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gutted oem down-pipe vs. aftermarket cat-less downpipe


turbotool

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  • 4 weeks later...
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I heard that 07 and up have no cat in the up pipe? Is this true?

 

I'm going to get the AP for my otherwise stock 07 LGT. How tough is it to remove the down pipe to gut it? I searched but didnt see any how to info.

 

So is the downpipe the only thing I need t gut on my car to run a stage 2 AP map?

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That's what I did and you're ready for stage2.

 

Down the road if I decide on more power I would probably get a USED catted 3" DP. Even used we're talking $400.00. :eek:

No the MR DP full length cattless is only $195 shipped.

Racer X FMIC for '05-'09 LGTs, '08+ WRX and '10+ LGT,'14+ FXT, and '15+ WRX TMIC Racerxengineering.com
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My main concern is/was smell in the cabin. Gas, rotten eggs, etc. I have the catless flex uppipe, have had it for months but never installed it so I wouldn't pay overlapping labor for the DP down the road. Have kept lurking the boards for a cheap high flow catted downpipe. I wanted to eliminate the possibility of smell, although I wouldn't mind some noise :)

Yesterday I was at my shop, they do custom work and both mechanics that I know told me "dude, just gut the OEMs".

 

So, besides the uppipe cat for the pre-07s or whatever, the downpipe cat, how many are there left? Anyone have smell issues with the two dp/up cats gone?

 

So then the consensus is that, for a standard Stage 2 set-up on the stock everything else, there really aren't many gains from an aftermarket DP? If so I'm just gonna gut my stocker and call it a day :)

To be sure, for a Cobb Stage 2 map all is needed is a catless up/dp or hfc?

 

If I may, allow me to run down the "to do" list for Stage 2 and please correct me if I am wrong:

-catless uppipe

-catless downpipe

-remove sensor in uppipe, buy a resistor to avoid CELs

-reinforce the stock TMIC to avoid bent/broken tabs

-what to do with downpipe sensor?

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I have a question on this as well...

I'm getting(in the mail right now) an 05 catless STI UP and planning on just gutting the OEM DP. The midpipe has the final 3rd cat correct? Also, will the STI UP have a sensor bung or do I need to buy a resistor? Also wondering exactly what I need to buy and where... lol... I'm kinda dumb bout that part ;)

 

Also, gutting the DP, Im worried about damaging the pipe when I'm doing it... How easy does the cat come out, chance of poking holes in the pipe pretty high? I dont wanna screw myself if I jack up my pipe... lol

If I pass you on the right, I'm flipping you off.
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Not sure if the STI up has a bung...I think it will not and you will have to do the resistor mod. I purchased a gutted stock up and just re-installed the sensor. There is a small chance that the sensor could break up, but I think I am safe.

 

I also gutted the stock DP (shorty section) myself..there is really no chance of you damaging the pipe unless you use some superhuman force..it is a solid piece. I gutted mine in about 20 minutes using a really big screw driver and a small crow bar..I wailed on it pretty good getting the last pieces off, and there is no visible damage.

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If you manage to puncture the pipe, then you should either consider a Superman costume or replace the pipe altogether as it was rusted inside out to all hell :)

Spec B, you're betting a lot on that "I think I am safe" for $3 or however much that resistor costs. If the sensor breaks down, it will get sucked up by the turbo and it will get destroyed pronto.

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im running at catless up and downpipe. i still have the main cat and i get a slight rich odor every now and then in the cabin. i also broke a tab on the intercooler already after less than a month on stage 2. just got finished jb welding whats left of the end tanks. im gonna start saving for a avo ic
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Spec B, you're betting a lot on that "I think I am safe" for $3 or however much that resistor costs. If the sensor breaks down, it will get sucked up by the turbo and it will get destroyed pronto.

 

I know, I know...I think I secretly want it to happen so I could upgrade the turbo without getting the wife's "stare of death". :)

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Haha. Stare of death. Teh shudder! I know what you mean all too well :(

You know, before we got married she loved it when I'd gun it. Now she gets upset at me. Go figure. I can't wait to go Stage 2, I won't say anything for like a week and then one time I'll romp it out of the blue to freak her out :D

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I cant wait to go stage 2 either... Just got the STi up pipe in last night, gonna have a friend weld some re-enforcement on the heat shield. Got the AP coming in the mail, probably be here tuesday. New gaskets for the UP ordered today, should be here tuesday as well... Gutting the DP (might do both cats, not sure yet though...) When you gut the OEM DP, you gut the first cat right? Closest to the engine... Leave the last one? Anyone have both gutted? Experiences?

Cant wait to get it all done... Prob next friday/saturday... :)

If I pass you on the right, I'm flipping you off.
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How bad is the stink with both cats gone? And gutting the first cat will bring on the stink as well? How bad :S

Stink never was bad to me atleast. I went from a competely gutted DP to a catless MR as well.

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Wait, is the problem inherent with gutting stock pipes, or are you just talking general terms? My 95 Sentra has the stock exhaust pipe and it's seen nothing but Minnesota and Nebraska winters, which means plenty of salt.
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I would/will go aftermarket eventually... But seeing as money doesnt grow on trees in my area, I gotta stick with the cheaper options for the moment.

If I had my ideal setup I'd say a grimmspeed UP and a highflow cat COBB DP... But for that kind of money I can buy a lot of used stock DP's and gut em... lol

If I pass you on the right, I'm flipping you off.
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I gutted the first cat only...no stink at all. Gutting the 2nd will probably net you a few extra ponies but not a ton more.

 

Also not sure if this is cat related or not but my buddy decatted both cats on his 06 STI and he gets a pretty nasty backfire on quick shifts and when letting off the throttle at high RPM.. Also, he complains about the stink but I never sensed it at all when driving his car...some people are more senstitive to it than others I guess.

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