4 speed vs 6 speed automatic
Thread Starter
Intermediate
Joined: Feb 2008
Posts: 27
Likes: 0
From: Marco Island, Florida
4 speed vs 6 speed automatic
If I bought a used C6 coupe and severely upgraded the horse power anywhere from 550 or 650 hp what would be the better transmission to use? I heard that the 4 speed automatic was "stronger" than the newer 6 speed. Should I buy an 05 or an 06?
Melting Slicks
Joined: May 2006
Posts: 2,891
Likes: 1
From: NJ..."the way I saw it, everyone takes a beating sometimes."
Well the '05 has the weaker dif. However if you're planning on modding to 550-650rwhp then I'm sure you'll build up the rear as well....right? I don't know which trans is stronger however the 4 speed has been around for quite a while and there are several shops building bullet-proof, race proven versions of them. I don't believe there is a lot out to beef up the 6 speed auto yet.
Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,403
From: Bethesda MD
With the A6 speed you will be on the cutting edge and hoping the aftermarket catches up before you break it. Or maybe you live close by to a shop that wants to do some R&D work on your car's tranny when it breaks.
If you have 650 rwhp coupled with a good torque converter, the value of the extra 2 gears in the A6 from a drag racing perspective is not very signficant.
Team Owner
Joined: Feb 2001
Posts: 27,246
Likes: 130
From: Short Hills, NJ
With the A6 speed you will be on the cutting edge and hoping the aftermarket catches up before you break it. Or maybe you live close by to a shop that wants to do some R&D work on your car's tranny when it breaks.
If you have 650 rwhp coupled with a good torque converter, the value of the extra 2 gears in the A6 from a drag racing perspective is not very signficant.
as well...I do LOVE my A6 and it is a great (and very strong) transmission but a properly built and stalled A4 with gears is tough to beat from both a performance and strength perspective.I drove Dennis50nj's stalled A4 just last night and that car feels like a beast in every gear.
Drifting
Joined: Dec 2002
Posts: 1,613
Likes: 0
How will you make the power? if you limit the power on shifts IE spray with a window switch you can get more out of the A6
But most seem to think the stock A6 is good to 500-550RWHP
The 05 A4 can be built to handle more power today. But the rear is week.
If you get the A4 the 3.15 gears work well with 600rwhp
But most seem to think the stock A6 is good to 500-550RWHP
The 05 A4 can be built to handle more power today. But the rear is week.
If you get the A4 the 3.15 gears work well with 600rwhp
Le Mans Master
Joined: Jul 2005
Posts: 5,328
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http://forums.corvetteforum.com/show....php?t=1938983
Former Vendor
Joined: Sep 2007
Posts: 5,511
Likes: 22
From: Southern MD
I say A6 all the way. It will perform the same (or better) at the track..and get better all around milage.
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Safety Car
Joined: Nov 2007
Posts: 4,537
Likes: 1,403
From: Bethesda MD
So far there have been only a couple people who have had close to 600 rwhp in an A6, so while positive, the sample is pretty small.
As far as the input torque rating goes, it may seem high but how many engines make much torque around 2000 rpm, the typical stock stall speed? Put a 3200 stall with a 2.5 STR in the car and the torque being pumped through the tranny increases substantially.
It would be great if you are right and the A6 will stand up reliably to 550 HP motor with a 3200 stall. I just don't belive it has been proven at this point.
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