Gutting the cats vs. what stage?

So I'm sure there will be some people piping in to tell me to search the forum, but I've been doing that for the last 3 hours and found a bit, but not the specific answers that I would like.

1. If I gut the 1st (uppipe) and 3rd (midpipe) cats, can I still run stock, stage 1, economy, etc. or do I need stage 2 or some sort of CEL fix?

2. If I do decide to gut the DP also, is there any way to still run stock, stage 1, enconomy, or do I need to always be on stage 2?

3. Can the UP be removed with common shop tools? I read one thread that suggested undoing the engine mounts and hoisting it up a bit - far beyond what I want to get into.

While I appreciate any info, guesses won't help me.

Thanks in advance!

So I'm sure there will be some people piping in to tell me to search the forum, but I've been doing that for the last 3 hours and found a bit, but not the specific answers that I would like.

 

1. If I gut the 1st (uppipe) and 3rd (midpipe) cats, can I still run stock, stage 1, economy, etc. or do I need stage 2 or some sort of CEL fix?

 

2. If I do decide to gut the DP also, is there any way to still run stock, stage 1, enconomy, or do I need to always be on stage 2?

 

3. Can the UP be removed with common shop tools? I read one thread that suggested undoing the engine mounts and hoisting it up a bit - far beyond what I want to get into.

 

While I appreciate any info, guesses won't help me.

Thanks in advance!

1 - Gutting the up pipe is a good idea..... if you understand the difficulties involved. But if you are only contemplating stage 1, don't bother. The CEL is cured with the resistor fix. The midpipe is the least of any problem and won't help you whatsoever.

2 - Gutting the DP will require dealing with CEL issues. However, the DP has the ONLY cat directly related to staged power. With the CEL taken care of you can run whatever 'stage' you want.

3 - Though some have involved the engine mounts, I didn't nor did many others. The critical element here is the EGT sensor.... with it removed PRIOR to trying to get the UP out of the car the pipe should wiggle out the bottom. Common tools otherwise, but there are lots of threads that detail the work and processes. The CEL, again, is cured by the resistor fix.

I suggest you do more searching, all the way back to the beginning and not just recent posts. This is stuff people were "into" years ago and any number documented their efforts, so it is all there.

Your post indicates you need a lot more reading and research before turning a wrench on your LGT.

Thanks for the quick response! I have stage 1 already and want to go to stage 2, but I still want to be able to put the AP on economy for commuting.

So just for clarification:

The CEL's on both the UP and DP can be "fixed with the resistor fix?

With the DP gutted - as long as you have the DP CEL fixed with the resistor fix, you can run economy, stock, stage 1, or stage 2?

I know that the AP Stage 2 map has a CEL fix built in, I just don't want to rely on it because I want to be able to go to economy the odd time.

Thanks again

Thanks for the quick response! I have stage 1 already and want to go to stage 2, but I still want to be able to put the AP on economy for commuting.

 

So just for clarification:

The CEL's on both the UP and DP can be "fixed with the resistor fix?

 

With the DP gutted - as long as you have the DP CEL fixed with the resistor fix, you can run economy, stock, stage 1, or stage 2?

 

I know that the AP Stage 2 map has a CEL fix built in, I just don't want to rely on it because I want to be able to go to economy the odd time.

 

Thanks again

Only the UP CEL is corrected with the resistor. The DP need the AP.

With the DP gutted and the AP married you can run whatever map you can load with the AP, stage whatever.

With the AP married, and an appropriate Base Map flashed to your car, that CEL as well as others are turned off. The Economy Map is a Real Time map, and as such has no influence on the Base Map parameters. This means that with the AP and Cobb maps installed you can run any of their Real Time maps such as economy or valet, etc. and switch back and forth without worry you will throw a CEL.

It might be good to read all the Cobb data on the AP.

One more comment about your gutting the UP.... don't do it. It is a BIG PITA that done incorrectly can destroy your turbo, engine, or both. Get an uncatted variant and install it (with factory gaskets!).

And gutting the mid pipe will net you a smelly exhaust you won't be able to ignore, but not any discernable power.

Thanks SeeeeeYa! That was exactly the info I was looking for!

I'm not going to gut the midpipe cat or the UP cat, but I will gut the DP and replace the UP with a used aftermarket one. Thanks!

I suggest hitting up nasioc and trying to find a used STI up... They are catless and a direct fit, they work great! And, its much cheaper than getting a different brand like turboxs and invidia, etc... There really isnt a difference in up's for the most part. Best case scenario would be a couple of HP and TQ diff... But thats best case. So stick with a good used STI up, they'll run you $50 or less shipped to your door.

Good luck with the install, stage 2 is very nice

when i did my up in my wrx, i found it easier if you just remove the manifold at the same time and the up will drop right out

The only thing I can add is to remove the entire manifold assembly as one piece, don't just take off the exhaust manifold for one side. By not disturbing the crossover pipe and shielding you eliminate the issues many have had that did it that way. Just the six manifold to head bolts are involved after disconnecting the O2 and UP (and of course its EGT sensor).

It is a bit of a heavy piece, but I did it alone in my garage just fine. I suggest, as always, new factory gaskets, a little copper spray (holds things in place while you work), and a GOOD TORQUE WRENCH. The block's aluminum is almost as soft as butter, be precise when torqueing anything to it.

On the other hand, and don't quote me here, I used more than factory torque on the UP and DP nuts and bolts (it's an experience thing, if you don't have it, don't do this), along with copper spray on gaskets and bolts. Numerous removals and installs of these components have resulted in zero leaks.

1. If I gut the 1st (uppipe) and 3rd (midpipe) cats, can I still run stock, stage 1, economy, etc. or do I need stage 2 or some sort of CEL fix?

Sorry to nitpick but I have to point out that it's not the 3rd (midpipe) cat you would gut if you're planning on keeping one of the stock catalytic converters and going stage 2. It would be the 2nd one in the downpipe directly aft of the turbo (the first being the one in the up pipe before the turbo).

Yes, from your other posts I gathered that this is indeed what you did, but I just wanted to make a point to correct you here in case other folks are reading this and contemplating doing these modifications.

Otherwise these are some very good questions. Thanks for bringing them up.

Cheers!

gutting the dp right now should i gut that last cat if im trying to remain stock looking to the dealer?

Gutting will not affect how a pipe "looks."

But, no, don't gut the last cat for multiple reasons. One, your exhaust will STINK if you do. Two, you'll gain nothing, except the stink.

Gutting will not affect how a pipe "looks."

 

But, no, don't gut the last cat for multiple reasons. One, your exhaust will STINK if you do. Two, you'll gain nothing, except the stink.

thats what i did i only gutted the first two and it worked out great.