This guy claims that you can get +3.9hp and +15ft lbs of torque by deleting the cat and putting in a custom resonator that is approximately the same area as the cat. Has anyone with an S2 tried this? I imagine this in combination with a Rogue tuning MAF would get us very close to 968 power.

Thanks!

 

Before adding the MAF, my car made 13lbft more than factory (and no change in peak HP) with the only change being a SMALLER diameter cat...2" vs 2.25" pipe.

With the MAF installed, on the same dyno and similar conditions, its 19 lbft over stock rating peak, and even gained +14lbft over the AFM at 2400RPM.

While my car is smaller engined and less valves, the cat is plenty big for an NA car...leave it be unless it's totally clogged up.

The MAF will make a much bigger difference than exhaust work, short of changing headers...

 

Yes, but is that maf power increase a result of the maf itself or the retune that went with it. A better comparison would be same fuel and ignition maps with and without maf.

 

MAF flow and tune did make a big difference yes.

But I was trying to say that the exhaust isn't necessarily as restrictive as it might be claimed...the part the OP asked about claims +15lbft by removing the cat, but I got almost as much by using a smaller cat than stock and no other changes (including the early DME/AFM combo) with no change in peak power.