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Power upgrades - best bang for the buck?


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I have an '05 LGT 5MT wagon with Perrin 3" catted DP, OBX 3" catback, and Cobb stage 2 91 octane (I'm in Denver). What are my best next steps in getting more power without endangering the life of the engine? Will a bigger IC or catless UP make a difference, or do I need a bigger turbo to make any difference?
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Big tmic like the new soon to be a group buy item, Grimmspeed tmic, then add some more boost.

 

See my sig, that's on stock fueling. 93 octane.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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How can the catted up-pipe blow up the turbo/engine?

 

The cat material in the UP can become dislodged and get pushed into the turbo, causing turbine failure. When the turbine fails, it causes shaft play, which causes the turbo to shed little metal flakes into the oil, which, circulate throughout the engine and eventually get caught in places they shouldn't, like in bearings. This seizes or "spins" a bearing, and causes the motor to fail.

 

An engine rebuild is usually about 5k. A catless UP can be bought for as low as $75. Which would you prefer?

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Your new around here...the cat breaks lose and then the pices get eatten by the turbo.

 

It's that simple.

 

Once again, MrTris beats me to it... LOL

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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The cat material in the UP can become dislodged and get pushed into the turbo, causing turbine failure. When the turbine fails, it causes shaft play, which causes the turbo to shed little metal flakes into the oil, which, circulate throughout the engine and eventually get caught in places they shouldn't, like in bearings. This seizes or "spins" a bearing, and causes the motor to fail.

 

An engine rebuild is usually about 5k. A catless UP can be bought for as low as $75. Which would you prefer?

 

Yikes! And thanks! I'm off to NASIOC for an UP.

 

On a related note, what's the current wisdom on the turbo's banjo filter? Keep it or yank it?

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Getting confused on the STi UP - what years will work?

 

07+

 

It had to do with emissions, specifically cold-start emissions. So when they removed the cat in the UP, they added the airpump and, of course, also changed the heads to accommodate this. 05-06 had B25 heads and a catted UP. 07-09 had catless UP and D25 heads with the addition of an airpump, which is still in use today.

 

Long answer, I know. Simple answer is anything 07 and up will fit fine. The good news is that all turbo Subarus can use the same UP. So if you can find a good aftermarket one for a decent price, go for it, too!

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I have an '05 LGT 5MT wagon with Perrin 3" catted DP, OBX 3" catback, and Cobb stage 2 91 octane (I'm in Denver). What are my best next steps in getting more power without endangering the life of the engine? Will a bigger IC or catless UP make a difference, or do I need a bigger turbo to make any difference?

 

I'm in Denver as well. How do you like the upgrade to a catted downpipe and exhaust? Is that obx too loud?

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Seriously, though, check your turbo while you're there.

 

Also, are you tuned? If not, you should be.

 

How do I check the turbo? You mean just eyeball the blades when I'm swapping the UP?

 

Regarding tuning, I have a Cobb AP and am running Stage 2. What else should I do?

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How do I check the turbo? You mean just eyeball the blades when I'm swapping the UP?

 

Regarding tuning, I have a Cobb AP and am running Stage 2. What else should I do?

 

Check for shaft play on the exhaust outlet, you need to remove the downpipe to get the uppipe out. See how much play there is in the wheel (both side-to-side and in-and-out).

 

Edit: as for what else you should do. I would add a

 

DW65c (no tune needed)

Pro tune

Larger TMIC (or bulletproof mod)

EBCS

Equal length header if desired (You'll have the header off anyway for the uppipe)

 

Also decide if you ever want to go external wastegate, if you do, nows the time.

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Thanks! Which of these gain me the most power without substantially risking engine damage?

 

Also, do aftermarket up-pipes improve power compared to an STi catless? I'd be happy to throw down the extra $200 for 10 horsepower.

 

Nope catless is catless... get the cheapest one you can find!

03 WRB WRX (RIP)

04 JBP STI (sold)

07 DGM Legacy GT (RIP)

12 OBP STI (DD)

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Also, do aftermarket up-pipes improve power compared to an STi catless? I'd be happy to throw down the extra $200 for 10 horsepower.

 

Don't fall victim to one of the biggest fallacies of modding; You'll find that the difference in performance of a "big tube" UP vs a stock catless is only negligible at best, and the price points are all across the board. A $75 UP is pretty much as good as a $200 UP, just doesn't come with brand snobbery.

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