PICTURES
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Hi there. I know a dump pipe install isn't that exciting but I thought I would post this so others could benefit from the experience and hopefully will answer some questions. Most of this can be applied to any aftermarket dump install but this one is specifically for TurboXS V2 with Grimmspeed Downsizer.
Background
I had been looking into aftermarket dump pipes and exhaust for some time and because I wanted to keep the STI mufflers I came to the conclusion that I was better off replacing dump pipe only as this way I could install an exhaust downsizer (Grimmspeed you legends - http://www.grimmspeed.com/3-subaru-down ... m-catback/) for a smooth transition. Also the factory cat back exhaust does not look restrictive to me for my application. I expect that just replacing the dump will give me 80% of the benefit as opposed to 100% with complete exhaust and mufflers.
Requirements (mandatory)
1) Must be a direct bolt-on (so I can do all the labour),
2) Must be a high quality item with good design for flow and fitting in mind,
3) Must have a CAT built-in,
4) Must have an O2 bung post CAT.
Wish list (not mandatory)
a) Stainless for longevity and looks ,
b) Bung hole for wideband in bellmouth,
c) Open bell mouth, no divorce or splitter (these can cause problems with turbo interchangeability and have negligible impact IMO)
The Shortlist
These are only my opinions I don’t expect everyone to agree. These opinions are based on lots of reading, scrutinising design via pictures and experience and cost. In my opinion these are the top 3 choices of those I looked at. I expect that there is probably less than 10% performance difference between any on the market. In saying that 10% can be worth it.. I do however think that some are simply overpriced given the quality and materials. I obviously have more knowledge of the TurboXS dump as I have installed and scrutinised more closely – good and not so good.
• inVidia Oz version – Pros: Excellent quality item. Splitter. CAT. Cons: Cost.
• TCP – Pros: High quality item. Nice open bell mouth, CAT and flex included. Cons: Cost.
• TurboXS V2 – Pros: High quality item. CAT. 3 O2 bungs. Cost (in my case). Cons: Minor. Turbo flange is thinner than CNC cut steel. Didn’t supply compact nut for bottom right turbo stud. Internal cast to Stainless pipe join is not perfectly smooth - I am a perfectionist though .
Purchase & Supply
I purchased it from 'ht0258' on EBAY. The dump box was marked V2 which I think was a newer version that addressed some fitment issues on previous models. It came with:
• 2 x steel 2-bolt gaskets,
• 4 bolts, nuts and spring washers,
• A small bolt and spring washer which I am not sure what it is for but suspect it is for mounting - not needed on my vehicle.
Unfortunately I was to learn later that it did not come with a compact nut required for one of the turbo flange studs. The cast angle does not allow for a standard integrated washer style nut to be used and I know this is the same for some other dumps e.g. TOMEI but they supply the nut.. Lucky I had one laying around! Edit: I provided this feedback to Grimmspeed and they were very grateful so hopefully this means future shipments include the nut. Not a biggy really.
Installation & Tools
I have installed many dump pipes on older libs and this was not that much different. The most time consuming part was removing the plentiful heat shield bolts (about 10 but didn't count). The whole job took me around 3hrs not rushing. This is not a complete list of tools but I recommend the following:
• Inox or other quality penetrating oil,
• Antisieze (optional, I use Nulon)
• Ultra Copper (optional heatproof O2 safe silicon for sealing bungs)
• Socket set including 10, 12, 14 & 17mm sockets (14mm impact hex socket 1/2’ if possible)
• Various extension bars (I like to use 3/8 extensions with a ½’-3/8’ adapter as they get to places thicker bars won’t.
• Breaker bar or torque wrench to help crack the turbo exhaust nuts/bolts,
• Need nose pliers (to help release cable ties for O2 re-route)
• Open end spanners in 10, 12, 14 & 17mm (a 14mm offset ring spanner is handy)
• Flat head screwdriver (helps flex hanger hook while you unhook dump)
• Tin snips & file for heatshield adjustments.
Step 1: Raise vehicle to a height you can safely and comfortably work under. Make sure it is properly supported, I recommend ramps or a hoist. Be careful when using ramps not to scrape on way up. I use concrete blocks, wood blocks and a spotter to make sure I don't damage the front bar when driving up the ramps.
Step 2: Remove engine cover and Intercooler, nice and easy.
Step 3: Spray all bolts/nuts you intend to remove with Inox penetrating oil. I used this on heat shield bolts (the ones I could reach!), 5 bolts/nuts mounting dump to turbo, support bracket bolts and exhaust flange bolts. Leave for 1hr if possible.
Step 4: Remove bellmouth flange bolts/nuts. I recommend a quality hex 14mm socket (impact type) to loosen with breaker bar of something with some leverage. Hex sockets will not round bolts or nut heads. Once loose, you can use a normal 14mm socket or ring spanner using different extensions etc to make it easier.
Step 5: Remove 2 x 14mm bracket/support bolts under vehicle.
Step 6: Remove O2 Sensor - I used a shifter as it is larger than 20mm which is my largest open ender Actually came out easy.
Step 7: Remove dump<->mid-pipe flange bolts. At this point you can remove the dump from under vehicle.
Step 8: Re-route O2 sensor cable if required to gain length. This is a two piece cable with connectors. It starts under IC adjacent to pitch rod (turbo side). The loom runs over the bell housing and down the passenger side through some zip ties where the connector is mounted to the side of the gearbox. At this point there is a connector to the second loom that is a shorter length and connects to the O2 sensor. I unclipped, removed the entire cable and once the new dump was in I routed from the O2 sensor back following a very similar path and using as many of the factory ties as possible. On the TurboXS dump I wanted to use the most rear O2 bung as it is post cat and I am hoping for a close to factory install with no disabling of CELs in the ECU. This is the only reason I need to re-route.
Step 9: Fit the bung plugs to those O2 holes you don’t intend to use. I used a very small amount of Permatex Ultra Copper on the thread to prevent leaks (optional).
Step 10: Install the TurboXS dump in two parts is easy. Make sure the gasket is still attached to the back of the turbo (or replace – not necessary usually), line up dump from under vehicle with a couple of the previously removed nuts in your hand to fit and hold in place. From under the bonnet put the other nuts and bolts back on but don't tighten everything right up just yet.
Step 11: Trial fit the second part of the dump to the mid-pipe flange. Check where the O2 will be and if required trim the under body heat shield with tin snips to allow enough clearance around the sensor (at least 10mm in any direction) remembering that everything moves a bit once tightened right up. Use a file to smooth edges of the snipped section to prevent injury or damage to other components.
Step 12: Re-fit O2 sensor with some anti-sieze, check clearance and tighten.
Step 13: Tighten all exhaust nuts & bolts starting with the flange between the top and bottom section of the dump as this is the most difficult to align. Do this while it is not sitting in the hanger mount. Don't forget to use the supplied gasket and spring washers!
Step 13b: OPTIONAL GRIMMSPEED Downsizer. Remove the factory donut gasket from old dump pipe using a large flat head screwdriver and rag and gently pry it evenly off be careful not to damage. Fit this donut onto the Grimmspeed flange. Install the large end of the Grimmspeed adapter (with supplied gasket) into your new dump pipe. I found that due to the large holes in the factory midpipe I needed flat washers on this side and with the spring washer on the other the supplied bolts were not long enough. I decided to use the original bolts with springs removed. A bit of a fiddle but they fit through.
Step 14: Systematically check everything is tight, all gaskets are installed, hanger bolts are re-attached, O2 sensor is installed and not at risk of fouling on the shield, the O2 cable should be safely out of harms way of moving objects and potential crushing from movement in gearbox mounts.
Step 15: This would be to cut the factory heatshield to fit over. I don’t want to butcher mine so I will source a second hand one (probably from an earlier rex as there is less to cut).
Step 16: Re-install IC and engine cover.
Step 17: Apply your updated tune for this upgrade. You should not run without adjusted tune.
DONE!
Conclusion
Overall I was very happy with the quality and fitment of this dump pipe. It provides excellent access to all of the turbo flange bolts (except the minor nut issue) and although like any exhaust fitment requires some man handling I was surprised at how well the factory hanger and everything lined up. The factory donut gasket also allows for some movement so a flex is not needed.