Arrwin

Hey guys,

Being that I just bought a Porsche and seeing that I'm fairly new to 3 pedal cars, I was wondering at what rpms do you guys shift for each gear? I try my best to rev match and stuff, but probably successful only 25% of the time.

My questions are basically:

1. At what rpm would you shift from a stop, 2nd to 3rd, etc.
2. At what point are you actually "burning the clutch"?
3. What are good shifting techniques? Not for the track, but for regular street/highway driving.

I'm just trying to avoid a premature clutch bill after spending all my $$ on the car. If there are any links out there that would do the trick, I would appreciate that as well.

As usual...thanks for the education.

ScottMellor

Hoo Boy. There are probably people with far more credibility than me to answer this one.

1. I pull away at the lowest possible RPM and engage the clutch quickly but smoothly. I never ever do drag race starts.
After that, once the engine has warmed up, anything up to redline is fine on the rest of the shifts.

2. Anytime the clutch is slipping is is wearing.

3. When shifting up, use little force (three fingers) and wait for the revs to match and "feel" it into the next gear. Don't slam it.
It's kind of like: rev, let-off-gas-dip-clutch, gear-shift into neutral , pause, gear-shift into next highest gear, release-clutch-apply-gas.

When shifting down I heel toe all the time, as I just have become accustomed to it.

CP

Arrwin,

Check out these videos. They are excellent for up-shifts. The guys on the M5 borad love it.

Also check out this Rennlist thread. Otherwise, there are other threads on shift points.

https://rennlist.com/forums/showthre...hreadid=107316

Just one clarification. You talked about shift points and rev. match at the same breath. Are you talking rev. match on up-shifts, or on down-shifts? We try to rev. match (single clutch, double-clutch, heel-toe double-clutch etc.) on down-shifts as the engine speed is lower than wheel speed upon down-shifts. I don't rev. match on up-shifts, as engine speed is already high.

This topic could be another 10 page thread all by itself.

CP

CP

Scott,

I'm confused. You brake every time you down-shift? Or you mean to say you 'double-clutch' on every down-shift?

CP

Adrienne

Great question! I was just wondering the same thing myself. I use the same technique ScottMellor recommends. I do however have another ponderance based on the way I have seen/felt friends drive my car. Regarding point #3, some friends of mine tend to shift quickly, which feels like it is shoving the car into gear rather than allowing the synchros to do their job, and I am wondering if this may end up wearing out the gears, or if I'm just being a worry wart from the passenger's seat. Gotta protect my baby, ya know. Any further clarification on #3 would be appreciated.

Arrwin

Thanks Scott. So....

"2. Anytime the clutch is slipping is is wearing."
Would you be burning or hurting the clutch when you apply gas and the clutch is still down? Basically, you would want this period to be as short as possible(?).

"3. When shifting up, use little force (three fingers) and wait for the revs to match and "feel" it into the next gear. Don't slam it."
Ok...so easy and don't force the shift. I saw an instructional video regarding shifting techniques and the instructor said that you shouldn't shift when the rpms are going down. When I shift, I press the clutch, which at that pt., the rpms drop to almost zero. I shift (clutch is still down, foot of the gas). Then I would blip the throttle and slowly release the clutch at the same time. Most of the time that's smooth like an auto tranny, but other times there's a slight jolt at which time i'm assuming the syncros are matching the revs with the speed. I'm usually ok at highway speeds, but find it much harder getting it smooth from a stop. I'm finding it's smoothest releasing the clutch at about 1100 rpms.

So...how bad am i killing the clutch?? Give it to me.

Arrwin

CP,

Thanks for the thread. I remember reading that in my pre-993 days and it was definitely informative. However, I don't see the link to the videos, which I think I have already seen and saved on my home computer. The guy is demonstrating shifting techniques in his ///M5, correct?

When I mentioned rev-matching, I was indeed referring on up-shift. How I understand it is that when say you're at 4000 rpms in 4th and about to shift into 5th, you need to press the clutch and release the gas, at which time the revs rapidly drop, eventually to zero. I would then shift into 5th, blip the throttle to about 3000 rpms and then slowly letting the clutch out? OR would you not blip the throttle at all, let the clutch slowly out and let the syncros do the work, at which the rpms will skyrocket from 0 to 3000 rpms?

CP

Arrwin,

On up-shifts, if your RPM drops to 'near-zero' before shifting, you need to quicken your motion.

The sequences are:
gas off (some people don't even lift), clutch in (almost simultaneousely).
Up-shift with no (or little) lingering through neutral.
Clutch out, gas in (almost simultaneous, but NEVER WOT before clutch is fully out, or you can toast your clutch, especially in lower gears).

If you do this quick enough, the rev. should not drop much. Michael Schumaker supposedly can do all of the above in 0.4 seconds (?).

I must also say that it is common for drivers new to the stick-shift to shift slow (ala carefully), not realizing that can actually hurt the mechanicals, e.g. slowing easing the clutch out on every shift. Remember, any time the clutch is neither fully-in or fully-out while under load, it is slipping. NOT a good thing. It is probably better to let the clutch out fast, and have some jerky motion, then to ease it out slow and slip it. The worse is esing the clutch out while applying gas at the same time. You are literally burning your clutch doing that.

Smooth car motion is highly dependent on shift-point RPM, especially in lower gears. After some time in your car, you will find the shift points that make for the smoothest up-shifts.

CP

ScottMellor

CP: I meant when braking and shifting down. I only double clutch when I'm down shifting but NOT hard on the brakes as it screws up my rhythm.

Arrwin: When the clutch is partially engaged and it is slipping it is wearing. 1100 sounds reasonable to take off.

If your RPMs have dropped to zero on an upshift, you have missed the boat and shifted to slowly. In that case, the synchros have some real work to do. The object is to be into the next gear and back on the gas without a jolt. Get some instruction with a real live person to help walk you through this, I think.

Arrwin

Thanks CP and Scott. I think our posts may have crossed, so please ignore my previous post.

I am going to print these "instructions" out practice shifting with these instructions at hand. In the garage first of course.

I hope Pete doesn't see this as it may make his heart a little squeamish.

Thanks again!

ScottMellor

Just to expand a little:
The pause that occurs in neutral on the upshift is quite slight, and is dependant upon your particular setup.
My car has a short shifter and a lightweight clutch and flywheel, so it is pretty microscopic.

Arrwin

Went back and carefully read this. So...it's better to fully let the clutch out and then apply gas? I was under the impression that one should let the clutch out while applying gas. In this case, there will be a point that both gas and clutch is applied.

I'm killing my clutch, huh?

kkim

Arrwin,

To add to what the others have mentioned, during shifting, up or down, I "blip" the throttle slightly between the gears. Seems to make the transition smoother going from gear to gear. I learned this a while back riding sport street bikes and have been using the technique ever since on all the cars that I've owned.

It takes some practice, but it can be done very smoothly and quickly after you get used to it.

CP

Arrwin,

Let me clarify: it is bad if you are still letting the clutch out and apply high RPM throttle (say 3,000 RPM and up). You are definitely hurting your clutch as it is slipping under high torqure load. Low throttle of course is less damaging to the clutch

In lower gears, you need to have sufficient throttle not to lug or stall the engine. Thus you apply gas as you let the clutch out. Once at second or higher, unless you are going up a steep hill, there's little chance you will lug or stall. Thus there is little need to apply a lot of gas before the clutch is fully out. So the best habit is to get the clutch out before the right foot goes deeply in.

During the M5 Driving Experience, we did a segment of 1/4 mile runs (8 runs per driver). The most common mistake is us anxious drivers burying the right foot before the clutch is fully out. If you want to know what a toasted clutch smells like, that's the place to be.

Real life example. You are in first and hit 4,000 rpm. You up-shift to second. By the time the clutch comes out, you should be about 2,500 RPM or so (not the steady-state 750 idle RPM I hope). The car will run in second gear without stalling (even without additional throttle). There is little reason to have the engine at 4,000 RPM when you clutch out in second. In fact, you will definitely feel a jolt if you did that.

CP

Arrwin

Thanks for the clarification CP. I think i've got it. Now...to put the words into action. Too bad it's storming outside here in NY.

My clutch thanks you!