DAMN!!! That 12a is loud
 

I had to move my car tonight so I put my un-finished header on it.

All I can say is DAMN!!! makes me wonder why the stock cast stuff is so quiet.

I have no clue, but not many people can tell you, onyl listen to the people with over 3000 post lol :squint:

Well the engines are basically 2 strokes, they also have a fair bit of overlap

Forgot to mention I figured out why it runs like shit, there's a distinct smell of old fuel when I first turn it over, I guess sitting for two years will do this to gas.

the stock exhaust manifold aids in muffling the sound by having both exhausts pulses exiting into one chamber in the manifold. installing a header seperates these pulses, increasing noise level. but yes, just header alone is extremely loud. when i first got my 808 done with the rotary swap, i got a chance to drive it to the muffler shop up the street from me to get the rest of the exhaust done. i got to wind it hard thru 1st and 2nd to really let it sing, and even tho it was extremely loud, i loved how it sounds when u wind it out.

I noticed the noise too, especally in a 30'x50' shop.

IMO the exhaust note sounds so much better with the header than with the manifold.

I guess I won't answer the question then.

What I will say is the first time I fired up a 12A in the shop, headers only, and reved it to 7k, my ears rang for 10 minutes. What's even more fun is to fire them up without a manifold at all and watch the flames lick the frame rail.

yeah thats always good fun, then i did it on my plymouth V8, 4x the fun of the RX flames :P

Well I had a comment to make, but I guess it will have to wait. lol

im here, what did you want to know? :)

I thought about it, and decided not to

Give it a try, it's even more fun in the dark. Ear plugs mandatory.

I'll wait until I get it running right then i'll do it. (the things others get me into)

I was a little a fraid to wind it up with that little ammount of pipe because I've had it spitting flames with the muffler under the car and didn't want it warming something up under the car.

I've always thought it would be fun, if I had a track only car for the strip, to run the exhaust pipes straight up through the hood. Should be a crowd peaser and maybe distract the cometition in the other lane.

How much louder is it without the header than with?

I'm not sure if it'll be any louder than two 18" pipes off of the exhaust ports.

ohh come on i was just kidding! :shooter:

Post count is not an indicater of knowledge, there is, however, often a relationship. I've bagged you on your comment a couple of times just to give you the hint.

The stock manifold quiets the exhaust noise in several ways. It's shape causes the pressure waves to reflect back on each other, thereby canceling some of the noise by merging the individual pulses. Another big factor is it is heavy cast iron. The sound doesn't transmit through the log as easily as it does a standard exhaust pipe or header. This is one reason the RB system is quieter, the thicker walls.

Larger diameter pipe and thinner walled pipe will be louder than narrower and thicker pipe. The closer to the engine that the pipes merge and the pre-silencer is placed, the quieter the exhaust will be.

I hope the reason you posted that smiley was because you shot yourself in the foot with the post count comment. :molepoke:

I was thinking about that last night, wondering what it'd be like if a person ran the pipes all the way out without merging the two.

the ehxaust manifold does make a big difference! I have a straight pipe in between the mani and the muffler and the car still isnt that loud.

Thats what the racing beat street port system does

Eriks85Rx7
u wouldnt have any decebele ratings do you
i was thinking to do what u just posted to save some money
any maybe if its too loud grab a precilencer later in life
so whats best road header or the race header that goes two pipes
seeing its cheaper ill get the road race and just merge it on the rest of the exhaughst

blwfly, its not loud at all, even at WOT.

Both my 81 and the my 85 were straight through from the manifold to the muffler and it was too quiet for my tastes

no i do not having any ratings for u but i can tell u it will not be that loud. Maybe with the racing beat header it will but with stock exhaust manifold it wont be loud at all.

:balls: