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Hot exhaust after turbo upgrade

8K views 36 replies 8 participants last post by  GSMNZ 
#1 ·
Hi!

Im throwing CEL 0546 which is HOT uppipe exhaust sensor from what I've read on here. I recently replaced the stock TD04 turbo with a Garrett GT30BB and just ran into my first problem. I have catless exhaust throughout the car and have for years. I've never thrown this code until I started driving with my new turbo, even with the catless uppipe, it has never caused a problem in the past. I didn't change anything else besides the turbo. I still have an OEM TMIC and K&N filter feeding the turbo. IM trying to figure out why I am running hot here. I understand the sensor can be removed and tricked with a resistor, but I'd like to fix this problem the right way. I dont know if i need a bigger intercooler now? if my timing is off and im shooting flames down my exhaust (dont think this is the problem cause it was just highway driving when the CEL started). Does anyone have any idea?? please help!
 
#2 ·
Just guessing here but, maybe the sensor is bad. I don't think it would have anything to do with the turbo since the sensor is pre-turbo. Intercooler upgrades are almost a must on the wry when upgrading the turbo though. I would defiantly upgrade that as well.
 
#16 ·
I assumed he had a tune at least with a turbo of that size and at least some supporting fuel mods WTF. I figured if i asked about a tune I would just be :beatentod Guess i was way off!

You sir need to revert back to the stock td04 until you can get a tune and the mods to support a turbo like that. Upgrading turbos without a proper tune, fuel delivery, and cooling capacity is a big :nono. Even the catless exhaust and k&n really should be tuned for. Like Tyler said, surprising this is your only problem.
 
#12 ·
Sorry to get back so late. I havent had a change to get it tuned. Im running the new turbo at 14 lbs, which is what i ran my TD04 at. Im just getting a quicker spool time, but not much more additional punishment to the car. I dont imagine ratios have changed much since im running the same PSI, I was thinking this turbo is creating hotter air which is in return being forced through the motor back up the uppipe. Its just weird this happened fairly soon after I installed the turbo. If it is a broken sensor that would be some timing on the sensors part. I cant tell how hot my exhaust is but i now its hot enough to throw this code.

What do you mean upgrade everything else aswell?
still have stock TMIC, BOV what parts are you referring to when you say upgrade aswell?
 
#15 ·
With a GT30 you should have upgraded injectors, fuel pump, intercooler(probably front mount) and a tune at the least....You do realize that a stock TD04 doesn't push the same CFM as a GT30? At 14 psi you are probably pushing almost twice the amount of air....

Td04 is 380 cfm and the GT30 is around 750cfm...so yeah big difference there.
 
#18 ·
I understand injectors and all that would help greatly, it's a matter of money at this point. Have good tires and struts, bigger breaks down the road. I know im getting by with the setup I have. Im not interested in a FMIC, I know with a better TMIC i can cool the air enough to not have much effect. Grimmspeed makes a good one. The car is tuned for the 3" exhaust from head to tail already. It was a pain in my ass getting that thing to fit stock location, I know its the biggest turbo you can physically fit in that location. I now I have a shit ton of work ahead of me. I'm driving the car easy for now, im not gonna break her yet. Its really all great advise, trust me im taking note. I really just want ideas on this hot ass exhaust and why the hell I get this code now. I erased the CEL code and it came back on about a week later. I dont think its a bad sensor. So why is that light on??
 
#24 ·
If you understand it then do it. Your trying to justify doing stuff incorrectly to a guy that has probably been working on cars since before you were born. Simply put you don't know what your doing and when the car blows up your gonna blame Subaru or the previous owner like everyone else that did/does it wrong. At least 2 of us have told what is wrong and how to fix it, simple choices.
 
#20 ·
A buddy has a 2004 sti with the same turbo and hasnt had breakdowns derived from the turbo. Im not turning this into a race car. This turbo has so much more potential I can pull out of it when I get the right parts. Im doing my best to keep this car healthy with the set up I have. As i mentioned above. Im more curious about the hot exhaust. The engine runs normal temperature.
 
#23 ·
This guy should not be modifying his car. The guys on here no there shit man. Take there advice before you blow your motor. Pull turbo and and put back to stock that turbo has no reason being on your car with out the supporting modifications. Your trying to save money but what your actually gonna do is screw your motor and cost
You a shit load more down the road. If you can't afford to do something right don't do it man


Sent from AutoGuide.com App
 
#33 ·
I managed to avoid spending 10-15K...i decided to not go with 24k gold plate everything and went with used items..i do appreciate the bashing, and i appreciate the help. i got enough support mods to make sure she runs healthy. eventually a new motor, for now shes perfect.
 
#36 ·
STI TMIC is a bit too small for a turbo that size. Once you get to 20G sized turbos (yours is bigger) they get to be restrictive and you need to go with a larger and freer flowing core.

What bout engine and transmission builds? This turbo is much larger than what you should be running on the stock bits components if you're using it anywhere close to its potential. That makes up most of the budget I mentioned.
 
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