Smooth gear shifting

Discussion on Advanced and Defensive Driving.

Postby jont » Sun Jun 28, 2015 11:36 am


stefan einz wrote:Porsche is essentially unique in encouraging owners to use their cars on track.

I know you're a Porsche-ist, but let's not forget about Lotus, Caterham, Radical, Ariel, Zenos, Ginetta, etc etc. It's far from unique :lol:
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Postby stefan einz » Sun Jun 28, 2015 6:37 pm


jont wrote:
stefan einz wrote:Porsche is essentially unique in encouraging owners to use their cars on track.

I know you're a Porsche-ist, but let's not forget about Lotus, Caterham, Radical, Ariel, Zenos, Ginetta, etc etc. It's far from unique :lol:


You're right. What I meant to say is that it is essentially unique amongst mainstream manufacturers.

Cheers
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Postby akirk » Sun Jun 28, 2015 6:48 pm


jont wrote:
akirk wrote:so that should never happen if the software is written well

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

You're clearly not a techie, are you :twisted:


well as I spend my days coding and run a tech based company.... :lol:
I know that of course software is always written perfectly :D :shock: :D
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Postby akirk » Sun Jun 28, 2015 6:54 pm


stefan einz wrote:The rev range monitoring gives Porsche valuable data in this regard. Whilst you can only enter the dangerous over-rev ranges by a mis-shift in manual car (or potentially in a spin), if you see that the driver is constantly banging off the rev limiter it does tell you something about their driving style!


My apologies for removing the rest of a fascinating and very enlightening post - many thanks for taking the time to write that...
this gives a lot of comfort - from the various discussions on here / PH / elsewhere there is a very skewed impression that seems to imply that active driving of a modern porsche is going to be recorded as a black mark and the value of the car halved!

it is an interesting thought that perhaps this form of recording / analysis could become more common and perhaps give a more accurate understanding of a car's condition before purchase...

I agree that Porsche are unusual in mainstream cars in promoting racing - however a lot of their cars are sold to consumers with no understanding of racing - whereas those friends I know who race are far more aware of the stresses on a car and its potential impact - the average porsche buyer is possibly unaware and simply thinks that they can take it out and do as they wish with full attack...

interesting discussion - the enlightenment is received with gratitude!

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Postby TripleS » Sat Jul 04, 2015 1:53 pm


I have a question for the obviously extremely knowledgeable Porsche enthusiasts here.

The 917 car, which enjoyed considerable success in sports car races around 1969 - 1971, had (as I understand it) a flat 12 engine arrangement, comprising two six cylinder units side by side; but was it two crankshafts geared together onto a common output shaft, or did they share a single crankshaft, like a V12 flattened out to 180 degrees instead of the usual 60 degree included angle?
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Postby TripleS » Sun Jul 05, 2015 11:43 am


StressedDave wrote:It's both more and less complex than that. As any fule kno, the Porsche engine was exceedingly modular, with separate barrels for each cylinder (rather than an engine block) bolted to a common crankcase at one end and a cylinder head. So using much of the same kit of parts, Porsche could put flat-4,6,8 and 12 engines together with the only difference being the crankcase, cylinder head and crankshaft.

So the flat twelve was six barrels per side with unique bits to either end of the barrels.


Thanks, Dave, but I still don't know whether each half of the total unit has its own crankshaft, or whether the 12 connecting rods are arranged as pairs side by side onto the six crankpins of a single crankshaft - if you see what I mean. Obviously having a single crankshaft would permit the overall width of the complete unit to be less than would be the case with two crankshafts plus the gearing onto a common output shaft.

Having recently watched the film "Le Mans", it's just of academic interest y'see; I'm not thinking of buying a 917. :lol:
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Postby TripleS » Mon Jul 06, 2015 3:20 pm


StressedDave wrote:Nope, just a bog standard V12 with a 180 degree bank angle and six crankpins. Porsche chose not to make it a Boxer which would have needed twelve crankpins and mucked around with the firing order.

the other concept you're thinking of is the W12, as used in the Bugatti Veyron. Here have a link http://www.volkspage.net/ssp/ssp/SSP_248.pdf


Thanks again, Dave, but the link doesn't work for me, but don't worry about it any further, you have answered my question. I'll have a look at W12 stuff and the Veyron.
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