Thanks 'Zoomer.. good to know. I suspected all of that to be the case and it would bolt up to anything, but I've seen stranger so decided to ask.

I will now have Stage 2 on my shopping list for some time later this year.

*sigh* until then I'll just deal with the mixed blessing that while the Stage 1 I ordered a month or two ago still isn't here, the fact that we are supposed to get a couple cm of snow this afternoon means my car still won't be coming out of storage for a while yet anyway....

 

The midpipe, stock, is from the downpipe to the cat-back lead-in pipe.. The mid-pipes we are having made is to replace the stock one piece with a new two piece version.

The cat is in it's own short section, so that one can easily remove just the cat, such as for when you want to run on a track, off-road. Also the resonator is optional so one can get the rear section with or without a resonator.
It is a modular system.
It also weighs about half as much as the stock midpipe, and is made of 2.75" mandrel bent stainless steel pipe.

See pic of stock midpipe first. The stock midpipe incorporates the cat, the resonator muffler, and in this pic runs from the downpipe flange in front of the cat ( on the left) to behind the resonator muffler. This is the point where the two yellow springs are over the flange bolts.

 

Here is the replacement 2 piece midpipe.
The version shown here does not have a resonator muffler in the longer rear section. I will have the versionwith the resonator by Monday. Fedex managed to lose the paperwork, so it is still on it's way here.
This view is from the top of the unit. Note the threaded bungs on the pipe for the stock rear O2 sensor and a rear pyrometer probe.
On the cat there is another 18mm threaded hole for a wide band O2 sensor, and the front pyro probe.
The 2 pyro probe bungs and the extra O2 bung are for installation of instrumentation for tuning. When you are not using the instruments you thread in plugs that are supplied with the kit.

 

Here it is, installed in my car.
Note that th new cat and the O2 sensor probe do not hand down. On the stock RX-8 the cat and sensor are the lowest points underneath.
With the new pipe they are above the cross members and are protected. This gains about an inch of ground clearance.

 

Here are a couple of pics of the cat assembly.

 

In this pic we see the inside of the cat.
The catalyst substrate is a wound steel strip, which provides much more surface area than the ceramic bricks substrate in the stock cat. This allows the cat to be much smaller.
It also is much less restrictive to exhaust gas flow.

This substrate type can withstand higher temperatures than a stock ceramic brick unit (about 300F hotter than stock).

 

Here is the cat as seen from the other side, so you can see the bungs for the front pyro probe and wideband O2 sensor installation.

The stock rear O2 sensor bung is aft of the cat section, in the midpipe.

The catalytic converter shown is these pictures is a 4" diameter unit. Our production model that we sell in our mipipe kit comes with a 5" diameter cat.
These are only recommended for use with an RX-8 that is tuned.

We are concerned that in stock tune the extremely high level of hydrocarbons (unburned fuel) the car spits out might ruin the cat.

 

This is a close up shot of the midpipe section that bolts behind the cat. This shows the bung for the stock rear O2 sensor and a rear pyrometer probe.

 

Bottom view of the assembly.

 

Will the midpipe with the resonator on it result in less horsepower gains compared to the midpipe without the resonator?

 

Very true, I'll back this one up no questions asked. 2 cars ago, I had a 320+ hp wrx. There is a precat that comes from the headers and goes up to the turbo...... very high heat, so the steel saturated catalyst is not only durable, it can withstand huge amounts of heat.

We tried drilling out the WRX version to get better flow, and it's hard to even drill an inch with standard steel 1/2" bits!

Good stuff Maurice!

 

No. The resonator is a free flow tube, perforated with round holes. Wrapped around that is another tube that is 4 1/2" ID, and in between the tubes the space is packed with a mineral fibre. That is what deadens the sounds, taking the "ringing" off and dropping it a few more dB.

There are no bends or restrictions in it. The one we are using is 3" internal diameter, so it is actually 1/4" bigger than the 2.75" ID pipe it mates to. That way we can flare the pipe to meet it and there will be no restriction or turbulence caused by the welds.

The only reason I can think of to run with no resonator is to save the extra 6 lbs.

 

I have the midpipe with the resonator now fitted on my 8.
Yesterday morning I went over to my friend Bill's house.
Bill is a sound and lighting tech, and among other things does sound for the Edmonton Oilers, various bands, etc
He has some nice gear.

We set up stereo microphones on a stand 1 meter ( 39") behind the car . I ran the car, revved it, ran at various rpm levels, etc.
We recorded the sound to his Tascam DAT recorder, and also took sound pressure level readings.

Maximum sound pressure level, standing still, was at 8,700rpm and yielded 88dB. This was recorded at 1 meter from the exhaust tips.

If you would like to hear the unedited file ( rather large at 4MB) you can get it as an mp3 file (128 bit) from:
http://www.canzoomer.com/exhaust/MID...ONATOR_SP2.mp3

Most of the action is at the end of the clip.
I have not had a chance to edit it yet so there is a lot of time in the middle where the car is just idling.

 

We have had a chance to get the cat we are using tested in California last week, on an RX-8.

Some good news arises from this testing:

Announcement:

If your RX-8 will pass emissions testing with the stock exhaust system, we will guarantee it to pass US EPA2, California, and other US State and Canadian Provincial emissions tests with out midpipe installed in place of the stock midpipe.

Please bear in mind that it is still illegal to tamper with your emission control system, so this does not mean that installation of the midpipe is legal for road use.

However we guarantee it will pass an emissions test.

 

Schweet!!!! :D

Got any pics of the whole setup, with cat and resonator, yet?

 

Just to clarify... If I go with the High Flow Cat, midpipe and a Borla Bat back I should be emmisions legal?? Also Will this setup cause a CEL? What would be the average HP gains from doing all this? You mention tunning. Will this mod only work correctly if we get your stage 1 kit, or is there a way to get the stock computer to work with this?

Thanks,

Nat

 

What Canzoomer means is you will pass a sniffer test. This does not necessarily mean you are emissions legal if they do a visual test and disagree with you removing the stock cat regardless if it passes the sniffer test or not.

Also, any external modifications like exhaust do not require additionaly fuel tuning (ecu mod) but will benefit much more from the presence of it. A well tuned A/F always does more for you than any other mods.

 

I have never had them do a visual... I gues you could say that something hit and damaged the old one. I don't know of to many inspection places that would even know what they were looking at. I am more concerned I guess with the HP and the comment

 

Exactly.

Inspection is only as good as the guy doing it. Passing the sniffer or obd-II codes is as much work as most want to do.

 

I agree with murix^^^^

 

If nothing else I realy like the clean look of canzoomer's kit... But added HP would further entice me to buy.

 

From Canzoomer's comment, you will need the Stage 1 piggyback (with it tuned specifically to work with the midpipe/cat, basically Stage 2) for it to work correctly and not throw up a CEL.

 

adrian-1 thanks for putting it all together for me.

Nat

 

Question for Canzoomer:

SCCA STU class (which the RX-8 is in) states that a high flow cat can be used, but it must not be more than 6 inches from the original location. They are no more specific than this - just "6 inches." Do you think your setup would be legal? It looks like it would be in the pictures.

 

Pics....waiting on the new midpipe pics with the resonator...