Best way to downshift?
 

I'm trying to learn the best way to execute a proper downshift.


Is it best to: first go to neutral, then blip the throttle, and still with the clutch in, switch to the lower gear and quickly let the clutch out?

Or is it better to drop down a gear and then blip the throttle without going to neutral?

And is it safe and good for the car to downshift? Even if its higher rpm?

You need to rev match (blip) in order to save clutch and gear wear. There are vids on youtube teaching technique.

I don't downshift in street driving, brakes are cheaper than a clutch.
At the track I downshift into corners by rev matching (heel/toe) and straight from gear to gear, no neutral.
Sometimes I don't match revs quite right, sometimes to high and sometimes to low.

If you check the back of your boxster manual there are recommended specs for what range to downshift in. Downshifting to a very high-rev will slow your car down, but at the expense of transmission longevity. Rev-matching helps so that you don't put the strain on the tranny. Even so I don't usually downshift unless the gear I am in is at 3k or lower. I believe the manual says for downshifts that is generally the limit of what you'd want to do. ie:3k start = 4k in new gear. Doing downshifts higher might be a bad idea.

Also if you were to accidentally go into the wrong gear and be WAAY to high (above redline), that is known as "over-revving" and will be recorded in the computer as it can cause damage to the engine. Usually a tech will check for over-revs as part of a PPI when buying the car...anyhow...I digress...

I tend to blip the throttle late, once in gear. If you wait too long the revs will drop and you won't be rev matching anymore. I tend to ease off of the clutch in a downshift in case I am off, otherwise I am going to very quickly slow down the car. heh. I tend to downshift and rev-match all the way quite a bit...it's fun so why not. Usually down to 2nd...by the time I am in first I am just braking to a stop light. That said I down shift to be in the proper gear for power, not for "stopping". ie: I don't downshift to slow the car down.

comet

For straight line braking, use the brakes not the transmission.

Prior to a turn use heel and toe to rev match and complete your shifting prior to the corner. A proper rev match means that you may have to wait for the car to slow to an appropriate speed to match the revs smoothly. Too early and the engine over-rev's, too late and the blip doesn't matter much. Heel and toe rev matching ensures that you are in the right gear on corner entry so you can control the car in the corner with the throttle (if needed) and so you can accelerate smoothly out of the corner.

With practice (and practice and practice), braking while heel and toeing is one continuous fluid movement and its like dancing with the car. I do it on the street all of the time without even thinking about it, its second nature now.

Can you rev match with the PDK?
 

I was wondering if you rev match with the pdk transmission. I was also wondering what is rev matching? Of course I have researched the topic but I have never gotten my head completely around it. My experience with a traditional manual is very limited. I find myself shifting about 90% of the time and would consider purchasing a manual in the future. For now, I love the freedom to shift when I want...


Thanks,

Justin R.

I downshift like this. As soon as I put the clutch in I rev the motor and simultaneously move the gear lever for the downshift, so that the car is revving as I pass neutral. Shifting to the lower gear and then rev matching does nothing to relieve the wear on the synchro's, although it will lessen wear on the clutch, which can be very substantial when downshifting without rev matching.

Any time the car lurches when you release the clutch on a downshift, you are slipping the clutch and causing wear.

No convinced synchro wear is that much of an issue with these modern boxes.

No need to double declutch. Rev matching prior to clutch engagement is plenty.

I'm not saying you have to double clutch, but if you reev as you are going through neutral, there is enough drag in the drive train that it will get the input shaft spinning up, which will help save the synchros. If you blip the throttle after you have selected the lower gear, you are getting the most synchro wear.

Well, you'll have to blip twice or hold the revs constant to do that, otherwise, you'll have blipped too early and the revs will have dropped when you engage the clutch.

But like I said, not convinced worn synchros are something you have to worry about. My car is on 113,000 miles. No signs of any issues. I've had BMWs on 150,000 miles plus, ditto.

No, it's all in one quick movement, you put the clutch in and immediately blip, at the same time, you move the shifter smoothly to the lower gear. No double clutch no second movement no hesitation.

But the point where you start the blip you're going through neutral right?

Yes. At the same time you push inthe clutch, you blip and simultaneously move the gear shift so that you are blipping as you go throuhg neutral.

brake
left foot: clutch in/ right foot: roll ankle from brake to throttle.
downshift
release clutch/ get on throttle fully

I think that's right....

I don't downshift nearly as often in the Boxster as I used to with my old Miata.
Usually in a turn I just wait let the car slow down until the revs are 2K or lower, quickly slip into neutral, tiny blip and shift into 2nd. Kind of the lazy way to do it.

Rev matching is moderating the engine speed so the engine output shaft and the transmission input shaft are at nearly the same RPM when the clutch is engaged. This will minimize clutch slippage, wear, and help keep the car balanced.

Most drivers tend to do this already somewhat naturally on upshifts by moderating the throttle in the middle of the upshift to ensure that the clutch engagement to the next higher gear is smooth. For example, when shifting up at high RPM's, the driver will naturally give the engine more throttle when engaging the clutch for the next gear.

Rev matching is doing the same thing for downshifts - especially if you want to keep the rev's in the upper range through a corner (instead of letting the rev's fall to idle or nearly idle). The tricky part is that the driver is usually also braking at the same time - thus the technique known as "heel and toe" is used to brake and perform a rev-matched downshift at the same time.

PDK transmissions can do the rev matching for you. After receiving the signal to downshift, the computer matches the engine speed to the transmission speed and smoothly performs the shift.

I always downshift since with the gears engaged you are in full control of your car.

When you are in neutral you cannot accelerate or decelerate with the engine so you have taken away some of your control.

Take a PCA Performance Driving school for a real eye opener on how to drive and control your Porsche.


It takes much practice but rev matching is the goal to minimize wear on the clutch.

It took me 6 months to get it perfect in my Boxster 6 speed and now I can shift smooth going up or down the gears at will.

I do still miss a shift now and then though but I just go back to the previous gear when that happens and try again.

When down shifting I use the blip method where enroute to the next stick position(gear) I blip the throttle to match the revs then let the clutch back in at just the right speed so that everything hooks up perfect without a lot of jerkiness.

When doing Max performance shifting it does get more jerky but smooth stick and clutch work non the less.

You never want to shift down where the new gear ratio over revs the motor.

With 6 speed that does not happen very easily unless you are way up in the revs 6500+ but with a 5 speed you may have to pay a bit more attention.

If you keep all your up and down shifts between 3500-5500 rpm you will have no worries.

Practice is the best way to get smooth, and heel/toe or blip is up to you and what you find is your prefered method.

[QUOTE=san rensho;324418]I downshift like this. As soon as I put the clutch in I rev the motor and simultaneously move the gear lever for the downshift, so that the car is revving as I pass neutral.
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Definitely a multi-tasking motion, using clutch, gas and shift as San Rensho explained, sort of all at the same time.
Anticipating the RPMs for the next gear is what I attempt to do. For my six speed, 1st, 2nd, 3rd are around 750-1000 RPMs apart. The higher gears are around 500. So trying to blip the RPMs (When clutch pedal gets pushed) up to were the next gear will run is the goal. You will see the RPM differences during normal up shifts. They're the same for down shifts. It not always down a consecutive gear either. It may be a couple or gears. Ex: 5th to 3rd, 4th to 2nd. Depends on how fast you had to slow down