The Technical Questions Thread

[f6fhellcat13]

Is there a discrepancy in economy between identical cars with different suspension setups?
For some reason my intuition tells me that a harder setup would be more efficient, but I don't know why that would be.

[NSXType-R]

Just curious, how does a long wheelbase affect a car's handling, etc. as opposed to a shorter one?

I guess a longer wheelbase will handle not as well as a shorter one- harder to place in corners and all?

[LeonOfTheDead]

Originally Posted by f6fhellcat13

Is there a discrepancy in economy between identical cars with different suspension setups?
For some reason my intuition tells me that a harder setup would be more efficient, but I don't know why that would be.

Not sure what you mean, like easier to design?

Originally Posted by NSXType-R

Just curious, how does a long wheelbase affect a car's handling, etc. as opposed to a shorter one?

I guess a longer wheelbase will handle not as well as a shorter one- harder to place in corners and all?

Basically that, but it's more stable than an swb one.
don't want to enter the details now, I'm tired.

[NSXType-R]

Originally Posted by LeonOfTheDead

Basically that, but it's more stable than an swb one.
don't want to enter the details now, I'm tired.

That's okay. That's pretty much what I wanted to know.

[culver]

Originally Posted by NSXType-R

Just curious, how does a long wheelbase affect a car's handling, etc. as opposed to a shorter one?

I guess a longer wheelbase will handle not as well as a shorter one- harder to place in corners and all?

It has to do with weight transfer. If the CG is basically at the same height but the wheel base is larger each tire will see a smaller change in load as you turn, brake and/or accelerate. That's good because the more even the load between the four tires, the more grip you will have. It also makes the car more stable because the tires have a longer lever arm over which to act.

It does come with a price, longer wheel base and track width hurt on really tight tracks. The problem is that a wider or longer car can't "cut the corners" as much as a narrow car. This is why a Miata can do so well on a tight autocross track as compared to more powerful cars that would handily beat it on a road course. On a very tight track the Miata is simply able to run a straighter line through the corners. However, on a larger circuit with faster turns the Miata's short wheelbase and narrow track become a liability. Some people might assume the Miata losses out to more powerful cars simply due to a lack of power. However, if the more powerful car's CG is lower with respect to it's wheel base then it may also perform better in turns as well as through transitions.

[NSXType-R]

Originally Posted by culver

It has to do with weight transfer. If the CG is basically at the same height but the wheel base is larger each tire will see a smaller change in load as you turn, brake and/or accelerate. That's good because the more even the load between the four tires, the more grip you will have. It also makes the car more stable because the tires have a longer lever arm over which to act.

It does come with a price, longer wheel base and track width hurt on really tight tracks. The problem is that a wider or longer car can't "cut the corners" as much as a narrow car. This is why a Miata can do so well on a tight autocross track as compared to more powerful cars that would handily beat it on a road course. On a very tight track the Miata is simply able to run a straighter line through the corners. However, on a larger circuit with faster turns the Miata's short wheelbase and narrow track become a liability. Some people might assume the Miata losses out to more powerful cars simply due to a lack of power. However, if the more powerful car's CG is lower with respect to it's wheel base then it may also perform better in turns as well as through transitions.

That makes good sense, I know it's a horrible way to learn, but I remember in Gran Turismo 4 I was driving a real classic car (Honda S800 racer maybe?) and I was putting out pretty respectable lap times. It's a really small car, so it definitely makes sense now.

[Ferrer]

Originally Posted by NSXType-R

That makes good sense, I know it's a horrible way to learn, but I remember in Gran Turismo 4 I was driving a real classic car (Honda S800 racer maybe?) and I was putting out pretty respectable lap times. It's a really small car, so it definitely makes sense now.

Driving two cars with different wheelbases will teach you all the differences. But for real

[NSXType-R]

Originally Posted by Ferrer

Driving two cars with different wheelbases will teach you all the differences. But for real

True. No replacement for experience.

It's funny, because I was checking out GT5 Prologue TV, and these people they interviewed learned tracks by playing GT4. I think we've discussed it before. Although it's not 100% exact, it certainly helps with the layout in general.

[f6fhellcat13]

Originally Posted by LeonOfTheDead

Not sure what you mean, like easier to design?

More in terms of fuel economy/consumption etc...

[hightower99]

I would say that with harder suspension setups, less energy is dissipated in the dampers and possibly less friction losses in the springs but the vehicle will be raised more over bumps which takes more energy.

Whereas soft suspension setups will absorb more energy in their dampers and the springs but the actual vehicle will not be raised as much over bumps.

My guess is that it depends highly on the type of terrain you are driving on and the speed, and therefore neither setup is definitely more efficient than the other at all times.

[Alastor]

Originally Posted by culver

On a very tight track the Miata is simply able to run a straighter line through the corners.

It seems like all else being equal the short wheel base car should require less steering input, or run a straighter line as you say. That should allow the car to operate at more optimal slip angles, whereas the longer wheel base car would be operating at higher slip angles with diminishing returns.

[Matra et Alpine]

"run a straighter line" ?
LONG wheelbase provides stability in straight line.
Biggest problem with powerful short wheelbase RWD/AWD is the tendency that if one wheel slips then the driving wheel at the rear will kick the car out of line.
GroupB rally cars were the ultimate AND a real handful to keep straight ( and safe ).

[drakkie]

I got a test on stuff like this wednesday Gotta love these huge formula's !!

[culver]

Originally Posted by Matra et Alpine

"run a straighter line" ?
LONG wheelbase provides stability in straight line.
Biggest problem with powerful short wheelbase RWD/AWD is the tendency that if one wheel slips then the driving wheel at the rear will kick the car out of line.
GroupB rally cars were the ultimate AND a real handful to keep straight ( and safe ).

A wider track has more to do with the straighter line as I put it. A longer wheel base is better for front to rear weight transfer which in turn improves stability.

[culver]

Originally Posted by Alastor

It seems like all else being equal the short wheel base car should require less steering input, or run a straighter line as you say. That should allow the car to operate at more optimal slip angles, whereas the longer wheel base car would be operating at higher slip angles with diminishing returns.

The short wheel base car does require less steering input but you have to balance that against the poorer weight transfer characteristics. Ultimately under most conditions the improvement in weight transfer offered by the longer wheelbase and track win out. This is why you see rules often limit maximum wheelbase and track.