I absolutely LOVE the 6L80. 
C6 Auto Trannies
Thread Starter
Burning Brakes
Joined: Jan 2005
Posts: 790
Likes: 8
From: Charleston SC
C6 Auto Trannies
I'm hearing chatter of people talking about the new auto trannies being more efficient and robbing less horsepower than manual transmissions.
Normally, I'd argue this to the grave simply because I've owned LT1 and LS1 automatics and 6speeds. I've dynoed both and I've witnessed hundreds of dyno sessions. All things being the same on the motor, the manual trannies routinely allow more hp to the rear wheels. Over the years you hear the standard drivetrain reductions 15-17% for manuals (pending lightweight clutches, driveshafts and beefier differentials) vs. 20-22% for automatics (pending high stall converters, lock or unlocked).
Admittedly, I havent bothered to read anything on any of the newer trannies 05' and newer. Is there any truth to it?
Thanks,
Jeff
Normally, I'd argue this to the grave simply because I've owned LT1 and LS1 automatics and 6speeds. I've dynoed both and I've witnessed hundreds of dyno sessions. All things being the same on the motor, the manual trannies routinely allow more hp to the rear wheels. Over the years you hear the standard drivetrain reductions 15-17% for manuals (pending lightweight clutches, driveshafts and beefier differentials) vs. 20-22% for automatics (pending high stall converters, lock or unlocked).
Admittedly, I havent bothered to read anything on any of the newer trannies 05' and newer. Is there any truth to it?
Thanks,
Jeff
Team Owner
Joined: Feb 2001
Posts: 27,253
Likes: 134
From: Short Hills, NJ
Yes automatic's might be a little more efficient than they used to be but the typical torque convertered automatic is NOT more (or even equally) efficient or capable of making the same rwhp/rwtq as a manual, all else being equal.
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
Tell that to all the 5 and 6 speed manual tranny cars that get a view of my taillights at the track. IMO, I belive the A6 is probally the best auto tranny to come along in a long time. Even with a stock stall, these cars hand defeat to M6 cars in most cases, granted, driver error is not calcualted.I do agree the manuals tend to show more rwhp and tq on an identical car, but it's all how you use it.
Race Director
Joined: Dec 2007
Posts: 19,574
Likes: 167
From: Frederick, MD
GM cars usually seem to have decent auto trannies that perform very close to their manual siblings. Unlike some imports where you lose 1-2 seconds to sixty when it is saddled by an automatic.
Drifting
Joined: Dec 2002
Posts: 1,613
Likes: 0
The M6 will show more hp on the dyno but in the real world and my testing the A6 (06+) pulls away at the dragstrip and all the way to 179.
I have tested it stock to stock and bolt on to bolt on A6 360rwhp vs M6 390rwhp The lower powered auto ran a quicker ET and Higher MPH 3 out of 3 passes
It may simply by he gearing advantage of the A6 and/or the shifts.
Remember the A6's 4th is not 1:1 but slightly better.
I have tested it stock to stock and bolt on to bolt on A6 360rwhp vs M6 390rwhp The lower powered auto ran a quicker ET and Higher MPH 3 out of 3 passes
It may simply by he gearing advantage of the A6 and/or the shifts.
Remember the A6's 4th is not 1:1 but slightly better.
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Burning Brakes
Joined: Mar 2006
Posts: 946
Likes: 0
From: Midland, TX........ 550 RWHP/520 RWTQ (A6)
I've poured over ALOT of dynos and this is what I've found (on average): MN6= 12% drivetrain loss
A6=17% loss
The losses are not as great as you might think, but the standard still transfers more to the wheels.
The above firgures only apply to the C6.............
A6=17% loss
The losses are not as great as you might think, but the standard still transfers more to the wheels.
The above firgures only apply to the C6.............
Melting Slicks
Joined: Nov 2004
Posts: 2,514
Likes: 1
From: Orwigsburg Pa.
While my LS3 with the mn6 makes more power then my LS2 with the A6, THE LESSER powered automatic would be my choice for the 1/4 mile. Launching and wheelspin is always a problem with the manual with the Z51 runcraps. The A6 is very effecient for the quarter mile and frankly the standard runcraps seem to grab better. From a roll , the mn6 is king .
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
While my LS3 with the mn6 makes more power then my LS2 with the A6, THE LESSER powered automatic would be my choice for the 1/4 mile. Launching and wheelspin is always a problem with the manual with the Z51 runcraps. The A6 is very effecient for the quarter mile and frankly the standard runcraps seem to grab better. From a roll , the mn6 is king .
Intermediate
Joined: Apr 2006
Posts: 47
Likes: 0
From: Tacoma WA
Tell that to all the 5 and 6 speed manual tranny cars that get a view of my taillights at the track. IMO, I belive the A6 is probally the best auto tranny to come along in a long time. Even with a stock stall, these cars hand defeat to M6 cars in most cases, granted, driver error is not calcualted.I do agree the manuals tend to show more rwhp and tq on an identical car, but it's all how you use it.
