Since I've successfully turbocharged my iX without any major issues, I figured I would share what I learned building my setup. I daily drive my iX to and from work (mostly highway) all year round. I live in Michigan so this means pretty harsh winters with a fair amount of snow and negative temps.
Feel free to ask questions--the hardest part about the build is that information was sometime hard to find and scattered over different forums. I'll be updating the thread as I find links to what I've purchased/threads with useful information.
1990 325iX coupe MT
M20B25-completely stock and un-opened.
Holset HX35W @ 7.5-8PSI (Wastegate spring)
Megasquirt MS2 DIY PNP
DIYPSI turbo manifold
Tial Q blow off valve
Tial MVR 44mm wastegate
2.5" Intercooler piping
3" Exhaust
Mishimoto Radiator
Bosch 0280155831 30lb/315cc injectors (used from Volvo XC70)
STOCK CLUTCH
STOCK FUEL PUMP
Turbocharger:
Holset HX35W (had internal wastegate)
I bought this turbo used on eBay. I figured I would roll the dice, but to my surprise it arrived to my doorstep clean and without any shaft play. It was 135$-ironically one of the cheapest parts of the turbo setup. Being a internal wastegated turbo and planning on running an external wastegate, I needed to weld the wastegate flap shut. This can be done with MIG or TIG, make sure sure you preheat the housing first with a torch since it is cast. This was done with the exhaust housing completely removed from the center housing as to not damage the turbine during welding. I also welded a larger v-band to the outlet flange for my downpipe using the same procedure. Lastly, I ground down the ugly bracket on the exhaust housing using an angle grinder with a flapper disc. This is optional but ended up making the turbo a lot lighter and as a bonus, looks better.
Turbocharger oil lubrication and cooling:
This turbo is only fed by oil, no coolant necessary. I used AN fittings to get the job done. I clocked the turbo center housing straight up and down vertically and ran the lines. The feed is -4AN. It runs from a oil filter sandwich adapter which are readily available on eBay to a banjo fitting on top of the turbo.
The banjo bolt fitting for a HX35 is 12x1.5mm. I used one that has a 1.5mm restrictor which apparently the correct size for journal bearing turbo. Doesn't burn a drop of oil yet.
The drain is -10AN. I used a straight fitting out of the bottom of the turbo with an adapter flange. From there it runs down to a 45ish degree fitting that is threaded into the side of the block. I drilled and tapped a 1/2"NPT hole into the block and installed a 1/2"NPT to -10AN fitting. I chose to do it this way for a couple of reasons.
-you have to remove the entire subframe to get the oil pan out
-there is virtually no sump depth in the front of an iX oil pan
-I saw a thread where someone else did it and it worked out well
Drilling was difficult. I used a 11/16" drill bit and drilled through the passenger side wheel well. Did I mention I needed to lower the engine? I attached an engine crane to the engine and removed the subframe bolts. I carefully lowered the engine, making sure not to stress any hoses. I kept the drill bit well lubricated and cleaned off as much metal swarf as I could before the bit went through the pan. I realized that I would get some swarf into the pan so when I was done I opened the oil drain plug and flushed the sump with a couple gallons of used oil.
Turbo Manifold:
The manifold that I decided to go with is the DIYPSI manifold. Its pretty good. The wastegate runner is on the bottom, which puts my wastegate in the path of road debris and salt, but its a Tial so its really a moot point. The only issue I ran into was clearance for the nuts on the bottom front 4 holes. The runners in this area did not have enough clearance, so I used some M8 allen socket head bolts. I replaced all the studs with BMW#11627583110. They are for turbo MINI's, same size stud but they have a inverted hex on the end of them for easy installation. I feel good about reusing the stock M20 exhaust manifold nuts. For one, they do not have a flange and they were very corroded. I work at a BMW dealer so I took a look at what newer models use and I came up with #18307620549. N55/54's use these. They are nice because they have a flange on them and are cheaper than the stock M20 ones.
Note: if I decided to go with the stock ones they still wouldn't have fit the bottom front row.
Pictures and more later....
Feel free to ask questions--the hardest part about the build is that information was sometime hard to find and scattered over different forums. I'll be updating the thread as I find links to what I've purchased/threads with useful information.
1990 325iX coupe MT
M20B25-completely stock and un-opened.
Holset HX35W @ 7.5-8PSI (Wastegate spring)
Megasquirt MS2 DIY PNP
DIYPSI turbo manifold
Tial Q blow off valve
Tial MVR 44mm wastegate
2.5" Intercooler piping
3" Exhaust
Mishimoto Radiator
Bosch 0280155831 30lb/315cc injectors (used from Volvo XC70)
STOCK CLUTCH
STOCK FUEL PUMP
Turbocharger:
Holset HX35W (had internal wastegate)
I bought this turbo used on eBay. I figured I would roll the dice, but to my surprise it arrived to my doorstep clean and without any shaft play. It was 135$-ironically one of the cheapest parts of the turbo setup. Being a internal wastegated turbo and planning on running an external wastegate, I needed to weld the wastegate flap shut. This can be done with MIG or TIG, make sure sure you preheat the housing first with a torch since it is cast. This was done with the exhaust housing completely removed from the center housing as to not damage the turbine during welding. I also welded a larger v-band to the outlet flange for my downpipe using the same procedure. Lastly, I ground down the ugly bracket on the exhaust housing using an angle grinder with a flapper disc. This is optional but ended up making the turbo a lot lighter and as a bonus, looks better.
Turbocharger oil lubrication and cooling:
This turbo is only fed by oil, no coolant necessary. I used AN fittings to get the job done. I clocked the turbo center housing straight up and down vertically and ran the lines. The feed is -4AN. It runs from a oil filter sandwich adapter which are readily available on eBay to a banjo fitting on top of the turbo.
The banjo bolt fitting for a HX35 is 12x1.5mm. I used one that has a 1.5mm restrictor which apparently the correct size for journal bearing turbo. Doesn't burn a drop of oil yet.
The drain is -10AN. I used a straight fitting out of the bottom of the turbo with an adapter flange. From there it runs down to a 45ish degree fitting that is threaded into the side of the block. I drilled and tapped a 1/2"NPT hole into the block and installed a 1/2"NPT to -10AN fitting. I chose to do it this way for a couple of reasons.
-you have to remove the entire subframe to get the oil pan out
-there is virtually no sump depth in the front of an iX oil pan
-I saw a thread where someone else did it and it worked out well
Drilling was difficult. I used a 11/16" drill bit and drilled through the passenger side wheel well. Did I mention I needed to lower the engine? I attached an engine crane to the engine and removed the subframe bolts. I carefully lowered the engine, making sure not to stress any hoses. I kept the drill bit well lubricated and cleaned off as much metal swarf as I could before the bit went through the pan. I realized that I would get some swarf into the pan so when I was done I opened the oil drain plug and flushed the sump with a couple gallons of used oil.
Turbo Manifold:
The manifold that I decided to go with is the DIYPSI manifold. Its pretty good. The wastegate runner is on the bottom, which puts my wastegate in the path of road debris and salt, but its a Tial so its really a moot point. The only issue I ran into was clearance for the nuts on the bottom front 4 holes. The runners in this area did not have enough clearance, so I used some M8 allen socket head bolts. I replaced all the studs with BMW#11627583110. They are for turbo MINI's, same size stud but they have a inverted hex on the end of them for easy installation. I feel good about reusing the stock M20 exhaust manifold nuts. For one, they do not have a flange and they were very corroded. I work at a BMW dealer so I took a look at what newer models use and I came up with #18307620549. N55/54's use these. They are nice because they have a flange on them and are cheaper than the stock M20 ones.
Note: if I decided to go with the stock ones they still wouldn't have fit the bottom front row.
Pictures and more later....
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