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

[bmw m3 s50]

I have Supersprint Stepped V1 headers with the oversized 2.5" non-catted section 1. I plan on installing a 2.5" Supersprint resonated section 2. I am looking to get rid of that exhaust smell that comes from running no cats. I was looking at the HJS cats that they sell separately and was looking at having them welded into the section 1. The question is how big of a catalytic converter will I need?

I plan on using the 200 cell metallic substrate version but they vary in sizes. What size would I need to get rid of exhaust smell and not hurt performance or exhaust flow?

Also my car has a 3.4 stroked s54 with high compression pistons, 288/280 cams, Dinan oversized throttle bodies and CSL airbox so it is moving more air than your standard s54.

[Slideways]

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/130445-suggestions-on-aftermarket-catted-section-1-or-weld-on-cats

[bmw m3 s50]

https://nam3forum.com/forums/forum/m...r-weld-on-cats

The issue with that thread is hat it doesn't get into the actual catalytic converter size just that most used 200 cell cats which I already knew. HJS sells various diameters and lengths. I am trying to figure out which length and diameter would be best in my application.

[Slideways]

The issue with that thread is hat it doesn't get into the actual catalytic converter size just that most used 200 cell cats which I already knew. HJS sells various diameters and lengths. I am trying to figure out which length and diameter would be best in my application.

OP in that thread has already tried those and they fit the chassis. Any other one is going to be trial and error and these things cost a fair bit. You might be able to email HJS and ask them, but doubt they will know for sure. Your main concern is fitment.

[fattycharged]

I've got the same question. Those cats listed in that thread are 61.5 OD, what I see is a part number 90 95 0072 has a 63.5 OD

[Slideways]

I've got the same question. Those cats listed in that thread are 61.5 OD, what I see is a part number 90 95 0072 has a 63.5 OD

72 meets Euro 3 standards and weighs 1.7kg

92 meets Euro 4 standards and weighs 2.3kg

[fattycharged]

72 meets Euro 3 standards and weighs 1.7kg

92 meets Euro 4 standards and weighs 2.3kg

So which, if either, of these is included in the SS sec 1 for the V1 stepped direct from supersprint?


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[Slideways]

So which, if either, of these is included in the SS sec 1 for the V1 stepped direct from supersprint?


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

[DJAM3]

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.

[fattycharged]

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.

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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[Slideways]

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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Since you already have the straight V1 section 1, that is the best way to go. You'll just need a set of O2 bungs similar to Supersprint unless you go the coding route.

[bavarian3]

These worked for my stock section 1:

https://nam3forum.com/forums/forum/main-forum/member-build-journals/244030-2001-m3-journey-laguna-seca-blue-edition?p=276541#post276541

[x Spades x]

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.

[heinzboehmer]

I have the SSV1 catted Sec 1, and you still smell it.
GESI gen 2 cats are 390 cell, yet move the same exhaust flow. I would look at them.

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

+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.

[maupineda]

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