Im looking for a new exhaust system. Now i got a home made 2.5" dual exhaust.. It lets me boost WAAAAY to much but the sound is also way to much.

Im going to rebuild my engine soon and im aming at around 400rwhp.
Which wxhaust will be "best"?
It can not be above 95db!
The price is also interesting.

Sindre

 

If you want a quiet setup....i think you might want to check out racing beat

 

just have a shop custom make you one. like 100 for fab and piping and you pick your own componets. if you go dual apexi style then get 2 silencers and baffles. if you are going single then get one 36" high quality silencer and muffler of your choice and a baffle. i did that and my exhaust sounds so cherry. none of my friends rx7's sound as good and i even had them weld in a cut out for the track. 3" mandrel bend all the way out for a total of $230 is not bad at all

 

has anyone ever hit 400 rwhp with a racing beat dual? I can't remember one.

If you want quiet then it won't be too performance oriented because quiet = restriction and restriction = less power.

Now you can make your own exhaust and use straight through race exhausts from borla or magnaflow. The change the sound of the car from a high pitched sound to a lower deeper (ferrari'ish sound) and you will not loose much performance because they are still a straight through exhaust. I added a 3 inch oval borla mid pipe to my straight pipe and it gave it a nice rumble. I am building a new complete 4 inch setup now with magnaflow and I am very impressed with them. I stuck the 4 inch oval magnaflow onto my friend Dave's vert /with hks hyper , just held it on to the back of his tip and had him rev it up and the sound was completely changed. Here is a few pics of the 4 inch magnaflows I got from jeg.com to build my setup. I will never buy a off the shelf rx7 setup again.

 

HMM, maybe i should build a single myself!
How many silencers is necessary ? Now i got a dual home made with 3 silencers and i cant talk with my passangers with a normal voice because of the sound.
Is 3" single exhaust good enaugh for 400rwhp? or do i need 4"?

 

3" single will not affect whatever setup you have for making 400 to the ground....
question though why bother making a 400 hp car and then stick a plug up the exhaust? you should look at the t-shirt for sale at polak graphics one of the reasons you know you own a 7 is that people hear you coming for miles - LOL

I would experiment with silencers though...put one on and see how you like the sound level and go from there - its hard to tell you which one to buy to get 95db since it will vary so much with your setup.

 

The reason why i got to stick under 95db is if i have above i cant drive at trackdays...

 

you don't need a silencer if you change the high pitched rattle to a deep tone. Just build your exhaust with one oval muffler as the midpipe, and the one round exhaust for the end just like I showed in my pictures. Also uses stainless steel only. You can get rid of that honda sound by using a thicker higher grade metal. Don't use that bs pipe that they sell at your local muffler shop. Get the SS exhausts from jegs.com and all your ss pipe and ss mandrel bends from ATPturbo.com
Also make sure that the exhaust pipe its not touching the body of the car anywhere. If the exhaust touches the body of the car I have noticed that the sound level is 2x as high as it should be due to ribration turning the exhaust into a megaphone and driving you crazy.

You can also weld a turn down onto the end of the tip of your exhaust that they also sell at Jegs.

Here is a camera phone shot of the 3 inch oval borla midpipe welded to my 3 inch down pipe/mid pipe from thunder fabrications. It was just to loud connected to a corksport. Now its drivable with this in the middle. My new 4 inch setup will be even better and flow like a bit*h. I am shooting for 500+ rwhp on s4 stock ports

 

your screwed. i had N1 dual's on my old FC they wernt that loud and but its pricey you can try them i didnt have any kind of silencer or nothing and it wasnt to bad

 

Racingbeat it 80MM from the DP to the inlet of the Y then IIRC 62?/65?mm to each muffler All components are straight through on that setup and all FC setups i've seen from RB.

 

Dual would be less noise becuase the exhaust velocity is split.

This guy round here put a borla muffler on the end of his downpipe, then ran two empty straight through pipes to where the mufflers were for a stock appearance. It sounded INCREDABLE. BUT it was LOUD. Not too too loud, but loud enough.

Another guy runs a 2 1/2" pre-silencer and a baffled, Directed flow Magnaflow single exhaust on his Superchargered RX-7 and it will make your ears bleed.