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> Megaphones, for track use
Trekkor
post Jul 4 2006, 11:46 PM
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I like really LOUD open exhaust. Who doesn't? (IMG:style_emoticons/default/cool_shades.gif)

with the exception of Laguna, the the Db limit is 103.
My SIX goes to 7300 rpm's. How loud will it be?

I'm planning on making a set. (IMG:style_emoticons/default/dry.gif)

Any ideas?


KT
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Heeltoe914
post Jul 5 2006, 01:18 AM
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I have a used two bolt set that worked great on my 3.2 with 1 3/4 headers. Its sounds like a race car should. LOUD as all get up. But at the same time so sweet.

will sale 50 for set.
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Trekkor
post Jul 5 2006, 07:59 AM
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I want them...

Can I see a picture?


KT
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Trekkor
post Jul 6 2006, 11:42 AM
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I was wondering is there any danger to the engine, specifically the valves, when running an open exhaust? Cool air rushin back to the valves and warping, bending etc?


Thanks,


KT
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redshift
post Jul 6 2006, 11:50 AM
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Not that I have ever heard of. Only time I know that is a problem, is with a leak at the head.

I got a set of phones with a /4 I bought once, and we put them on, and went driving around Miami for a day... and only got pulled over once.

(IMG:style_emoticons/default/laugh.gif)


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slivel
post Jul 6 2006, 11:54 AM
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QUOTE(trekkor @ Jul 6 2006, 10:42 AM) *

I was wondering is there any danger to the engine, specifically the valves, when running an open exhaust? Cool air rushin back to the valves and warping, bending etc?


Thanks,


KT


There is a fair chance that your mixture will need to be richened if you uncork the exhaust. I typically go up one jet size on my mains (Weber 46's) when I go from mufflers to open pipes.

Steve
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Joe Bob
post Jul 6 2006, 01:23 PM
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My seat of the pants dyno on my 2.0/6 S motor found a significant loss of bottom end power....
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grantsfo
post Jul 6 2006, 01:34 PM
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Good! I need to be able to hear what you are doing if I ever get out on the track with my car. Note people will also hear your mistakes a little easier too.
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jgara962
post Jul 6 2006, 01:36 PM
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QUOTE("Z" @ Jul 6 2006, 12:23 PM) *

My seat of the pants dyno on my 2.0/6 S motor found a significant loss of bottom end power....


(IMG:style_emoticons/default/agree.gif)
I put on a GT style open exhaust on my car. Just driving around, I can tell a difference in a lack of low end power vs the Birsch. But man, does it sound bitchin'! (IMG:style_emoticons/default/aktion035.gif)
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Trekkor
post Jul 6 2006, 08:56 PM
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Yes, the sound is important too. (IMG:style_emoticons/default/smile.gif)

I don't think low end will be an issue as I am at 4500 rpm's and above on track.

( am I wasting my time? )


KT
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J P Stein
post Jul 6 2006, 09:10 PM
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You'll loose mid range power due to the loss of the ballance tube effect of a properly
engineered muffler.

You want noise?
Do a GT engine lid & remove your rear window....trust me.
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Randal
post Jul 6 2006, 09:16 PM
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QUOTE(J P Stein @ Jul 6 2006, 08:10 PM) *

You'll loose mid range power due to the loss of the ballance tube effect of a properly
engineered muffler.

You want noise?
Do a GT engine lid & remove your rear window....trust me.


I totally agree. Listen to good advice Trekkor.
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campbellcj
post Jul 7 2006, 01:00 AM
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Yep the midrange can drop; however you might pick up significant power at the top-end. If you keep the revs in the meat of the powerband then there is no problem. For autocross it would be problem if you have to hold a particular gear to avoid a shift and need to pull cleanly from low revs but this is not typically an issue on the track. FWIW my car seems to pull much better up top with the megaphones than the Dansk sport muffler...
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Root_Werks
post Jul 7 2006, 07:31 AM
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Some have already said it, you'll loose the cross extraction you have now. Which means less torque. Unless you run above 6000rpms all the time, leave the muffler on.

If you want loud cross extraction, just put on a dual tip muffler.
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john rogers
post Jul 7 2006, 09:06 AM
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I run stingers on my 2L vintage race car and as Steve noted above the jetting has to be fattened up some when switching from a muffler. I have to go from 160 mains to 170 mains on the Weber tripple throats. Above 7K they make a very high pitched sound and I have started to wear ear plugs as my eard ring after a 30 minute race. If the car is dyno'd for the megaphone/stingers then you wull make more power as was shown on my dyno tests with 185HP at the rear wheels with stingers and 172HP with the muffler with dual outlets that makes exactly 92 DB. If you do change the exhaust, invest in some dyno time to get things set right because as Wayne Baker sez "an hour of dyno time is worth at least 4 hours of work at the track". My experience has shown this to be true.
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Joe Bob
post Jul 7 2006, 09:10 AM
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HUH....WHAT????

I LEFT MY EAR PLUGS AT HOME....I'M NOT SHOUTING......
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Trekkor
post Jul 7 2006, 10:38 AM
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Thanks for the replies.

Another "creation" I've been dreaming about is taking two "Cherry Bomb" glass packs , shortening them to 18" an welding a mounting flange to them for fun.

Maybe I'm just bored (IMG:style_emoticons/default/idea.gif)


KT
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Van914
post Jul 7 2006, 12:23 PM
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trekkor,
Why go to all that trouble. Just buy race muflers from Jeg's or Summit.
van914
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Trekkor
post Jul 7 2006, 12:42 PM
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I like a project... (IMG:style_emoticons/default/welder.gif) (IMG:style_emoticons/default/smash.gif)

Phase 9's would be nice though. (IMG:style_emoticons/default/idea.gif)


KT
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TimT
post Jul 7 2006, 12:58 PM
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here a project,

Pair of Coast mufflers, with a crossover I made.

The mufflers are straight through. Plenty loud if thats what your after

The systems really shrieks at 7500 RPM

Burns stainless makes a similar muffler to the Coast. Both the Coast and Burn mufflers are available witht either glass packing, or stainless wool packing, and are rebuildable.

werd up yo


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