Ive been noticing the gains from it alot more now. It feels like its pulling harder. IMO Well worth the money.

 

Nice, what brand and size is the cat?

 

I asked in the other thread but I think it got overlooked: do the joints have to be TIG welded or will a normal wire feed arc welder be ok?

 

cool. is that the universal one?

 

As long as you can fuse the metal together and not leak, then it should be fine.

 

Cool, thanks!

 

Yes its a universal high-flow cat that this shop near me had. I do not know what the difference between the welds are so i can not answer your question. They reccomended putting a smaller size cat on instead of one with larger chamber. The one i have is about 10" long. The stock cat, flange to flange, measures to 17 and 13/16".

 

thats cool man does it sound any different?

 

deffinately. Sounds louder at lower rpms. And you can really feel it open up at higher rpms. My car pulls much harder now with this cat on.

 

its physically pretty big

 

I was thinking of doing the same thing with a very similar cat. The only thing that I wasn't sure about was moving the O2 sensor to after the cat. I thought it might throw a code. But it looks like it's working fine on your car. So that will probably be my next mod

 

Any low end torque loss? That's usually my experience with high flow cats and straight pipes.

 

It would be nice to have before and after dyno comparison.

 

Its really hard to tell if i lost any low end torque. A before and after dyno really would have helped but i really didnt want to spend $65 bucks for each run. At times it feels like i have to give it a bit more gas to get going, or this could just be decieving, because of my exhuast being louder now, making me think im accelerating harder. All i know is my car really pulls now, especially above 4k.

Also if anyone remembers the problem with the hesitation when vtec kicks in on hondata'd A/T's, well it seems to be completely gone now. Adding a header helped take about 75% of the hesitation away, but since i added the highflow cat, the car pulls nice and steady throughout each gear.

I really didnt think the high-flow cat was big, it was actually one of the smallest they had. Compared to the stock one, it was almost half the size.

 

Where can I buy the piping to connect the void between the cat and the flanges?

 

This was my concern as well, since the secondary O2 sensor sits INSIDE the catalyst on the OE cat. No problem for me either.

I should be getting my car on a lift this Saturday, so I'll try to get a picture of mine for you guys, including closeups of the welds and such. It looks a little different.

 

if u dont mind me asking, how much did that cost?

 

I just took it to a muffler shop, Muffler 4 Less, and charged me $180 for a high-flow cat install. Included cutting off the oem cat, welding on the high-flow cat onto the stock flange where it was cut towards the header side, then they cut a pipe for the remaining section, weld in onto the cat and the other end to the cut pipe toward the exhuast flange. They then cut a hole for my O2 sensor on the piping behind the cat and welded it there. Seemed like an easy job.

 

dang you really want to be fast huh?

hehe.

i doubt that i will ever do this mod - i dont want my check engine light comin on.

hope yours doesn't

gotta give me a ride when you come back.

 

You shouldn't get a CEL as long as your functional secondary O2 sensor sits behind the honeycomb. It's there to verify the cat is functional and sends the signals to the ECU for comparison. That's why a straight through test pipe on an OBD2 car will trigger the CEL, as the primary and secondary O2 sensor have the same reading. OBD1 cars (<1996) have only the primary O2 sensor.

 

Yeah jtso is correct, my cel wont come on. Its reading the same type of exhuast fumes as it was on the oem cat. So im not worried about that at all.

I dont see why you wouldnt consider doing that dzuy. I mean you spent like 2-3 grand on your engine alone, not like $180 would make ya broke. I dont really want to be fast, i have an a/t, but i wouldnt mind get some extra hp and i really wanted it to make my exhuast louder. I figured why not, since i had the rest of the i/h/e setup.

 

we'll see. i always say i wont buy anything but i always do haha.

if it made a big diff in your car - i'll consider it. but at this time - i have no plans on modding the engine.

and i didn't spend 3 grand modding it either.

 

Alright, I got my car on the lift this evening to do a few things and while I was at it, I took pics of my Magnaflow. Got some close-ups of the welds for JTso, hope it helps.

First, here is the OE cat. The left side of the pic is the side that bolts to the downpipe, facing the engine. Note how huge the cat is, and the secondary O2 sensor bung that places the sensor bulb deep inside the catalyst itself:


Front side, bolts onto downpipe. This is the proprietary Honda flange that you either must fabricate an analog of, or do like I did and use one from my old OE downpipe:


Rear side, standard 3 bolt flange:



Here is the Magnaflow installed. As you can see it is much smaller than the OE cat. It also weighs about 1/3:


Front weld:


Rear weld, secondary O2 sensor visible on distant side of pipe:

 

Honestly, for $160 you can't go wrong. This thing absolutely owns. The only other upgrade that is in the same ballpark is my Hondata reflash. No emissions worries and the exhaust note is only a tad louder. Why Honda uses such a heavy, restrictive, piece of crap cat on the TSX I have no idea, but I'd put the price/performance of this mod equal with a CAI and rear swaybar. If you want your money's worth from a intake, header and catback then removing the catalytic converter bottleneck is mandatory. Everyone on this board who at all wishes the TSX had more balls should jump on this. You know you want to!

Edit: If you still have your OE downpipe you can use the flange from that and be able to swap the aftermarket cat in/out at will.

I'm still looking for a straight-through resonator like JTso mentioned in my other thread about this because I'd like to see what else I can pick up from a freer flowing exhaust tract. Haven't been able to find anything yet though.

 

Thanks for the pics guys.

 

sounds like changing the cat is really worthwhile - just need some b4 and after dyno runs now

Would simply chaning the cat do more than changing the whole cat-back section?

I wouldn't mind doing something to the exhaust aswell as thats generally more warranty safe.

rmpage, do u think spending $500 or so on replacing the cat (for hp) and mufflers (for sounds) would be more beneficial than buying a catback exhaust?

 

Since I have have to conform to emmissions standards I would want to see the results of a proper emissions test before getting one of these.

 

Since the car is OBD2, there might not be any tailpipe emission test depends on where you live. In WA, all they do is to plug the tester to the diagnostics port under the dash and read codes. No need to start the engine.

 

That's a good question. With the stock cat, a catback only yields 1-2 whp. This could be due to the stock cat's bottleneck masking the advantages of a more free exhaust from the engine. I already had a Fujitsubo catback installed before I changed my cat. It would be interesting to see what somebody got doing this mod who has the factory exhaust system. I'm sure the gains wouldn't be as much, but how much less, I don't know.

To your second question, personally I would do the cat first and then see what you want or are willing to spend money on. But there is no question that a good catback will perform better than just replacing the stock mufflers. How much better is the question.

Welcome to the wonderful world of OBD2.

Any car manufacted for the USDM after Jan. 1, 1996 uses the On-Board Diagnostic II protocol. The secondary O2 sensor just after the cat constantly monitors CO and NOX levels in the exhaust gas stream and sends a reading to the ECU, which compares it to what it should be. In other words, the car is constantly checking its own emissions while the engine is running.

If levels are too high, you get a CEL. But if you don't have a CEL, you'll pass emissions, because all they do to inspect the emissions of an OBD2 vehicle is plug a scantool into the car's OBD2 access port and see if there's an error code present. I don't know where you get your inspection done but if they do it right they shouldn't stick the probe up the exhaust pipe unless they can't read the levels via the OBD2 port for some reason.

EDIT: beaten

 

I did the exact trace of the flanges last night and just about leaving to get some metal to make my own flanges. I will transfer the traces onto the metal and start cutting and drilling soon.

 

You're going to beat me to a dyno I'm sure. But I have a 5AT slushbox so I'd prefer to see the before/after on a 6MT anyway due to the higher resolution of a manual driveline.

 

In Ontario we get put on a dyno and use the tailpipe probe on all cars (unless you can get an emissions exemption for it being really old or a hot rod). They want true tailpipe emissions. They also check to make sure that there is no CEL.

 

Ah, ok. Well if there isn't a CEL you should still pass emissions. But since there appears to be some question about it, I suggest (if you do it) having some flanges made for the aftermarket cat so that you can swap it out with the OE cat if need be. That's what I did.

 

[evil laugh]

high flow cat for dzuy?