all you 3inch DP and MP people runnin 3inch... where do you get the flange??? i got the mazdatrix flange but its 2 1/2 inch..
http://mazdatrix.com/fabricators.htm
part # 16180

 

That makes me curious. How big is the outlet hole on the turbo? Right at three inches or???

Do you have enough material on the one you bought to open the hole to the turbo hole size?

 

Racing beat, I purchased there full exhaust, and I'm goiong to have to cut the flange off to weld it to my 13b-re including the portion with the 02 sensor. If you want it 20 bucks shipped.

 

actually you could be right.... its a stock s4 turbo... the bolts shouldnt be in the way should it?? i mean lots of people run 3 inch DP's
i dont think i have enough material to cut it for 3 inches... its already hacked up since i messed up the first time and made my DP and had to cut off the pipe from the flange.. the flange wont last another hacking..

 

can i even get one for the stock s4 turbo?? i checked out racing beat and its 2 1/2 to
http://racingbeat.com/FRmazda2.htm
is the outlet on the turbo capable for 3 inch without the bolts getting in the way?? someone please answer my question.....

 

I would have to say no, I'm looking right now at the racing beat downpipe, the inner diamater is a measured 2.55 inches. The downpipe itself is 3 inches inner diamiter. On the turbo side 2 of the 3 bolts have the pipe dimpled to be able to get them in. I don't think there is a difference between s4 and s5 in this case, as the exhaust fits either. And finaly ther is .28 inches from the inside of the lip to the edge of the bolt hole on 2 of the three bolts. The third is off center.

Sorry I told you the flange was 3 inches before that was bad info.

 

The turbo outlet is 60mm (~2-3/8"). Putting a 3" pipe straight on the back of the turbo will make getting a tool onto the DP nuts very diffucult. It's better to use a 2.5"-3" cone to go from a 2.5" flange (from Mazdatrix or Racing Beat) to the 3" pipe.

 

I'm holding the racing beat downpipe, it connects a 3 inch pipe directly to the turbo flange with no cone, the pipe is dimpled to clear the bolt holes. The racing beat turbo flange is 2.55 inches ID.

 

Exactly, you can't just whack a 3" pipe on the back of the turbo. That was my point. You need to make clearance for the nuts somehow, and personally I rather use a cone since there's no advantage to welding a 3" pipe to a 2.5" hole.

 

There is an advantage, it would have an aditional weld if it had a 2.5 in - 3in cone. It wouldn't look as cool, and it wouldn't be as simple as it could be.

 

PEPBOYS or CHIEF AUTO... they sell them

 

For the S4 turbo? I somehow doubt that...

The S4 turbo has a 2.5" outlet. There's no point in using a 3" flange and indeed there's no space for it anyway. The bolts are already very tight. If you're going to make a 3" downpipe you will want to use 2.5" for the initial 90 degree and then gradually expand to 3".

 

How is that an advantage? If you're worried about weld penetration, that's nothing a skilled welder and/or a die grinder can't fix.

How does that look "cool"? To me a proper taper looks far better than a pipe with dents bashed into it.

And how is that relevant? I'd hardly call it complicated.

 

Ok I should have prefaced that with in my opinion. But this is a very trivial thing to debate.

BTW the racing beat down pipe doesn’t look like there are dents “bashed” into it. I would call it precisely dimpled.

 

Since we are talking custom exhausts here, if you really wanted to go that way bashed dents would be far a more likely result than precision dimples. Fact is a cone will flow better because a rapid area increase (2.5" straight to 3") causes turbulance. That's not my opinion, that's fact. RB is mass-producing a part, so it does what's easier (and hence quicker and cheaper) to produce. For a custom exhaust a cone is easier to do than trying to make enough clearance around a 3" pipe for the nuts.