Here are some pics of the custom exhaust we did for my rx7 over the weekend.... We took the headers and cut them right before the Y section where they become one... We extended the two header pipes with 2 2 inch pipes about 4 feet back.... We then used the Y pipe we cut from the headers to join them into one.... Then there's a 2 inch pipe over the rear and then joins the racing beat muffler.... It's pretty loud,,, enough to annoy the neighbors and get a ticket if I drive next to a cop,,, but I love the sound.... The sound comes from underneath the car,,, not from out the muffler (rb muffler does miracles).... The power increase is very noticeable,,, the car is going to the track next week... What do you guys think???

 

another view

 

yet another view

 

one last view

 

a view of the engine bay

 

Looks good man, by the way is that a holley carb?

 

yeah,, holley 600

 

Do you like it and hows the performance?

peace

 

EEK! Nice Performance, Poor Engine Bay Cleaning..
Simple Green does wonders my friend..

 

Thats pretty cool what you did with your header. I did the exact same thing! I chopped off the Y, and placed it right before the muffler flange. Only difference though is I put a glasspak in each tube. Also, I paid SPECIAL attention to be absulotely sure they were the same length tubes were they collect.

 

is it louder than mines was.

 

whats that silver cannister just below the oil filter in the picture ?

... doesn't anyone use the genuine oil filters ? I do because 1 size fits my 323 , RX7 and my Dads 626 so we usually have at least 1 knocking about in the garage

 

Maybe I'm just being stupid, but what exactly does moving the splicer back along the line do?

 

I don't know for certain, but long vs. short headers is a performance thing. Their is a whole science to the tuning of exhuast that starts with the headers... I think it has to do with how much back pressure you get, and how much contamination the intake charge gets. That kinda of thing... So, there you have the stupid mans version....

Chris

 

DirectFreak: You should have seen it b4 I "cleaned" it. Maybe I should try that simple green stuff...

Treceb: It's a different type of sound like cans dragging,,, but I would say equally as loud...

MikeLMR: That's a guage to measure the fuel pressure.

357: What RotoHead said.... From what I've read,,, correct placement of where in your exhaust the greatest backpressure is created is key... All I know is the difference was huge in my case... Maybe it's because I have such a big carb,,, people are always telling me I should have gotten a holley 465...

 

So, on a percentage scale, how much more power do you think you have now? Oh, and what is the sound difference?

 

It's called pressure wave or resonance pulse tuning.

When an exhaust pulse travels down the primary it gets reflected back when it reaches the collector. The idea is to time the pulse arriving back at the exhaust port to coincide with the end of the exhaust duration as the negative wave travelling back down the pipe helps move the exhaust gasses (as well as draw the intake charge out during the overlap period?). The basic rule is longer = low rpm tuning and shorter = high rpm. Also keep in mind that engines with longer duration/more overlap require longer pipes.

 

There, the scientific answer! Better then my dumb mans answer! Hee hee hee.

 

I use and ONLY USE GEN. MAZDA oil filters... i buy them buy the case.....as i do lots of rx7 EARL(oil) changes

 

I use Mazda filters too.

 

pure one all the way, its almost a half quart.