CVambience

What's inside the sport decat/cat bypass pipe? How is it different from a silencer pipe?
My 1911 euro S2 had a silencer pipe installed in the place of the catalytic converter before; some parts were rattling inside the silencer so the shop replaced it w/ a cat. Now it's quiet and the car drives smoothly. But I feel the engine does not rev as quickly as it used to when the silencer was installed. Could it be the cat making the engine rev slower?
I had a Promax chip from UK in the ECU, and the comparison I made above were made both with the Promax chip.
How can I make the engine rev quicker so that the car would accelerate quicker?

Eric

L8 APEKS

If you want quicker revs, the most direct method is lightening the rotating assembly. Remove the balance shafts, have custom alloy pullies made. Get the A/C out of there. Lighten and knife-edge the crank. The single biggest gain though, while still being relatively easy and cheap, is a lightened flywheel. It will rev considerably faster. Fidanza's alloy unit is 6 lbs, or you can have your factory flywheel turned down.

CVambience

Will there be any disadvantage of replacing the factory flywheel to that of Fidanza's light wheel? Or there are only advantages? Does Fidanza makes one for the S2?

Eric

eohrnberger

As the flywheel would smoothsout the idle, I have a feeling that your idle RPM would start to wander a little bit. How much and how frequently would depend on how well the electronics can adjust things for a smooth idle as well as how efficient and accurate the idle adjustment mechanism the electronics has to adjust the idle is. IMHO.

95Juan

i'm just wondering where he got a 1911 944 S2????

CVambience

It's actually a 1991 S2. Sorry for the typo.
Eric

95Juan

i was just joking, but yeah.....get a muffler in place of the cat. unless you dont have to pass emissions....in that case- dump the cat!.