Has anyone gutted the pre-cats or is this not possible?

 

very possible, is it a smart idea though? NO

those cats are not cheap FYI


be easier to buy pre-cat replacent pipes

 

^this.

 

Pretty sure it's been done. Left alone though, you'll throw a code and get a permanent CEL.

 

PERMANENT CEL! How do the pre-cat deletes defeat the CEL?

 

Not sure exactly how they're doing it, but there are various methods to defoul and/or fool the O2 sensors.

My point is, if you ONLY gut the cats, you'll throw codes/CEL for emissions equipment failure.

 

This has been covered quite a few times, its easier and more "cost effective" to just replace them with the deletes. Those cats are not cheap and good luck selling your TL without them in the future.

 

let alone being to sell them separate when the car is sold


edit: the PCD's

 

They get rid of the CEL's by using a "defouler" for the downstream 02 sensor. The defouler simply moves the downstream O2 sensor out of the exhaust gas stream so that it reads lower levels. Some defoulers are just short extension tubes while others are "L" shaped for tight clearance issues. I'm pretty sure you can purchase just the defoulers from places that sell PCD's. For some vehicles I've even seen small devices that eliminate the downstream O2 sensor entirely and replace it with a plug in the exhaust and then a plug in resistor module that simulates an "all good" signal. I haven't seen them for the TL but then again I haven't looked either. They were available for my old Camaro Z28 though.

 

Thanks, jpgayan, that answer's my question.

 

Im confused. I was under the impression that the pre-cat deletes removed the pre-cats. How is that any better? As far as selling the car, it still will not have pre-cats on it if I go with the pre-cat deletes.

 

What he means is, if you gut the cat, you get something like a PCD, but you've ruined the cat.

OTOH, if you get PCD's, you get the gains, the defoulers, and later you can sell the PCD's and put the car back to stock. Less "wasted" money.

 

I understand completely, thanks Bearcat

 

A gutted cat is not the same as a PCD. Even with the cat gutted, the empty cat is still not free flowing. When I removed my oem cats to install the PCD, I was amazed at how small the diameter was in the necked down area (red circle in pic above) of the oem cats.

 

Beat me to it.

Gains from gutting stock primaries will not even be close to PCD's. No sense in destroying $800 worth of cats.

 

Agreed. They could have tried to put a radius on it instead of having the exhaust hitting a wall. I'm somewhat surprised it does not hurt performance more than it does.

 

Don't gut the cat

 

Thanks, guys, gutting the cats are no longer on my list of mods-PCD's will be the weapon of choice.

 

 

good choice. you'll love them. i just installed them over the weekend and i keep finding excuses to drive my car.

if you're doing precats, you might as well do a jpipe and catback exhaust. no reason to put the pizza in the oven unless you actually get to eat it afterwards.

 

richies V3 to be more exact, to also get rid of the 3rd cat



and

 

SharksBreath,

How do you like your PCD? How is the sound? Power? What were your first thoughts when you first started the engine, first drove it, first wot? Did the special oil help with making the oem fasteners easier to break loose?

 

^ Never mind. I found your write-up in your progress thread.

 

Free flowing...........

 

It would be a better picture to shine a light in each one.

 

^ I agree.

That picture does not do justice to the PCD.

It is not the inlet & outlet diameters of the oem cat that is restrictive. It is a few inches inward from the flange on the inlet side (see red circle in my pic above) of the oem cats that necks-down to a ridiculously small diameter, creating a lot of flow restriction.

 

For the amount of work involved with taking the cats out, gutting them, and re-installing, it would be worth it to just get the PCD's, which have the larger diameters anyways.

 

Gutting cats was really common in the Subaru world because the uppipes themselves were not inherently restrictive. I ran a gutted uppipe (similar to precats in the TL) on two different cars with good success. It is a messy, shitty process to smash out the cat though and I would not recommend breathing in the dust from it. It's easier and safer to just pick up the PCDs from Richie and save the stock precats for when you sell the car.

 

I gutted my cats on my 04 acura tl and now my car runs like crap it floods itself out and im using o2 defoulers too

 

Did you put the defoulers on the upstream sensors too? Upstream control fuel, downstream monitor the cats and don't impact fuel. Only down stream sensors need defoulers....

 

Yeah, that doesn't sound right.
The car should run great without them.