NA Exhaust
 

Hi everyone!


12A BP FB
Does anyone have any suggestions on exhaust pipe size and lenght ?
I think my exhaust is restricting me at the moment.

Will ne used occasionally on the road,but noise isn`t really a issue

Thanks!

Karis

(More detailed specs in ym sig)

id use a combo of stock exhuast+cut out

I was driving around my FC the other day with just a downpipe on and its really not as loud as people say. yes it is louder them most exhuast but not that much louder then a FD with a 3inch dp+4inch MP+4inch catback

Thanks for the reply!

I`ll look into it!

karis

For n/a engines, anything over 2 1/2 inch really doesn't gain you much in the upper RPM's and will hurt you in the lower rpm's. With a bridgeport i would get at least the 2 1/2 in exhaust. Racing Beat makes some really nice stuff. Mazdatrix also offers a race header and tubing to "build your own" system.

The way to get the most out of an n/a engine is to have a true dual system. ( dual pipes from the engine block all the way back to the outlets.) Kinda loud but the best gains by far.

http://www.mazdatrix.com/r-exh-85.htm Something like this for the First gen

Here is the true dual for the FC's.( just to get an idea.)
http://www.mazdatrix.com/r-ex86nt.htm

For a bridge ported engine you do not want true duals. A bridge ported engine needs the exhaust scavenging that can only be provided by a collected system.

- Cooper Lacy

From what i have learned...the pipes must be collected at the rear axle.I just wanted to make sure about this

So 2.25 inch should work fine ?
Thanks for the info provided.
Cheers
Karis

Read through this thread. There is great info on collected v. uncollected systems and a brief discussiong of diameter and it's effects. You make the call.

https://www.rx7club.com/showthread.p...ning+resonance

for the B.port buy the custom make it yourself header from RB and go dual till right before the rear axel ( same size pipes that come off header) and then 3" over the axel into a 3" straight though muffler

Again, read the link. The collector cannot be place at an arbitrary point somewhere near the rear axle. There is a specific point it is place to best effect the scavenging. You'll need to snake 6-8ft of pipe around underneath the car to get the collector where it needs to be.

Goodness me,what alott of math!The problem:I cant send it to the dyno,before my fueling,and exhaust is sorted,so its hard for me to say,at what rpm the hp will start climbing,and where it will peek.

If i`am using the same size header,as the rest of the exhaust....i`ll have to scratch my head alott to fit 2 x 2.25" pipes under the car ,and still have it high enough to drive it.

Thansk for the info..i`ll continue searching