I know I need a test drive but...

What kind of RPM's are you seeing in the 5AT at 70MPH? My Integra GSR is pushing 4k at that speed and is loud as hell! I am assumung/hoping the TSX is much quiter at highway speeds.


Thanks!

 

Ah, you can be serious too!

Can't tell you exactly (maybe I'll check when I go out), but I'd say maybe 3k.

Anyway, I can tell you for sure it's quiet, quiet, quiet. And smooth as silk.

 

2.5k?

it's 2.1k at 60.

 

As a reference, 6MT is 3000 at 70, but the 5AT is considerably lower from what I've heard.

In any case, the TSX is very quiet at highway speeds (especially with regard to wind noise). So smooth and quiet, it's easy to rev too high without noticing (i.e. I sometimes neglect to shift into 6th on the freeway because it doesn't feel like it's necessary)

 

I agree with Larch and rzee. It's right around 2500 for me at about 70mph. Quiet as a mouse too with the windows up and nothing on!!!
I think I read that the 5th gear in the AT is for quieter more fuel efficient cruising.

 

At 80mph I am registering 2700rpm's

 

Yes. When I said 3000 for 70 mph, I was just guessing off the top of my head.

RZ was probably just about right with 2500.

 

Can someone explain to me why the 6mt runs at higher rpm when cruising at highway speeds (~70mph) than the 5at? I understand the 6mt is more agressively geared, but isn't the whole point of the sixth gear to be able to get better mileage when cruising on the highway? Ie, why would the 6th gear be tuned agressively? Thanks!

 

The MT is built more for fun and performance than the AT. 6th gear ratio in the MT is 0.659. 5th in the AT is 0.566. Plus the final drive ratio in the AT is numerically lower - 4.44 vs 4.76. Some of the engineers here can answer it better, I'm sure, but the AT can get away with it because of the way it uses torque and because of the ease of kickdown when a lower gear is needed.

You are right to raise the question, though, because traditionally the highest gear in a manual is longer (numerically lower) than the automatic offered in the same car.

 

It could be the final drive ratio. The AT gets better gas mileage remember. Theoretically, if they were both geared the same, the MT would get better gas mileage since it is more efficient.

Another thing helping out the TSX is its VERY good coefficient of drag. Its .26 I believe. Just for reference the LS430 is .26 and the Honda Insight (2 seat hybrid that looks so "funny") is .25

 

Thanks for the explanations! I guess I'm more just wondering why they made the 6th gear so agressive. I understand the goal of the MT is to be sportier/quicker than the AT, but I didn't think the 6th gear needed to be so agressive. Why would you race/drive agressively in 6th gear? Wouldn't you just downshift if you needed a quick boost?

 

2400rpm for 70mph.

 

Don't know. Although for 50-70mph highway cruising, 5th is too short, and 6th is just right. I'm sure if there was a 7th gear for "super-long" trips that would be okay, but I don't really see the benefit of it in 95% of my driving.

 

75 mph @ 2500 rpm
90 mph @ 3000 rpm

The 5AT is just getting ready to go at 70 mph. At 60 mph passing is a little tougher from the downshift. At 70 it's ready to fly.

 

2350 rpm at 70mph - 5sp AT

 

It's not 6th gear that's aggressive, it's the final drive ratio. In other words, every gear is aggressive on the 6MT. It fits the character of the car. If you are driving at 70mph in 6th gear, you can accelerate without downshifting.

 

I find myself asking the same thing. I'm not racing anyone at 130 MPH, so I don't need 6th gear to be so close to 5th. I'd be happy if it was taller (or if i had a "7th" ) for nice quiet (high MPG) highway cruising, but it's not a huge deal.

Here's the numbers: 6MT / 5AT

Top gear ratio: (6th) 0.659 / (5th) 0.566
Final Drive: 4.76 / 4.44

Multiply these together to get total reduction: 3.14 / 2.51

Reduction means that the wheels turn this many times slower than the engine. As you can see the 6MT reduces more, so the 6MT's wheels turn slower than the 5AT's in top gear at any given RPM. This translates to a lower road speed. To get the 6MT to go the same speed as the 5AT, you have to turn higher RPMs

Bottom line: it's all in the gearing. The 6MT's ratios are very, very agressive. Of all the things people have talked about changing in later model years, making 6th taller (numerically lower) is the only one I'd really like to see.

 

Kind of a late follow-up here, but...

At first (on paper and on my early drives) I thought 6th gear in my MT was excessively aggressive and high-strung. But after some experience with it, I think it's in just the right place. There's just enough pickup/torque in 6th to pass or cruise uphill on the freeway. I wouldn't change it if I had the chance. Maybe I'm just enjoying or getting accustomed to this beautiful Honda engine's characteristics.

 

I agree! I can leave the tranny in 6th on a two-lane highway and pass at will.