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Discussion Starter · #1 ·
What type is it?

VF I am guessing could it be VF34 or VF35?



Also how many cats are there in the STi?

Two or three? Is there a precat before the turbo (like the WRX has)?

Where are the other cats located; downpipe and mid pipe like the WRX?

Anyone?


Cheers

Nick
 

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well, i would expect to get a stainless steel exhaust, i'm thinkin about how big the exhaust and other pipes r gonna b. u gotta get rid of that back pressure, and nothin helps that like 3" pipin.
 

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ehhehehhe :lol: im gunna keep the stock exhasut in my garage and slap me on an 4" full though turbo back exhaust without any cats and just a muffler!! :evil: :D :lol: hehehhehe thats wha ti would dooo!!!! now no more back pressure alright this car will literally SCREAM mad!!!!


::warms up hands::

im gunna make it run a good 500hp easily on the street when she comes to my hands!!!! :eek: :D
 

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u gotta get rid of that back pressure, and nothin helps that like 3" pipin.
With low back pressure you lose torque, but helps the high end. I don't know, thats a tough one since high hp is cool, but usable torque is important. I just don't want any flat spot or lulls in the power delivery.
 

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Discussion Starter · #10 ·
It needs to be balanced. If indeed it has 3 cats, then the uppipe cat and some tuning should offer an nice bump of 20hp at the wheels. This is why I love my Vishnu Stage 0.

Next step would be the TXS down pipe and the stock echaust. It comes with one cat (with the option of cat elimination) mated to the stock exchaust. Still pretty stealthy. A possible 20 more hp with some nice custom dyno tuning.


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Nick
 

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I agree. The uppipe needs to be replaced to get rid of that light-off cat, but I think I'll leave the other 2 in there. Just not worth it.

I'll be looking for STi to import the STi rear section exhaust. IMO it is very clean looking and if STi feels only the rear section needs to be replaced....I'll settle for that!
 

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Discussion Starter · #12 ·
The downpipe cat is a big restriction. I had a catless downpipe and the response was much faster(only one high flow cat left). I would have full boost (an incresed 16.5)at 2600rpm. Then I went back to the stocker and I was like what happened... :roll:

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Nick
 

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Once again, removing any of the cats is not street legal anywhere in the USA. But to each his own, I guess.

Maybe someone will provide higher-flow up- and down-pipes that still have cats. And I'm still hoping Prodrive USA will provide the PPP, which in the UK is nothing more than a new high-flow cat, rear section (or just a muffler?), and retuned ECU. And factory warranteed.
 

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Discussion Starter · #14 ·
Well this is the deal with CARB (at least and I think fefderal laws). You cannot legally change the cat unless it mulfunctioning. So I am betting that the PPP will be for "off road use only" and Subaru dealers will not install. Also you cannot touch any of the emissions equipment unless the replacement has a CARB #. This is to make it 50 state legal.


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Nick
 

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Actually, even for the track, I'd take more torque over more top end HP. That's why Peugeot is killing everybody in the WRC because they have tuned their 2.0L to make insane amounts of torque (I think I heard once on the Speed channel 500ft*lbs, or maybe it was 50kg*m, something with a 5 for sure :)).
 

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The facelifted Subaru WRC 2.0 makes 60 kg-m at 4000 RPM, which equates to 434 lb-ft. So it doesn't surprise me if Peugot is similar or better. However, 50 kg-m = 362 lb-ft, so if the first digit was a 5, it makes a pretty big difference what units you're talking about.

BTW, the recent article about Prodrive UK in Sport Compact Car said that the output of the Subaru WRC engines could jump to 650 hp without that mandatory restrictor. 2.0!
 

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I remember hearing something in the 500 range.

From http://www.peugeot-avenue.com:

Engine
Type : XU9J4.
Installation : front-mounted, transverse.
Number of cylinders : 4
Capacity : 1997.5 cc
Bore x stroke (mm) : 85 x 88.
Maximum power : 300 bhp at 5250 rpm.
Maximum torque : 535 Nm at 3500 rpm.
Head : aluminium.
Valves : 4 per cylinder.
Cylinder block : aluminium.
Double overhead camshaft.
Engine management : Magneti Marelli Step 9
Turbocharger : Garrett Allied Signal.
Lubrication : via carbon wet sump.
 
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