Automakers exagerating mileage

[batmanuel]

Originally posted by: Bullhonkie

Originally posted by: Soccerman06

Wow 110mph in the rain in a Scion XB.

The engine just does not have enough power to keep a 3000lb car moving at say 65mph at 3000 rpm. Cars need considerable power to move at 65mph, and the XB just doesnt have the proper gearing or power to achieve that specific load.

Anyways, I just wanted to show a rough example of how the engine power (at the crank) and rpms are related. I wanted to say how the engine performs under certain conditions, you can say the engine powerful enough to get you from A to B with decent mpg, but it doesnt have enough oomph for me.

This is how much hp/torque is created at the wheels of a Scion XB 5 speed manual. As you can see, there is little hp below 3000 rpm (less than 50). I dont remember any of my aerodynamic physics so I cant say how much power is required to keep the vechile moving at a constant speed, but its atleast 3500 70hp.

So you're telling me you have to be flooring it at 3500rpm just to maintain speed on the highway? I find that pretty hard to believe. BTW the xB is more like ~2400 lbs.

We're not taking his mom into account. Maybe she's weighing the car down a bit.

 

[Jzero]

Originally posted by: Soccerman06
The engine just does not have enough power to keep a 3000lb car moving at say 65mph at 3000 rpm.

You have offered nothing to back up your claim that at 65MPH in 5th gear and xB will lose speed even if you've got the pedal floored.

I simply cannot believe that, sure my Civic is more streamlined, but it has only slightly more HP, and has no problem keeping speed at 80MPH in 5th gear without having step on it very much.