NYsNumba1Man

iTrader: (1)

Since i've had my FC its had an exhaust leak, nothing TOO bad that i had to get it fixed and it passed emissions with the leak. A couple days ago i hit a bad pothole/lifted manhole cover and i heard a LOUD CLANG; after, it made a terrible exhaust note and was about 12 times louder that usual, as well as it back firing after every hard pull. I'm 99% sure that i destroyed 1 or more cats (they were already rusty and leaking) but i can't live with this.

I was looking at bonez high flow cats and found this
http://www.rx7.com/store/rx7/fcexhaust.html#Nonturbo
Which one would i need? Would i also have to buy headers?

Stock exhaust system with an hks silent hi power catback.

Also, does anyone have any experience with them? Before i hit the pothole i liked my exhaust note minus the slight exhaust leak. Will it sound the same? how well does the bonez high flow cat quiet the exhaust? will my aux ports still work?

Scrims

iTrader: (2)

bonez cat is a decent replacement on the cheap. Might be a touch louder than stock, but not much in my experience. Keep in mind that the bonez cat is not as good with emissions as the stock one, so might run into trouble there.

Look underneath your car before you buy so you know exactly what broke. If it's the pre-cat (like what happened to mine) you can just buy headers (gunna be louder) or find a replacement in the classifieds.

NYsNumba1Man

iTrader: (1)

If its headers then it shouldn't be too bad, i'll just pickup racing beat headers.

Also i forgot to add, i smell gas/exhaust through my vents sometimes, and i'm pretty sure my headers are leaking. Could this smell be from the leaking headers? or is my pulsation damper going?

misterstyx69

iTrader: (142)

The car will pass without the two pre-cats on the exhaust.
The only thing that the new cat requires is that it have a Split air pipe on it,for aux port activation(s4).
I had 2 cars with an aftermarket pipe made up to replace the precats,and they both passed with a Stock style Cat on as a main cat.

beefhole

iTrader: (29)

NY no longer does emissions testing on the rollers. But they will "look" for cats and air pump.

GuiltySoul

iTrader: (7)

funny i just installed the Bönez Superflo System tonite and it works great! I have a 2.5" CorkSport exhaust with stock headers and this sounds like what an fc should, not loud and annoying but just right, its no Racing Beat but good enough for me. The only problem you might have is the split air pipe as the Bönez cat does not have a flange to connect to the air tube so I had to get 1 welded on and these wont work with aftermarket headers as this is meant for the stock exhaust manifold as the Bönez Superflo System is long enough to connect to stock manifold not short enough for long aftermarket header tubeing. But as Scrims said check it 1st before u you spend money.

Scrims

iTrader: (2)

My bonez came with a little length of high temp tubing so all i had to do is use a pipe cutter and take off the flange on the split air pipe and connect the two ends and tighten down with some hose clamps.

Only Racing Beat headers are longer than the stock manifold. Others, like corksport, will bolt up just fine to the stock, or aftermarket, cat.

daviddeep

iTrader: (4)

I had a Bonez cat on my old NA and it passed Pennsylvania emissions easily for the first couple years. It failed Maryland emissions when I moved there; at that point the cat was five years old. I replaced it with a new cat from Random Technology and it then passed easily. The car did have a mild streetport which supposedly will shorten the life of a cat.

088

iTrader: (9)

Passed my s5 na track car with streetported engine in California twice, using an old Bönez Superflo System (single cat + resonator). At the time, the car had a functional air pump, split air pipe, and ACV, but no pre-cats. The sound level (inside the car and outside) was equivalent to having a minor exhaust leak, at most.

The first time included an idle test, with marginal results. The car had a terrible idle, bouncing, quite randomly, between 500 - 1200 rpm. Drove the emissions tech nuts.

Second time was a 15 mph test on the rollers, and it passed by a decent margin.

About 3-4 years later, I sold it on craigslist. By that time (early 2011), California emissions thresholds were lowered, making it relatively difficult to pass old rotaries. But, the buyer also passed, and that's with a cat that had 6+ years of use.

IMHO, with a new Bönez unit, functional split air delivery, and decent idle, you should be able to pass.

For $20 more and extra assurance, you could buy the Bönez Dual Cat System. It might be overkill, but two cats are better than one, I suppose. Make sure you spend the extra buck or two on new gaskets at your local shop, plus new fasteners if your old bolts are too rusty or damaged (otherwise you'll be back where you started with a possibly louder exhaust that may fail emissions if your state checks for leaks (too much oxygen at the tailpipe sniffer)).

Bönez cats include a split air inlet (look at the enlarged pictures, e.g. the fourth one down on that page). A "high-temp" rubber hose may deteriorate after a while (several months or longer, depending on your driving conditions). I think the original Mazda cat had a small flange on the air inlet that would mate to a similar flange on the split air pipe. A competent exhaust shop should be able to fab/weld these flanges if you wanted to trouble yourself with such a project.

Rotary Performance haven't updated their website in a few years, so make sure you call them for availability, price, and ordering. And if they still sell those units, please post your experience here, for the benefit of others.

blockedwizard

I just replaced my whole cat system with the Bonez high flow for my 87 NA.

The sound is deeper and actuallty quieter, maybe because my cat was leaking.

Bolts right up to the exhaust manifold and you cut you air pipe that goes to the air pump and connect with the rubber hose provided.

I also ordered the gasket and bolt kit, and it was missing some like 2 bolts, but other than that I love the result, no more tin can sounding exhuast.

nycgps

iTrader: (4)

i passed NY roller test 2 years ago with just a magnaflow cat.

they dont do roller test anymore ? you sure ?

beefhole

iTrader: (29)

^Yes. No more roller/sniffer test in NY. Just a "visual".

NYsNumba1Man

iTrader: (1)

Thats good news then, i thought they still had the roller test.

When I have the time/money i'll take it to a place to lift up and check it out, if i have to i'll buy the single cat from bonez and connect it to my stock exhaust manifold and then to my hks catback.
Hopefully everything fits nicely and wont involve any/much improvising.

Thanks for your help!

nycgps

iTrader: (4)

really?

I guess that means "EVERYBODY" will pass 100% then.



why don't u just get a Mangnaflow cat ? mine works fine, it has 5 yr warranty. I got it for around 70 bux after the reward credits at Autozone, if it dies or whatever just bring it back to Autozone, free replacement (within warranty)

vrracing

iTrader: (1)

The Rotary Performance folks are really helpful if you call them on the phone. We have their cat system on the Tii vert and pass TX two-stage sniffer tests easily.

I called them a month or two ago about new cat/midpipe gaskets (AutoZone, Orreilys and Advance seem to specialize in pine tree air fresheners and dont carry 2.5" 2-bolt exhaust gaskets) and he was earnestly trying to find the cheapest way to go; individual gaskets or the gasket/bolts combo! I told him it was pocket change but he really wanted to make sure he got me the best deal. If you have questions about the system give em a call

NYsNumba1Man

iTrader: (1)

The magnaflow cat is good? I've always heard good things about bonez so i thought i'd go with that. I just need a replacement for my busted cats that sounds good, will let me pass emissions, and be able to activate the aux ports

088

iTrader: (9)

If your aim is to pass a visual exhaust system check then you should *not* install headers until after your test. Here in California, the level of scrutiny varies from one smog station to another, so you can sometimes get away with a mod or two; but then the subsequent sniffer test won't lie. In your case, since they *only* perform a visual, I would imagine the smog techs would catch something as obvious as headers.

Exactly. For the "streetable" collected system (Part #16130 / 16131), you'll need the Bönez cat with correct length connecting pipes that bolt up to the stock or aftermarket catback, also available on the Rotary Performance site. If you later on decide to remove the cat, you either have to buy the pre-silencer (Part #16408), or fabricate a custom connecting pipe. With the "road race" dual, uncollected header (Part # 16128), you'll have similar challenges, unless you buy the entire RB dual system. This one isn't really intended for street applications and you'll need to get creative to incorporate a cat (e.g. fabricate a collector, bolt to cat, then to your catback.)
Keep in mind that any header system will significantly increase the sound output, depending on whether you keep your cat and the design / condition of your mufflers.
As others have mentioned, you have other options here. The Racing Beat and Corksport are considered "short primary" systems. If you can do your own fabrication or are willing to pay a good exhaust shop to do the fitment for you, you can also look into longer primary systems. I recently ordered a custom system from Defined Autoworks, which looks to be on the order of 55" to 60" measured straight end to end (actual primary piping is longer, I think). It's a collected system, which means I'll need a custom connecting pipe to bolt up to my Mindtrain duals -- that pipe could incorporate a cat or muffler if needed. It all depends on your budget and goals (power vs. streetability, etc.). Squeezing maximum power out of a stockish port NA would take you on a path with many incremental mods, each of which will add a few hp at a time. Exhaust system is a good place to start. Then you also have to consider whether you are willing to compromise low- or mid-range power for max output at high rpm. But I digress.....

A leak in the exhaust manifold, or *any* part of your exhaust system, including the connections (i.e. deteriorated gaskets) can contribute to this. Also, check out all your exterior seals -- door seals, hatch area, inner and outer rubber shifter boots. Gasoline smell under the hood could be any part of your fuel delivery system, FPD, deteriorated fuel hoses, etc. Definitely something to be checked out.

The Bönez cat systems are reputed to flow fairly well and stand up to the punishment of a rotary's exhaust stream. I used to switch between a straight pipe and Bönez cat and didn't see much difference, although I don't have dyno comparisons to demonstrate more precisely. Then again, my car was making less than 100 hp at the time due to some elusive fuel delivery issues, so I can't claim to have a good comparison on a properly running car.....

Jdrift

Thanks for the info guys. And the link to Bonez. I never heard of the site, but it seems that will be a route i'm probably going to take. I have a rather eye watering exhaust smell if you were to stand behind the car. I'm running through Delaware inspection tomorrow and they do a two speed idle test as well as a visual check. So, we'll see how it turns out. The car doesn't smoke badly, and it seems to run pretty well.

Driftology

i know this is an older thread but i just wanted to add that the racing beat headers to bonez cat with the stock catback is pretty loud. i just had that installed due to a clogged cat. the power you get over stock is amazing tho! and just my luck on my way home from the shop a cop pulled up behind me and seemed interested in the noise. i almost stalled it trying to baby it off the line. now its time to get rid of some of this noise

mwalters

I have an exhaust leak and its coming from the cat. I was looking for a replacement. Good info guys.

MadScience_7

On that first link, all the N/A cats look like they're extended to replace the pre-cats too. I have CS headers and just need a drop in replacement for the main cat. This cat looks like a stock fit, but it's listed under the turbo parts. Will this work for an N/A? Or should I just get a blank cat and find a shop to swap the flanges over from the blown cat?

Thanks
Andy

ColinShark

I have the bonez cat replacement pipe on my N/A, and I like it. It's a bit louder than stock, but that's expected when it replaces 3 stock cats with 1 high flow cat. Aux ports work with it.

alex1206

iTrader: (3)

does anyone have a presilence and the bonez cat?

I currently have the presilencer but because of the smell of fuel in stop and go traffic I want to switch to the bonez cat. I have the complete rb system.

Did the bonez cat help with the fuel smell???

Thanks in advance!

spivey3

Any cat should help with fuel smell.

jackhild59

iTrader: (7)

If your car is running right, a cat will tame the fuel smell.

If your car is NOT running right the cat will help with the fuel smell until the cat burns up, which could be a matter of days.