Slynky

So, I think I'm 75% sold on my first automatic transmission since I drove an automatic Opel Manta Ray in Germany in 1977. (now that I think about it, it's kind of a weird coincidence to have driven an automatic "Manta Ray" and now be considering an automatic "Stingray")

My current 370Z is a stick shift with rev-matching. It's OK, but it's not the "holy grail" of gearshifting.

My question is to those who have been around a while.

I drove a '64 Falcon Sprint (stick) and a '69 Plymouth Sattelite (stick) when I "muscled" around my small town. In those days, the transmissions had synchronizers to "rev-match" the gear you were changing to--whether it be down-shifting or otherwise. When I was on the drag strip, I could change gears in a split-second. I kept the gas pedal to the floor, stomped the clutch in an out as fast as I could move my left foot, and shifted during that split second. The synchronizers did a good job of getting me into the next gear.

Even down-shifting--though a bit slower to snchronize the next gear--worked OK (but not exactly race-worthy). You could hear the gear spin up to speed when the synchros were doing their down-shifting job.

So, my question is, just what's all the fuss about rev-matching anyway? I mean, it's not leaps and bounds beyond the technology of the 60s. Do the new manuals have synchros and rev-matching?

I know there are a lot of guys out there who are more technical about these things than I am...and this, I guess, is one of the things I think about when looking at the C7 (and deciding which to get).

Thanks in advance.

punky

Good question Slynky. There are many of us here I am sure that are not quite up to speed on the state of the current Rev Match technology and just how it will function. It sure sounds great in the very brief descriptions that I have heard and read.

gthal

The syncros in a manual don't "rev match" per se. The rev match feature in the C7 actually blips the throttle to match engine speed and transmission speed. Essentially heel-toe downshifting. Syncros in an older MT don't do that.

This allows you to downshift more quickly without unbalancing the car. Try this... decelerate very quickly and downshift. Don't blip the throttle and simply quickly release the clutch... the car will jerk and buck as the engine speed is very different then the transmission speed. On a track this is a great way to lose control of the rear end... heel-toe downshifting is essential and you can't be effective on track without doing it... the C7 basically just does that for the driver now so even people who don't efficiently know how to heel-toe can get the same benefit. For street driving, it will be a cool but not very important feature.

Syncros help the car syncronize and engage gears smoothly, the rev match feature matches the transmission speed to the engine speed to simulate heel-toe shifting. The throttle blips it generates sound cool too

BlueOx

There is a bit of a difference...

Slynky

Thanks for your reply.

Perhaps that's the distinction I'm missing.

The synchro in a transmission spins the next gear and matches the speed of the drive gear so the two "mesh into place" smoothly. Rev-matching adds one additional step (above what the synchro does) and adds in matching the engine speed to the upcoming gear speed.

And, yes, the experiment you suggested has been done by myself many times when I was younger (and really evident on wet roads).

Bobcatt

Without rev matching the rear end can lock up for a second or two. I know you probably have seen people squawk the tires down shifting.

Slynky

I'm not sure what my current rev-matching does in my Z. It's obvious on downshifting. Not sure I see anything happening on the upshift. It is predictive because you can "swim" around in the "neutral" area and listen to the engine change RPMs as you get near a gate.

I get irritated at upshifting in my Z because I have to "wait" for it when I want to speedshift. You can feel a bit of a, hmmmmm..., hinderance when going into 2nd (and 3rd a bit) at high RPMs. My worry is that all manuals do that now and that I can't shift any of the new manuals like I could in the "old days". It's like they don't make them as well. And when I get into some of my spontaneous "red light races", the last thing I want to do is get behind because my transmission can't prepare for my next shift fast enough--the reason I'm considering an automatic--and the reason the AT in the Z beats the manual in runs. I'm worried the Corvette will be the same. And I'll be dammed if I want to be in a prestigious car like the C7 and lose out because the transmission hedges between 1st / 2nd / and 3rd.

Slynky

Yeah, I kind of mentioned that above..."especially in the rain". (well, the squalling doesn't occur in the rain ).

BeaZt

I didn't know it did it on upshifts also. How does that work? I couldn't imagine someone needed it on upshifts.

Slynky

Almost forgot...

SO, last week or so, we (one of those rare moments when my wife was brave enough to get in the car with me ) were driving back home in the subdivision and a couple of teen guys were sitting on their bikes at an intersections I was approacing to turn onto. When I downshifted to 2nd, the rev-matching kicked up the engine a bit. Both guys smiled. Wife then says, "You did that on purpose." I had to explain and demonstrated on the next turn the car did it automatically. (of course, I didn't admit to the part where I like the sound it makes... ).

BlueOx

There is a sensor (Hall-effect, I think) that detects shifter movement in the direction of the next shift and will blip the throttle in response to that very slight movement.

Again, if you don't want it on, you can easily turn it off.

pmzangag

Is it an acutal throttle blip (momentary rev), or are the RPM's held at the propper speed until the clutch is let out? Tryed looking at some youtube vids of rev matching with the 370Z, and it looks like the RPM's will stay at the same speed indefinately as long as the clutch is depressed.

Slynky

That might be correct. If memory serves me correctly, there have been times when I've been coasting up to a stop and had the clutch in a bit longer than usual and I seem to recall being annoyed at the unnecessary revving sometimes (as I lingered too close to a gate).

Of course, as we all know, the C7 might not be like that at all.

JudgeNjury

Nissan rev match only on downshift. Corvette is first 2 seater to offer it on upshifts.

Should be more in line with your question.

Slynky

Interesting. Will be interesting to see how it works on the new C7 (although I'm not sure what the benefit would be to pulling the revs down to match the upshift target gear).

torquetube

The revs will drop ASAP to the matching RPM instead of the lazy return-to-idle.

Automatic rev-matching seems like a natural addition to the long list of duties performed by the PCM. The direct connection between the gas pedal and the throttle plate was eliminated two generations ago, allowing the computer free reign to partially or completely implement idle control, cruise control, rev limiting, traction control, engine drag control, etc. using the same butterfly.

On the C6, instead of rev-matching, the computer just lets the revs drop slowly when you lift between shifts. That's the best solution given that the car has no idea what's coming next. But if the gate were equipped with sensors, the engine could go straight to the right RPM rather than take a slow-motion tour of the wrong RPMs. Why not?

JudgeNjury

Upshift will be perfect and smooth for faster acceleration .

Reliability. Wear and tear diminished as well.

Benefit is faster acceleration as the end result

AVETTE

Obviously if this car is your daily driver and you will be used in lots of heavy stop and go traffic, go for the auto... BUT... If you are in an area like me and that is rarely the case then the manual is FUN.. I realize that autos have progressed a lot, and one mistake and you will lose to the auto, but, maybe I really AM old (just turned 45) but there is something exhilarating about driving a stick.

In addition, if you do occasionally track your car as I do, autos are NOT good on a racetrack (not drag strip), if you can drive the car well, it WILL overheat, I am so excited about the rev matching feature as I am not a good heel-toe down-shifter and that is really necessary on the track, plus, it DOES sound cool

Unless your situation is what I outlined above, I suspect if you get the auto, given your history of fun with manuals, you will be disappointed at the lack of "participation" involved in the driving experience
Just my .02 cents Good luck with your decision

Slynky

Good points and information.

Slynky

A lot to think about and thank you for your reply.

It's unlikely (at my age) I'll ever track the car (though the thought does give me a thrill). Spirited drving would be the best description of my tendancy these days. And beating Mustangs down at red lights .

But all good points and in the back of my mind, I do worry I might get bored out of my mind with an auto...