Porsche 956 - Turbo Lag??

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Michael88

Michael88

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Hi all,

I have a question about the video linked here: http://www.youtube.com/watch?v=yni-W7s3Hp4

Its a cockpit-camera Video of a Porsche 956 driving around the circuit De la sarthe without the turns.

My question is, why does the driver slow down so much after he passed the turns instead of accelerate as much as possible? I dont think he wants to avoid too much wheelspin, he slows down too much for that. The best example is Arnage.

Is that turbo-lag?
Bad shifting?
Bad driver?
Bad engine?

I really dont know, the sound is bad and I wasnt able to hear him shifting every time.:dunce:
 
I think the best answer is turbo-lag, even if I find it a little exagerated. I mean...it's ok to have, but like this, it's too much.

Maybe it's the driver. Some mechanical problem or whatever, also because I've never seen a porsche slowing down this much coming OUT of a corner.
 
The driver is multiple LeMans winner Derek Bell - so bad driver's out of the question. To me it doesn't look to be slow out of the corners, its just that he's doing 200+mph before most of the slow corners, your eyes just get used to seing things zip past and it seems slow after that.
 
This thread would be more appropriate in the Automotive section, but I'm here so I'll see what i can do:

No, the answer is none of your ideas. THe answer is that the sound throughout the video is delayed behind the video by about 1-1.5 seconds. Surely that engine from that era would have some turbo-lag, but the delay you are speaking of is most definitely a delay in the actual sound clip. That's the only way to explain why he downshifts in the middle if a turn and accelerates way after. The delay is very consistent througout the video. I've seen many videos with a sound delay, for an unknown reason.
 
I think Keef has got it spot on. The strange thing is some gear changes look to be in time, and at some points, your brain can fool you to make you think that the sound is synchronised.
 
I have 'In-Car 956', the DVD which this lap is taken from, so I watched the Le Mans section and compared it to the you-Tube video.

One observation first is that for all of the circuits on the In-car 956 DVD you get three laps (with the exception of the Nurburgring) an out lap, a flying lap and an in lap. Only the flying lap has commentary on it, yet the you-Tube one is from the flying lap.

I can also state quite categorically that the sound is out on this by a good half a second, one of the biggest giveaways is at the end of the Hunaudieres straight, look at the amount of opposite lock he has to apply, no way is he slow or is the power not being laid down.

I strongly recommend with this one actually spending the money and buying the DVD, the quality is so much better that the ripped videos you see on the web (this you-tube one is also slightly cropped), its worth the cover price just for the 6min 41sec lap of the 'ring (which I think also dispels any doubts about the driver).

Regards

Scaff
 
I have 'In-Car 956', the DVD which this lap is taken from, so I watched the Le Mans section and compared it to the you-Tube video.
Click to expand...
I want one!
956 DVD :drool: Is it old or still available? I have to check amazon.com!:dopey:

However, the sound delay sounds like the answer, but there is still a big throttle-hole because the lack of engine sound is much longer than the turns.:scared:
I guess its the bad quality thats bothering me.
 
Michael88
I want one!
956 DVD :drool: Is it old or still available? I have to check amazon.com!:dopey:

However, the sound delay sounds like the answer, but there is still a big throttle-hole because the lack of engine sound is much longer than the turns.:scared:
I guess its the bad quality thats bothering me.
Click to expand...

Still very much available, its produced by Duke video.

http://www.dukevideo.com/Cars/DVD/Marques/Marques p to t/In-Car 956 DVD.aspx


The sound quality on the you-Tube clip is very bad, but you also have to remember that this is early in-car footage (is mid 1980's) and the lap you linked too is on cold tyres out of the pits, on the DVD you can hear and see clearly just how much the car is moving around on corner exit. The lap of the Nurburgring is simply amazing.


Regards

Scaff
 
Technically that is turbo threshold. That means the point at which the turbo acually starts giving power, like a certain rpm. Turbo lag is when you let off the throttle while already at high rpms, then how long it takes the turbo to spool back up to speed again when you step on the gas.

http://en.wikipedia.org/wiki/Turbo go here and scroll down to lag.
 
Today I've got the DVD Scaff was talking about (Porsche 956 in-car), and I have to say its awsome; the quality is way better than that fugly video I've found; and its quiet good for a in-car video. (Thanks Scaff!)

However, I've found out that the internet Video of Derek bell's round at Le Mans is not turbo lag or anything like that; its sound delay. The original DVD sound is at the right place and it shows that the engine RPM drops in the turn. In fact there is only a bit of turbo lag after he passed the turn.
The video delayed the sound somehow to make it looking like Turbo threshold*, and the driver is indeed on its first round with cold tires.


*Thanks for clearing that up perfect balance!
 

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