drago86

Well my car finally passed CA emmisions. The only problem stopping it was the front nipple on the acv had no vacume (as per a forum members suggestion) when it having vacume sends air to the cats and ports.

I purchased the duel catalytic converter system from summit racing for ~160 dollars, plus 20 dollars for second day air shipping. The cats came very quickly. Upon reciving them, i opened the packae and was pleased with them. The pipes are all stainless steal, as are the cats. The converter bricks are nice and fre flow looking. however, the pipes do not apar to be manderel bent, the pipe is slightly restricted as it turns down from the exaust manifold, but it looks like less then a .25 restriction, and it is not wrinkled or anything. Also the flanges do not appear to be stainless steel, as they had a few surface rust spots out of the box. It came with gaskets too, which i wasnt expecting, and there nice and thick.

Installation + fitment
Installation is easy, drop the old cats, put in the new, they just bolt up. i did have to purchase two 10mm(shank size) nuts bolts and lockwashers, because the stock main cat used studs. The hanger location on the catco's isnt even close to fitting, so i left it off. And the split air pipe is forced forward to fit, it's about 2-3 inches to far forward. Other then that the fitment is good. I had some reservations about the floating flanges, but they all sealed up tight w/ no leaks. The catco system also feels less then 1/2 the weight of the origonal system.

Smog:
With no air goign to the cats or exaust ports from my ACV mix up i passed CA emmisions at idle, but failed CO at 2500 by .2 (1.20 max, 1.44 measured)

With air going where its suppost to i passed with flying colors:
idle:
HC: 9ppm
CO:0.00
2500:
HC: 3ppm
CO:0.00

This was on a CA Smog Check 2 station, with out the rollers yet.

Performance: Well it feels faster, but that doesnt really tell you anything. Top end seems alot better, other than that i cant really say because i dont have money to dyno it, so you'll just have to go on my butt dyno.

Sound: The sound is great now, really deep. I have blow out rear mufflers, and its quite loud with the hi flow cats in. The old system with a big exaust leak was alot quieter. The sound is also really really deep, and powerful sounding, i like it alot. My only gripe on sound is there is a resonance at about 2500 rpm, that gets annoying when trying to keep it quiet around town, it gets REALLY loud at 2500, but its a deep, nice loud.

Durability: Im unsure as of yet. The gaskets have held up so far, and it hasnt clogged or burned out yet, but it hasnt been on that long. When i put the header back on Im going to purchase a catco to use as a presilencer, that will be the real durability test, as this pipe will probably be used soley for passign emmisions.

Overall im very pleased with the catco cats, and will use them again.

HAILERS

Well that's still a puzzlement about the lack of vacuum to the nipple above the acv at idle. There is a possibility that the problem is ECU related. Have you ever noticed that where they describe setting the tps using the two light method how at one time the light comes on then goes out as you set the tps????? Its not voltage that is coming and going, its a ground that is coming and going to turn the lights on. That same ground that turns the light on and off is spliced into the Relief and Switching solenoids. That ground signal is what determines if the Relief solenoid opens or shuts which in turn determines if there is/is not a vacuum at the nipples above the acv.

Two lights......when one light is lit, its respective solenoid is activated. When the other light is lit, then the other solenoind is activated.

At idle, the Relief solenoid should be getting a ground and the Switching solenoid should not be getting a ground. But both should be passing a vacuum to the acv, because.......the two solenoids are physically different. Take a look at them. If they are the samel...one is in the wrong place.

drago86

my solenoids are all screwed up from the previous owner. I put hard vacume on the releif, and hard vacume on the switching valve to pass. A forum member had suggested no vacume on the switching, which is reverse of what it should be to pass. I discoverd it when i checked the o2 sensor voltage, and it was .8 at idle. with vacume to the switching ( nipple closest to the front of the car on top of acv) it went down to .02. I need to go get the proper solenoids still.

abarlas

what was the part number from summit racing? I'm in the market for a new cat system.

Boost Lee

iTrader: (3)

CTO-4489 Mazda: 1986-92 1.3L RX7, 1986-89 1.3L RX7 turbo, 2-1/4 in. flat flare inlet and 2-1/4 in. flat flare outlet $100.69

CTO-4689 Mazda: 1986-92 1.3L RX7, 2-1/4 in. flanged inlet and outlet, direct fit, catalytic converter $165.39

Fingers

The idiot mazda dealership that replaced the intake gasket for the previous owner last year reversed the vacuum lines on the front of the TB, and as a result, the releif solenoid wasnt working right.

Check your lines see that everything's where it's supposed to be.

CarmonColvin

I am having noise issues on my '91 n/a car. It has full stock exhaust but is way too loud to drive comfortably. I am 99% sure the previous owner gutted the stock cats.

When compared to stock and using a stock cat-back exhaust what difference do these Catco cats make for the sound level? (I have no concern about performance, I am looking for near stock noise level)

CarmonColvin

Yesterday I received my Catco Cats from Discount Converter in Houston, TX (drop shipped from Catco in Hobart, IN)

When I ordered them I talked at length with a man at Discount converter. He seemed to know what he was talking about, he explained that all aftermarket cats sold in the US have cores made by Dow Corning and they all had (x)number of grid squares per inch (I forget the number). And that all OEM cats sold in the US have a different (higher) amount of grid squares per inch. So legally ALL aftermarket cats sold in the US could be considered "high flow".

I asked about fitment for a '91 RX, non turbo and was assured it was a bolt on process.

First thing I did was weigh the new converter assembly. 13lbs 2oz, my stock assembly with absolutely no cat material in them weighed in at 26lbs 5oz. I imagine a fully working stock cat assemly would weigh 30+lbs. It is a nice looking assembly with crush bent pipes. Performance is not my goal so the crush bent pipes are not an issue for me.

My first issue: The floating flanges are terrible and the gaskets supplied had to be modified because the holes did not line up and the gasket would of seated off center of the opening. In the end I did get both to seal completely with out leaks but it was not easy.

Second fitment issue: The original main cat has studs out the back of it where the cat-back system bolts up. I had to dig around my garage to find bolts & washers large enough to use.

Third fitment issue: The exhaust hanger was not even close. If it had been welded upside down from its current orientation I might of been able to hang it. Right now nothing is attached to it. I don't have a welder so this will require a trip to an exhaust shop.

Fourth Issue: The fresh air hose inlet is ~5" too long. Luckily I had a spare fresh air hose from a parts car that I cut out a 5" section and joined it back together with some 10AN braided s/s hose I had. And the rod type hanger for the front part of the fresh air hose does not exist on the new cats. Not a big deal but I think I heard it knocking around on the drive to work this morning.

"Direct Fit" by any stretch of the imagination does NOT mean, Needing bolts, not using hangers, and modifying original parts. This is NOT an acceptable description.

Now for the good news. When I started the car it was silent compared to the gutted out cats I had before. The car was almost undriveable with the gutted cats and now for the first time it was a pleasant drive to work.

And more bad news. After 5 minutes of idle the front of the new main cat started to glow. I found that it did not glow after hard driving and I was not able to check it this morning. The glowing might of been a one time thing with them being new and burning off oil and crap from the inside of the tubing.

Considering the price as long as you know what you are getting into when buying these "direct fit" cats these issues will not be a big deal.

DaleClark

iTrader: (55)

I'll be interested to see how these do in the long haul. I've seen MANY RX-7's with muffler shop exhausts with Catco cats, and EVERY one of the Catco cats were clogged badly.

But, the newer ones might be a whole 'nuther story.

Out of curiosity, does it just replace the main cat, or does it go from cat-back to manifold? As in, does it replace the pre-cats with pipe?

Dale

j9fd3s

iTrader: (3)

yah ive seen that too

mike

CarmonColvin

The system I received replaces everything from the exhaust manifold to the cat-back exhaust. It has a small pre-cat and a medium sized main-cat.

Here is the pic of it from DiscountConverter.com. Mine looked exactly like it.

DaleClark

iTrader: (55)

Thanks for the pic, Carmon. That's not a bad deal for someone who just needs to get something on the car to pass emissions with!

Dale

ZoomZoomH

got mine installed a few days ago as well. Exhaust definitely doesn't smell as bad as the old stock cats did.

the $1 paper gaskets I got from Advanced Auto Part burned through and I had to drive around with a bad exhaust leak for a few days.

thankfully I was able to replace them with OEM Mazda gaskets yesterday. So far I THINK there are no more leaks (after getting toasted with exhaust for 3 days EVERY burning smell smells like exhaust lol)

gonna try to pass emission this weekend! (cross fingers)