aerostreamer

Hi all,

New to posting in the forums and unfortunately my first post is about my first real problem with my S2000. I've had the car just over a year now. Love it, daily driver, go everywhere. It's a UK 55 plate with low mileage, just shy of 20k when I bought it and just creeping up to the 30k mark soonish. Then, a rattle appeared!

I've had the car up on a lift and confirmed (also with second opinion) that the rattle is coming from the cat, 99% sure its not the heatshield. I'm confident to bolt a new one in myself with the help of a friend. As much as I'd love it to be easy enough to approach honda and just get an OEM one, I'm not willing to pay the quoted £1495 from the dealer!

So I'm here for advice on how to proceed, cat seems to vary in price from £80 all the way up to the aforementioned "dealer special".

What would you guys suggest I do?

Cheers,

Alex

sillyboybmxer

Berk high flow cat. 220 usd or about. Cant be beat and will not throw a cel

aerostreamer

From what i understand, they use a magnaflow core which I can get on ebay for around £80. Local place will weld it in for me for £100. Sounds alright to me?

Car Analogy

That will work. But... will they use the correct welding wite for stainless? If not, the stainless pipes may never rust, but the welds will.

Also, make sure they weld both flanges onto the new cat. Don't let them weld the cat direct to the header or direct to the exhaust. Otherwise its a major pain to replace components down the road. Ask me how I know (idiot PO).

In the states, its easy to find a good, low mileage stock cat for cheap, since so many fit test pipes or aftermarket high flow cats. Plus the cat for any year S fits any year S (there are slight differences, but they bolt right in with no issues).

I expect things are stricter over there...

Chuck S

Good luck getting the cat off. And the shields off the cat after that. We had to cut the cat bolts off my buddies car. High flow cat, OEM heat shields, "cat back" exhaust went back on.



-- Chuck

SpitfireS

Don't wait too long with whatever you do.

The first shiftin'&rattln' core will damge / decapitate the sec. O2 sensor and they are NOT cheap.
There is one part of the S2k that is not high quality like the rest: the converter.
I mean, it works well and it IS a metal foil high flow converter, but those cores are not very well attached to the pipe.
Plus: the 2 cores have a slightly different diameter (only 1 or 2 mm difference) and they put the bigger one in front making it easy to shift back as the space between the cores, where the sec O2 sits, is the same diameter as the first.
Had they used the diameter of the second core for the space between the cores the first would still rattle but not be able to shift back and ruin the sec.O2.
Did I allready mention those sec.O2's are expensive?
Like.. very expensive?

Oh well..

B serious

Looks like a Denso downstream sensor is $183 on rockauto. It is fairly expensive for an O2 sensor. Not as scary as the last post sounded lol...but an inconvenience that should be avoided, for sure.

OP...why don't you remove your cat and inspect it. If the catalyst is busted, remove the O2 sensor and smash out the catalyst with a pipe. That way, you can reinstall it, and drive until your new cat comes in. If down time is a factor.

If it isn't busted...look for the rattle elsewhere. Something usually has to bust the catalyst. Its extremely unlikely that it just broke apart by itself. Did you have a lot of misfiring lately? Or smash the bottom of the car on something?

Depending on how rusted your bolts are, they should come out with some pre-heating with a mapp or acytelyne torch. The spring bolts don't always give you issues. The three rear nuts usually do.

The O2 sensor unscrews with some heat as well. I'd use stainless steel and anti sieze for the replacement exhaust hardware.

SpitfireS

It's not that easy to "smash out the core".
It's made of metal foil, not ceramics, it will not break into pieces.
Plus the ends of the cat are tapered so..
I've tried, with bars and big screwdrivers and you just get stuck in the foil.
The only way I got the core out was to cut the cat in half, remove core and weld it back together.
You'll need something like this to keep the length and the angles to spec. (and you need to be able to (tig)weld with backing gas...)



The picture also shows I was wrong about the diameters.

The first core is the smaller one and the space between is the bigger diameter of the second core making it easy for the core to slide back.
That's why they invented IIRC

Why does this converter have 2 sec.O2 threaded holes?
Because it's a mix-n-match of the 3 converters I have.
The back is empty and the first core is kept in place by wedges that are welded in, it still rattles a bit but ¯\_(ツ)_/¯
The sec. O2 is in the back, far away from the core.
I'll never buy another sec. O2!

vtaky0

I have a Walker sec o2 sensor from Rockauto. Wasn't expensive at all and works great.

B serious

You got lucky.

The only ones that consistently seem to work well are Denso/NTK. I would never ever use anything besides that for a primary.

The secondary doesn't do much...so as long as you get lucky enough that the heater or element resistances aren't manufactured incorrectly, then you should be fine with something besides Denso/NTK.