Question on the fitment between my Mazdaspeed Dual Sport exhaust and the RX8Store High flow Cat.

I have my high flow cat on for a few of days now and am getting acquainted with it. I am hearing a slight leak some where so I thought to look it over good. All the welds seem good but I am noticing the fitment between the muffler tail piping and the high flow cat do not line up quite right.

I looked closely to the stock cat piping and notice that it bends very slightly down where it connects to the muffler piping. I see that the high flow cat doesn’t have that slight extra bend in it so it doesn’t match up well with the muffler. So there is a gap at the top where the flanges connect together.

I cannot get a good seal because of this and it is making a pfffffffsssst sound in the upper rev ranges.

Has anyone else noticed this on this same setup or any other exhausts and high flow cat setups?

What would be a solution to this?

 

Add another gasket on the side thats leaking.

 

If this is the connection where the HFCat connects to the catback then there should be a doughnut gasket at that connection. Did you try to reuse the stock doughnut gasket? Also, did you reuse the stock bolts and springs for that connection?

 

I did not use the stock bolts because I could not get them off, however I went and bought new bolts and used the stock springs and the doughnut gasket.

So if you look at the drawing I did on this picture.

The pipe shown is the stock cat pipe.

Think of 1 is the mazdaspeed sport muffler.
2 is the high flow cat, see how in diagram 3 it creates a gap at the top because it doesn't have that bend like the stock cat has. so they do not match up flush with each other.

So I take it that most aftermarket exhausts are straight and do not have that bend in them. If that is the case then they would match to the HFC perfectly.

 

I cranked down on the bolts with the springs that hold these two parts together and it seems to have closed the leak.

 

lol. you solved your own problem. gj

 

I might just get some 1" stainless steel bolts and take the springs out.

Hopefully this is usefull for others.