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Board: Other Sports Cars
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Re: CGT question
Quote:
cer300 said:...
I heard about clutch issues...
The "clutch issue" is a non-issue. It's become an urban legend.
Reports that the clutch is tricky came from people who didn't fully appreciate the spectacular nature of the Carrera GT engine. It has very low rotating inertia compared to any other engine except those found in motorcycles. This is, in part, because of the very small diameter clutch pack and amazingly diminutive flywheel.
The engine has truly amazing throttle response and instantaneously accedes to the driver's finest throttle inputs. It revs like a super bike and loses RPM just as rapidly when the throttle is closed. When one turns off the ignition, the rotations stop so quickly that it sounds as if the engine has seized up. I doubt that the crankshaft even makes a complete revolution after shutdown.
Its a desirable characteristic for an engine, no?
This low engine inertia situation means that the engine (not the clutch) is a little tricky to manipulate during launch-from-rest without some basic recognition of its nature. One can't sloppily rev the engine a little and then absent-mindedly ease off the clutch without risking a stall.
In cars with heavy flywheels (and poor throttle response), a slight rev of the engine stores enough energy in the rotating masses that the clutch release doesn't need to be paired with any particular amount of throttle. One can be quite imprecise with the throttle and have no problem with the engine continuing to run.
In a car with so little rotary energy storage as the CGT, if one doesn't pair clutch engagement with a coordinated application of the gas pedal, it's possible to exhaust all the stored rotational oomph, and stall.
For neophytes, the engine idle speed control has enough correction range built in that if one doesn't touch the gas at all, and tenderly engages the clutch, the CGT will simply drive off from rest on its own. The clutch is very progressive and easy to modulate. I can creep around a parking lot with great finesse (without ever touching the gas) by only working the clutch.
However, if one applies even the slightest throttle pressure, the idle servo disengages and allows the driver to directly and precisely control the engine. This dual-option engine nature seems to me like it's the best of both worlds, and takes only a short time to learn. I've now adapted to the extent that I can use as little as 1,200 RPM of beginning throttle and move off up an impressive grade with no drama or concern. I started my learning procedure using around 2,000 RPM. It's really pretty easy.
I stalled the engine once at the first intersection I encountered after accepting the car from the dealer. I now have over 2,000 blissful miles behind the wheel (a pleasant amount of which are track miles) and can count on my fingers the number of inadvertent engine stalls to date.
Any stories one hears about the CGT and a tricky clutch are either hearsay or from people who didn't have enough motivation to understand what was going on. They're wrong about the clutch and don't "get" the masterpiece which is the the Carrera GT engine.
Since their troubles started as soon as they released the clutch, they leapt to an unwarranted conclusion and blamed the clutch. They're wrong.
rant=off
Re: CGT question
Quote:
MKSGR said:Quote:
ed_moree said:
Initially they say that the production number it will be 1500 cars, but they have stopped at about 1250 cars.... It is not the exact number but more or less there, the more or less being very small.
The exact number is 1270, BTW.
Thanks MKSGR, I knew about that number but not having an official answer from Porsche I didn't wanted to advance it, but as you say the 1270 is the number of cars that they have build.
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