BRZ Ratios and Speeds

[BRZ-OwnzJo0]

Originally Posted by OrbitalEllipses

I would never want to be your passenger.

Like you'd even notice. I'm not downshifting from 6th to 2nd at 65 MPH. If you know your RPM to speed raitios at all then it shouldn't matter at all.

Judging by your issues UPSHIFTING without it being jerky, I wouldn't want to be your passenger. Clearly you have a hard time driving stick.

[dbrandt01]

I know I commented earlier, but to second BRZ-OwnsJo0 above ^^

My father has been driving manual for longer than I've been alive. He never rev matches and he drives 100% smooth. Never once has it been jerky. You'd never know he downshifted.

[72widebody]

Part of this car's character is probably just the challenge of smooth shifting. For some, this may come easier than to others. And to some folks, it may not be something they notice or that bothers them. I am probably over-focused on the little things about all my cars.

In any event, I find that rev-matching is pretty important to smoothness on this car. As little as a 200 rpm disparity between ideal and actual rpm at the moment of clutch action can result in a really clunky driveline engagement. And sometimes, even a perfect rev-match will still result in a clunk.

And of course, you can mitigate this with slower clutch engagement/disengagement. But the more time the clutch spends engaging or disengaging, the more clutch wear you experience, and the greater chance of glazing the flywheel. So that's not free.

Also, when first putting it into 1st gear at a standstill results in a pretty obvious driveline clunk. As I mentioned before, the shifter is also quite balky, mainly going into second.

Overall, I hope that all of this are just basic characteristics of this tranny and don't relate to long-term reliability. I am looking forward to what I see on the magnet when pulling the plug. From some pics I have seen here, folks are seeing a lot of metal particles. I suspect (hope) that the fluid these trans come with is not optimal, and that new fluid will reduce some of this, as seems to be the case for many.

[dontpanic]

Originally Posted by 72widebody

My sense is that the smoothness and balkiness varies from car to car quite a bit, based on the threads here.

When we test drove a few we found some variability in clutch take-up less so in the shift character of the transmissions between BRZs. I find I can drive this car very smoothly an easily whereas my wife (who is quite adept with a manual transmission) struggles a bit more. In our case the balkiness derived from the driver not the car.

[dontpanic]

Originally Posted by 72widebody

Also, when first putting it into 1st gear at a standstill results in a pretty obvious driveline clunk. As I mentioned before, the shifter is also quite balky, mainly going into second.

The clunk is your input shaft momentum being taken up by driveline slack when your first gear syncros bite. Your input shaft will spin freely anytime your clutch is in and the transmission is in neutral. It will be most noticeable if your habit is to coast up to stops in neutral from speed with the clutch in then try to shift into first against an input shaft that's still spinning at 2000+ rpm.

[Newguyottawa]

I have driven about 700,000 km on standards and it took me 6 months to shift the BRZ smoothly. Keep practising.

[Suberman]

Originally Posted by Newguyottawa

I have driven about 700,000 km on standards and it took me 6 months to shift the BRZ smoothly. Keep practising.

This becomes very obvious when driving in very slippery conditions. This clutch is very fierce.

I suspect the linings have been selected with drifting and high rpm shifting in mind because the equivalent Impreza clutch is softer. However, even the Impreza clutch is tricky to modulate.

Lowering the clutch pedal has improved my clutch actuation a bit but not much when trying for traction on ice.

[Suberman]

Originally Posted by BRZ-OwnzJo0

Like you'd even notice. I'm not downshifting from 6th to 2nd at 65 MPH. If you know your RPM to speed raitios at all then it shouldn't matter at all.

Judging by your issues UPSHIFTING without it being jerky, I wouldn't want to be your passenger. Clearly you have a hard time driving stick.

Don't try this, you will see around 8,000 rpm on the tach ... Briefly. Don't ask me how I know this.

[OrbitalEllipses]

Originally Posted by BRZ-OwnzJo0

Like you'd even notice. I'm not downshifting from 6th to 2nd at 65 MPH. If you know your RPM to speed raitios at all then it shouldn't matter at all.

Judging by your issues UPSHIFTING without it being jerky, I wouldn't want to be your passenger. Clearly you have a hard time driving stick.

I mention a single shift, this is what I get.


Y'all enjoy not rev-matching.

[Suberman]

This link is interesting:

http://kaizenfactor.wordpress.com/20...n-or-is-scion/

[Suberman]

I did a little maths.

Max speeds in gears for the automatic, using the tables in this thread ans multiplying by the difference in gear ratios (by %) are:

Automatic speeds in gears are 1.02%, 1.06%, 1.1%, 1.21%, 1.40%, and 1.22% higher ( and 1.09% for reverse).

max speeds at 7,400 rpm are 58, 100, 147, 205, 288, 328 km/hr, Top speed of 210 km/hr is reached in 5th as compared to a higher top speed of 226 km/hr in 6th with the manual.

Published figures put the automatic 1.08% slower 0-60 mph (7.9 - 7.6 seconds).

Most of the difference in acceleration between auto and manual is gear ratio.

A small amount is wheelslip effect, likely.

[BRZ-OwnzJo0]

Originally Posted by OrbitalEllipses

I mention a single shift, this is what I get.


Y'all enjoy not rev-matching.

I was just giving it back to you.

I don't rev-match because I don't think it's necessary when downshifting to slow down. I use the combination of brakes + downshifting to come to a stop gradually and it keeps the RPMs in control (not jerky at all ). I know you're probably a fine driver, just like me. :P

[qqzj]

Actually I was thinking of a different question. The calculation so far is not that important, b/c it is speed vs. rpm when you floor it. most of time people do not drive that way. the more meaningful question is when we drive at certain speed, typically at 2k-3k rpm, which gear we should stay at?

Let me try this first. at abound 2k-3k,
2nd gear: 10-17
3rd gear: 18-25
4th gear: 25-35
I do not care about others. 1st is useless unless starting from stand still. 5th and 6th are about the same to me.

[Frost]

I started driving stick on a car that didn't even have a tach (1999 Corolla CE) so I didn't have the luxury of watching my RPMs.

The way I suggest doing it is as follows:

1- Have someone who drives stick take you and your to a place that is as flat as possible and isolated so no one will hit you nor will you block traffic.
2- Get into the drivers seat and start the car with the clutch in (pushed in all the way).
3- VERY slowly let off the clutch and be prepared to hold it at a position where the car starts moving forward. This is what I refer to as the "bite point" where the clutch starts to engage. Let the car roll a little and push the clutch back in.

Repeat step 3 multiple times till you get this in your head. This is important because when you shift at all speeds, this is the point where your clutch bites and you have to match RPM-speeds BEFORE you clutch is out to this point. It also gets you in a position where if you have to go, you know you can go right away.

Side note: I had a friend who never drove stick and bought a 2002 Accord V6 and scared himself shitless on his first left hand turn. He stalled trying to make the turn!

Once you master this point, the next is accelerating up first gear and then coming to a stop and redoing that on a whim.

Since by now you know your bite point, you can now apply a little gas. This is the point where you have feel it out and see if you are burning the clutch or actually putting the energy to forward motion.

My car for some odd reason, when switching from 4th to 5th requires a little blip of the throttle for a smooth shift. It seems my revs drops too quickly but I suspect its a combination of light fly wheel and super long 4th to 5th throw.

Hope that helps!