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GT86Jay

Best Cat Position?

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So thinking about this from a future plan point of view. 

 
Does anyone have any experience / knowledge to suggest if there is a 'sweet' location for the Cat?
 
I am currently running Stock manifold with a full non-res 2nd Cat Delete exhaust. 
 
Future plans are to get a new manifold. But the question is...
 
Is there any difference in having a Cat in the Manifold or the Front pipe?
 
My options are to either get a high-flow cat in the manifold, and leave the 2nd cat removed, or replace my front pipe with a cat and have the manifold catless?
 
Wondering if there are any benefits / advantages to either?

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The main benefit of manifold cats is that they heat up quicker and therefore emissions are better on start up.

 

Standard front cats are wasteful of power - ask Mark at Abbey -  I recommend you replace with a high flow secondary cat just after the overpipe.

 

Works for me...

 

Spec K

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SpecK's comments are confirmed through the HKS website, they have a catless manifold run with a catted system against a catted manifold and catless system (i.e one cat only either way) and when the cat is in the manifold the difference is about 5bhp at the top end. The HKS systems seem to do strange things at the bottom end on their graph but it could be that the engine needs some extra pressure at the low end to help cylinder scavenging...

 

Cat position comparison: http://www.hks-power.co.jp/en/product_db/exhaust/db/15165

 

System descriptions (scroll down to manifold section): http://www.hks-power.co.jp/en/product/project/hks86/exhaust/index.html

 

I'd love an HKS system but I don't want to think how much it would all cost...

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