Center of Gravity Difference Manual/AT

[makesdrivingfunagain]

Hi fellow enthusiast,

Since the automatic weigh nearly 50lbs more does the Auto have a different center of gravity? Newbie non-engineer question I know.

http://www.motortrend.com/news/2013-...s-first-drive/

[churchx]

As most probably all the extra weight will be in transmission/gearbox at bottom of car, overall CG of car might be even lower on heavier AT. Unless they started to mount gearbox on the roof of car

[guybo]

I don'tthink there would be enough of a difference to measure. 50lbs over a 2800 lb object isn't much and since the COG of the car is 18.1"- that's about the height of the center of the tranny.

[mav1178]

The weight distribution may be shifted depending on how the transmission weight is distributed. But otherwise there's going to be zero difference you can feel...

[Ashikabi]

It will be lower since the transmission is low in the car. That extra 50lbs will be unnoticeable COG wise. Should trade up to a manual for weight savings

[Dadhawk]

As others have said, it is minimal, and most likely would lower it because the weight is in the transmission. It is only minimal, however, because the weight is already near the CG. If the same 50lbs was put further out on the "arm" (say in the trunk) it could significantly move the CG rearward.

Basically, its determined by the weight distribution at the wheels. Here's a good diagram, although this does not take into account the height of CG.

[Ashikabi]

Originally Posted by Dadhawk

As others have said, it is minimal, and most likely would lower it because the weight is in the transmission. It is only minimal, however, because the weight is already near the CG. If the same 50lbs was put further out on the "arm" (say in the trunk) it could significantly move the CG rearward.

Basically, its determined by the weight distribution at the wheels. Here's a good diagram, although this does not take into account the height of CG.

I thought COG was in a verticle plane, not front to back

[Dadhawk]

It's both. The vertical CG would exist at a right angle to the horizontal CG. They impact one another. The vertical is a little more complicated to determine. Here is an example.

[Ashikabi]

Originally Posted by Dadhawk

It's both. The vertical CG would exist at a right angle to the horizontal CG. They impact one another. The vertical is a little more complicated to determine. Here is an example.

You lost me... either way the transmission is low and in the middle front to back so it really doesn't matter much

[Dadhawk]

That was my point, it would have minimal impact because it is already pretty much at the horizontal CG, and would only act to lower the vertical CG.

My point was if you put the same 50lb weight in the trunk of the car, it would have a much greater impact, moving the CG towards the rear and up.

This is why a 200lb passenger/driver in the car has very little impact on CG as they are very close to it, but put that same 200lbs elsewhere and it has an impact.

[gramicci101]

Originally Posted by Dadhawk

It's both. The vertical CG would exist at a right angle to the horizontal CG. They impact one another. The vertical is a little more complicated to determine. Here is an example.

You don't have a cool Army-proof picture for determining vertical CG?

[Dadhawk]

Originally Posted by gramicci101

You don't have a cool Army-proof picture for determining vertical CG?

Sadly no. Apparently on wheeled vehicles the military is only concerned with center of balance (the horizontal component). They do have it for aircraft though where true CG is more important than the center of balance.

Technically, in most applications (if I recall correctly) the horizontal component is more important than the true center of mass (both of them together).

[gramicci101]

Originally Posted by Dadhawk

Sadly no. Apparently on wheeled vehicles the military is only concerned with center of balance (the horizontal component). They do have it for aircraft though where true CG is more important than the center of balance.

Yeah, horizontal CG is necessary for shipping. Especially for air movement, so you can make sure your load plan is balanced and your plane isn't too nose or tail heavy. Vertical CG, not so much.

[Dadhawk]

Originally Posted by gramicci101

Yeah, horizontal CG is necessary for shipping. Especially for air movement, so you can make sure your load plan is balanced and your plane isn't too nose or tail heavy. Vertical CG, not so much.

Yep, in aircraft a CG moved just slightly too far forward means you'll never take off, and too far back means you won't survive the landing.