What size HJS Catalytic Converter is needed to get rid of exhaust smell

[bmw m3 s50]

I was in the same boat. I wanted to swap the SS straight sec 1 with the catted version. With the cost of the cats and welding labor, I decided to just order the SS sec1 during black friday sales. The cats on the SS sec 1 are about 9.25" long (235mm) so they're probably the 072 p/n.

A Catted Supersprint section 1 is currently over $3k even with Black Friday sales its going to be over $2k new.

[bmw m3 s50]

Not sure because they only have a serial number on them and nothing else to identify which ones they are.

I am assuming a euro 4 cat will clean exhaust smells better due to the stricter control on emissions.

[bmw m3 s50]

Definitely not with current price of SS sec1, its gone up quite a bit…I can have a set of 072's delivered for $1100 + the catless sec1 I purchased in the GB for like $300. Still about 50% of what I saw yesterdays pricing


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Agreed.

Where can you get 072's delivered for $1100?

[bmw m3 s50]

I have the SSV1 catted Sec 1, and you still smell it.
GESI gen 2 cats are 300 cell, yet move the same exhaust flow as 200 cell. I would look at them.

I was driving behind my car last month... dude floored it and it smelled like it was catless, lol.

They are G-sport now, I think. I also thought of those cats as well. It was either GESI or HJS. The prices on GESI have gone up quite a bit putting them on the same price levels as HJS.

[fattycharged]

https://www.turboperformance.shop/en/

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[DJAM3]

A Catted Supersprint section 1 is currently over $3k even with Black Friday sales its going to be over $2k new.

I got it for about $2k + shipping. At the time I was seeing prices for the HJS cats at about $700 each. I figured I'd pay a little more and save the headache of piecing it together. Planning on selling the cattless sec 1 to recoup some money.

[Slideways]

I am assuming a euro 4 cat will clean exhaust smells better due to the stricter control on emissions.

That is my assumption as well.

There does seem to be a difference in substrate design for the SSV1 HJS, Euro and HJS 092s. The euro and SS HJS V1 appear to be the HD design, but the euro looks much dense than the SS HJS V1. It might be worth emailing HJS and getting their opinion.

https://hjs-motorsport.de/en/products/tuning/technology-check#

Euro

HJS 092


SS HJS V1

[ZHLPR]

Great thread, have been wondering the same.

To add info, these are too big: https://nam3forum.com/forums/forum/c...92997-hjs-cats

[Slideways]

+1. It stinks unless the cats are truly hot.

Been wanting to graft the E92 M3 secondary cats into my section 2, but haven't gotten around to it.

Since the euro cats have a heat shield with insulation, it could be that the universal HJS cats need something similar to retain heat and stay at operating temp. Without it, they are probably running at a cooler temperature and being less efficient.

[heinzboehmer]

Since the euro cats have a heat shield with insulation, it could be that the universal HJS cats need something similar to retain heat and stay at operating temp. Without it, they are probably running at a cooler temperature and being less efficient.

Interesting. Might be worth ceramic coating them to try and keep the heat in.

[Slideways]

Interesting. Might be worth ceramic coating them to try and keep the heat in.

https://www.summitracing.com/parts/hsp-177094?srsltid=AfmBOopcs0lVUOnXce-sEck94LO0kszx9mTngzIhzhPyzI1NbAdxmmkAM5o

#racetested lol

[heinzboehmer]

https://www.summitracing.com/parts/hsp-177094?srsltid=AfmBOopcs0lVUOnXce-sEck94LO0kszx9mTngzIhzhPyzI1NbAdxmmkAM5o

#racetested lol

I mean, that would be a super quick way to test the theory.

I'm just afraid it would become one of those temporarily permanent things...

[maupineda]

Is all about metal content load. A certified Euro 4/5 car will do a good job a removing the smell, smell is directly related to gas catalyst / reduction.

so you need as much as possible surface area coated with active metals (platinum, radium, etc.) so the more dense, the more effective but will reduce flow. From those photos is obvious that the factory mesh is more dense.

the problem I see with the size needed to fit our chassis is that it limits the active surface, that is why the factory euro cats are long to compensate for the limited cross section area.

[0-60motorsports]

Interesting. Might be worth ceramic coating them to try and keep the heat in.

My plan was to Switch back to my OE Euro Headers if i found a good set of Euro Cats and have both of the ceramic coated. Right now running SSV1's Catless.....

[0-60motorsports]

That or you can source z4m section 1.

i bang my head for not putting those on when I could. Damn things are in Mexico

Would they really fit.............with Euro Headers on an E46 M3?