RE: Homebrew Porsche 917

[Hugo a Gogo]

bobberz said:

Good luck to him! Sounds massively ambitious but I'd love to see the finished product! I don't care where your allegiance lies, the 917 is one of the greatest series of race cars of all time!

I think if it were my project, I'd splice together three VW Typ1 flat-fours! Should be good for around 120 BHP! Tuned it might make 300 BHP which, in an alloy tube-framed, fiberglass-bodied car should still be pretty quick! Should at the very least sound amazing.

you can easily build say a 2.4 vw flat four with about 200 bhp

so a 7. something litre flat 12?

i posted this thread ages ago, about a flat 8 VW in Brazil
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[fourwheelsteer]

tr7v8 said:

GC8 said:

GTRCLIVE said:

In the US he might be able to register a Ally Tube chassis but I cant see a IVA station letting you register a Ally Tube chassis. Just to weak on side impact. FYI

Wont this depend on the body? Was the body structural on the 917? It certainly was in the cars which had preceded it.

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

I can't remember where I read about that feature. As I recall the drivers were instructed that if the gauge fell to zero they should drive gently to the pits. However one of the drivers, unimpressed with the handling of the 917 even when the chassis was intact, replied that he'd park the car where it happened and walk back to the pits!

As for side impact and other crash protection. In the real 917 there are only a few, thin tubes and the glassfibre body between the driver's feet and a front-end impact. I've just dug out a 22-year old copy of Supercar Classics where they got behind the wheel of a 917K; I remember thinking then what an amazing, frightening machine it was. It still sounds awe inspiring re-reading the article today.

If I win the Euromillions I'll have a flat-12 version, I'd even invest some of my money to make it happen.

[kamilb1998]

Absolutely fascinating!

[tr7v8]

fourwheelsteer said:

tr7v8 said:

GC8 said:

GTRCLIVE said:

In the US he might be able to register a Ally Tube chassis but I cant see a IVA station letting you register a Ally Tube chassis. Just to weak on side impact. FYI

Wont this depend on the body? Was the body structural on the 917? It certainly was in the cars which had preceded it.

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

I can't remember where I read about that feature. As I recall the drivers were instructed that if the gauge fell to zero they should drive gently to the pits. However one of the drivers, unimpressed with the handling of the 917 even when the chassis was intact, replied that he'd park the car where it happened and walk back to the pits!

As for side impact and other crash protection. In the real 917 there are only a few, thin tubes and the glassfibre body between the driver's feet and a front-end impact. I've just dug out a 22-year old copy of Supercar Classics where they got behind the wheel of a 917K; I remember thinking then what an amazing, frightening machine it was. It still sounds awe inspiring re-reading the article today.

If I win the Euromillions I'll have a flat-12 version, I'd even invest some of my money to make it happen.

Yup Frank Gardener he wasn't that polite as I remember!

[GC8]

tr7v8 said:

GC8 said:

GTRCLIVE said:

In the US he might be able to register a Ally Tube chassis but I cant see a IVA station letting you register a Ally Tube chassis. Just to weak on side impact. FYI

Wont this depend on the body? Was the body structural on the 917? It certainly was in the cars which had preceded it.

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

I appear to know more about the 904.

GC8 - earlier said:

Can you make a chassis out of aluminium and it be safe? Even Porsche couldnt do it on their own and, from memory, had to enlist the help of Heinkel (the pressurised alloy tube technique used originated in what we would call the aerospace industry now).

Better to pay a weight penalty and not have to drive with one eye on a pressure gauge looking for chassis impending failure...

I did know all about the chassis though.

[fourwheelsteer]

tr7v8 said:

Yup Frank Gardener he wasn't that polite as I remember!

I had a feeling that was the case.

[DJRC]

Don't forget though that there was a big difference between the earlier 917s and what happened after the Brits sorted it. When Porsche first released it, it was a terrible thing, lift, lousy handling and just downright dangerous/undriveable. Sorting out the front end, esp reducing the front end lift (axes were used at one point if I recall correctly) changed the car considerably.

[pagani1]

A bit like the 996 then

[shoestring7]

A 12 cylinder built from two 911 engines wouldn't be so for off the original. Its power take off was from the middle of the crank to avoid whip and 911 barrels and head lend themselves to a unitary approach. A 6litre engine base on couple of SC engines giving ~500bhp would push it along a bit.

SS7

[ayseven]

To the chap enquiring about the 962:

http://www.slackmotorsport.com/Porsche%20962.htm

[tr7v8]

This is an exploded real 917 lump!

[shoestring7]

tr7v8 said:

This is an exploded real 917 lump!

Here's another one:



SS7

[Housey]

For me, no greater car exists, I would give both tuds to own a 917.

[bobberz]

Hugo a Gogo said:

bobberz said:

Good luck to him! Sounds massively ambitious but I'd love to see the finished product! I don't care where your allegiance lies, the 917 is one of the greatest series of race cars of all time!

I think if it were my project, I'd splice together three VW Typ1 flat-fours! Should be good for around 120 BHP! Tuned it might make 300 BHP which, in an alloy tube-framed, fiberglass-bodied car should still be pretty quick! Should at the very least sound amazing.

you can easily build say a 2.4 vw flat four with about 200 bhp

so a 7. something litre flat 12?

i posted this thread ages ago, about a flat 8 VW in Brazil
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

I know, I was saying that tongue-in-cheek, simply adding up three, stock 1200s, which made 40 BHP (gross, so actually quite a bit less in the modern net hp rating.)

I'm always amazed at how much power people are able to wring out of VW's original flat four. I'm aware of some turbocharged 2400s making 400+ horsepower, plus I have a magazine that features a top-fuel sand dragster with a 2.4 loosely based on the VW mill putting out 1200 bhp!!!

[Gary C]

fourwheelsteer said:

I can't remember where I read about that feature. As I recall the drivers were instructed that if the gauge fell to zero they should drive gently to the pits. However one of the drivers, unimpressed with the handling of the 917 even when the chassis was intact, replied that he'd park the car where it happened and walk back to the pits!

As for side impact and other crash protection. In the real 917 there are only a few, thin tubes and the glassfibre body between the driver's feet and a front-end impact. I've just dug out a 22-year old copy of Supercar Classics where they got behind the wheel of a 917K; I remember thinking then what an amazing, frightening machine it was. It still sounds awe inspiring re-reading the article today.

If I win the Euromillions I'll have a flat-12 version, I'd even invest some of my money to make it happen.

They did not all have the same material for the chassis.

[stew-S160]

Respect to the guy, and I look forward to seeing the finished car.

[crofty1984]

tr7v8 said:

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

Really? That's pretty interesting!

[tr7v8]

crofty1984 said:

tr7v8 said:

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

Really? That's pretty interesting!

This book, a few on Abebooks. Frank raced everything from saloons to F1 & has a very "Australian" perspective on things. Some really funny stories in there & a fantastic read if you're in anyway interested in Racing.

[GC8]

crofty1984 said:

tr7v8 said:

Nope body wasn't structural on a 917, the spaceframe was pressurised with nitrogen & a gauge to measure it on the dash. If the chassis cracked then the gauge dropped to zero. One of the details from Frank Gardners book.

Really? That's pretty interesting!

The chassis was pressurised in order to allow a gauge to be used to indicate a failure in the welding or other integrity issue. Its an aerospace technique, required because the aluminium tube chassis integrity was borderline at best and deadly if any part failed.

I am surprised that Porsche didnt make the body at least semi structural after the success that theyd had with the GRP semi-monocoque 904 (which also used aerospace techniques).

[e21Mark]

Riyazc said:

Could make it even faster by simply lifting the body shell and plonking it on a 335d ....

Maybe even a chipped one?!

I'd give anything to own a 917. It's the first race car memory I have from Brands Hatch. It certainly sounds like the guy has the required skills to make this something very special indeed.