don't understand what I mean by "aggressive". What I mean by that is that the car puts a lot of power down, whereas you mean by "aggressive" that a certain gear is shorter. In AT the gears are further from each other meaning that a gear shift puts you down on the rev range where there is less power. Closer ratio MT puts you less down to the point with nice hp to begin with the new gear. So you end up putting more power down with MT.



"Top of 4th is like 120mph" doesn't mean anything. You can take whatever speed (rolling start, not from 0mph) and close ratio MT tranny is more likely to have a good gear for the starting speed. And when the race is on, the gears being closer to each other keeps MT using the highest power rpm-range only, whereas at each shift AT falls further down in the revs (and power).

I'm not saying that AT wouldn't be fast. It is especcially since the gear changes are fast independent of a driver. But I would say that AT tranny has short gearing (1-4), not aggressive, because AT gears are far from each other putting less power down on average.

I don't get it. If you shift out of second in the auto at redline (65mph) and then into third which redlines as 100, how is it that the auto gears are, as you say "far from each other" compared to the manual which you whould shift out of second at 70 and into third which redlines at 105? Seems like the auto has the gears more closely spaced.

[Driver72]

Originally Posted by bnj

You wouldn't say that because you don't understand what I mean by "aggressive". What I mean by that is that the car puts a lot of power down, whereas you mean by "aggressive" that a certain gear is shorter. In AT the gears are further from each other meaning that a gear shift puts you down on the rev range where there is less power. Closer ratio MT puts you less down to the point with nice hp to begin with the new gear. So you end up putting more power down with MT.



"Top of 4th is like 120mph" doesn't mean anything. You can take whatever speed (rolling start, not from 0mph) and close ratio MT tranny is more likely to have a good gear for the starting speed. And when the race is on, the gears being closer to each other keeps MT using the highest power rpm-range only, whereas at each shift AT falls further down in the revs (and power).

I'm not saying that AT wouldn't be fast. It is especcially since the gear changes are fast independent of a driver. But I would say that AT tranny has short gearing (1-4), not aggressive, because AT gears are far from each other putting less power down on average.

I understand what you are saying about the spacing between the gears now. But that doesn't really describe aggressive gearing, what that is is "close ratio gearing".
You can have gears that are super close together, but if they are not "short" or aggressive, you aren't going to accelerate any faster just because they are close together.

Another example of my point:

If the manual and auto are starting off in 2nd gear at 30 mph, the auto's more aggressive "shorter" gearing will have it turning more rpms and therefore be more in the powerband from the start. Then as the race continues the auto will shift to 3rd before the manual and start climbing up the powerband again. At this point the manual will shift to 3rd and be again in a lower rpm as the auto is pulling higher up the power band.
On top of that, with the autos shorter gearing, it will spin THROUGH the rpm range faster in 1st-4th gears as well

[bnj]

So in AT 3rd is 54% taller than 2nd. In MT 3rd is 50% taller than 2nd. So you begin the third gear at lower revs i.e. at lower power with AT.

[Driver72]

Originally Posted by bnj

So in AT 3rd is 54% taller than 2nd. In MT 3rd is 50% taller than 2nd. So you begin the third gear at lower revs i.e. at lower power with AT.

No. Because the AT 3rd gear has a multiplication of 5.259 whereas the MT has a 4.866, so you will be spinning more rpms in the AT than the MT.
At ANY speed in 1st through 4th gear you will be spinning more rpms in the AT than in the MT. The MT might drop less BETWEEN each gear shift, but the AT will still be spinning more rpms as it has a "shorter" more aggressive gearing in 1st through 4th gear.

[bnj]

From 30mph you kick down 1st? Now its better for MT since its 1st is better suited at 30mph. Sure you can find speeds that are sweet spots for AT. Most of the starting speeds are better for MT.

[Driver72]

Originally Posted by bnj

From 30mph you kick down 1st? Now its better for MT since its 1st is better suited at 30mph. Sure you can find speeds that are sweet spots for AT. Most of the starting speeds are better for MT.

You only kickdown IF you push it past the kickdown stop.
You are still wrong about starting speeds.
Pick a gear and speed that's below 100 mph and the AT will be turning more rpms at that point.
It doesn't matter if you start in 2nd at 20, 2nd at 40, 3rd at 50, 3rd at 70, the auto will be turning more rpms and rip through that gear quicker, then shift faster, and start ripping through the next gear faster than the manual.

The manual makes up for a lot of that by putting 5-10 hp more to the ground than the auto, but still doesn't quite overcome the autos gearing and shift speed advantage. Again, maybe a perfectly driven manual might take a slight advantage over the auto, but 95% of the time the auto will win a drag race. There's a reason nearly all the best acceleration times of the 335i have been done with the autos.

[bnj]

Originally Posted by Driver72

No. Because the AT 3rd gear has a multiplication of 5.259 whereas the MT has a 4.866, so you will be spinning more rpms in the AT than the MT.
At ANY speed in 1st through 4th gear you will be spinning more rpms in the AT than in the MT. The MT might drop less BETWEEN each gear shift, but the AT will still be spinning more rpms as it has a "shorter" more aggressive gearing in 1st through 4th gear.

No. MT revs until red line and at each shift revs drop less than in AT. There is no way AT revs more. As an example what are the revs at 69mph?

[Driver72]

Originally Posted by bnj

No. MT revs until red line and at each shift revs drop less than in AT. There is no way AT revs more. As an example what are the revs at 69mph?

I don't think you still understand.
Revving to redline doesn't mean ultimate speed.
Redline is set by the manufacturers as the "maximum amount of revs the engine should be revved for safety and durability".
It is not "redline is set as the best point at which to shift and give you maximum acceleration".

Many cars get their best acceleration runs by "short shifting" which means shifting before redline.
The AT does not rev more than the MT, it revs faster. The shorter, more aggressive gearing gets the wheels turning faster and therefore gets the engine through the rev range faster.
It's the same principle that your car runs through 1st gear A LOT faster than 6th gear. 1st has much shorter gearing.
The auto has shorter gear and will accelerate the car through a given gear faster than the manual because of this.

[bnj]

Originally Posted by Driver72

I don't think you still understand.
Revving to redline doesn't mean ultimate speed.
Redline is set by the manufacturers as the "maximum amount of revs the engine should be revved for safety and durability".
It is not "redline is set as the best point at which to shift and give you maximum acceleration".

Many cars get their best acceleration runs by "short shifting" which means shifting before redline.

I understand this perfectly well. I gave this example for you to understand that it is not possible for AT to rev any higher as MT during acceleration. In reality, it makes sense to shift below readline when the power curve starts dropping rapidly.

Originally Posted by Driver72

The AT does not rev more than the MT, it revs faster. The shorter, more aggressive gearing gets the wheels turning faster and therefore gets the engine through the rev range faster.
It's the same principle that your car runs through 1st gear A LOT faster than 6th gear. 1st has much shorter gearing.
The auto has shorter gear and will accelerate the car through a given gear faster than the manual because of this.

You need to think the big picture. Take a random speed. It is very likely that AT needs to shift sooner and thus run at low revs soonr than MT. AT starts running low revs not only sooner than MT, but also lower than MT.

Take for example 50mph. AT needs to change soon to low revs whereas MT can be kept on the high powerband a lot longer. From this speed to top speed the sum of the integrals under the power curves at each gear is much much more favourable for MT than for AT. Do some integration and you will see

This is self evident for people having spent time with competition cars. It is essential to have close-ratio gearing. Typically the first gear is tall and the subsequent gears are close to each other so that the top gear is comparatively short. This is the way for a car to deploy the highest possible part of power curve all the time. Never dropping too low in revs.