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Uppipe replacement (no cats) on WRX

33K views 34 replies 13 participants last post by  04WagonRX 
#1 ·
I have a quick question about doing an Uppipe install on my WRX (yes I searched endlessly)....

I will be doing a retune after the install, but I'd like to know beforehand whether removing the cat in my uppipe/buying an aftermarket one (say HKS) will throw a CEL? In the forums, someone claimed that the uppipe mod will throw a CEL due to the EGT recording higher temps????

Does the cat cool the exhaust? :confused: Sounds fishy........

Or, will an O2 sensor CEL come up instead? (Got a stock downpipe so never had to do any CEL fixes before). If so, I gotta clear it by reflashing the ECU?

Got a stock exhaust on my car btw (don't like that much noise).


:beatentod
 
#3 ·
Yes you'll get a CEL but from eliminating the EGT sensor all together. You do not want to put this back in because the probe could break off (increased airflow) and grenade your turbo with no cat to block it. I don't believe the cat actually lowers your EGT but I'm not 100%. Most EM's will clear those CELs.
 
#6 ·
A cats job is to conduct heat from the exhaust to become hotter than the exhaust it'self. Thats to aid in the removal of "the ozone depleting Bull S!$%" from it, and put out nice ozone friendly Corbondioxide....hahaha. Yeah you can put a resistor in, 2.2 ohm in the egt sensor plug and just plug the hole with a short like 10mm 1.25 thread pitch bolt. If you dont have an ecu tune like me, i guess it is always nice to when you put on a part that could throw a CEL to just reset your ecu so things will work in harmony....hopefully haha
 
#9 ·
If you have a form of EM you can simply clear the CEL and it won't come back. I'm currently in the process of getting an internet tune by DTRacing (GetaDomTune) and he made revisions to my stock ROM based on the mods I have. Well yesterday while driving home on the highway I threw a CEL. Immediately I think WTF but a few seconds later it comes to me that he most likely never "enabled" the Cat fixes on my map. The car is running great but I'll need to go into Enginuity today and enable those fixes, then flash that map on my car. And oh yeah the CEL I'm sure if from the complete removal of the EGT sensor, with the bung plugged with a bolt. What I'm saying is that if you have EM just get yourself the correct bolt and plug it up.
 
#15 ·
Taken from the Perrin online instructions for their Uppipe install.....


You're taking a 2.2 kohm resistor (1 watt?) to solve the CEL.

It basically invovles unplugging the O2 sensor plug (last one underneath near where all the plugs are on the pssger side sturt tower) and sticking the resistor into the female ends of the plug.
 
#18 ·
The resistor in the picture is 2.2kohm but it's not really possible to judge the wattage rating. The markings are "2" (first red band), "2" (second red band), "x1000" (third orange band), "gold tolerance" (fourth gold band).

in other words, it's says it's a decent quality 2.2kohm resistor.

Any power rating should work. 12v over 2.2kohm is V^2/R watts which is 12^2/2200 which is 65 milliwatts so even a quarter watt resistor is more than enough.
 
#21 ·
If you have a Cobb AP or similar EM, you don't need either because you can simply disable the code from triggering a CEL.

If you don't, you either need to put the resistor in or yes, you can re-use the sensor in an aftermarket up pipe but that's really not recommended. It can break off and destroy your turbo just like the cat you're replacing (which is the whole point of the mod).

Get em to disable it or use a damn resistor. It's not hard.
 
#25 ·
Doesn't the EGT CEL trigger only if temps get too high? So in theory you won't trigger a cel if you decat?

I did the resistor mod as a precaution, but re used my EGT probe in the bung on my new BPM uppipe.....I didn't have a bolt short enough to seal properly....didn't reconnect the sensor though.

will a up pipe make my cars exhaust any louder?
^^Well here's my take on it. I've found that in lower rpm/beginning of turo spool the car sounds a bit heavier...exhaust is a little more pulsing (on a stock DP) than it was before.

It isn't amazingly louder...but for my setup....it is noticeable.
 
#26 ·
yes, you can do that White GDA, you also now have an EGT sensor dangerously exposed in a way it was not designed to be and in many cases, they break off and blow your turbo. Much like the cat you just replaced...

In other words, the entire purpose of the mod is for turbo safety and putting the damn sensor back in there makes the whole thing kind of moot.

Also, it will trigger a CEL when it gets hot.
 
#28 ·
i have a magnaflow catback it is a littile to quiet for me and i dont have the money to buy a downpipe so i was hoping that the up pipe might help a little. ups is having trouble finding my house i have been waiting sience the 12th for my uppipe i see them drive by my house every day how hard is it fedex found it yesterday for my boost controller it ended up being broke so i had to send it back
 
#30 ·
yes, you can do that White GDA, you also now have an EGT sensor dangerously exposed in a way it was not designed to be and in many cases, they break off and blow your turbo. Much like the cat you just replaced...

In other words, the entire purpose of the mod is for turbo safety and putting the damn sensor back in there makes the whole thing kind of moot.

Also, it will trigger a CEL when it gets hot.
Well I disconnected the EGT sensor and did a resistor mod. I only used the prope to plug the bung in the uppipe. Yep I should have gotten a bolt I guess...but it was too dran hard to find.

I think my EGT sensor was grenaded anyways....as it looked like tiny stubby piece of metal. LOL. Could it really cause all that harm? Out of curiosity....this ever happened to anyone before?



IF it does cause damage then...well...I got an excuse to get a bigger turbo. :D :rocks:
 
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