^^ Oh no, you di'n't! I test drove a Journey sedan and a coupe S back-to-back when shopping and the sedan S definitely has stiffer damping and sway bars, maybe even higher durometer bushings than the plain Journey. I wish could have driven the sedan S back-to-back with the coupe S, but c'est la vie. Also wished I could have found a new sedan 6MT but there was only one in the southern half of the US and it was black. I'm not owning another black car in Texas. Just couldn't wait the three months it would have taken to order the 6MT from Japan.

 

You are wrong. The RWD "Sport" 7AT/6MTsedan has the Akebono big brakes, sport tuned suspension, tighter steering rack ratio and a viscous limited slip differential.

The AWD "Sport" sedan is the one that is purely cosmetic.

I own a G37S RWD 7AT Sedan...

 

The shocks are different, but the RWD Sedan gets the exact same swaybars, Sport and non-Sport alike.

Is that different in the Coupe? IDK. But IMO, test-driving a RWD Journey Sedan vs. a RWD Sport Coupe isn't a good basis to form the opinion you did. Just saying.

 

I commented to the sales person after the Journey test that while the car was competent it felt like a magic carpet that understeered. The S suspension was so much more connected and involving. That's why I opted for the S sedan.

 

Am I reading this graph and statements wrong? Our cars put down 3,000-4,000 foot-pounds of torque?!?

 

I was trying to figure this out too..I thought there might be a typo in the graph title/labels...or its just over my head...usually its the latter

 

It has to be a typo, maybe an extra 0 thrown in, but even then I don't think we're making 350 ft lbs.

 

The graph is correct. Engine torque times transmission gear ratio times final drive ratio. Gears are called torque multipliers for a reason.

 

I wonder what the numbers look like for a 65 AMG. Those things have 700+ft/lbs of torque.

Twin Turbo 6.0L V12

We have a wimpy 260ish.

 

That's a very unusual way to try to demonstrate differences in gearing. The important thing it misses is driveline losses. The numbers might make more sense if you strapped A/T and M/T cars on the same dyno.

 

Personally, it was a little hard for me to understand, but I think Sonicvq mentioned assumptions about efficiency in some other posts in the thread so its a reasonable frame of reference for discussion purposes

 

This is a common way to determine optimum shift points for maximum acceleration. Hot Rodders in the 50s did this. Read more here: Understanding Torque And Horsepower ? Let?s Try This Again with Tractive Force : OnPoint Dyno

In my first post, I did state that it does not factor in any driveline loss. A manual transmission is about 95-97% efficient and a auto is 88-90%. PLUS the loss in the differential PLUS the loss due to friction at the wheels.

As for strapping an auto and manual car on the dyno, that would't tell us anything since we wouldn't know if one engine made more HP (at the crankshaft) than the other. However here is a link to dyno comparison of an auto and manual 370z: http://www.370z.com/MagazineArticles...EW-VIDEOS.aspx

The point of this thread was to have a conversation about the difference in gearing between the auto and manual and to point out that in first gear we have over 3,000 foot-lbs of torque at the WHEEL.

 

Think about it this way:

Our cars weigh about 4,000 pounds (3800 for car, 200 for driver)
The engine torque of 270 foot-lbs is MULTIPLIED by the transmission, differential and sent to the wheel and is now over 3,000 foot-lbs of torque. (BUT turning much slower than the engine - you don't get anything for free)

When in first gear, we have about 3,000 foot-lbs of torq accelerating 4,000 pounds, it will accelerate quickly.

In 6th gear we have a little as 500 foot-lbs of torq accelerating our 4,000 pound car, it will accelerate very slowly.

Does this explain it better?

 

I see what you mean about using equations to try to figure out shift points, but in practice you are better off relying on the sound of the engine as in racing you simply don't have time to focus on the tach for each shift.

I get that you are trying to explain one reason why the A/T could be faster than the M/T- gearing. Maybe I missed it, but I did not see the actual gear ratios, final drive, or evidence of a RWD A/T and M/T car raced against each other on the same day, same road, same driver proving that the A/T is actually faster. Maybe that is mentioned in the original article you got the graph from.

My point is that a hypothetical torque graph (no dyno in the world would show our cars having 3,000-3,500hp at the wheels like you mention above) does not prove that one car is faster than another. There are too many other variables like driveline loss, shift points, surface, temperature, driver, etc. Again, maybe the original article you are referring to actually had one driver race both cars in the same conditions. I just did not see those facts in your post proving that the A/T G37 is actually faster than M/T.

 

Scoping this conversation to purely gearing advantages and taking a second look at the graph, it's actually quite interesting to see that the AT runs out of steam sooner in each gear (perhaps because of the Final Drive).

The points at which the dotted line crosses the solid line, until the solid line caves down, is a speed where the MT gets the higher acceleration.

In other words, between 36MPH and 42MPH, 55MPH and 70MPH, 85MPH and above, the MT has the gearing advantage.

AT has the gearing advantage from 0MPH to 36MPH, 42MPH to 55MPH, and 70MPH to 85MPH.

First gear advantage goes to AT, without a doubt.
However, the amount of "MPHs" that MT has an advantage to accelerate on looks different when discounting speeds under 35MPH.

If we are talking about a min speed of 35MPH and a top speed of 100MPH (to be conservative/fair, because launch advantage is a wash after turn 1, and our cars are governor limited to 135MPH):
MT has advantage on 36 "MPHs"
AT has advantage on 28 "MPHs"

In other words, MT can stay in each gear longer. The difference is more pronounced when driving 2nd and 3rd gear at the top of the power band.
These 2 gears cover the vast majority of the turning speed in technical tracks.

4th gear is a wash, and if should you choose to race in 5th or 6th, MT has the advantage.

Seems like Nissan knew what they were doing with the AT and MT tuning. One's great for the stomping in town, the other's great for taking the car to its sporty limits