Resonated & Sport's Cat Vs Non Res No Cat Help ??

Charlie23

Registered User
Hi Guys,


Just bought another S3 (No 8) lol and its come with a Full Milltek exhaust, but has a Sports cat and resonator.
I'm going 2+ again like usual but want to know if anyone has noticed any difference in BHP etc between having a Cat & Resonator as I usually go for No cat and no resonator and the Gains and drive are superb.

Thank you :)
 

prt57

Registered User
I think it is more to do with the overall design of the system rather than if it has a cat and a resonator. The 100 cell cat in a BCS system is huge and so poses very little restriction to the gas flow. The resonator is not restrictive. Worth having if you are to avoid motorway drone. Reading reports on other forums suggest that the Milltek system is not the best flowing overall anyway but that is what you have on the car. The dyno figures may be a bit lower but whether you can feel it is questionable. The overall health of the engine probably has more effect and the efficiency of the other hardware to take the car to stage 2+
 

samuelh_888

Registered User
The back box on the Miltek is the restriction.
 

Charlie23

Registered User
Hi Guys,

Thanks for the replies.

I have always had Miltek always kept with what I know and the cars have always produced some good figures and performance, But I understand if the design is a problem and restrictive and there are better out there. The Car came with the exhaust on it so pointless changing it just wanted to see if anyone had noticed much difference.

Cheers
 
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