I'm home finally...

I had to go to a Midas shop because the new midpipe was missing the hanger. I had to have the shop torch the old one off the OEM pipe, and then weld it on the new pipe. That missing hanger cost me $70

First impressions are OMFG! :D

I never knew there was that much power to free up until I felt it myself. I gotta dyno this thing this week. I'll PM you dmp if I get the dyno setup. Of course it is louder now, but I was prepared for that. I think it sounds awesome. The guys at the Midas shop thought so to. I cruised around town and it was pretty quiet. I then hit the onramp of I5 and let her have it - WOT never sounded better. What a kick in the pants. I'l record some clips on Tuesday and post them up on the website.

 

No Cel

 

Awesome. Sounds like a good buy. Its still emissions legal due to having a cat, correct?

If you dont mind I'd like to tag along for your dyno and check out this mod.

 

It's not C.A.R.B. certified yet, but they are working on that I was told. So, yes the mod kept the O2 sensor in place. Looks great under the car. I forgot my camera, so I'll snap some photos tonight if I can crawl around on the garage floor.

 

3"

 

What's the price on this? Any more info about the cat itself or how it compares to others?

 

Hey, Im looking for RB catback and Hi-flow cat for myself.

How's the sound in the cabin? Is that really loud?

So is it basically the new design hi-flow cat from RP?

 

Cost: https://www.rx8club.com/showpost.php...5&postcount=19 :p

I'm going to get the details on the CAT from Rocky at RP.

 

I'll take my digital camcorder with me on Tuesday to the office and record some sound clips. My tires are at the wear bars, so the clips will have that famous Potenza rumbler going also. I'm ordering new treads tonight.

Yes to your last question.

 

Do you know if the design of the cat similar to the bonez ones they sell? Since rotaries run hotter generally than piston engines they need a cat that can handle the heat, and that's what the bonez series did. I was always unsure about if the random technologies cat in a midpipe would hold up to the rotary heat over time or not.

 

I'm waiting on RP to send me the CAT data - just buzzed Rocky again. I think you are right about this being Bonez. Will post it up when I get it.

The ride into work was perfect. I set the cruise on 67 MPH, and the noise was not overwhelming at all. In fact, I am getting more tire noise right now than exhaust noise. My Potenzas are at the wear bars. I'm ordering the Pirellis PZero Nero's today.

I'm also going to sound proof the doors and trunk this spring with B-Quiet Extreme

 

Sh*t and i though Canzoomer's midp-4 was the best to go right now...I have Sp2 and he siad to me it would make a BIG noise when hitting the gas..No problem with that but he said maz 10whp...PLease Dyno your car midpipe nemesis8...Thanks...

 

Arranging the dyno soon - most likely within the next few days...

 

Very anxious to hear how it goes. I always really liked Rotary Performance's parts that I put on my RX-7's.

 

Turns out I did not need the hanger after all. Rotary Performance said the pipe was so lightweight, they felt it did not need it. I guess I have it on for added support. :o

The CAT is a secret that they will not let out to the public, but they did say that it was designed for rotary engines.

 

So there not going to sell this part to the public, or your have to specifically call them and ask to order it?

 

Dear confused, yes they are going to sell this to the public. They might not be up to speed on production of them. You will need to call them and ask for Rocky. The secret part is that they do not want to divulge their CAT supplier. It seems that they have a custom CAT design with months of testing on rotaries due to the high heat generated. They wanted the best CAT life possible along with the highest flowing highest HP producing setup.

 

Update: 220 miles and no CEL

 

One thing I noticed about your new cat is that it is very small. Don't let this sound like I am criticizing it. I also noticed that the inlet and outlets to the cat element are subsequently a very gradual taper rather than an abrupt sharp angle with most other cats. One thing I have found with my airflow experiments is that this area plays almost a larger role in how well the cat flows than the main element itself! I was inspired by a David Vizard book that mentioned that he could greatly increase the airflow by changing this area. It took an old cat and flowtested it. I wish I'd have actually documented the numbers but I didn't. I then cut the endtanks off and made entirely new ones. Mine were much longer and a much more gradual taper. Obviously this would be a space issue under a car but on a test bench it didn't matter. I was sceptical that it would improve performance since there was now alot more open area inside the cat for the gasses to slow down. I ran the new mod on the bench and doubled it's inital airflow amount. A 100% increase! This was only a first attempt and I never tried again. David Vizard did mention in the book that I saw that a similar mod on one of his cat's showed a 250% increase in airflow! This was only due to a change in the inlet and outlet and not a change in the ceramic element. Your new cat has a very gradual taper and hopefully this will mroe than offset the small element inside. It's neat the things you learn when you test!

 

^OOOOO that is interesting. guess i'll be looking at getting RP's mind-ppe/cat instaed of sr's which has a random tech cat ,also rather abrupt change and not gradual...which who would've though made such a big difference..hehe thanks rotarygod..enlightful post as always:D

 

Good observation - concentric increaser and reducer - that was a item of interest myself as well. I am a mechanical engineer in wastewater pumps. It is truely amazing analyzing systems for friction loss. Even though I deal primarily in water and sludges, shapes of pipes and fittings play a huge role in drops in pressure that can occur there.

One thing I can tell you so far, is this thing flows excellent :D I'm working on scheduling a dyno since I have a base dyno from 2/26 SAE corrected.

 

A 15 degree taper (max per side) seems nice to use before we start to lose some flow away from the outside edges. The problem with alot of cats out there is that the inlet side expands at a rate that the air flowing through it can't mimic well. The reducer side is usually much worse. The whole element really isn't being utilized. They only flow as much as a small one but have flow losses due to shape so we may as well just use a smaller one but utilize the whole thing. This makes more sense. As I'm fond of saying, bigger isn't always better. You only need to go larger when you need more than what you already have is capable of.

I still only expect about a 6-7 hp peak increase from this sytem but I'd really like to see how much it changes over the average powerband. That's where it counts.

 

Hi Nemesis8 - now that you have had it on your car a couple of days, did it get louder (like the RB exhausts gets after a few days?)
Are you still planning on posting a sound clip?
How would you characterize the increase in volume? (On a scale of 1-10 where 10 is twice as loud and 1 is barely audible.)
Finally, what did the stock unit weigh?

Thanks and it does look very nice!

 

Well, I just posted a low quality vid here (missing currently)

I did it low quality to make it smaller, and really I think you guys are looking for sound anyway. This video has the windows down, has a hill to climb in third under some load, and has a short spirited session also.

At highway cruising speeds of say 67-70 MPH while on cruise control, it is not very loud at all. In fact sometimes I don't know it is there. Take it out of cruise, drop it down a couple of gears and hit it, and it opens up with a nice low roar. Trust me, at WOT it is making noise.

So, on your scale, humm I would say 5. When you don't have your foot into it, it sounds great, like I have HP under the hood. Coupled to my Racing Beat is a great sound.

Taking the stock in to the office on Thursday to use the same scale.

I'll make some short clips behind the car with me revving the engine and post them up.

I drive 70-80 miles a day roundtrip, so I'm at 300 and no CEL.

 

Hey Nemesis you ever go to In Tech racing up in Kent? Should check it out sometime. They have a sweet dyno setup.