Official A4 to M6 (T-56) Thread!
12-02-2008, 10:55 PM
#593
TECH Senior Member
iTrader: (6)
Join Date: Jul 2005
Location: Decatur, AL
Posts: 5,257
Likes: 0
Received 0 Likes
on
0 Posts
12-04-2008, 12:53 PM
#594
Teching In
Join Date: Feb 2008
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Trans gear ratios:
4L60E: 3.06, 1.63, 1.00, .696, 2.29 Reverse
T-56 F-body LS1: 2.66, 1.78, 1.30, 1.00, .74, .50, 2.90 reverse
T-56 GTO: 2.97, 2.07, 1.43, 1.00, .80, .62, 2.90 or 3.28 reverse (have seen conflicting data regarding ratios)
70 mph = 1914 rpm w/4L60E, 3.73 gears, 31.9" tire for all examples
49.9 mph @ 1st gear @ 6000 rpm
70 mph = 1375 rpm w/T56 F-body, 3.73 gears, 57.4 mph in 1st gear @ 6000
70 mph = 1681 rpm w/T56 F-body, 4.56 gears, 47.0 mph
70 mph = 1891 rpm w/T56 F-body, 5.13 gears, 41.7 mph
70 mph = 1705 rpm w/T56 GTO, 3.73 gears, 51.4 mph in 1st gear @ 6000
70 mph = 2085 rpm w/T56 GTO, 4.56 gears, 42.1 mph
70 mph = 2345 rpm w/T56 GTO, 5.13 gears, 37.4 mph
T-56 F-body ratios (2.66 1st) a 5.13 looks good for both street and strip.
If using a M12 T-56 (Like GTO) 4.56 looks good for the steet.
Since both trannies have 1.00:1.00 4th, the 5.13 gear looks better for 1/4 mile drag racing, since 6000 rpm in 4th gear = 111 mph, a reasonable trap speed. The GTO trans in 4th with 4.56 gears = 124.9 mph @ 6000 rpm.
The F-Body type gearing, w/2.66 1st has nice, progressivlely closer gear ratios 1-4, 1-2 shift 33% RPM drop, 2-3 27% drop, 3-4 23% drop, great for best acceleration.
The GTO gearing w/2.97 1st has larger rpm drops in the 2-3 and 3-4 shifts.
1-2 30% drop, 2-3 31% drop, 3-4 30% drop and only 20% drop 4-5 shift.
I've used both of these transmission in a LT4 equipped project car (25 in tires, 3.73 axle, 6400 rpm shift point). The GTO type geaing felt odd, with the 1-2 shift being almost too close in ratio, while the 2-3 shift felt ok and the 3-4 shift felt to big, and then shifting from 4-5 @ 120 mph was super close ratio, useless for drag racing but perfect for road racing.
The F-body type gearing 1-4 felt perfect for drag racing. The 4-5 shift was a big rpm drop, but provided a perfect top speed gear ratio.
An advantage of using the 4.56 gears with the GTO trans is you keep the driveshaft rpm down. Make sure you don't hit the critical rpm of the driveshaft when using a long single piece.
4L60E: 3.06, 1.63, 1.00, .696, 2.29 Reverse
T-56 F-body LS1: 2.66, 1.78, 1.30, 1.00, .74, .50, 2.90 reverse
T-56 GTO: 2.97, 2.07, 1.43, 1.00, .80, .62, 2.90 or 3.28 reverse (have seen conflicting data regarding ratios)
70 mph = 1914 rpm w/4L60E, 3.73 gears, 31.9" tire for all examples
49.9 mph @ 1st gear @ 6000 rpm
70 mph = 1375 rpm w/T56 F-body, 3.73 gears, 57.4 mph in 1st gear @ 6000
70 mph = 1681 rpm w/T56 F-body, 4.56 gears, 47.0 mph
70 mph = 1891 rpm w/T56 F-body, 5.13 gears, 41.7 mph
70 mph = 1705 rpm w/T56 GTO, 3.73 gears, 51.4 mph in 1st gear @ 6000
70 mph = 2085 rpm w/T56 GTO, 4.56 gears, 42.1 mph
70 mph = 2345 rpm w/T56 GTO, 5.13 gears, 37.4 mph
T-56 F-body ratios (2.66 1st) a 5.13 looks good for both street and strip.
If using a M12 T-56 (Like GTO) 4.56 looks good for the steet.
Since both trannies have 1.00:1.00 4th, the 5.13 gear looks better for 1/4 mile drag racing, since 6000 rpm in 4th gear = 111 mph, a reasonable trap speed. The GTO trans in 4th with 4.56 gears = 124.9 mph @ 6000 rpm.
The F-Body type gearing, w/2.66 1st has nice, progressivlely closer gear ratios 1-4, 1-2 shift 33% RPM drop, 2-3 27% drop, 3-4 23% drop, great for best acceleration.
The GTO gearing w/2.97 1st has larger rpm drops in the 2-3 and 3-4 shifts.
1-2 30% drop, 2-3 31% drop, 3-4 30% drop and only 20% drop 4-5 shift.
I've used both of these transmission in a LT4 equipped project car (25 in tires, 3.73 axle, 6400 rpm shift point). The GTO type geaing felt odd, with the 1-2 shift being almost too close in ratio, while the 2-3 shift felt ok and the 3-4 shift felt to big, and then shifting from 4-5 @ 120 mph was super close ratio, useless for drag racing but perfect for road racing.
The F-body type gearing 1-4 felt perfect for drag racing. The 4-5 shift was a big rpm drop, but provided a perfect top speed gear ratio.
An advantage of using the 4.56 gears with the GTO trans is you keep the driveshaft rpm down. Make sure you don't hit the critical rpm of the driveshaft when using a long single piece.
12-04-2008, 08:09 PM
#596
TECH Senior Member
iTrader: (6)
Join Date: Jul 2005
Location: Decatur, AL
Posts: 5,257
Likes: 0
Received 0 Likes
on
0 Posts
My normal driving I skip 2nd and 4th. 1-3-5-6 is my daily shift pattern. The others are too close together to be worth it. If I had a few more cubes or a slightly smaller cam, or just cathedral port heads with more velocity at low rpms I'd probably just do 1-4-6.
I have the Aluminum Metal Matrix custom shaft from these guys and it is dead smooth with my 5.13's. Around $425 with yoke and joints.
http://www.dynotechengineering.com/
I have the Aluminum Metal Matrix custom shaft from these guys and it is dead smooth with my 5.13's. Around $425 with yoke and joints.
http://www.dynotechengineering.com/
12-19-2008, 10:44 AM
#598
Staging Lane
Join Date: Oct 2005
Location: Atlanta, Georgia
Posts: 85
Likes: 0
Received 0 Likes
on
0 Posts
What differences would there be in converting an '07 and newer Silverado (GMT 900, New New Body Style: NNBS)?
Is the engine programming a lot different?
Has anyone done a manual transmission swap on a NNBS yet?
Thanks!
Is the engine programming a lot different?
Has anyone done a manual transmission swap on a NNBS yet?
Thanks!
12-25-2008, 05:42 PM
#599
Ok, I have an 04 scsb that was a 4.3 / 5 speed. Now it is a 7.4 / 5 speed. I can reuse the throw out assembly and just use an ls1 trans correct? The truck with me in it weighs 4500. Should I step up to a 4.10 (4.11?) 4.56 gear?
