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How To Cure Boost Creep By Porting

Ever since I purchased my Evo316g from Slowboy Racing I have been plagued with Boost Creep. Much of this could be blamed on my 3 inch free flowing exhaust, and the elimination of my cat. I was all excited after I first installed it until the first time I went WOT and hit fuel cut and 20+ psi. So as many others I cured my creep by adding a cat, but also lost some performance. After about 3 months I was fed up and wanted more power, so I decided to do the only logical thing and drop the turbo out for some extensive porting. Before I did this I created a Thread which helped immensely and I credit and all of its members for the success that I reached especially DSM Wiseman OLDMAN who guided me through the entire process of what I needed to port, how to do it, and answered any newbie questions that I had. That thread can be found Here . Before you begin to drop the turbo to do the porting be ready to order new gaskets, bolts, and other misc. items. For instance, my turbo to manifold bolts had seized up and I was forced to find a machine shop to remove them for me, so I had to order 2 new OEM turbo to manifold bolts. The thick metal gasket between my turbo and manifold had also cracked so I ordered a new OEM one of those, and also picked up a j-pipe gasket. These can be found at Extreme PSI's Gasket Section , they have the lowest prices and quick shipping. But here we go...
1. Drain the oil and coolant which will cause a huge mess if this step is skipped.
2. Disconnect o2 housing, downpipe, and all oil and coolant lines.
3. Disconnect J Pipe from turbo.
4. Remove all 4 Turbo to Manifold bolts and drop the turbo away from the car.
5. Remove the band clamp by unscrewing the nut, thus freeing the turbine housing from the rest of the turbo. Note the tiny mark on the housing as this lines the housing back up with the rest of the turbo when you are ready to put everything back together.
6. Now you are ready to begin porting the inlet and making the path to the wastegate entrance easier for the air to flow towards. I was confused at first, but once the turbo was off the car it became very clear on what to port and what not to. Porting may be very time consuming but just keep your mind on the end result as this will keep you porting when you can't feel your hands from the vibrations and want to quit and go to sleep.
7. Obtain something to do your porting with I personally have an air compressor so I had the luxury of using air tools, but get yourself a grinder and some carbide bits, I also found a wire brush that I could hook up to the gun after porting to make it smoother before sanding to make really smooth
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8. This is what a stock inlet will look like or if you payed the 50 bucks when you upgraded your turbo the ring will be ported away, and it will more than likely carry a polished finish.
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9. Turn on whatever you are using to port and begin to let it touch the inlet until the metal begins to grind away, make sure to control where the shavings go as they really hurt if they get stuck in your skin, really concentrate on knocking off the wall that covers the wastegate entrance. Now the air is forced to make a 90 degree turn into the entrance, the goal here is to make the path easier and take out this wall so the air can easily flow into the entrance without having to make such an abrupt turn. After some significant porting the progress will more than likely look like this....Note the wall blocking the entrance slowly being removed...
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10. Continue to port, still focusing on the wastegate entrance, just keep porting away, I found that an IPOD and some headphones really help pass the time, after some more this is what it will look like...
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11. After completing the wastegate entrance so that it can easily be accessed by the passing air your attention can be turned to the entire inlet, your goal here is to let the 7cm ring become one with the rest of the inlet while keeping the conical shape as seen here, this is what the final shot of the inlet should resemble...
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12. After completing the inlet we now focus to the actual wastegate flapper, the goal here is to ensure that the flapper is opening exactly parallel to let as much air in as possible. Here is the first one of mine, Slowboy had already done the 34mm flapper mod to mine, but the flapper seemed to open at about a 80 degree angle instead of a 90, yours may be worse.
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13. Begin porting so that the 90 degree angle is achieved. Open the wastegate flapper manually and see what is hindering the flapper from fully opening and port that away until you get the 90 degree angle you are looking for as seen here...note the porting behind the hinge...
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15. Go Back and double check your porting making sure you smoothed out all reachable parts, you don't wanna have to drop the turbo a second time and port things over, so take your time and do it right.
14. Congrats, you have now completed the hard part. Now you need to clean the port job up and mirror polish it to see the most out of your port job. I personally got the large knicks and notches out with a dremel using a sander on the end of it as shown here...
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15. Run the sander over all ported parts getting rid of all the large indentions and making it smooth, this will already begin to make the metal shine somewhat.
16. I used an air compressor with a blower on the end to get rid of all the metal shavings that were created throughout the porting, but also you could rinse the shavings away with water and then dry it out before starting with the sandpaper.
17. Next, grab your sandpaper and Mother's Mag Polish, start at a low grit and work your way up by wetsanding the scratches made by the previous grit I personally used a 220, 320, 400, 600, and 1000 grits spending about 3-4 minutes with each grit and hitting all spots. After completion of the sanding rinse everything off and add some Mother's polish, let it set for about 5 minutes and buff off, the inlet should be gleaming and resemble the finish of a mirror and should be extremely smooth...
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18. You are now ready to begin re-assembly of the housing to the rest of turbo. Reconnect the turbine housing using the notch to ensure that the positioning is correct. Check that your o2 housing or o2 eliminating downpipe allows your flapper to completely open, because on mine as on 90blackstiawd's car the o2 housing was keeping the flapper door from opening completely and some extra porting was necessary to allow the door to open completely.
19. Reconnect the band clamp and now you have your reassembled turbo freshly ported and ready to be installed back on the car.
20. Reconnect the turbo using your newly supplied bolts (if your others broke off) making sure to add some anti-seize to them so you don't make the same mistake twice. At this time add all new gaskets and seals that you have ordered if you needed them and torque the turbo to manifold bolts to around 40-47 pounds as stated in the manual. Reconnect the J-pipe, coolant hoses, oil hoses and lines, and all neccesary lines.

21. Install new oil filter and pour new oil back into car.
22. Add coolant until it is full.
23. Disconnect the coil and turn the car over a couple times to obtain oil pressure again and prime the turbo.
24. Reconnect the coil and start the car up.
25. After letting everything warm up and water/wd40 burn off the turbo, safely test the car to see if the creep is solved.

This not only solved my boost creep completely, it also helped the spike problem I was having as well. My car now holds all the way to redline at 15 psi with no spikes or anything through all the gears at WOT with a 3 inch free flowing exhaust with no cat. Thanks again to OLDMAN and 90blacktsiawd for helping me throughout the thread and getting my car running right with as much power as possible. Wish you guys the best of luck when you try this, and hopefully it will cure your boost creep as it has mine.
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