How do YOU downshift?
01-13-2011, 04:56 PM
#17
01-13-2011, 07:25 PM
#19
Registered User
It would be nice if Nissan implements this on the next generation G.
01-13-2011, 08:02 PM
#21
Honestly, it would be cool to have, but I doubt I'd use it. Maybe once in a blue moon.
01-13-2011, 09:07 PM
#22
Registered User
You got it backwards. Synchro-rev is more suited for the racetrack than for touring. The reason behind synchro rev is to make the driver more concentrated on hitting that apex while trail braking, and by not having to worry about rev matching your downshifts, it really makes a difference. I know for a fact when I used to do laps, I really wished I didn't have to heel-toe because I knew I could brake much harder and later if the car would do that for me.
01-13-2011, 10:16 PM
#23
You got it backwards. Synchro-rev is more suited for the racetrack than for touring. The reason behind synchro rev is to make the driver more concentrated on hitting that apex while trail braking, and by not having to worry about rev matching your downshifts, it really makes a difference. I know for a fact when I used to do laps, I really wished I didn't have to heel-toe because I knew I could brake much harder and later if the car would do that for me.
On the flip side, G37 owners are more likely to enjoy treating their cars as a grand touring car. And as such, if those G37 drivers have a manual transmission, they'd be more likely to use Synchro-rev. Now of course I'm generalizing here, because I'm a G37 driver who would rarely, if ever, use it even if I had it on my G37. But I still think Nissan would have been smart to put it on the G37 before the 370Z.
01-13-2011, 11:12 PM
#25
Registered User
I think you misunderstood what I'm saying. I'm not debating whether it is more suited to the street or the track. What I'm saying is that people who truly enjoy full manual control of a sporty car are more likely to want to do their own rev matching instead of letting an electronic nanny do it for them. 370Z drivers are more likely to track their cars than a G37 driver, but at the same time those guys are also more likely to enjoy heel-and-toe, rev-matching, etc...
On the flip side, G37 owners are more likely to enjoy treating their cars as a grand touring car. And as such, if those G37 drivers have a manual transmission, they'd be more likely to use Synchro-rev. Now of course I'm generalizing here, because I'm a G37 driver who would rarely, if ever, use it even if I had it on my G37. But I still think Nissan would have been smart to put it on the G37 before the 370Z.
On the flip side, G37 owners are more likely to enjoy treating their cars as a grand touring car. And as such, if those G37 drivers have a manual transmission, they'd be more likely to use Synchro-rev. Now of course I'm generalizing here, because I'm a G37 driver who would rarely, if ever, use it even if I had it on my G37. But I still think Nissan would have been smart to put it on the G37 before the 370Z.
Synchro rev can be turned off, so if the driver wants full control, he still can. A serious track racer would appreciate such feature a whole lot more than the average Joe on a entry level luxury coupe that might never see any track time. I say great move by Nissan, let's hope they make next generation 6MT G with such cool feature.
01-14-2011, 12:02 AM
#28
Registered User
Exactly. Someone that's grand touring would turn off all aids and try to enjoy the car on its purest form. Someone at the track is trying to beat his/her previous laptime, so any aids that will help achieve that will be used. Nissan did the right move IMO.
01-14-2011, 03:07 AM
#29
You have it mixed up. Double clutching is useful when UPSHIFTING to the next higher gear, if you have worn synchros or you want to avoid any wear on them.
When downshifting, double clutching isn't necessary at all because you are increasing the revs to match the faster speed (higher RPM) from the lower gear that you are shifting into. In other words, if you blip the throttle perfectly, you won't use the synchros at all because the shaft speeds inside the transmission will be equal.
When downshifting, double clutching isn't necessary at all because you are increasing the revs to match the faster speed (higher RPM) from the lower gear that you are shifting into. In other words, if you blip the throttle perfectly, you won't use the synchros at all because the shaft speeds inside the transmission will be equal.
. "Granny Shiftin, not double clutching like ya should. Now me and the mad scientist gotta rip apart the block and replace the piston rings that you fried." Classic. Hopefully no one would take anything but entertainment value from that movie. I have to hand it to semi-truck drivers though for their need to double clutch upshifts since their rpms drop quickly between shifts due to their cargo loads. Unless you upshift like a grandma whose never driven stick before, double clutching an upshift does nothing since engine and transmission speeds are already up due to acceleration. Are you Vin Diesel?To enlighten you, here's a race car driver Gary Sheehan's take on double clutching downshifts:
When you downshift, engine rpm must increase and transmission layshaft rpm must increase to accomodate the lower gearing for a given road speed.
Rev matching brings the engine rpm up to the appropriate speed, but since the clutch is in, the layshaft speed is not effected by the throttle blip (layshaft speed is actually decreasing due to bearing friction). As you move the shift lever into the next lower gear, the synchros are engaged to speed up the layshaft rpm to match engine speed and road speed. Synchro wear occurs here. Synchros are sacrificial and are designed to be used in this way. The wear is cumulative and could cause end of synchro life before end of vehicle life.
Double-clutch rev matching brings the engine rpm AND layshaft rpm up to the appropriate speed, essentially eliminating synchro wear. When the clutch is out, the layshaft is coupled to the engine, so the throttle blip increases the revs of both engine and layshaft. When you select the next lower gear, all rotating components are closely synchronized, so the synchro has little or no frictional wear because there is little or no difference in speeds.
Is double-clutching necessary? No.
Can double-clutching eliminate gear clash due to sychros wearing out before you are ready to get rid of your car? Yes.
StandardShift.com • View topic - Syncromesh wear
Rev matching brings the engine rpm up to the appropriate speed, but since the clutch is in, the layshaft speed is not effected by the throttle blip (layshaft speed is actually decreasing due to bearing friction). As you move the shift lever into the next lower gear, the synchros are engaged to speed up the layshaft rpm to match engine speed and road speed. Synchro wear occurs here. Synchros are sacrificial and are designed to be used in this way. The wear is cumulative and could cause end of synchro life before end of vehicle life.
Double-clutch rev matching brings the engine rpm AND layshaft rpm up to the appropriate speed, essentially eliminating synchro wear. When the clutch is out, the layshaft is coupled to the engine, so the throttle blip increases the revs of both engine and layshaft. When you select the next lower gear, all rotating components are closely synchronized, so the synchro has little or no frictional wear because there is little or no difference in speeds.
Is double-clutching necessary? No.
Can double-clutching eliminate gear clash due to sychros wearing out before you are ready to get rid of your car? Yes.
StandardShift.com • View topic - Syncromesh wear
Last edited by Ken; 01-14-2011 at 03:27 AM.
01-14-2011, 07:03 AM
#30
Actually, someone who was "grand touring" probably wouldn't downshift much at all. In reality, there's really not much of a reason to downshift when you're just cruising along enjoying the scenery. It's just not necessary in most situations. Sometimes I'll downshift as I come to a stop. That is totally unneccesary...I realize that, but I still do it once in a while because it's fun. Now downshifting before a turn is something that I always do, simply because it makes sense to power out of a turn in the correct gear. In a case like that, it makes sense to me to let Synchro-rev do it's thing instead of working the synchros themselves. That's especially true when I'm just cruising around and not driving/shifting for enjoyment.