cats
 

i have a 91 n/a and i want to take my cats off, is this a good idea. i've heard tales of taking my cats off can mess with my ports and such. what is really going on?

Ya lose your backpressure and the auxillary ports don't open. Search it up and you'll see there are other ways to actuate them, but if you have a stock exhaust the pressure should be enough.

but you gain higher flow. And you can also get pipes that will take place of your cats, but still have the actuators for the 5th/6th ports. :) Racing Beat rules. Overall, I recomend dumping the suckers.

-Kanaida

Not on a 91. All series 5 (89-91) N/A models have the 5th/6th ports (as well as the VDI) activated by the air pump.

So wait... I have a '87 T2 with 3" downpipe and 3' catback with stock cats. If I remove my cats and replace it with a 3' pipe, will my 5th/6th ports no longer open? I'm thinking that this would seriously lessen performance over 3800rpm, am I right? Or, am I completely wrong and the entire set-up is totally different for turbo cars?

Sorry for hijack. :(

TII's do not have Auxilary ports. the turbo engine is a 4-port design if I am emembering properly. You do not have to worry about any ports if you are putting in straight pipes. Just make sure you have enough fuel.

Santiago

Exactly. Just make sure you watch for boost creep.

better get yourself a walbro and FCD if you're planning a catless exhaust on any TII. porting that wastegate is also a good idea

I've got a Walbro, a FCD and I'm swaping in a turbo with a ported wastegate as soon as the weather gets nice enough for me to do it. Even with the cats on I still get crazy boost creep, hehe. Though, I'm going to keep my cats on at least until emissions inspection rolls around.

Oh, and another hijack question: I have two stock turbos; the one that's on the car now and another one that's ported. The guy who sold me the car threw in the ported turbo as part of the deal. What should I do with the non-ported turbo after I swap it out? It's got about 85,000 miles on it.