Anyone Master Downshift Rev-Matching

[pothole]

Originally Posted by san rensho

Sorry, you are wrong. The idea behind rev matching downshifting is to save both the clutch and the gear box. Your advice will kill the gearbox.

Nope, rev matching is for whatever you want it to be. For me, I initially learned to do it to allow downshifts without upsetting the balance of the car. For others, they may do it purely in the name of mechanical sympathy.

Secondly, it's hysterical nonsense to say my advice will kill the gearbox. Hardly anyone does any kind of rev matching with manuals and modern gearboxes are engineered in this context. They can cope fine, as I can attest from probably a couple of hundred k of manual driving myself.

Very, very few people heel and toe according to your method. That's not to say it's wrong. If it's what you prefer, that's just dandy. But you will not destroy gearboxes in any properly engineered modern car (that includes Boxsters) by heel and toeing in the conventional method as I described. That's just twaddle.

No doubt some of the older cars in your sig appreciate rev matching as you describe, but it's just not necessary in a Box.

[Johnny Danger]

I love to rev match . I'm doing it now !

[san rensho]

Originally Posted by pothole

Nope, rev matching is for whatever you want it to be. For me, I initially learned to do it to allow downshifts without upsetting the balance of the car. For others, they may do it purely in the name of mechanical sympathy.

Secondly, it's hysterical nonsense to say my advice will kill the gearbox. Hardly anyone does any kind of rev matching with manuals and modern gearboxes are engineered in this context. They can cope fine, as I can attest from probably a couple of hundred k of manual driving myself.

Very, very few people heel and toe according to your method. That's not to say it's wrong. If it's what you prefer, that's just dandy. But you will not destroy gearboxes in any properly engineered modern car (that includes Boxsters) by heel and toeing in the conventional method as I described. That's just twaddle.

No doubt some of the older cars in your sig appreciate rev matching as you describe, but it's just not necessary in a Box.

How much more difficult is it to blip the throttle in neutral, BEFORE you engage the lower gear? And do you doubt that blipping the throttle before shifting is better for the tranny?

[shadrach74]

Originally Posted by san rensho

How much more difficult is it to blip the throttle in neutral, BEFORE you engage the lower gear? And do you doubt that blipping the throttle before shifting is better for the tranny?

If the goal is smooth and quick shifts, than yes that extra step does take time and smoothness away from the process. The whole point of a heel and toe when driving is to match the engine speed to transmission speed for the gear I'm moving into. The clutch must be released at the precise moment the engine reaches that speed. What you are talking about is double clutching. It is necessary in older non-syncro crash boxes to blip the throttle in neutral. Today in a modern car, it's not needed, nor will it trash a gear box, it may be easier on the syncros, but it's not necessary...nor is it a recipe for quick/smooth shifts...

[san rensho]

Originally Posted by shadrach74

If the goal is smooth and quick shifts, than yes that extra step does take time and smoothness away from the process. The whole point of a heel and toe when driving is to match the engine speed to transmission speed for the gear I'm moving into. The clutch must be released at the precise moment the engine reaches that speed. What you are talking about is double clutching. It is necessary in older non-syncro crash boxes to blip the throttle in neutral. Today in a modern car, it's not needed, nor will it trash a gear box, it may be easier on the syncros, but it's not necessary...nor is it a recipe for quick/smooth shifts...

I'm not recommending double clutching, my method uses the clutch just once, just blip as you are going through neutral. Its no slower than putting it in the lower gear first, then blipping, it actually faster, you are doing two things at once, blipping the throttle and moving the gear shift.

And blipping while going through neutral does save a modern synchro mesh tranny. Even with the clutch depressed, there is some drag in the clutch and blipping the throttle while in neutral will spin up the input shaft some, which means the synchro has to do less work.

[pothole]

Originally Posted by san rensho

I'm not recommending double clutching, my method uses the clutch just once, just blip as you are going through neutral. Its no slower than putting it in the lower gear first, then blipping, it actually faster, you are doing two things at once, blipping the throttle and moving the gear shift.

And blipping while going through neutral does save a modern synchro mesh tranny. Even with the clutch depressed, there is some drag in the clutch and blipping the throttle while in neutral will spin up the input shaft some, which means the synchro has to do less work.

The problem with your position is that gearbox failures are pretty rare on modern cars. So it's simply not necessary to shift using your method.

I'd also dispute whether it's faster using your method or even if it's practical as you describe to blip literally within that tiny window as the box goes through neutral on a fast downshift. I'd have to see some video or preferable a first hand demo to really gauge what I thought.

[shadrach74]

Originally Posted by san rensho

I'm not recommending double clutching, my method uses the clutch just once, just blip as you are going through neutral. Its no slower than putting it in the lower gear first, then blipping, it actually faster, you are doing two things at once, blipping the throttle and moving the gear shift.

And blipping while going through neutral does save a modern synchro mesh tranny. Even with the clutch depressed, there is some drag in the clutch and blipping the throttle while in neutral will spin up the input shaft some, which means the synchro has to do less work.

Got it, I misunderstood what you were suggesting. It's likely that I am on the gas as the shifter goes into neutral... It's one fluid motion from one sift gate to the next. I get absolutely no resistance going into the lower gear when it's done correctly. I think that we're both recommending same method, it's just that you were more detailed in your explanation.

I thought that you were suggesting that one needed to release the clutch during the neutral blip and then re-engage it for the shift...

[sb01box]

at what rpm are you downshifting?
for me, in normal daily drive, it's when the RPM is about 3000 so that the engine rev is kept in the 3500+ region. When I'm having fun, the downshift rpm is about 1000 higher.. which keeps the engine rpm above 4000 and ready to provide torque once my foot is off the brake and back on the throttle.
since I'm on the brake for most of my downshifts, downshift does not have to be fast, but make sure I don't $$$$ shift.

[shadrach74]

Originally Posted by sb01box

at what rpm are you downshifting?
for me, in normal daily drive, it's when the RPM is about 3000 so that the engine rev is kept in the 3500+ region. When I'm having fun, the downshift rpm is about 1000 higher.. which keeps the engine rpm above 4000 and ready to provide torque once my foot is off the brake and back on the throttle.
since I'm on the brake for most of my downshifts, downshift does not have to be fast, but make sure I don't $$$$ shift.

It depend on what gear I'm changing into and from where. The ratios on my 02 S are not evenly spaced. There is no "one size fits all" rpm difference with the 6 speed box. The five speed may be different.

[Frodo]

Originally Posted by san rensho

I'm not recommending double clutching, my method uses the clutch just once, just blip as you are going through neutral. Its no slower than putting it in the lower gear first, then blipping, it actually faster, you are doing two things at once, blipping the throttle and moving the gear shift.

And blipping while going through neutral does save a modern synchro mesh tranny. Even with the clutch depressed, there is some drag in the clutch and blipping the throttle while in neutral will spin up the input shaft some, which means the synchro has to do less work.

I'm pretty much positive I'm over-thinking this...but I have to ask: When you're doing this your way (blipping as you are going through neutral---presumably you're talking about the instant before down-shifting), do you again blip as you release the clutch? Or is it just one longish blip that both meshes the synchros (as you down-shift) and makes for a smooth transition as the clutch is released in the lower gear?

[san rensho]

Originally Posted by Frodo

I'm pretty much positive I'm over-thinking this...but I have to ask: When you're doing this your way (blipping as you are going through neutral---presumably you're talking about the instant before down-shifting), do you again blip as you release the clutch? Or is it just one longish blip that both meshes the synchros (as you down-shift) and makes for a smooth transition as the clutch is released in the lower gear?

Its just one blip. Essentially, I'm doing two things at once, blipping and shifting. As soon as I put the clutch in I blip, at the same time, I'm also moving the gearshift to downshift.

[Frodo]

Gotcha. Thanks.

[jaykay]

Originally Posted by san rensho

Its just one blip. Essentially, I'm doing two things at once, blipping and shifting. As soon as I put the clutch in I blip, at the same time, I'm also moving the gearshift to downshift.

Yep if you can blip to cover the synchro and clutch engagement everytime you have got it down.....when I am on the track under pressure in heavy work zones and am worried about balky shifts I blip coming through neutral to make sure the lever moves into gear and another for the clutch...this is usually for 2nd. The revs stay up nicely but I am likely slower for it

I will start trying a longer blip to cover both a bit more in those cases

[Topless]

Originally Posted by san rensho

How much more difficult is it to blip the throttle in neutral, BEFORE you engage the lower gear? And do you doubt that blipping the throttle before shifting is better for the tranny?

You guys are both right. San Rensho's method is absolutely necessary in an Alpha or any car built in Italy if you wish to avoid scattering synchros all over the road. It is completely unnecessary in a modern German car, especially a Porsche.

That said, it is of course your car and you may downshift it anyway you like.

[jb92563]

What would be the best technique for a maximum performance takeoff from a standing start.

Shifting 1-2 seems rough if you clutch at 7000rpm into 2nd gear.

Maybe I'm not clutching slow enough before engaging 2nd and the enigne is still pulling too hard when I clutch in at 6800 rpm.

Feels like I might need to let up on the gas before the shift?

no problems with the other gears.

[san rensho]

Originally Posted by jb92563

What would be the best technique for a maximum performance takeoff from a standing start.

Shifting 1-2 seems rough if you clutch at 7000rpm into 2nd gear.

Maybe I'm not clutching slow enough before engaging 2nd and the enigne is still pulling too hard when I clutch in at 6800 rpm.

Feels like I might need to let up on the gas before the shift?

no problems with the other gears.

For the fastest launch, which is a real clutch killer, you need to get the revs up really high, around 6500 RPM, then start to let the clutch out and simultaneously, floor the throttle and hold it on the floor, then modulate the clutch so the motor doesn't bog down, over-rev or spin the tires.