The goal of this modification: to add an additional boost source for my car. I already have dedicated signal lines to my BOV, AFPR, and MAP sensor. I needed one more for my wastegate actuator. The turbo is an evo3 16G, and the car is a 95 GSX.
Tools used:
- Drill
- Vice
- 1/8" NPT tap
- Wrench for tap
- #27 Drill bit
- Air compressor
Note: Usually I recommend tapping into the upper intercooler pipe or the intake manifold for a boost signal line, but in my case I have no intercooler, so the turbo compressor outlet will provide the same signal as the charge piping.
There is a tapped hole already present in the compressor outlet, but it is for a 6mm x 1.0 x 16mm bolt, which holds the coolant lines on a 1G. Thanks to DSM Wiseman jusmx141 for this information.
In order to use this location, the hole must be drilled out and tapped again. The size I used and recommend is a 1/8" NPT. You can buy the drill bit and tap together at Pep Boys, or just buy an entire set now and save some time and money later. The drill bit was a #27 and the tap was a 1/8" NPT. The tap itself will be labeled 1/8 NPT - 27, this means use a #27 bit with this tap.
One of the benefits of using this location over the thinner or "easier" locations such as anywhere else on the turbo's compressor outlet, or on the charge piping itself, is the thickness of material. The tap allowed here is very deep, and the entire thread of the fitting is engaged. (The picture shows the drilling completed, and the tapping in progress, and shows the material wall still remaining).
Before you start: get some rags and stuff them into the orifices you wouldn't want tiny metal shavings. You can use anything that will seal well, such as tape. A little prevention here is worth the time.
Edit: It should be noted that the compressor housing can be removed from the turbo, which is a better way to prevent metal shaving contamination.
Drilling: Set up your turbo in a sturdy location, such as a vice (not shown), and drill softly into the metal with a firm grip. There is going to be a little play at first since there is already a hole there. Be careful, take your time and be decisive. The drill bit will quickly "bite" into the soft compressor housing, and straighten out. I drilled completely through into the compressor outlet (as seen in the image below) so the tap could run all the way through without bottoming out and stripping the threads. Keep the drill as stationary as possible, since any side to side movement will round-out the hole, making the fitting less secure.
Tapping: Again, keep the turbo firmly locked in place. I tapped nice and slowly, keeping firm, even pressure on the tap pressing INTO the hole. This is to make it as easy as possible for the tap to work correctly. The tap itself is tapered, so it will be easy at first and not even really start cutting until it's halfway in the hole. Then it will start cutting deeper and get harder to turn. Go 1/4 turn, then back it out and clean off the shavings. I used compressed air for this, which worked perfectly. Screw the tap back in, being careful to place it correctly in the threads you just made. Take your time repeating this until your threads are set. I used a wrench to turn the tap straight and apply pressure at the same time, but there is a dedicated tap tool you might consider purchasing if you feel more comfortable not cutting corners like I did.
Preemptive clean up: I used compressed air in the compressor inlet, holding the center of the compressor blade to prevent it from spinning. This will blow any shavings out of the compressor outlet, just in case some managed to find their way in there. Next, pull the rags, tape and covers off and again hit the turbo with compressed air. I did this from both sides of the compressor a bunch of times until I was certain nothing was hiding in there. I also cleaned up the entire work area at this time. Little metal shavings are not your friend.
1/8" NPT barbed fitting install: Get a socket or wrench which will provide a firm grip of the fitting, allowing for light pressure into the tapped hole. No sense in stripping any threads at this point. Since this is an obvious boost leak potential source, you'll want to apply something to the threads of the fitting. Some recommend teflon tape, but I used Loctite Red instead.
Another Note: A modified DSM (or any other vehicle) requires double maintenance. First is the normal maintenance of the car, oil changes and such, and second is maintenance of all the modifications you've done to the vehicle. Aftermarket rims? Check the lugs every oil change. Aftermarket fuel system? Check it every oil change. Aftermarket boost source tapped into your turbo? Do a boost leak test every oil change. This seemingly redundant maintenance will keep your car in top condition, and find issues quickly. Not only does this equal a better running car, but also helps prevent compounding issues, or issues that cause further damage to the vehicle.
With this modification I now have a dedicated boost signal for the wastegate, and it's just about as short as possible in this configuration. Signal line has a little extra length here until my turbo intake design is determined.
More pictures. In these the fitting is hand tight, and you can see there's a few threads of engagement left. After I applied a few drops of locktite, I inserted the fitting back in, and tightened firmly but carefully with a wrench. The fitting is nearly flush with the turbo, although not perfectly so.
Tools used:
- Drill
- Vice
- 1/8" NPT tap
- Wrench for tap
- #27 Drill bit
- Air compressor
Note: Usually I recommend tapping into the upper intercooler pipe or the intake manifold for a boost signal line, but in my case I have no intercooler, so the turbo compressor outlet will provide the same signal as the charge piping.
There is a tapped hole already present in the compressor outlet, but it is for a 6mm x 1.0 x 16mm bolt, which holds the coolant lines on a 1G. Thanks to DSM Wiseman jusmx141 for this information.
You must be logged in to view this image or video.
In order to use this location, the hole must be drilled out and tapped again. The size I used and recommend is a 1/8" NPT. You can buy the drill bit and tap together at Pep Boys, or just buy an entire set now and save some time and money later. The drill bit was a #27 and the tap was a 1/8" NPT. The tap itself will be labeled 1/8 NPT - 27, this means use a #27 bit with this tap.
One of the benefits of using this location over the thinner or "easier" locations such as anywhere else on the turbo's compressor outlet, or on the charge piping itself, is the thickness of material. The tap allowed here is very deep, and the entire thread of the fitting is engaged. (The picture shows the drilling completed, and the tapping in progress, and shows the material wall still remaining).
You must be logged in to view this image or video.
Before you start: get some rags and stuff them into the orifices you wouldn't want tiny metal shavings. You can use anything that will seal well, such as tape. A little prevention here is worth the time.
Edit: It should be noted that the compressor housing can be removed from the turbo, which is a better way to prevent metal shaving contamination.
Drilling: Set up your turbo in a sturdy location, such as a vice (not shown), and drill softly into the metal with a firm grip. There is going to be a little play at first since there is already a hole there. Be careful, take your time and be decisive. The drill bit will quickly "bite" into the soft compressor housing, and straighten out. I drilled completely through into the compressor outlet (as seen in the image below) so the tap could run all the way through without bottoming out and stripping the threads. Keep the drill as stationary as possible, since any side to side movement will round-out the hole, making the fitting less secure.
You must be logged in to view this image or video.
Tapping: Again, keep the turbo firmly locked in place. I tapped nice and slowly, keeping firm, even pressure on the tap pressing INTO the hole. This is to make it as easy as possible for the tap to work correctly. The tap itself is tapered, so it will be easy at first and not even really start cutting until it's halfway in the hole. Then it will start cutting deeper and get harder to turn. Go 1/4 turn, then back it out and clean off the shavings. I used compressed air for this, which worked perfectly. Screw the tap back in, being careful to place it correctly in the threads you just made. Take your time repeating this until your threads are set. I used a wrench to turn the tap straight and apply pressure at the same time, but there is a dedicated tap tool you might consider purchasing if you feel more comfortable not cutting corners like I did.
You must be logged in to view this image or video.
Preemptive clean up: I used compressed air in the compressor inlet, holding the center of the compressor blade to prevent it from spinning. This will blow any shavings out of the compressor outlet, just in case some managed to find their way in there. Next, pull the rags, tape and covers off and again hit the turbo with compressed air. I did this from both sides of the compressor a bunch of times until I was certain nothing was hiding in there. I also cleaned up the entire work area at this time. Little metal shavings are not your friend.
1/8" NPT barbed fitting install: Get a socket or wrench which will provide a firm grip of the fitting, allowing for light pressure into the tapped hole. No sense in stripping any threads at this point. Since this is an obvious boost leak potential source, you'll want to apply something to the threads of the fitting. Some recommend teflon tape, but I used Loctite Red instead.
Another Note: A modified DSM (or any other vehicle) requires double maintenance. First is the normal maintenance of the car, oil changes and such, and second is maintenance of all the modifications you've done to the vehicle. Aftermarket rims? Check the lugs every oil change. Aftermarket fuel system? Check it every oil change. Aftermarket boost source tapped into your turbo? Do a boost leak test every oil change. This seemingly redundant maintenance will keep your car in top condition, and find issues quickly. Not only does this equal a better running car, but also helps prevent compounding issues, or issues that cause further damage to the vehicle.
With this modification I now have a dedicated boost signal for the wastegate, and it's just about as short as possible in this configuration. Signal line has a little extra length here until my turbo intake design is determined.
You must be logged in to view this image or video.
More pictures. In these the fitting is hand tight, and you can see there's a few threads of engagement left. After I applied a few drops of locktite, I inserted the fitting back in, and tightened firmly but carefully with a wrench. The fitting is nearly flush with the turbo, although not perfectly so.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
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