Hey, I have a 1987 Turbo II. Just wondering if a 3 inch catback would trigger fuel cut? I know a full exhaust would which is why I'm considering just the CB for now! Thanks

 

I am gonna watch this one as I think fuel cut has nothing to do with the exhaust or Catback at all.
Boost creep?, Yes.

 

It will induce fuel cut... Well, when boosting OVER stock boost levels. That is why it is wise to run a FCD (fuel cut defender) when running a more free-flowing exhaust on a turbocharged 13B. Plus, you should really look into porting the wastegate on your turbo. -> Aaron Cake's "EXTREME S4 Wastegate Porting"

Since it isn't wise to buy a cheap used FCD... Look into the RTek7 ECU upgrades, as they are only slightly more than a FCD and give you more options when it comes to pushing over stock boost levels. I think you'll be pleased with what they have to offer. -> Digital Tuning: RTek7 ECU Upgrades

 

Free flowing exhaust -> Boost Creep -> 8.6 psi + -> Stock ECU cuts fuel

Also, Racing Beat makes the claim that you need an FCD if you upgrade the exhaust system. But if you put on in and do nothing else, the engine will grenade. FCDs are outdated and have lovely side effects such as not adjusting timing properly relative to boost. The Rtek 1.x option is 100x safer.