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Light weight hood gotchas ?

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Old 07-05-2012, 06:45 PM
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OZ951
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Default Light weight hood gotchas ?

I've just installed an ex race car GRP hood on my 996 (which is a streetable track car). I've currrently got the bonnet pins adjusted so that the leading edge of the hood is a good 1/2" lower than the trailing edge of the bumper so that air doesn't (hopefully) get under the leading edge of the hood. Are there any key point worth knowing or any gotchas with using these hoods at track speeds?
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Old 07-05-2012, 06:56 PM
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Lemming
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Always remember to latch them before heading out on track. Can't tell you how many broken windshields I've seen at tracks because people forget!
Old 07-05-2012, 08:17 PM
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jrgordonsenior
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Yea keep the OEM safety latch. Like Tim above I've seen many broken hoods/windshields from folks forgetting to latch them including myself.

Once last year I was black flagged on the out lap of a qualifying session because a worker thought my hood looked loose. The black flag worker took a quick look and said I was good to go . After the session I discovered the my latches were in fact hooked, but over the top not thru the hole. The black flag worker was pretty surprised when I drove back over to show him. We both learned something that day. Remarkably the safety latch held for 4-5 laps and this was at Cal Speedway where I hit 155mph. Cheap insurance....
Old 07-05-2012, 08:26 PM
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TRT41
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Originally Posted by jrgordonsenior
Yea keep the OEM safety latch. Cheap insurance....
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Old 07-05-2012, 08:38 PM
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Originally Posted by TRT41
+996
Hey I like that....

Another tip, keep your hood shocks installed. Makes life so much more bearable when your're messing with things under the hood like shock adjusters, Kool Suit cooler, fire bottle, etc. I hated that thing resting on my neck/back while I tried to accomplish something under the hood....
Old 07-05-2012, 09:05 PM
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sbelles
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The issue isn't so much air getting under but air flowing over it and producing lift.
Old 07-05-2012, 09:16 PM
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Originally Posted by sbelles
The issue isn't so much air getting under but air flowing over it and producing lift.
Assuming he has a 3rd radiator with proper ducting up thru the grill work would having his hood sitting down 1/2" really cause lift?...
Old 07-06-2012, 02:46 AM
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OZ951
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Thanks for the pointers.

I'm not sure of the origins of this hood, it was advertised as an original Porsche hood by the main dismantler here in the UK. It was removed from a race car in a Porsche series here. It has no bracing underneath so it is relatively floppy when held up by the shocks - and thus difficult to close against the hood shocks without a person pressing the hood shocks down on each side. For that reason I removed them and will resort to a prop.

The lack of bracing also means there is no mount point for a standard latch. Thats part of the reason why I was able to set the leading edge to be a little lower than the bumper. Since (some) of you guys are using a latch I gather your hoods are flush with the bumper - and also held in place by the latch so air isnt going to lift that middle part of the hood anyway.

In answer to JR's point the upper bumper vents on my car are functional rather than cosmetic.
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Old 07-06-2012, 11:16 AM
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J richard
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Really floppy ones without the interior frame will deflect under pressure at speed and collapse. Keep an eye on it or take it out on the freeway at speed... If it does you may have to add bracing on the interior of the hood or the surface will crack over time all depends on the construction.
Old 07-06-2012, 12:13 PM
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OZ951
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Originally Posted by J richard
Really floppy ones without the interior frame will deflect under pressure at speed and collapse. Keep an eye on it or take it out on the freeway at speed... If it does you may have to add bracing on the interior of the hood or the surface will crack over time all depends on the construction.
As it is the new piece of gear on the car I will be keeping an eye on it but as this came off a race car and showed some signs of having done some track duty I think it's probably going to be ok in that regard.

If anyone reading this thread does recognise the underside of this hood as being Porsche manufactured or otherwise please drop me a line.
Old 07-07-2012, 03:17 PM
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The new hood exhibited no issues on it's first track day fitted to my 996, thanks for the comments that were provided.
Old 07-07-2012, 03:52 PM
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From the picture of the underside, it looks like it was either fiberglass mat or made with a chop gun. I think everything the factory does anymore is carbon fiber, so I would say this might not be factory.
Old 07-07-2012, 04:48 PM
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Yep the factory stuff is CF all through, and has CF interior structure that looks like the steel part, also if it were off a factory race car you'd have a air jack notch or hole.
Old 07-07-2012, 05:28 PM
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It's an aftermarket one.
Old 07-08-2012, 04:01 PM
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OZ951
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The track day I attended was an all porsche track day and nobody there recognised its origins either. Its a pity really as the fit is not bad at all and weight wise at 5.5 kg it's a heck of a lot lighter than the 14.4 kg steel one it replaced.


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