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> Megaphone cookie cutter inserts ... Why?
Eddie914
post Nov 20 2004, 11:25 AM
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Porsche factory race cars from the 60's and 70's used megaphone exhaust pipes with "cookie cutter" inserts. The insert consists of six rotary vanes and a small diameter tube.

What is the purpose of the "cookie cutter". More torque? More top end power? Cool looks??

Porsche rarely puts anything on a race car except to make it lighter, faster or safer ... and safer has only been lately!


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Gustl
post Nov 20 2004, 01:33 PM
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QUOTE(Eddie914 @ Nov 20 2004, 06:25 PM)
Porsche factory race cars from the 60's and 70's used megaphone exhaust pipes with "cookie cutter" inserts. The insert consists of six rotary vanes and a small diameter tube.


can't tell you the purpose of'em

as far as I know, they were called "Flammrohre" (sorry, can't provide a translation)

but, there're two pics:


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McMark
post Nov 20 2004, 01:38 PM
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Looks more like an Apple Corer-Slicer than a Cookie Cutter to me. (IMG:style_emoticons/default/lol2.gif)
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Katmanken
post Nov 20 2004, 01:42 PM
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Flammrohre......

Could that be German for flame arrestor?

Don't want to start a big fire behind your car.....

Ken
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Trekkor
post Nov 20 2004, 01:45 PM
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I see you have the Yokohama A032r's.
How do you like them?

KT
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SirAndy
post Nov 20 2004, 02:15 PM
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QUOTE(Eddie914 @ Nov 20 2004, 10:25 AM)
What is the purpose of the "cookie cutter".

you use them to adjust the back pressure = shifting your HP/rpm/torque band ...

more backpressure = more low end torque, less high rpm HP

less backpressure = less low end torque, more high rpm HP

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SirAndy
post Nov 20 2004, 02:16 PM
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QUOTE(kwales @ Nov 20 2004, 12:42 PM)
Could that be German for flame arrestor?

Flammenrohr = Flame Pipe

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campbellcj
post Nov 20 2004, 02:23 PM
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I've heard they were simply to strengthen the tubes so they wouldn't get crushed so easily when unloading the trailer or backing out of a driveway.

I dunno the real reason, but they do look cool.
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Carrera916
post Nov 20 2004, 03:12 PM
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Here's what I learned when I was younger.....

There was a 904 and a 906 sitting by and I noticed the funny 'apple core' thing on the mega and I asked my old man about that....he learned from his connection with P.A.R.T. (Porsche of Amercian Racing Team, back in the late '60) that the factory put it there as a joke to freak the other teams (Ferrari, Matras, etc) thinking that the German has came up something new that increased engine power......well, I guess eventually they realized they've been fooled.....that's how it goes....


I also think the idea was to stiff the big end opening from crushing when bottoming out....

It sure looks cool ......and yeah, it does give ya more power!

j
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carr914
post Nov 20 2004, 05:40 PM
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They look cool & sound great. I would have to disagree with Andy about the adjustability. This theory works with a Supertrapp muffler where can add or subtract plate, but with the megaphones, They are what they are. There are no adjustments except choosing if you want the cookie cutter or just the straight pipe.
T.C.
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redshift
post Nov 20 2004, 05:42 PM
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QUOTE(Carrera916 @ Nov 20 2004, 05:12 PM)
I also think the idea was to stiff the big end opening from crushing when bottoming out....

j

I agree with that... makes much sense.
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SirAndy
post Nov 20 2004, 07:07 PM
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QUOTE(carr914 @ Nov 20 2004, 04:40 PM)
There are no adjustments except choosing if you want the cookie cutter or just the straight pipe.

i thought they were removeable ...

if not, you're right, it's looks only ...
(IMG:style_emoticons/default/cool.gif) Andy
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Jeroen
post Nov 20 2004, 07:34 PM
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Andy, you're confusing them with Super Trapps...

AFAIK the cookie cutters are only to prevent the tube from collapsing (like Chris mentioned above)
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Eddie914
post Nov 20 2004, 08:55 PM
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KT,

Regarding the yoko a032r tires. They are a very good all around tire. Not as fast as Hoosiers but much more durable. Comparable to the Kumho Victoracer V700. Very long lasting tires. The Toyo RA-1 seems to be a bit stickier.

Since I drive the teener to the track the durability and grooving is nice. When I ran a032r tires on my BMW 535is, the noise and tramlining were very noticable. On the 914/6 with Webers, minimal sound insulation (only the tar mats on the floor and bulkhead are still installed), and the baffled megaphones, I can't hear any tire noise. Tramlining is not at all noticeable on the teener.

I'm running 225/50/16 and 245/45/16 in the "H" compound. I don't plan on much autocrossing and I don't think the tires are available in the "S" compound in these sizes.

This is about my fourth set. They must be pretty good or I would not keep coming back. I got a smokin deal on these so they were hard to pass up.

Eddie
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Gustl
post Nov 25 2004, 11:43 AM
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just found on eBay: Flammrohre

short translation:
here's a new set of flame pipes for Porsche 911 and 914/6, including 2 gaskets
perfect for historic racing
s/h within Germany: EUR 7.00
s/h within Europe: EUR 17.00

Gustl
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Jeroen
post Nov 25 2004, 02:36 PM
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Yeah, this guy is having a blast with these. He's selling 'em week after week on ebay and I've seen 'm go up as high as €250
You can get em anywhere for around $90 or $100 (IMG:style_emoticons/default/lol2.gif)
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