Gear Shifting 101

[Onad]

I am by no means an expert, but I think the Boxster gearing is not conducive to 2nd gear starts unless you are drifting down hill.

[MNBoxster]

Hi,

You lug the engine when you try to accelerate in too high a gear . You make the Engine work harder than it's supposed to. Just like you would work harder if you rode a bicycle up a steep hill in 12th gear as opposed to first gear.

When the engine is over-worked, it overheats. The way it overheats is that the temperature inside the cylinders gets too high. When that happens, the Air/Fuel mixture which is supposed to combust as the spark plug fires, detonates unpredictably before the Spark occurs. That's called pinging , when those detonations make a sound like marbles rolling around.

And, under the worst of circumstances, you can also get piston slap, which is a clunky noise. Because you are getting uneven combustion inside the cylinder (the detonation doesn't necessarily happen at the right time or in the right spot), the explosion can force the piston off to one side when it descends during the power stroke. When that happens repeatedly, the cylinder walls get all scraped up, and over time, your Engine becomes less powerful, more noisey and will start to burn Oil prematurely.

It's important when Starting from a Stop to Rev the Engine sufficiently to match the Load imposed on it. From a Stop, the Engine is not aided by Inertia or Momentum (it has no stored Energy to draw on), it has to do all the work itself (unlike a Gear Change while moving).

You need to select the gear which gives the Engine the Greatest Mechanical Advantage (which happens to be 1st) and give it sufficient Throttle that is, RPMs, to create enough Power to do the Work you're calling on it to do. Then Feather the Clutch until the Car starts to move, then as quickly as you can smoothly, release the Clutch entirely, all the while adding Throttle.

You can start out in 2nd Gear, if you give it enough Throttle, but this has the drawback of prematurely wearing the Clutch Disc as it will slip more until it can seat properly. Hope this helps...

Happy Motoring!... Jim'99

[RandallNeighbour]

Originally Posted by MNBoxster

Hi, You lug the engine when ...

I do love your long, exhaustive, and teaching-oriented threads!

Luxury, the cliffnotes version is "Nope. Don't do it."

[MNBoxster]

Originally Posted by RandallNeighbour

I do love your long, exhaustive, and teaching-oriented threads!

Hey,

I don't have to do it... but for many years, a lot of Great People, a LOT Smarter than I took the time, and patience, to teach me.

I just feel like it's a form of repayment to them to pass it along, maybe lessen someone else's Learning Curve, and perhaps help people enjoy their experience more...

Happy Motoring!... Jim'99

[boxtex]

[QUOTE=MNBoxster]Hi,

Nicely explained, very informational and detailed

[Adam]

You can start in 2nd but your clutch won't last as long. 2nd gear starts require more slippage thus more clutch wear. Lugging the engine means using too high of a gear. Keep the rpms above 1,500 when driving around.

[SD987]

Luxury1, did you ask that question because you're experiencing occasional/frustrating/potentially dangerous lock-out in first gear of your 987 5-speed?

If so, there are some workarounds for that....

[luxury1]

Originally Posted by SD987

Luxury1, did you ask that question because you're experiencing occasional/frustrating/potentially dangerous lock-out in first gear of your 987 5-speed?

If so, there are some workarounds for that....

Actually I haven't experienced this just yet. Just learning the ropes with the transmission.

Originally Posted by SD987

Luxury1, did you ask that question because you're experiencing occasional/frustrating/potentially dangerous lock-out in first gear of your 987 5-speed?

If so, there are some workarounds for that....

What is lock-out in first gear?

[SD987]

The inability to push the shifter into first gear at inopportune moments, reported by myself and a couple of other over at ppbb.

Fortunately, this lock-out seems to be a rare flaw found in certain 5-speeds installed on 2005 987s (obviously, not the S model). There is a Porsche TSB where they realign the shifter for you, with mixed results. My guess is that the problem will go down in history as an isolated problem with the new Japanese tranny in the 987, that was "worked out" in subsequent builds and could be characterized as one of those minor glitches that frequently materialize in the early years of "new" models.

[eslai]

Originally Posted by SD987

The inability to push the shifter into first gear at inopportune moments, reported by myself and a couple of other over at ppbb.

Fortunately, this lock-out seems to be a rare flaw found in certain 5-speeds installed on 2005 987s (obviously, not the S model). There is a Porsche TSB where they realign the shifter for you, with mixed results. My guess is that the problem will go down in history as an isolated problem with the new Japanese tranny in the 987, that was "worked out" in subsequent builds and could be characterized as one of those minor glitches that frequently materialize in the early years of "new" models.

wow, I hadn't heard of that. Bummer.

[rickhuizinga]

Originally Posted by SD987

The inability to push the shifter into first gear at inopportune moments, reported by myself and a couple of other over at ppbb.

Fortunately, this lock-out seems to be a rare flaw found in certain 5-speeds installed on 2005 987s (obviously, not the S model).

I have this problem in my 987S 6 speed where I cannot shift from neutral into first gear when rolling (in neutral) above 4 or 5 mph. This is a problem because sometimes selecting second gear isn't an appropriate starting gear when rolling between 5-10mph (especially up hill). Whenever this happens, I have to stop the car, shift to first, then drive on - often pissing off those who are following. If I select 2nd, I have to slip the clutch and bog the engine.

Any suggestions?

[MNBoxster]

Originally Posted by rickhuizinga

I have this problem in my 987S 6 speed where I cannot shift from neutral into first gear when rolling (in neutral) above 4 or 5 mph. This is a problem because sometimes selecting second gear isn't an appropriate starting gear when rolling between 5-10mph (especially up hill). Whenever this happens, I have to stop the car, shift to first, then drive on - often pissing off those who are following. If I select 2nd, I have to slip the clutch and bog the engine.

Any suggestions?

Hi,

Even with Baulk Rings (Synchromesh) there has to be a certain relationship between the Speed of the Crank and the Input Shaft to the Tranny. This is most noticable in the Lower Gears. Try giving the Throttle a Blip and see if that doesn't cure the issue.

I don't know the answer to this, but could the DME (Drive-by-Wire and such) be preventing this? Some Cars do have a Lock-Out to prevent over-revving the Motor, does the Porsche have this too?

Happy Motoring!... Jim'99

[denverpete]

Originally Posted by rickhuizinga

I have this problem in my 987S 6 speed where I cannot shift from neutral into first gear when rolling (in neutral) above 4 or 5 mph. This is a problem because sometimes selecting second gear isn't an appropriate starting gear when rolling between 5-10mph (especially up hill). Whenever this happens, I have to stop the car, shift to first, then drive on - often pissing off those who are following. If I select 2nd, I have to slip the clutch and bog the engine.

Any suggestions?

Wow, I've only ever seen this problem on Harley's! I have absolutely no problems shifting into 1st (provided the RPM's aren't too high) and I don't see any reason not to. I like to pull up to the corners, downshift into 2nd while braking, then shift into 1st to pull out of the corner. I do notice that it works better if you don't completely let off the throttle.

Giggle. 987S can't shift into 1st. Ah, there's justice in the world after all!