topspeed difference between manual transmission and automatic transmission

[Sport-Tech]

Originally Posted by Turbowned

It's definitely not a highway car, that's for sure.

?? The only minor drawback a manual version of this car will have on the highway is a slightly higher 70 mph rpm in 6th gear relative to the auto, which will be more of a relaxed, gas-sipping cruiser.

[Lighting Red]

Originally Posted by Turbowned

It's definitely not a highway car, that's for sure.

Well in terms of roll-on acceleration, I agree with you 100%. That said, the BRZ may not coddle you the way an Audi or Acura does on the highway, but it probably holds its own nicely. Low drag and low rolling resistance tires should not contribute to rolling noise on the highway.

As far as top speed, all thing being equal, the auto should have a higher top speed than the manual car. The auto has higher gearing in the transmission. Both cars have presumably the same coefficient of drag, and the same final drive. So it comes down to the transmission gearing.

[Subie]

Originally Posted by Lighting Red

Well in terms of roll-on acceleration, I agree with you 100%. That said, the BRZ may not coddle you the way an Audi or Acura does on the highway, but it probably holds its own nicely. Low drag and low rolling resistance tires should not contribute to rolling noise on the highway.

As far as top speed, all thing being equal, the auto should have a higher top speed than the manual car. The auto has higher gearing in the transmission. Both cars have presumably the same coefficient of drag, and the same final drive. So it comes down to the transmission gearing.

There is one more aspect to the gearing that affects the top speed though. If a given car is able to reach the top of 5th gear, for example, but upon shifting to 6th gear isn't making enough torque to accelerate further, the top speed will actually be determined not by the overall gearing of the vehicle but by the difference between the 5th and 6th gear ratios. Without driving a BRZ I can't say for sure what the limiting factor will be, but in general, it's not as simple as which car has the taller 6th gear all else being equal.

[Dave-ROR]

Originally Posted by matt30

Well if the car is not electronically limited the auto should have a higher top speed.

Final drive ratio: 4.100
MT top gear: .767
AT top gear: .582
and wheel size of 24.8 inches

That's a limit of about 170mph for the manual and 200+ for the auto.

Screw electronic limiters, this car will be drag limited WELL under redline in 6th gear with EITHER transmission.

Ignoring low electronic limiters, the MT will most likely have the higher top speed, the car doesn't have the power to overcome the drag and it's worse with the ATs gearing.

[Dave-ROR]

Originally Posted by Lighting Red

the BRZ may not coddle you the way an Audi or Acura does on the highway,

You obviously have never driven the acuras I own :P

The BRZ is going to be a Lexus in comparison.

Originally Posted by Lighting Red

As far as top speed, all thing being equal, the auto should have a higher top speed than the manual car. The auto has higher gearing in the transmission. Both cars have presumably the same coefficient of drag, and the same final drive. So it comes down to the transmission gearing.

ONLY if the car has the power to overcome drag and hit the gear limited top speeds.

That is NOT the case with the BRZ/FR-S which means the car will be drag limited and the MTs gearing is much better suited for that. I'd be extremely surprised if the AT car has a higher top speed in reality (intead of gear limited theory). I'd even go so far as to say 99% positive the MT car will have the higher top speed.

[TheRipler]

Originally Posted by Subie

There is one more aspect to the gearing that affects the top speed though. If a given car is able to reach the top of 5th gear, for example, but upon shifting to 6th gear isn't making enough torque to accelerate further, the top speed will actually be determined not by the overall gearing of the vehicle but by the difference between the 5th and 6th gear ratios. Without driving a BRZ I can't say for sure what the limiting factor will be, but in general, it's not as simple as which car has the taller 6th gear all else being equal.

Actually, it the the rate of torque delivery, horsepower, that determines the ability to overcome drag.

You would probably never get out of 5th in the AT, and whether the AT 5th or MT 6th is better for top speed is an unknown at this point. It might even be a duel between AT 4th and MT 5th. I haven't done the calculations yet. I don't know the frontal area, or I'd give it a go.

[enzo15637]

Why is anyone in that much of a hurry?? Top speed who cares.

NO licence = NO more driving that amazing car

[Dave-ROR]

Originally Posted by enzo15637

Why is anyone in that much of a hurry?? Top speed who cares.

NO licence = NO more driving that amazing car

The ability to accelerate to higher speeds is a good thing on longer road courses. At RRR in GA for example I'd expect 125-130 out of the MT car but let's say the AT has a drag limited top speed of 130, you'd probably never pass 120 on the front straight.

All of these numbers are made up of course. The top speed itself doesn't matter to me as a number but it's a clue as to the cars ability to accelerate in higher gears. As a track guy, that's useful information.

For a street car, it's bragging rights I guess? Some of my cars have lower top speeds than they did when they were new due to gearing changes (shortened gearing, so lower top speed but changes speeds on track, sometimes good, sometimes bad (requiring extra shifts in some courses, etc) I've made on purpose.

[TheRipler]

Originally Posted by enzo15637

Why is anyone in that much of a hurry?? Top speed who cares.

NO licence = NO more driving that amazing car

There are places without speed limits, and I visit them. (It's addictive) I'll try it at least once with this car, just to see. If I go turbo, it will be for that purpose.

[Enemies]

If I ever get up to 200 KM/hour on the road I hope a cop busts my ass.

[torquemada]

Originally Posted by enzo15637

Why is anyone in that much of a hurry?? Top speed who cares.

NO licence = NO more driving that amazing car

<- location germany

I care, a lot, like any other german who is interested in the car

[mufasis]

So who wants to test this first, lol?

[speedracer38]

Originally Posted by mufasis

So who wants to test this first, lol?

I will as soon as the break in period is done

[Lighting Red]

Originally Posted by Dave-ROR

You obviously have never driven the acuras I own :P

The BRZ is going to be a Lexus in comparison.



ONLY if the car has the power to overcome drag and hit the gear limited top speeds.

That is NOT the case with the BRZ/FR-S which means the car will be drag limited and the MTs gearing is much better suited for that. I'd be extremely surprised if the AT car has a higher top speed in reality (intead of gear limited theory). I'd even go so far as to say 99% positive the MT car will have the higher top speed.

I had a 1995 Integra GS-R, so I have some idea of what you are talking about. It's actually part of the reason I want the BRZ. I want to go back to the low inertia days

Now you go me thinking about the top speed.... And I believe you have a very good point. I guess it partly depends on how low on the tachometer they begin to hit the wall. Perhaps there will be enough room for the gearing on the MT car to push a little harder.