Megaphones
#1
Rotary Freak
Thread Starter
Megaphones
I was cleaning up my old car magazines on the weekend and I came accross my old RX7 Performance book by Jim Downing and Dave Emanuel and I was really interested in how they did the exhaust back then. They were really firm on the ID's of pipes and length of pipes, but what I thought was really interesting and something that I had forgotten, was the use of an exhaust extraction megaphone on the end of the exhaust pipe.
Anybody still use them and any reason why they have dropped out of favour? I can really understand the concept and how it works and it may be something to try on my setup, though they go from a 2"id to a 4" id. That looks like a 100% expansion rate. Seeing as my outlet pipe is 3", I would need to expand to a 6" pipe. Tuner city here I come, LOL.
Thoughts, idea's on megaphone exhausts?
Eric
Anybody still use them and any reason why they have dropped out of favour? I can really understand the concept and how it works and it may be something to try on my setup, though they go from a 2"id to a 4" id. That looks like a 100% expansion rate. Seeing as my outlet pipe is 3", I would need to expand to a 6" pipe. Tuner city here I come, LOL.
Thoughts, idea's on megaphone exhausts?
Eric
#4
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,802
Received 2,577 Likes
on
1,831 Posts
i don't really know, i haven't gotten that far yet. i'm thinking i'll have a short one, but i'm letting the engine decide what it wants
#5
Exhaust Manifold Leak
maybe once could get the benefit of a megaphone (I dont see or know or have verified there is one) and make a certain volume after the mephone, and then use a reverse con or bellmount to a muffler. much like a 2 stroke exhaust
Trending Topics
#8
Rotary Freak
Thread Starter
In the old Mazdaspeed build charts, they show a megaphone on their IMSA motor setup charts and even give the dimensions and how to build one. They are at the very end of the exhaust. I may try to build one and see what happens.
Eric
Eric
#10
Moderator
iTrader: (3)
lately, I've been kicking around the idea of playing with a megaphone ... but possibly placing it midstream - leading to an expansion chamber.
not sure if you prefer to build or not, but if you don't necessarily want to try building one, if you check out Burns Stainless, they have some. maybe see if they have what you're looking for.
not sure if you prefer to build or not, but if you don't necessarily want to try building one, if you check out Burns Stainless, they have some. maybe see if they have what you're looking for.
#11
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,802
Received 2,577 Likes
on
1,831 Posts
should work fine, the long systems use the universe as the expansion chamber, but really its just because 90" headers on a 95" wheel base car do not leave much room for anything else
Thread
Thread Starter
Forum
Replies
Last Post
jameseastman@hotmail.com
General Rotary Tech Support
11
01-14-12 11:54 AM
rotor-motor
1st Generation Specific (1979-1985)
7
03-23-10 11:01 AM