Mazda Talk Forums

So I recently purchased the CARB approved 99-00 mid pipe. The unit came with flat gaskets for the junction between the mid pipe and down pipe and also between mid pipe and muffler. The OE donut gaskets don't fit with the new flat gaskets but the new gaskets are leaking at both flanges. What do I do, please help?

I say play a little more with clocking position of the flanges to get more flat connection (don't just jack them together with the hardware as we see some folks do). We install those daily here with the flat gasket without issues....it just takes getting the flanges nice and flat before you add the bolts and nuts.

Will do, Brian. I was thinking of playing with the clocking a bit too...it seems like the pipe is also slightly rubbing the diff housing when it vibrates. Just to be clear, the old donut type gaskets are not used in conjunction with the flat gaskets, corect?

Hitting diff means midpipe is adjusted too short. Give it some more length at the slip joint.

I have customers use the factory donuts all the time and swear they get good results, but I prefer the flat gasket because there is reduced danger of bending the flanges around the gasket (which causes leaks).

I just purchased the Roadster mid pipe for my 99 miata and found that we needed to shave a very small portion of one of the cooling fins on the rear differential to get it to fit. Other than that no problems and I'm enjoying the system.

How much of a gap should be present between the flange of the midpipe and the flange of the header (Goodwin Street Header) after installation? I only ask because after torqueing the nuts to spec, I can still get my pinky finger between the flanges. It seemed like the stock midpipe mated tighter to the stock header. No identifiable leaks after install, but the gap seems larger than it should be.

Big gap there intentionally in both stock install...and any aftermarket install....because it is a ball joint gasket, allows for motor movement without snapping flange bits off the exhaust items. The Stock was the same gap.

Will I have problem to install it on my 2000 base model with Racing Beat header and RB muffler. Do I have to put a new donut gasket at the muffler ?

Thanks

Installed the RS Street (catted) mid-pipe, along with the Super Q, on a '15 6AT yesterday.

Despite the warnings here, there was lots of clearance between the pipe and the silver bracket on the side of the transmission. Trimmed the bracket anyway.

I wonder what changed?

Any chance that the clearance problem between the street header and the lines to the ATF cooler has also gone away?


Looking forward to hearing it on the road today.

I finished my header/midpipe/RoadsterSport II install today and I noticed something strange. The joint between the muffler and midpipe is leaking condensation. I loosened and adjusted the joint multiple times trying to get it to seal but it still leaks. The middle portion of the flanges don't seem to flatten when torqued to 37 ft/lbs. When running, there is no bubbling so it seems there isn't an exhaust leak? Has anyone else run into this? I have an extra gasket due to ordering my kit in pieces. Should I put two gaskets in? I attached a picture of my flanges. Thanks in advance for any advice.