Questions, how so? Thinking...

Questions, how so? Thinking...

Ok, i was in history class today, trying to sleep. Well, i got to thinking about cars.

I had to drive my dads automatic 1997 celica convertable last night, and i remember hearing the brakes as you let off them. I was thinking, do brakes of a manual car last longer, or just rotors? Cause if you think bout it, the automatics are always trying to move the car, so the brakes work harder, and rotors everytime you stop and go. Manuals would be a lot easier on that, as they are not always giving power to the wheels while brakes are on. Is this true? or what?

Also, how do manuals use less gas? You see manuals are always 1-2 miles a gallon better than autos. If your driving 60-65mph steady, on a manual your rpms are at about 3000-3500, on an auto, they are only like 2000-2500. Both are in overdrive gears. 5th on man, and 4th on auto. So wouldnt the auto be better on gas? or is there something im missing.

If anyone else has questions and want to know, post here. And people that know answers, post them.

Not always. It all depends on the gear ratios. If the ratios are very close and the car is aggressively geared then the automatic counterpart with more spaced gearing, taller and moderate gearing will get the better gas mielage. My XRS even in 6th gear is usually revving at 3500 rpm at 70 mph as opposed to my previous auto Corolla S that revved only at 1900 rpm. Usually, 6 speed manual cars give less gas mileage than the 5 or 4 speed auto counterparts.

I cannot compare my 05 Corolla XRS to my previous 04 Corolla S auto because of different engine, but here is a comparable example ( taken from acura.com

Acura TSX:

EPA Estimated Fuel Mileage (city/highway)

Manual: 22/29* mpg

Automatic: 23/32* mpg

They both have exactly the same engine and everything. The auto weighs 100 lbs more than the manual, yet the auto gives better gas mileage than the 6 speed manual. The reason is the gear ratios, 6 vs 5 speed manual and the close spacing makes the 6 speed manual rev higher than the auto so the auto has the best mileage.

dude , i don't agree with you on this one.



Manuals would be a lot easier on that, as they are not always giving power to the wheels while brakes are on. Is this true? or what?

It depends on how often u brake.... if u've notice, MOST women brake unnecessarily. therefore their brakes and rotors die faster.

It also depends on how you drive the car. When they list the manual with higher mpg that does not including shifting at redline.

...if you are at a stop it wont matter anyhow because no friction is in play..and it all depends how a person drives..a str8 drive can save in pads b/c u can down shift to slow down slowly but in that respect u also have a clutch which will be pressed..and also as long as u dont ride the brakes all of the time on a auto then they can last just as long as a manual so it all depends on the driver and their habits..

You guys are forgetting about one fundamental difference between the automatic and manual trannys. The automatic use a fluid coupling (the torque convertor), which slips constantly. The torque convertor will never transfer near 100% of the torque from the engine to the tranny. So for example if the engine is at 3000 RPM, you output of the torque convertor may be 2900 RPM (loss of 3.4%). The standard clutch should not slip nearly as much (not at all actually i wouldn't think). This difference would effect gas mileage as well. Modern torque convertors lock up when going into overdrive, which will reduce the drivetrain loss.

Mark