High rpm cruising in 6th

[abutterman]

I'll start by saying i'm really still learning the manual transmission so feel free to tell me i'm just doing it wrong. And if i am, any tips you have would be welcome

so on the A/T fr-s i had up until last weekend, if i was holding steady at around 65-70mph on the parkway, my rpm would sit somewhere in the low 2000's up to maybe 2500 on occasion. I noticed today while holding the same speed in my manual brz i was holding steady at around 3000 rpm in 6th gear.

Is this higher cruising rpm cause for concern? Is it something i'm doing wrong? or is this normal?

[carbonBLUE]

Originally Posted by abutterman

I'll start by saying i'm really still learning the manual transmission so feel free to tell me i'm just doing it wrong. And if i am, any tips you have would be welcome

so on the A/T fr-s i had up until last weekend, if i was holding steady at around 65-70mph on the parkway, my rpm would sit somewhere in the low 2000's up to maybe 2500 on occasion. I noticed today while holding the same speed in my manual brz i was holding steady at around 3000 rpm in 6th gear.

Is this higher cruising rpm cause for concern? Is it something i'm doing wrong? or is this normal?

they have different gear ratios, you are fine...

my last car would cruise down the highway at 4k rpms in the 75-85 mph range... good thing i had 9800 rpms to play with... still got 35 mpgs too lol...

[abutterman]

Originally Posted by carbonBLUE

they have different gear ratios, you are fine...

my last car would cruise down the highway at 4k rpms in the 75-85 mph range... good thing i had 9800 rpms to play with... still got 35 mpgs too lol...

ok i had a feeling it was probably normal. I guess that's why they estimate lower mpg than the automatic. although i'm actually averaging the same 20 or so i did with the automatic with the shitty Long Island stop and go traffic off the parkways

[Subie]

The manual is geared for performance; the automatic is somewhere in the middle of the performance/economy scale, as befits each transmission's demographic.

[sierra]

The auto ratios are more like a 4 speed with 2 over drive ratios, while the manual has a set of ratios that I think are spot on. There's a bigger gap between 5th and 6th than the other ratios, to keep top tall enough for quiet economy but in the real world that doesn't matter for performance because we will lose our license when we start pulling 4th.

I've never driven the auto but appreciate it's one of the best out there and the ratios work, still I can't help wondering how it would have been with the manual ratios instead? Maybe a slightly taller version but nothing like the huge difference of about 25% lower rpm.

[jflogerzi]

Normal. Manual and AT's have different ratios as stated. But don't worry and just enjoy the manual. The only way to enjoy this car!

[fistpoint]

7800rpm redline RSX-S is around 3000rpm @70mph. Pretty normal for a high-revving 4 banger. The 2000rpm @70mph is the oddball number here.

[abutterman]

good to know it's normal behavior. after driving autos for the last 9 years it caught me by surprise. i just wish i wasnt living in such a high traffic/low speed limit area. i really want to get this thing on a good open road and really get a feel for it. I guess the plus side of the traffic though is it's forcing me to learn faster so i don't keep stalling out on single lane roads lol

[cmspooner]

You'll get there...the BRZ was my first manual and it was all terrors for the firs week and a half or so...and then everything just clicked! Now I'll never go back.

[bcj]

Do any of the techie people know where the higher MT/AT ratios come from?
Used to be, on American RWD cars an auto came with a taller ratio in the differential way at the back.
Is the FR-S/BRZ differential the same in all cases?

[sierra]

Originally Posted by abutterman

I guess the plus side of the traffic though is it's forcing me to learn faster so i don't keep stalling out on single lane roads lol

If you picked this manual up brand new last weekend then the ECU will still be doing it's learn cycle and the throttle will still have some delay that makes it much easier to stall.
This will go away within a few weeks and make things much easier for you.

[Porsche]

Originally Posted by bcj

Do any of the techie people know where the higher MT/AT ratios come from?
Used to be, on American RWD cars an auto came with a taller ratio in the differential way at the back.
Is the FR-S/BRZ differential the same in all cases?

Yes. Both the MT and AT use a 4.10 rear end, i.e. differential or final drive.

On the MT, 5th = 1.000, whereas on the AT, 4th = 1.000.

Overdrive (for fuel economy, but generally poor acceleration) on the MT is 6th = 0.767, whereas on the AT, both 5th and 6th gears are overdrive gears, hence the marked improvement in fuel economy vs. the MT car when cruising the highways in the two top gears in the AT. These tall 5th and 6th gears in the AT come at the expense of performance, however.

AT, 5th = 0.713 an even taller gear than 6th on the MT car.

AT, 6th = 0.582, which is a remarkably tall gear, not what I’d expect to see on a small 2 liter car. It’s a wonder the car can propel itself up a hill in that big gear. My guess is that the AT drivers often find it necessary to change down to 5th gear on a hilly Interstate (or the car’s doing it for them).

Top gear in the AT is so big that, if it could pull redline:

AT, 6th gear @ 7400 rpm = 220.5 mph

AT, 70 mph = 6th @ 2350 rpm

MT, 70 mph = 6th @ 3097 rpm

Note that the AT cannot pull redline in 6th. In fact, in one of the magazine road tests, they found the AT could only manage 120 mph top speed in 6th gear. That was a bit misleading, since the car could have gone faster in 5th, I’d think. Actually, the AT car should pull 128 mph in 4th gear @ 7400 rpm. That’s the same gearing as the MT car in 5th at 1.000 ratio.

So, the AT car will feel comparatively “sluggish” in 5th and 6th gears vs. the MT car. AT drivers will do better staying in the first four gears when having fun on back country winding roads. Remember, the AT will top out at 128 mph in 4th, which should provide sufficient excitement.

[abutterman]

Originally Posted by sierra

If you picked this manual up brand new last weekend then the ECU will still be doing it's learn cycle and the throttle will still have some delay that makes it much easier to stall.
This will go away within a few weeks and make things much easier for you.

ahh good to know! the hardest part for me so far has definitely been finding that spot where i get just enough gas to get it going so that'll help once it breaks in a bit