'77 & '75 Turbo Look 3.0

[keith]

Keith:
The 1974 RS, 3.0 l. M491 "for street use" has the 85 ltr. tank

The 1974 RSR, 3.0 l. M491 "competition type" has the 110 ltr. tank

Ernie, you never cease to impress, sir! - now if I can find some photos....

EDIT: Wait; why is the document giving the part number for RSR injectors under the 85L tank heading?



The more I think about it, short of any photo evidence to the contrary I'm leaning toward the opinion that the claim that the plastic 85L "RS" tank was actually installed in '74 3.0RS is an error in the Snodgrass book.. Every photograph I can find shows the standard 74-on steel tank, is it possible it is also being referred to by Porsche as "85-liter" (albeit actually 80) at the time?

[Ernie W]

Ok, Thanks... This is out of the FIA Homologation 3053, Carrera 2.7 for 1973. And the injectors with the fuel tank, it's the only page in the book that pertains to engine/fuel...

[letsrollbabe]

Ernie, you never cease to impress, sir! - now if I can find some photos....

EDIT: Wait; why is the document giving the part number for RSR injectors under the 85L tank heading?



The more I think about it, short of any photo evidence to the contrary I'm leaning toward the opinion that the claim that the plastic 85L "RS" tank was installed in '74 3.0RS is an error in the Snodgrass book.. Every photograph I can find shows the standard 74-on steel tank, which I suspect is also being referred to by Porsche as "85-liter" (albeit actually 80) at the time?

Kieth,

I believe the tank in the 3.0 RS was the standard production tank based on photos from various 3.0 RS cars.

[keith]

Kieth,

I believe the tank in the 3.0 RS was the standard production tank based on photos from various 3.0 RS cars.

Gib, that's what I was thinking also, based on everything I've seen; however Ernie offers some compelling documentation to back up Snodgrass' assertion!

Curiouser and curiouser..



Ernie, that last document is from '72, yes? so it comments about the '73 RS/RSR most likely?

[letsrollbabe]

This would not be the first time that the factory docs don't represent how cars were built. I would be surprised if all the pics of the 3.0 RSs show a replacement standard steel tank if the originals came with an 85L plastic tank. My guess is that the plastic 85L tank was originally listed to achieve the 900 kg (1989 lb) weight of the 73 RS for homologation, but in practice the standard steel tanks were supplied.

[keith]

I would be surprised if all the pics of the 3.0 RSs show a replacement standard steel tank if the originals came with an 85L plastic tank.

I agree. I doubt any of them did; although I like that one could get away with installing one in a project if one wanted, per the documents that we're discussing.

[letsrollbabe]

According to Paul Frere, the racing RSR versions never got down to the 900 kg...most were 925 to 950 kg he says. The 3.0 RS was designed to be an 'evolution' of the Carrera 2.7 RS, which allowed the 3.0 RSs to remain in Group 3 where it 'proved virtually unbeatable' according to Frere. The plastic tank listing most likely would have been necessary on the homologation papers for the 'evolution' designation.

[Ernie W]

some of my thoughts...

Since the 1974 RS and RSR were a homologation variant of the 1973 RS and RSR, factory just added on to the original 73 modifications, to meet the 1974 car updates, then the tanks in post #322 (all 6 tanks) would be legal ?

The steel vs. plastic fuel tank in not legal is all markets, some countries require a different type of tank material, so they can pass import/safety laws... Gib, is the yellow car RHD ?

The 1974 Carrera RS 3,0 Ltr. "Street Version" used a "BFG Space Saver Spare" which would determine the type of tank ?

A street car, would have fuel vapor system, and a fuel recirculation system for the MFI ?

And I guess, the 1974 Carrera RSR, 3.0 Ltr. "Competition type" could use any size/type tank depending on the type of racing it's used for...

Last, the below page of the 1973 Homologation Nr. 3053 listing the "Variante" for the Carrera RS, model year 1973/1974, Note: Pos. 7, 80 Ltr. , is that the space saver tank ?

I think the biggest factor would be the cost and being able to find a special tank...

[letsrollbabe]

Ernie,

The yellow car is the James Hunt car which was a RHD. The 80 L 'space saver spare' tank is the standard steel tank. There probably were a few 3.0 RSs built with the plastic tank, and the country it was going to was the key factor, plus the customer preference I suppose. On the pbase site where there are pics showing the tanks, all have the standard 80 L tanks except for 9033 which has a 100L steel ST tank, and 9046 which has a 110L plastic tank.

[keith]

great thread you guys; keenly interested in getting to the bottom of this!