14 replies to this topic

[cjpani]

Fellas,

I´ve also posted this thread on Nostalgia Forum, but I´m guessing you might also be very able to help out.

I´m looking for the porsche 917´s gear ratios -any porsche 917, any year, any configuration- as well as some numbers, like handling in g´s (if such thing is viable) or braking distances (with any of the brakes used during the exixtance of the car, girling, bendix, whatever)

Any pointers on the matter??

Best regards
cj

[da Silva]

Have you tried gunnars racing? http://www.gunnarracing.com/

Take a look at this project, comments?
http://project917.itgo.com/

[cjpani]

da Silva:
Thx for the links. I´m afraid I knew both of them, but I admit not investigating thorougly enough.
The second link is of no use, because the engine to be installed on the car is not the original engine, hence using a 911 one.

Gunar racing has great knowledge on the matter, but still, couldn´t find any info. I might as well try to contact them.

Thanks again

cj

[da Silva]

cjpani

Do you have the 'Motorsport' issue of February -99?
It´s got much info on various Porsche models, including chassis #22 917K
There´s a picture showing the exhaust and current gear ratios

1 - 14 - 29
2 - 21 - 29
3 - 24 - 27
4 - 27 - 25

If that was any help

[cjpani]

Da Silva,

THANX!!!
Unfortunately i don´t have such magazine, because, obtaining such "precious" material in mexico on a regular basis is very hard, and kind of expensive
But the info is excellent, thanks a lot!!

cj

[da Silva]

I´m glad I could help you with atleist one thing.
I´m a big Porsche enthusiast myself and I have an Vintage Porsche 356 coupe -64
for restoration at the moment. I´m planning to make it an historic racer hopefully.

cheers

[Ben]

Without wanting to be boring, it's more than likely (as with the majority of race cars) that the gear ratios were changed for different circuits and probably for different versions of the engine.

I can imagine the ratios for a 917 K (short tail) being very different from the langheck version at Le Mans and as for the 1100hp 917-10 that Folmer and Donahue drove in CAN-AM well something different again I should think.

Ben

[Bumblyari]

The best source of technical info on Porsches of this era has got to be Paul Frere.

He quotes 'absolute best' figures of 1.65g for lateral acceleration and 1.50g for braking deceleration. These figures were recorded on a 917L (042) at Hockenheim in 1970.

He also quotes the gear ratios for the 5-speed boxes used on the long-tailed cars if you want them.

[cjpani]

Please, by all means, do post them!!!!

And welcome to atlasf1

cj

[Bumblyari]

Here we go then:

Le Mans 4.5 litre long-tail: 15:29, 21:29, 23:24, 26:21, 30:21
Le Mans 4.9 litre long-tail: 15:29, 21:29, 23:24, 26:21, 31:21
Le Mans 4.5 litre short-tail: 15:29, 21:29, 24:23, 27:20
Le Mans 4.9 litre short-tail: 15:29, 21:29, 24:23, 32:23

Monza 4.5 litre short-tail: 14:29, 22:29, 23:24, 26:21
Monza 4.9 litre short-tail: 14:29, 22:29, 26:26, 29:22

Spa 4.5 litre short-tail: 15:29, 22:29, 24:23, 28:22
Spa 4.9 litre short-tail: 15:29, 22:29, 24:23, 29:22

all with 8:37 crown wheel & pinion

(Source is Paul Frere's 'The Racing Porsches')

I was going to ask what you did with all this information but then I went and had a look at your website - wonderful stuff

[cjpani]

Aaaaaaahhhhhh....... this has made my insomnia worthwhile....

Thanks A LOT for this.

Glad you liked the page (don´t forget to sign the guestbook )

Cheers

cj

[P1 Senna]

Nice piece on 917's in this weeks Ask Nigel column. I especially liked this bit from the always entertaining Brian Redman:

"The spaceframe of the original 917 was pressurised, gas-filled, so that if the gauge lost more than so much pressure, you knew you had a crack. When that happened, they'd go round all the joints with a cigarette lighter!"

[imaginesix]

Originally posted by Bumblyari
Here we go then:

Le Mans 4.5 litre long-tail: 15:29, 21:29, 23:24, 26:21, 30:21
Le Mans 4.9 litre long-tail: 15:29, 21:29, 23:24, 26:21, 31:21
Le Mans 4.5 litre short-tail: 15:29, 21:29, 24:23, 27:20
Le Mans 4.9 litre short-tail: 15:29, 21:29, 24:23, 32:23

Monza 4.5 litre short-tail: 14:29, 22:29, 23:24, 26:21
Monza 4.9 litre short-tail: 14:29, 22:29, 26:26, 29:22

Spa 4.5 litre short-tail: 15:29, 22:29, 24:23, 28:22
Spa 4.9 litre short-tail: 15:29, 22:29, 24:23, 29:22

Man those must be really thick gears to necessitate an entire rear bodywork extension for one more ratio!

[Bumblyari]

Absolutely - just as well they didn't have a 6-speed box at Le Mans otherwise the tail would have wiped out half the funfair going through the esses.

[Paul Taylor]

Can anyone confirm either from Paul Frere's book, or Walter Näher's book, the actual weight and front/rear track widths of the 1971 Porsche 917s?