So my setup now is: AEM intake, Greddy catback, rx8store midpipe (no resonator)

I had the intake and catback already installed, and did the midpipe today.


Well it's a little raspy, as I expected. And it's pretty damn loud.
I also think it's leaking, since I had to ghetto rig some stuff. I bought 3 bolts for the front (10M 30mm) with lock washers and nuts and they work great. I was thinking I could re-use the bolts in the back with springs and all but the nuts were welded in from the factory. So I ended up ghetto rigging some smaller bolts and 2 washers each and it fits like crap. Plus I re-used the old donut gasket that goes between the midpipe and the catback. I plan on fixing all that next weekend and I'll let you all know if it's any better.

Anyway, feels like I gained a smidgen of power in the low end. I can never really feel gains in the top end from the butt dyno.

Oh, and no check engine light, yet...

One question I have is, do I really need to get a new gasket that goes between the midpipe and downpipe? It's made of metal and doesn't look worn out to me.
I really wish vendors shipped hardware with their midpipes, it would be so much easier. Other than that the pipe fits great, O2 sensor came out of the old cat and into the new pipe much easier than I expected it to. Much easier than those front bolts! Those were a *@#$% to loosen! I ended up breaking one of them too. If anyone has any questions post them. I don't have a video camera so no sound clips or vids.

 

are you referring to the ring gasket between the exhaust manifold and midpipe or the cone mesh gasket between the midpipe and the rear exhaust?

 

One question I have is, do I really need to get a new gasket that goes between the midpipe and downpipe? It's made of metal...

 

What are you calling a downpipe????

The RX-8 doe not have a turbo, hence no downpipe. The OE gasket at both ends is metal, just two different styles.

I can only assume you mean the exhaust manifold, in which case the metal ring gasket is a crushable type. In general it should be replaced everytime in order to have the proper seal. I always replace it, but some people here don't.

 

my bad, I thought the downpipe was the one that came down from the engine

anyway, yeah it's the gasket between the manifold and the catpipe (now midpipe)

I'll probably end up replacing both gaskets, it's leaking pretty bad. Sounds real gross and you can smell exhaust in the car.

Looks like those 2 studs that connect the catpipe to the catback are replaceable and would work with the midpipe. The midpipe flange is threaded though, I hope the threads are the same. I'll have to pick some up and try it out.

Do you think the M10 30mm bolts I got for the manifold-midpipe connection are adequate? They seem to be doing the trick in my opinion.

 

No kidding. When I put in my rx8store midpipe I broke 2 of the bolts that hooked the midpipe and exhaust manifold together. Not only that, but in the process of trying to get them off my socket CRACKED right down the middle. Pretty nuts.

 

dDub, were you able to re-use the studs in the rear, did you get new ones, or did you have to do something different? I'm heading to the dealership today to get new ones if they can be threaded into the rx8store midpipe.

 

I used new ones, just whatever I had laying around.

 

RP has an actual gasket/bolt kit they sell that they recommend when you swap out the stock cat section. Bought it for my car when I swapped out the stock unit to RP Supercat. With crush-type gasket highly recommended that you replace them, as they might not fit the new unit correctly.

 

If your guys are refering to the bolts that reside in the front of the cat and connect it to the manifold, they are splined on the cat side and do not turn-only the nuts comes loose. You need to replace the front crush gasket as teamrx8 mentioned. Your bolt selection should be fine. Were these at least grade 8 bolts? You can reuse the rear gasket, plus a new one of these will set you back about 40+ bucks. I have the B&B and was very pleased. Hope you are able to get your leak sorted out so you can enjoy it more!
Jeremiah

 

Does it include the two rear studs?

 

You can re-use the one between the midpipe and the exaust....with no problems. You can't re-use the one between the exaust manifold and the midpipe without having an exaust leak. It's a cheap gasket anyway (7-8$) You can't even use sealant to help...even the ultra high temp stuff just vaporizes after a few days

 

Yea I'd reeeallly like to have those rear studs so I do not overtighten down on that donut.

How can a donut gasket cost 40 bucks? I used to sell them at Advance Auto for less than $10 each.

I was noticing something when I put the metal crush gasket back on; it didn't seem to fit around the new midpipe as well as it did the catpipe, almost as if the gasket was too large in diameter.

 

Update:

$15 for the metal crush gasket between the manifold and cat/midpipe
$12 each for the studs between the cat/midpipe and catback

$53 for the donut gasket between the catmidpipe and catback! (I'm going to pass on that one)

Also, my check engine light came on the second day I drove my car :p

 

The new front gasket works great; no more leaks.
The 3 bolts I used up front are working nicely too, they came off easily today when I replaced my gasket.
The studs that go in the rear thread into the back of the rx8store midpipe perfectly. I'm glad to have that part setup exactly like stock. There's no way to overtighten it now.

The exhaust is still a littel raspy/buzzy at certain rpms, so I would definitely recommend the midpipe with resonator. I'll probably revisit this thread in a few months or so and let everyone know how it sounds with the greddy turbo installed.

 

I think you should find a better dealer - those prices are not Kosher.

The metal manifold-to-pipe one is half that price, everywhere I checked.

...keep looking.

S

 

where do you buy that gasket? and how much?

 

i also forgot to ast if you can put a 3" midpipe with the factory exhaust system? i have one but have not installed it yet. i just received a part from ebay thats suposed to eliminate the check engine light. i use to have the b&b one and took it off because of the check engine light. ill let you guys know if that piece works or not. it was only $15 bucks so i figuered i would give it a try...

 

please list the part # for the back studs, it's not shown in the parts list

 

Sorry, I threw away the bag and receipt.

Yes, you can add a 3" pipe. That is what the rx8store midpipe is.
If that part you're talking about is just a non-fouler it won't help much, if at all. All you end up doing is putting a larger restriction inside the pipe. A scan tool would be a good investment. Not only can you reset the lights and read the error codes, you can get all kinds of other useful information.


BTW, anyone know what happens if you just totally remove the rear O2 sensor? Would be a nice place to put an aftermarket wideband.


Oh and Stealth, there are only 2 dealers around here and they have the same prices. And yes they suck, both parts departments and service. I had my girlfriend call up for the catpipe hardware the first time. They wanted to sell her the whole assembly and said it was going to be ~$1800