GhostGT

I've been noticing this lately and wanted to ask fellow TMS members..


My 5-speed automatic is awesome, and has a 2nd gear that is pure sex. At WOT, I only drop 1000rpm's from 1-2 shifts, and this really helps in acceleration.


The thing is, however, that I've noticed the 5-speed manuals dont have this. Am I correct? Me being an exhaust freak, ive been listening to people driving so long that this really caught my attention...


Look at this video:

EmperorJordan's GT with STICKSHIFT http://emperor666jorden.web.aplus.net/SLP2.wmv

Now, take a listen to this clip:

Kenny's GT (auto) http://www.2006-mustang-gt.com/videos/06gt...masters_wmv.wmv



You can tell what I mean when you try to listen to the WOT 1-2 shifts. The manual GT's sound like they lose at least 2000rpm, maybe even more(like emperor's video)....while us autos lose like a 1000prm (like kenny's video)


Am I dreaming? :scratch:

dustindu4

manual has 3.55 gears and auto has 3.31s. I agree that you lose a lot of character in the car with an auto.

don_w

Evidently Dustin is smoking something... but we'll ignore that for now.

Back to your original post, Chris... there is a much bigger difference between 1st and 2nd gears in the manual vs the auto. So your perception of the rpm drop is probably accurate. FWIW, here are the specs.

GT Five-speed manual (Tremec 3650) Gear ratios:
1st: 3.34
2nd: 2.00
3rd: 1.32
4th: 1.00
5th: 0.68

GT & V6 Five-speed automatic (5R55S) Gear ratios:
1st: 3.25
2nd: 2.44
3rd: 1.55
4th: 1.00
5th: 0.75

V6 Five-speed manual (Tremec T-5) Gear ratios:
1st: 3.75
2nd: 2.19
3rd: 1.41
4th: 1.00
5th: 0.72

GhostGT

Does that kind of mean that auto's COULD have been designed with a shorter 2nd gear to be a little faster? Or is it just like that?

SixtySix

Not so much to be faster than a manual per se, but designed to work better than previous auto's and work better with the 3.31 rear gears.

2005MineralGT

The ratio of 2nd gear on the autos has nothing to do with making it faster, etc. 2nd gear is simply 1st gear plus overdrive. You can verify this with some simple math: 3.25 x 0.75 = 2.44. While these transmissions are definitely different, they are largely based on the old 4 speed A4LD's. Ford figured out a while ago that they could use O/D with 1st to get another gear, making a 5 speed electronic version that was before this transmission. All of your other gears are the same as before. 3rd is what used to be 2nd, 4th used to be 3rd, and 5th used to be 4th. Hope that helps clear things up some.

GhostGT

Well...kinda, but i'm still not clear as to why our AUTOS only lose about 1000rpm when shifting from 1-2. It reminds me/sounds like an F1 car. NO other car i've ever had/rid in/heard has this...

Burke0011

I thought they were specifically set up this way as part of the new auto and part of what makes it better than previous ones - because it keeps you in the higher power band as much as possible. I remember all the talk about that when the car first came out.....

SixtySix

Actually it's easy, with a manual you'll lose as much RPM as the DRIVER allows. If a manual driver is a good power shifter, you'd hear/feel the same thing.

The Auto takes the driver out of the equation and in essense will do the power shifting for you at WOT.

This comes at the cost of additional weight and power train loss however.

The Boss Hog

It is strickly a result of the different gear ratio's:

New RPM = (2nd gear ratio / 1st gear ratio) * old rpm

For an auto (assuming no T/C slip)

New RPM = (2.29/3.22) * 6200 = 4409 rpm ( you drop about 1800 rpm)

For a manual (assuming no clutch slip)

New RPM = (2.00/3.38) * 6200 = 3668 rpm ( you drop about 2600 rpm)

don_w has slightly different ratio's than I do but the idea is the same.

The Boss Hog

don_w

Boss Hog... you are absolutely correct. I grabbed the numbers for the 5R55N, not the 5R55S. Sorry about that. Unless I messed up again, here are the correct ratios for the 5R55S:

1st: 3.22
2nd: 2.29
3rd: 1.55
4th: 1.00
5th: 0.71