Porsche 917 - am I crazy?

[Jimmy P]

Chaps, this thread is just a damn good read regardless of what car one is considering be it a 917, GT40, SLC , P4. The past few posts should be required reading for anyone getting ready to spend on a car they THNK they know. Howard and Graham provide solid details and marvelous insight of what building, owning and driving these cars is really all about. Each car is so different then any factory production car and it really is "buyer beware." I'm mainly speaking to those forum members who are doing their research and are looking for insight. Well, to all those lurking or looking or dreaming you just got it from some of the most respected names on the forum.

Trev, I say go for it mate. My brother just got through beating stage 4 cancer and life looks a little different through his eyes now. He told me life is short and if it ain't going to put you in the poor house or adversely affect yours or someone else's life then do it.

Graham, where is Suffolk do you reside? I grew up in Ipswich and when I return I'd love to see your 917 if your about.

 

[Michel]

Yes Jimmy I agree with you and am +1 with others posts but there is one important thing not to forget ; MOTIVATION
Cars like 917 are rare cars ( on realty and in kit car!!) watever brand you choice ( 4 manufacturers avaible) if you do not have sufficient motivation to make your dream become real you will never have any 917 in your garage !!!!

Assembling a Gt40 and Iva's her is quite a tuff work and many there know what I mean !
But following a 917 project specially in Uk ( and whorse in europe) to have it IVAed you need big big skills and lot of interest each time to go working into the shed ; if not this will take 10 years to be achieved!!!!!!!!!!!!!!!!!
Every area require a lot of thinking in order to be ok with IVA rules as this car have not be engineered to be a road car ; as stated by Chris this is not an impossible task but depend on the builder's level of skill
So to me first of all is for any one thinking into an 917 on road first thought is AM I ready to jump from a DREAM into REAL DEAL !!!!!!!!!!!!!!!!!!!!:drunk::drunk:
Then the choice or the manufacturer is more linked to " who is more able to guide me in doing UK homologation"????????????????????????:stunned::stunned:

 

[Chris Huck]

Wow, is it possible for a 917 to pass IVA? Now that would be a car!

There's only one way to find out!! Am sure it won't pass first time but it has been constructed with a view to the IVA test. Screens were a concern but we have now solved that issue, headlight height also an issue but ours are further back on the wing (hence slightly higher) but as I said a long way to go yet.
Why get it IVA'd?? Because everyone I spoke to said it wasn't possible!!
As Graham said though, I cannot imagine what it'll be like with 500bhp, mind blowing I suspect. Although I'd love to put a GT3 Porsche engine in one, 400 and normal atmo rev box!!

 

[Chris Huck]

Westski_2000, this is a link to my picture stream/build log so far. I work part time on it and to date have been on it for a little over 4 years.

https://www.flickr.com/photos/47153142@N03/sets/72157623861979360/

 

[Jimmy P]

Chris, stunning mate. Mind blowing work! I'll look forward to seeing the finished product.

 

[TrevS]

Thanks everyone for the replies, really good to get some opinions on this as it's easy to jump in with both feet thinking it will be a straight forward prospect which is exactly what I did with my gt40.

I just want to clear up a few points about what i am looking to do and how I plan on using the car:

• I am not building a 917. I don't have the motivation or time to start another project so am speaking to Bailey about an assembled car, so that hopefully solves some of the concerns around time required to spend on one of these cars

• I am happy to use the car as track only, while it would be great to get one IVA'd for the odd use I agree with Graham that it's not really suited for road use especially here in the UK

• I am not looking for either a track day weapon or the perfect replica. I want a useable track car that looks and feels like a 917 without some crazy horsepower engine. I think 300-400hp would be more than enough in a 917 and still feel stupidly quick.

I think Howard summed up perfectly how I'd like to use the car, I love the idea of doing 5 or 6 trackdays a year and also taking the car to shows. For me it's more about the ownership prospect than it is about lap times and if that means it won't get lots of use well that will probably suit me and still allow me time to work on the GT40 which will be my road going car.

I still have to sort out a few details such as shipping etc and I also have the small matter of selling my Aston.

 

[Alex]

Just remember the standard rule of thumb and you'll be fine - LOL SAFETY.

E.g., Please do not bump me from behind, otherwise L-O-L S-A-F-E-T-Y

 

[Jac Mac]

Just remember the standard rule of thumb and you'll be fine - LOL SAFETY.

E.g., Please do not bump me from behind, otherwise L-O-L S-A-F-E-T-Y

Might have to change your user name to EFNHOT if someone does bump you

 

[Keith]

Dang! Is that the rad? :stunned:

 

[Graham T]

Dang! Is that the rad? :stunned:

No Keith, it is the fuel tank.

Alex, please, please, please try to put a secondary "screen of some sort between your engine and that tank. Not only do you have a heat absorbancy issue but with tail heavy attitude that your car will have, if you do lose it the tail end will be the first to cop it, let alone someone rear ending the car.

If you go in nose first then you will probably only need a short coffin as you will be burnt legless anyway !!!!!

Trust me Alex. You must have better shielding and make sure your cockpit to engine bay bulkhead is really sealed up.
Give me side pod tanks any day over that set-up.

 

[Graham T]

Trevor,

what type of engine are you thinking of putting into your possible purchase, as 300-400bhp in an air cooled Porsche 911 set -up, plus suitable gearbox is going to be expensive.

Your Aston might not be all you will need to sell !!!!!!!!!!!!

 

[Fran Hall RCR]

I disagree...
If you actually look at any modern Le Mans car the fuel tanks are in front of the engine and behind the seats for the most part.
There is an aluminum bulkhead between the engine bay and the cockpit and its pretty stout....4mm actually..nothing like the flimsy ones in an original 917.

When an air cooled 911 engine (preferred) is used there is also an engine plate that mounts the engine and creates yet another full bulkhead between the engine and the fuel tank..
We are having one of our 917's go through ADR in Australia and the chassis and set up shown flew through the test with aplomb. The chassis actually bettering the requirement by 3x in torsion and beam.

Or one could just look at any VW beetle or 911 built in the last 50 years and complain that a front mounted fuel tank wont work or be safe either..

 

[TrevS]

Trevor,

what type of engine are you thinking of putting into your possible purchase, as 300-400bhp in an air cooled Porsche 911 set -up, plus suitable gearbox is going to be expensive.

Your Aston might not be all you will need to sell !!!!!!!!!!!!

Agreed, engines are not cheap. Think last time Peter emailed me he was offering a refurbished 3.6l Porsche engine with G50 gearbox and Go-tech management system. Think power is around 315bhp, sounds like plenty to me.

 

[Keith]

Graham is fast becoming the Forum's 917 S.P.O. :laugh:

Do it Trev, just Do It mate....:thumbsup: (in mono of course)

 

[Graham T]

I disagree...
If you actually look at any modern Le Mans car the fuel tanks are in front of the engine and behind the seats for the most part.
There is an aluminum bulkhead between the engine bay and the cockpit and its pretty stout....4mm actually..nothing like the flimsy ones in an original 917.

When an air cooled 911 engine (preferred) is used there is also an engine plate that mounts the engine and creates yet another full bulkhead between the engine and the fuel tank..
We are having one of our 917's go through ADR in Australia and the chassis and set up shown flew through the test with aplomb. The chassis actually bettering the requirement by 3x in torsion and beam.

Or one could just look at any VW beetle or 911 built in the last 50 years and complain that a front mounted fuel tank wont work or be safe either..

Fran,

quite right ........................

but none of what you have written has anything to do with the picture that Alex has posted.
His engine is not a air cooled Porsche and tortional rigidity does not come into it. As the gearbox tail is beyond the structural chassis point any way on ANY 917 derivative, a rear ender will always be pushing whole assembly forward. The rear tubing framework is merely a support for the rear decking/luggage trays/light bar and could be radically reduced without affecting the chassis strength. Original cars had removable framework to remove gearbox, etc, and many removed surplus outriggers to save weight and give easier access for maitainance. I,ve "lost" several on my own car

Beetles do not have a hot engine with external moving parts and inch away from the fuel tank either.

Good advertising for your product though, PROVIDING one uses a Porsche engine which is set further back and that they do not want a more accurate rear end look.

 

[Michel]

Hello Graham
Just to help on your excellent demonstration and advises these are some pics
very very significant !! isn't ???

And also some information about modern LMP cars ; tank is in beetwen the engine and driver seat but this fully homologated rubber tank is inside the carbon fiber monocoque , that means there is behind driver a thick wall of carbon fiber plus 25mm honeycomb and again carbon fiber , then the reservoir then another thick wall of similar composite ( 29 mm thick in total )
On those cars engines are directlly bolted to that firewall thru hudges aluminium or titanium insert both side and these drives any compression due to a frontal choc and coming from the inertia of the engine
Special test on a FIA homologated jig is done to check all this area as well as pusching test on top of rollbars taht are fitted just top of that fuel tank .

What we are building are replicas for hobby and we all know that sport car hobby is something "risky" so beside the fact am always as Graham thinking about safety ( chocks or fire) we will always have in the cars we built a small part of risk we cannot manage ( Rain , breaking of a hose or mecanical bit)
All 917 's manufacturers have tried to avoid or minise this risk with different solutions and this is something intersting to analyse as each solution have positives points ;bravo to them
Just reminding what happened recently to one of our super nice German member a Gt40 is perhaps safer but life is life ... A 917 project just add more risk but depends how carefull the owner can be with his own life and the one of passenger in case of track day parad or watever.

Apologise for my bad english language in such long ( perhaps boring !) writing

 

[Alex]

No Keith, it is the fuel tank.

Alex, please, please, please try to put a secondary "screen of some sort between your engine and that tank. Not only do you have a heat absorbancy issue but with tail heavy attitude that your car will have, if you do lose it the tail end will be the first to cop it, let alone someone rear ending the car.

If you go in nose first then you will probably only need a short coffin as you will be burnt legless anyway !!!!!

Trust me Alex. You must have better shielding and make sure your cockpit to engine bay bulkhead is really sealed up.
Give me side pod tanks any day over that set-up.

The tank is very stout now - my friend added ribs and braces inside of it and re-tig-weld all the welds for extra strength. There's a 1/4'' aluminum lower/medium firewall infront of it, and a ?1/8''? aluminum upper firewall, as well as the steel frame before the aluminum wall. I also only plan to carry 40% fuel at any time (just like my slc ... not a fan of the tank being right behind me, so I fill up at home before i go out and carry less than half).

The engine is solid mounted to the frame, as is the transaxle, so it shouldn't be moving unless i get hit from behind ... just gotta avoid that, lol.

 

[Graham T]

Michel,

well said.

Fran failed to mention any of that in his post.

What Alex, and possibly other builders are doing also, is making a fundamentally dangerous car even more vunerable, and all I am saying is beware.

Most builders of these 917 derivatives see a wonderful looking car and build them with massive power engines (very often not Porsche) and think that they are going to have trouble free motoring.

If you think that a 40 is lairy with 500bhp, just wait till you try even 300bhp in a lightweight 917 .............

Oh, I only want it for track days or odd demonstrations I hear said so often. Does not make it any safer.

 

[Fran Hall RCR]

One other thing to think about is that a lot of the faster/modern track day groups do require a fuel cells.
We have FIA FT3 bladders available for all of our cars.

The sweet spot for most of this genre of car is 350-400 hp imho.

Having the ability to drive the car and not have the car drive you is something many people seem to overlook

 

[Alex]

Michel,

well said.

Fran failed to mention any of that in his post.

What Alex, and possibly other builders are doing also, is making a fundamentally dangerous car even more vunerable, and all I am saying is beware.

Most builders of these 917 derivatives see a wonderful looking car and build them with massive power engines (very often not Porsche) and think that they are going to have trouble free motoring.

If you think that a 40 is lairy with 500bhp, just wait till you try even 300bhp in a lightweight 917 .............

Oh, I only want it for track days or odd demonstrations I hear said so often. Does not make it any safer.

Don't worry, I'm well aware and not going into this blind with my head stuck in the sand. All about compromises ..... plus I think my testicular fortitude will fail me whenever I try to leave my driveway, LOL

300 or 500 is no good .... I've got almost 700 =)