Why do they recommend just replacing the cats with a presilencer? Wouldn't the gains be greater with the header/replacement/presilencer instead of just the replacement/presilencer???

"For optimum performance gains for this application, we recommend that a header be used on an engine configured with a carburetor intake system. For this reason, we suggest another suitable configuration for use on a fuel-injected engine is the Racing Beat Catalytic Converter Replacement Pipe with Presilencer combo. These components offer comparable performance gains, quieter performance and a price advantage as compared with the header/presilencer combination. These components replace only the stock exhaust components located between the stock exhaust manifold and the Y-pipe."

Just confused, that's all.

PS: If not using the header has the same gain, wouldn't using the header double the gain?

 

well the cat's reduce the exhaust flow more than any other component in the system so your biggest gain would be replacing them or getting rid of them if possible. But I would agree a full replacement would be the best option but the gain on the header replacement will probably be a minimal difference........

 

I completely agree with what you're saying, that's kinda how I've always felt, but why would there be purpose for using a header on a carbed system??? What would the difference be there?

 

I also wondered that? Why say it works better with a carb system?

 

coulda just been them pushing their Carb setup :

 

Yeah, they are just saying for even more HP use the carb set up (which does not have switching provisions for the aux ports).

They suggest the stock Fuel injection set up with the pre-silencer because of the exhaust driven aux port activation on the majority of the FCs made (150,000 S4 vs 30,000 S5).

 

the hp difference between the headers and just the bypass pipes on an otherwise stock car is very small, its like 5hp.

mike

 

That's pure bullshit. The stock ECU will adjust the increased demands of the header install. The ECU isn't optimized for power, but and S-AFC can adjust the fuel curve down for another 10hp or so.



-Ted