perfectlap

I read an article in Excellence "Best Convertibles" where the magazine asked many contributors to rank their favourite Porsche convertibles. One contributor
ranked the Carrera GT and BoxsterS at the top. He cited the BoxsterS in a manual gearbox because according to him the tiptronic transmission shaves power in between shifts resulting in a loss of torque when its needed (in between gears).
Another forum member says that the contributor was wrong or biased (or both) and that the tipS produces more torque than the manual transmission because the increased Torque from the torque converter.

any thoughts on who is right?

schvetkaaks

Torque/power/throttle response is all slower/less because of the torque converter.

I just sold my 986S which I loved dearly for 3 years, until I found out at the track that the throttle response is grossly delayed due to the torque converter. I drove a friend's 986S around the track (6-speed) of the same year and it was night and day, particularly on exit speed.

It only affected me as of late, when I became more confident and competent on the track. Earlier stages, I was happy to have it because it allowed me to concentrate on being a better driver with braking, steering, handling, throttle steer, learning the lines, etc. Now I simply can't bear to drive around the track with a tiptronic anymore because of the rather significant performance lag. Know that this was in manual mode, too, not automatic, which is a whole new ballgame.

If you don't track the car, you won't notice as much difference, but you would notice the difference once you drove another 6-speed, as the throttle response is far superior.

perfectlap

doesn't the added 8 HP in the 2003 986S make up for this peformance lag vs. manual?

m21sniper

You don't get better throttle response from a manual, what you get is instantaneous driveline response.

Same overall effect, but there you have it.

perfectlap

instant driveline response = no lag?

tip = lag?

but I guess the question was does having a tip cost you a net loss of torque in between shifts?

ljd-924SE

the amount of time that power/torque is being transfered from the engine to the wheels is decreased, not the value of power/torque.

m21sniper

An A/T will normally suffer more parasitic HP loss than a manual will. How much is a matter of the A/T in question.

I have no idea how efficient the tiptronic is, but a safe bet is about a 10-15% higher parasitic loss than a manual.

You can make up for that loss with a high performance rebuild in most A/Ts.

ar38070

One thing you cannot not make up for is the added weight. Somewhere around 50-75 pounds.

m21sniper

True.

Jay Laifman

But what is reality when you put the human element into the mix? Yeah, just about every bonehead who lays down the cash for the latest Porsche, Corvette, Mustang, Ferrari, you name it, thinks he knows how to shift. But, does he really? What about those guys who wind it up way past the power band? Or shift too soon? Or take way too long on the clutch?

Then there is the whole part of drivers perception. Yes there is slippage when an automatic shifts. And, the driver really notices it because he is not doing anything else other than sitting there while the car shifts. But, the driver in a manual transmission who is shifting is pushing in the clutch, moving the shift lever, matching rpm, releasing the clutch. There is a lot of time delay in that and a lot of car motion. But, the driver never senses that as much as the passenger because the driver is engaged in doing it all. So, what is the reality? Ever notice it is the passengers who "feel" the motion and get motion sickness and never the driver? Again, that's because the driver is engaged and knows the motion is coming. So, is that driver of the manual really shifting faster and smoother than an automatic? Or, does his ego just tell him that? I'm willing to bet that if a car magazine did a test on the duration of shifts by joe blow on a manual and the automatic, and some measurement of car motion from the shift, a HUGE majority of joe blows will be slower on the manual than they think.

That's my theory and I'm sticking to it (until someone convinces me otherwise :-)

designman

Good post Jay. I’ve always believed the average Joe with an automatic will beat the average Joe with stick. I’ve seen it happen over and over on the street by less-than-savvy hot dogs who not only don’t how to shift, but don’t know the power/rev profile of their engines. A manual transmission does not a fast car make. That’s one of the things I like about it. To get the performance edge you have to educate yourself a bit and then practice.

m21sniper

I agree completely. Not only does a properly race prepped A/T shift faster than any human being ever born, it will also deliver spine shattering shift firmness with zero slip if that's what you set it up to do.

IMO manuals are better for road courses(mainly because of heat issues), but for those into drag racing/max acceleration, there is no substitute for a properly prepared A/T, especially from a consistency standpoint.

perfectlap

so there is no net loss at all of torque in between shifts with a tip?
(this sounds like a question for Excellence's letters to the exditor section).

Ray S

The manual and the tip both got the 8hp boost. However this power increase is somewhat offset by an increase in weight on the '03's making the real difference with the earlier cars somewhat negligible.

Ray S

Race prepped A/T?? Give me a break. Let's not confuse a Porsche Tiptronic with the typical sequential manual gearboxes that are found in many race cars and some Ferrari's, BMW's etc. The tiptronic is really a standard A/T that Porsche "taught" to hold gears and shift on command.

I have driven multiple "Tips" and there is no way you can tell me that I can't shift my manual in less time than it takes you to push the thumb button on the steering wheel, have the car think (read pause) and decide if it should really listen to your request, and once it decides "ok", finally fire off a fast shift. The shift the Tip makes is reasonably fast, but the "lag" prior to the shift ruins that quick shift. Add an extra 100 or so pounts for the Tip (and a power robbing torque converter) and you can see why the term "race prepped" is a little funny.

Now.......a true sequential manual......that can shift faster than any human ever born!