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I have a noob question. I've been reading through the threads here and in more than one, it seems as though people think that, once they are able to tune the computer in the 392, the automatic tranny will be quicker in the 1/4 mile than the manual. I don't understand that. Is the 6 speed that difficult to launch? I had a 12 second 87' Mustang 5 speed which wasn't all that hard- albeit with slicks.

I have the hots for these cars and I'm looking to buy soon for a weekend toy. If the consensus is that a simple computer tune will make the stock Automatic 392 that much quicker and easier to get moving fast, I "may" go that route so that my wife can enjoy it. Something about auto's being better just seems so wrong though...
 

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Automatics always have been "consistent" the only stick that will ever be as consistent as an auto on the drag strip is a full professional level race transmission that is computer/air shifted...

You launch a stick car wrong and you've already lost the race. But in the automatic it's just easy to repeat. If you are a seasoned pro at driving a stick then I see no reason why you can't lay down fantastic numbers though.
 

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Automatics always have been "consistent" the only stick that will ever be as consistent as an auto on the drag strip is a full professional level race transmission that is computer/air shifted...

You launch a stick car wrong and you've already lost the race. But in the automatic it's just easy to repeat. If you are a seasoned pro at driving a stick then I see no reason why you can't lay down fantastic numbers though.
:thumbsup:What he said, but I would never trade my stick for an auto.
 

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It just takes practice, either way it's a lot of driver skill. I've beaten folks with the same car as me but auto. It's just your preference.
 

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Thank you for the quick replies. I really want the manual.
It's really all about personal preference. If you really want the manual, then get the manual. Some people prefer the auto, so that's what they should get.

I've seen the arguments about how the auto is a few tenths faster in the 1/4 mile. If that means something to you then you should consider that.

I have a six speed 2010 SRT (daily driver). I love it, and I really wanted a stick, too. The stick and auto are both fast as hell, and both versions are a ***** to run against on the road. Those few tenths in a straight 1/4 mean little running down the highway, and the few cars that have played with me (Charger, 2011 Mustang GT, 2011 Camaro SS) didn't come out on top. Light to light I may have lost (I'm stock), but I don't generally run that way.

Don't spend that much money on something you "almost" want. If you like the stick (like me) get it. I look at it as an "entertainment" expense. My six speed entertains the hell out of me.
 

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The primary advantages of the auto are:

- the torque converter (TC) really helps on the hole-shot
- the TC absorbs drive line shock and reduces chances for broken CV and half shafts
- faster shifting with no acceleration loss between gears
- it can be power-braked at the starting line to pre-load the TC at the stall RPM
- it's much easier to cut a good light at the tree
- more consistent 60' times when used with DRs or slicks

The only real advantage the current M6 has over the current A5 (aside from the obvious fun factor) is more gears with shorter and more closely spaced ratios. From a 10 MPH roll, I wouldn't be surprised if the M6 walked the A5 a bit.

The gearing/ratio-spacing advantage of the M6 will end whenever Chryco decides to put an A8 into the Hemi-equipped cars. Would be nice if it was a dual clutch unit to, which would put shifts into the 150-200 millisecond range with zero power loss between shifts.

The vast majority of drag racing cars are auto trans for the above reasons. If you want a manual tranny to really perform on the hole-shot, then it's best to use a 2-step launch control, a racing spec clutch, and a heavy duty live rear axle. Watch videos of modified 5.0 Mustangs and Boss 302's with 2-steps launching at 6 grand with drag radials and a live axle and it brings a tear to the eye of any old-school drag racer who grew-up in an era where brutish manuals like the M22 rock crusher lashed to indestructible live axles ruled the street and strip.

 

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The only real advantage the current M6 has over the current A5 (aside from the obvious fun factor) is more gears with shorter and more closely spaced ratios. From a 10 MPH roll, I wouldn't be surprised if the M6 walked the A5 a bit.
I don't think there is even an advantage there. Both utilize a typical 4-speed setup for the gear reduction (not much difference as far as spacing), and the additional gears above that are simply overdrive ratios. The automatic has 1 overdrive ratios, and the manual has 2 overdrive ratios.
 

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Get what you want. MosT people will be faster with a Auto. I believe I am pretty good with a manual, but I believe I am faster with a Auto. I have a couple of 4 speed cars now (68 Firebird conv and a 70 SS Chevelle) and I love to drive them, but my go fast car (08 Challenger) has a Auto. Depends on what you want out of your car. Also the more HP you add to your car the more the auto will benefit you (ask Rubble). If you are not going to mess with the HP it may not be as big of issue. Good luck and enjoy your Challenger
 

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Auto all the way if your interested in the fastest off the line.
 

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I test drove both, and the M6 had a totally different feel. I have ran a 13.5 stock with my car, with a 2.0 60ft, so they can be launched if you take your time. i love my car and would never trade it for an auto.
 

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Since I'm not a drag racer, the "fun factor" was what was of most interest to me. Therefore, the decision was to get a MANUAL shift.
 

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I have a noob question. I've been reading through the threads here and in more than one, it seems as though people think that, once they are able to tune the computer in the 392, the automatic tranny will be quicker in the 1/4 mile than the manual. I don't understand that. Is the 6 speed that difficult to launch? I had a 12 second 87' Mustang 5 speed which wasn't all that hard- albeit with slicks.

I have the hots for these cars and I'm looking to buy soon for a weekend toy. If the consensus is that a simple computer tune will make the stock Automatic 392 that much quicker and easier to get moving fast, I "may" go that route so that my wife can enjoy it. Something about auto's being better just seems so wrong though...
My thought on the whole matter is that if you like manual transmissions, you will never like the automatic. I am in the camp of the few who believe auto transmissions are getting worse, not better. Given your previous experience with a manual transmission, I'm providing the details below.

From my experiences with modifying the same automatic transmission in my previous 600 ft-lb AMG Mercedes -
The auto transmission (NAG1/5A/722.6 or whatever the companies want to call it) should not be compared to a TH400 or 727 that has been modified for drag racing. It also can't be compared to an "F1" tranny system that is on, say, an SMG BMW, Ferrari, etc. It started life as a luxury automatic transmissions for Mercedes. No matter how much the line and shift pressure is cranked up, it still takes forever for the fluid to energize through the valvebody and to take up the slack in the clutch packs. It you expect it to be like a modified TH400 or 727, you'll be disappointed.

There is a long term ownership aspect to consider as well. Loose torque convertors, aggressive torque convertor lockup, and wide ratios are short term fun but a bad combination over the long term. The car companies don't worry about this it doesn't become a problem until after the warranty expires.

If you like manual transmissions, the automatic will always feel like -
1. It is slipping (the torque convertor is loose for good 0-60 times, when the clutch isn't locked it is slipping)
2. It is hunting for the right gear
3. It is flashing between gears. This is an unintended consequence of torque redution. The new Charger R/T commercial has a part where a flash occurs during a gear shift ... geez. In fairness, the six speed auto in the Fords and GMs does this as well.
4. It is never in the right gear

For these reasons, I traded my AMG for my manual transmission SRT8.

To be honest, will the auto beat a manual at the drag strip? In the majority of times, most definitely. The launch from the torque convertor is a definite advantage. Also, IMC the auto has two shifts to get to the end of the quarter and the manual has three.

Some have mentioned personal preference, you've mentioned wanting to have it set up so that your wife can enjoy it but that you've also like the manual, so in the end there's a balancing of what you want the car for.
 

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I don't think there is even an advantage there. Both utilize a typical 4-speed setup for the gear reduction (not much difference as far as spacing), and the additional gears above that are simply overdrive ratios. The automatic has 1 overdrive ratios, and the manual has 2 overdrive ratios.
The M6 does have shorter and more closely-spaced gearing in 1st-5th compared to the A5. With less parastic loss and shorter gearing, it will accelerate more quickly in each gear than the A5. But it will lose time between gears unless powershifted. And it lacks the TC advantage on the hole-shot.

These off-setting variables are probably why they are so close in 1/4-mile times. I wouldn't be surprised to see the A5 get the shorter 60' times and the M6 reel in the A5 because 2nd-4th is a considerably shorter. The A5 is still in 3rd at the stripe and the M6 is well into 4th.


M6 with 3.91 diff:

1st 2.97 / 11.61
2nd 2.10 / 8.21
3rd 1.46 / 5.71
4th 1.00 / 3.91
5th 0.74 / 2.89
6th 0.50 / 1.96

A5 with 3.06 diff:

1st 3.59 / 10.98
2nd 2.19 / 6.70
3rd 1.41 / 4.31
4th 1.00 / 3.06
5th 0.83 / 2.54
 

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Buy the car with the tranny you want so you wont have any regrets. The auto guys are proven to be quicker and faster in the 1/4 by far while the 6-speed guys are still learning and trying to overcome challenges, some with the drivers and some with the tube. Remember, the auto has been out since 2005 or so (Charger/300) while manuals have only been out since 09.

I am shooting for 1000rwhp with a manual to see what is possible. I know that an auto will be quicker and faster and I fully expect to blow up my tranny a couple of times this year when I finally get to the track. Maybe next year it will get an auto conversion if I decide to really pursue drag racing again.

On a side note, remember rubbles manual had some big problems from the builder and he sold it to and converted to an auto. I dont believe that car made a single pass with a manual. I could be wrong.

Its your car and a lot of money to invest, dont have regrets as soon as you get it. Unless you are taking it to the track a lot you wont feel the difference and you shouldnt be street racing it anyways. I compromised with my Z roadster and got an auto so the wife could drive it. I really would have preferred a manual but the wife has to be happy and she compromised with the SRT transmission choice.
 

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The M6 does have shorter and more closely-spaced gearing in 1st-5th compared to the A5. With less parastic loss and shorter gearing, it will accelerate more quickly in each gear than the A5. But it will lose time between gears unless powershifted. And it lacks the TC advantage on the hole-shot.

These off-setting variables are probably why they are so close in 1/4-mile times. I wouldn't be surprised to see the A5 get the shorter 60' times and the M6 reel in the A5 because 2nd-4th is a considerably shorter. The A5 is still in 3rd at the stripe and the M6 is well into 4th.


M6 with 3.91 diff:

1st 2.97 / 11.61
2nd 2.10 / 8.21
3rd 1.46 / 5.71
4th 1.00 / 3.91
5th 0.74 / 2.89
6th 0.50 / 1.96

A5 with 3.06 diff:

1st 3.59 / 10.98
2nd 2.19 / 6.70
3rd 1.41 / 4.31
4th 1.00 / 3.06
5th 0.83 / 2.54
Look at the ratios from 1-4. They are nearly identical. It's the same number of speeds distributed from reduction to 1:1. There isn't much room to achieve "closer spacing" when we are talking about 4 speeds vs 4 speeds. The chief difference between these transmission is just like I said...1 overdrive vs 2 overdrive speeds.

Now if you wanted to say the difference in axle ratios makes the relative spacing closer, then you might have a point. However, you should also be quite aware that it isn't straightforward to quantify effective ratios on an automatic, anyway, due to the fundamental nature of a fluid coupling. The primary duty of the torque converter is to slip in response to engine load, and by virtue of that slip, convert it into multiplied torque. You can see that as effectively changing the axle ratio (or changing each individual gear ratio, but it may be easier just to take it out of one axle ratio). It's like an additional 1.4x reduction (with similar multiplication to torque) at high engine loads. So "3.06" becomes more like "4.28" when the engine is working hard.

That said, it is very shaky to say which really has "closer-spaced" gearing by virtue of gear ratios that you can put a number on. On a technical basis, the 2 transmissions are very close, if not the same, as far as gear spread over the gear reduction to 1:1 range. With the torque converter taken into effect, you could also argue that the automatic is actually a step ahead in shorter gearing.

I don't even know if you can say a shorter axle even results in "closer-spaced" gearing. The spacing is still determined by the transmission ratios. Slap a different axle ratio on it, and the percent difference between each gear is still the same. It just results in different road speeds for a given rpm.

To truly have closer spaced gears, you simply need more speeds at work in the range of gear reduction to 1:1. Otherwise, the best you can achieve is closer spacing between some gears at the expense of farther spacing in others.
 
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