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-   -   Anyone Master Downshift Rev-Matching (http://986forum.com/forums/showthread.php?t=35837)

shadrach74 06-09-2012 05:20 PM

Hi guys, I'm new here. Bought a 2002 S about 3 weeks ago and I'm still sorting through it.

The difficulty with the Boxster (or at least the 6 speed S IME) is that the ratios between gears are not spread evenly. 3rd, 4th, 5th and 6th are relatively close, 1st and 2nd are relatively tall. The 3rd to 2nd shift in my car requires about 1300rpm rise, while a 5th to 4th requires about 800rpm rise. I'm getting better, but am still not able to drive the car as well as the other two manual cars I spend time in (330CI and Cooper S). The fact is the only way to shift this car well is to recognize that the cogs are spaced differently and and account for it when heel and toeing. The pedals are presented perfectly, it's just a matter of discipline...

Bigsmoothlee 06-09-2012 05:32 PM

You just need to practice until it becomes 2nd nature.

When you get really good, you'll be able to downshift without the clutch. And in some cases, you may feel like popping it out of 4th without the clutch, putting the gas pedal to the floor,and popping it into 2nd gear to accelerate without even lifting the throttle....:cheers:

I spent years mastering that technique on old BMWs. Rev matching is a must for me on any downshift, city or track.

ekam 06-09-2012 05:35 PM

Watch the first part of this video:
Heel Toe Driving Technique - YouTube

Quote:

Originally Posted by Bigsmoothlee (Post 293495)
When you get really good, you'll be able to downshift without the clutch.

There's a reason why there's a clutch pedal.

Kianfar 06-09-2012 05:41 PM

I'm not too keen on the heal and toe method as I don't track this car. I just want smooth up****************s, and smooth downshifts. The closer I can get it to feeling like an automatic car, the better I feel. However, it seems like there is a lot of work involved. So far it seems like the recommended method is as follow. So example scenario coming from 5th to 4th, or 4th to 3rd.

1. Clutch in
2. Remove Gear to Neutral Position
3. Rev The engine - While clutch engaged
4. Move gear to new lower gear
5. Let clutch out

Now my only question is on step 2 to 3, when you put the gear in neutral, more than likely the RPM will drop from whatever it is to around 1500. I know this needs some speed, to not lose all the RPM say from 4000 or 3000, but is that ok?

pothole 06-09-2012 06:06 PM

Kianfar:

Heel and toe is great for the road. Do not be mistaken in thinking it's a track only technique.

I'm going to say that trying to save the synchros is overkill. For me, it's all about smooth changes and driving pleasure. It's just a nice fringe benefit that it saves the clutch if done well.

So, assuming braking is involved:

1. Lift off throttle
2. Apply brake and clutch in at roughly the same time (being sure to position your right foot on brake pedal so that you are ready to blip throttle while maintaining brake pressure)
3. select new gear
4. Blip throttle and then immediately pop the clutch out

If you're just coasting down without using the brake, or downshift for an overtake or whatever then simply change "2." to "clutch in".

Having said all that, putting this into a list is somewhat misleading - there's overlap in places and the whole thing is more of a single flowing process, if done well. Obviously at the outset you're going to nee to break down the steps. But the aim should bea nice smooth process and a gearchange where you can't feel the clutch being fed in.

san rensho 06-09-2012 06:18 PM

Quote:

Originally Posted by pothole (Post 293504)
Kianfar:

Heel and toe is great for the road. Do not be mistaken in thinking it's a track only technique.

I'm going to say that trying to save the synchros is overkill. For me, it's all about smooth changes and driving pleasure. It's just a nice fringe benefit that it saves the clutch if done well.

So, assuming braking is involved:

1. Lift off throttle
2. Apply brake and clutch in at roughly the same time (being sure to position your right foot on brake pedal so that you are ready to blip throttle while maintaining brake pressure)
3. select new gear
4. Blip throttle and then immediately pop the clutch out

If you're just coasting down without using the brake, or downshift for an overtake or whatever then simply change "2." to "clutch in".

Having said all that, putting this into a list is somewhat misleading - there's overlap in places and the whole thing is more of a single flowing process, if done well. Obviously at the outset you're going to nee to break down the steps. But the aim should bea nice smooth process and a gearchange where you can't feel the clutch being fed in.

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.

pothole 06-09-2012 06:26 PM

Quote:

Originally Posted by san rensho (Post 293505)
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 06-09-2012 06:37 PM

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

san rensho 06-09-2012 06:38 PM

Quote:

Originally Posted by pothole (Post 293507)
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 06-09-2012 07:48 PM

Quote:

Originally Posted by san rensho (Post 293512)
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...

Topless 06-09-2012 08:03 PM

Quote:

Originally Posted by san rensho (Post 293512)
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. :cheers:

jb92563 06-09-2012 09:56 PM

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 06-10-2012 05:41 AM

Quote:

Originally Posted by shadrach74 (Post 293520)
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.

san rensho 06-10-2012 05:47 AM

Quote:

Originally Posted by jb92563 (Post 293539)
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.

pothole 06-10-2012 06:04 AM

Quote:

Originally Posted by san rensho (Post 293563)
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 06-10-2012 07:21 AM

Quote:

Originally Posted by san rensho (Post 293563)
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 06-10-2012 12:46 PM

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.

Kianfar 06-17-2012 05:57 PM

This is working great for me:

1. Clutch in
2. Remove Gear to Neutral Position
3. Rev The engine - While clutch depressed
4. Move gear to new lower gear
5. Let clutch out

southernstar 06-18-2012 04:44 AM

I find that the pedals on the Boxster are set up perfectly in order to allow you to pivot the ball of your right foot side-to-side, rather than heel-and-toe between the brake pedal and the accelerator pedal (although I suppose that having somewhat wide feet helps!). I still double-clutch out of habit, although in a car with good synchronizers it isn't really necessary - all you are trying to do is equalize the revs so that upon release of the clutch in the new lower gear, additional strain is not put on the drivetrain and the balance of the car is not upset by engine braking. Even if you aren't pushing the car to a point where it is strictly necessary, smoother is better in driving any car (and the blip of the throttle on downshifts just sounds cool)!

Brad

shadrach74 06-18-2012 05:44 AM

Quote:

Originally Posted by sb01box (Post 293618)
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.


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