Cat Question

[SouthBaySurfer]

Happy New Year.
916 is fairly stock; only mods are a K&N cone filter, a TT 92 octane chip, a thermostat, and 100# valve springs. What kind of gain should I expect if I loose the cat?

 

[cottonpicker14]

Not sure, but you will definately get a call from the ASPCA

 

[DaJoker]

1 to 2 tenths and 1 to 2 mph. Only gained 1 mph with mine but I'm sure others will have different experiences. It will sound ALOT different!

 

[RatFink]

What's your boost at WOT? Less backpressure will help spool up quicker, it maybe will pick up a bit of boost pressure, maybe like .5 of a #.
Instead, Cut a hole in your downpipe, then you can keep your cat for emissions testing and then open your cutout for some REAL performance gains. If your town doesn't test emissions, then I would put a test pipe with a cutout in place of the cat.

 

[Scott89TTA]

Happy New Year.
916 is fairly stock; only mods are a K&N cone filter, a TT 92 octane chip, a thermostat, and 100# valve springs. What kind of gain should I expect if I loose the cat?

I had the same setup on mine but latter added a 3" DP with dump, test pipe and electric cut-out. With the cut-out open I gain about 4# boost...my stock adjustable waste gate accuator will not adjust low enough for me to run the dump wide open without going to 18-20# boost and getting a good bit of knock. Porting the waste gate hole may have fixed it but a new turbo, alky, and a few other upgrades will be fixing it much better

The cats from that time frame were pretty restrictive...unlike todays hi-flow cats. John Pearcy (John's Performance) claimed that the 3" dp and no cat was worth about 40+ hp on these cars if I recall correctly. I would think the cat is the biggest restriction and removing it would be worth while gain. Just keep a spare for emmision test time...that's what I had to do to pass. I have a 3" hi-flow cat from Summit that I can swap in and out with my test pipe.

 

[SouthBaySurfer]

Yearly inspections here require an emissions test, so I'll have to switch when that comes due. About 17 to 17.5 lbs. of boost at WOT. I'd like to see it spool up a little quicker.