Long-time lurker, finally diving into a build of my own and figured it was time to start a thread to document the process, ask questions, and hopefully get some insight from folks who’ve been down this road before.

Car/Engine:
I’m working with an M104 engine (non-VANOS) from a W124. Planning a turbo setup aimed at ~400-500hp for a fun street/track hybrid. Not looking to go crazy, but I want it to be strong, reliable, and cleanly done.

Current Plans / Mods:
• Turbo: Still deciding between a BorgWarner S257 or GT3582
• Manifold: Custom log-style or possibly a flipped stock manifold
• ECU: Considering MaxxECU or Megasquirt
• Fuel: 1000cc injectors, Walbro 450 pump, AN lines, return-style conversion
• Exhaust: 3” downpipe, full custom exhaust with resonator and muffler
• Internals: Stock for now, with MLS head gasket + ARP head studs

What I’ve Done So Far:
• Engine pulled and on a stand
• Transmission is a 722.6 from a later model – considering the OFGear controller or a full manual valve body
• Mocked up turbo positioning and initial exhaust routing

Questions:
1. Has anyone run a 722.6 with a turbo M104? Any tips on tuning or longevity?
2. Best head gasket for boosted M104 setups? Any reliability feedback on Elring vs Victor Reinz MLS options?
3. For MaxxECU – any base maps available for M104s to help get started?
4. Oil drain solutions for the turbo – tap the upper oil pan, or is there a cleaner way?

Would love any feedback, especially from those who’ve done a similar build. I’ll keep this thread updated as the project progresses. Thanks in advance!

Nice to see new projects.

Log style manifold might be restrictive at rpm, also higher egt's. Flipping oe manifold, not gonna work, bolt pattern wrong, issues with turbo location and so on.
Ecu - I think maxxecu is good choice because of 8hp support (I use ms and speeduino on my projects). Also if u dont do yourself tune, then look what friends or your tuner can work with, maybe something else is better then because of nearby support.
For injectors u would go 600cc, nothing to benefit from 1000cc.
For headgasket and bolts. For that power stock are ok.
For transmission, u need controller. Strength depends from what engine that box came, bigger- engine stronger box.
I have tapped oil pan but front cover or engine block is also option

turbobandit has nice kits

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