Quote:
Originally Posted by Nigel_S
What is the reason for the megaphone collector when it is going into a cat anyway? Do the lengths change when using a megaphone since the gas will be slowing?
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Now that you mention it.. Looking a bit closer into megaphones, they seem to be used in two ways:
1) If used without an exhaust pipe (race applications) it's used to substitute for a tuned exhaust length, for a short outlet to the air
2) If used with an exhaust pipe *without* a cat, it can be used to decouple the header from a 'wrong length' exhaust which would cause detrimental resonance
So AFAICT there's little benefit if either your exhaust is the right length, or you're using a cat. Ricer points maybe
Eliminating the megaphone takes the end assembly from
16" megaphone + 2" for step down / flange = 18"
to
3" for the end of the Y merge + 4" flex pipe (will have to check how much length a 4" flex *actually* adds...) + 1" flange fitting = 8"
... which will definitely make things easier - thanks!
Quote:
Originally Posted by Nigel_S
Why did Honda put the engine backwards? With my MG it is naturally the correct length since it starts off in the wrong direction and then comes back under the engine, you just need 2 90 degree bends plus straight pipe and the Ys, although it is hard to fit the flexi if you go for the version with long primaries.
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The D series engine in the civic has the exhaust ports at the front - the shortest / natural header layout (down & back) has about 37-39" (depending on cylinder you measure) from the exhaust valve to the cat flange, which is no problem and even allows a little 'wiggle room' in the header design.
The K swap is when a K series engine (which are larger displacement than the D series) is swapped into the car (which isn't an OEM configuration) - this engine, fitted into a 6th gen civic, has the exhaust ports at the back instead, hence the odd length problem that the k-tuned ram horn header addresses. (NB I don't plan on doing a K engine swap
)