Small displacement turbo. . ., Beginning to plan my new motor Options

[aircooledtechguy]

I love the reliability and drive ability of my completely stock 1.8L. . . However, it's just got no balls and w/ approx 160K on it, it's going through oil about 1 quart every 2-3K (burning, not dripping).

I have a completely stock 1.7L block with which to use as a base that has perfect 371Q heads (that will be rebuilt) as well as a spare set of Q heads. My desire is to remove the 1.8L and keep it as is in storage and build a small displacement turbo motor using MS EFI to run it. The goal is to make a completely street drive able motor that when needed can pump out around 140ish HP and plenty of torque without going too exotic. I'm not looking to get 200+ hp by boosting to the moon so one must think fairly mild turbo application. . . It must be affordable.

I've got a perfect TD04 turbo that I plan to use that only has about 10K miles on it. At this time, I'm unsure of the turbine and compressor specs but it's not a large turbo and should spool-up pretty quick and the waste gate is adjustable for tune ability. The car it came off of boosted around 10-12 psi if I recall. Pretty standard.

The quandary mainly lies in the basic internals of the motor. I'm planning to use a 66 stroke crank and have it welded and ground w/ type-1 journals and use 5.4" H-beam rods. I want the motor to rev easily to 6K. The bore at this point is unclear though. I could have the stock 90mm cylinders bored to 90.5 or 92 OR use a set of 93s I have and bore those to 94 all using forged VW type-1 "B" spec pistons. All these can be done for effectively the same price however for the 94s I would have to have the heads bored. I'm looking for good head sealing and conventional wisdom says keep it smallish to get the thickest walls possible. What think you folks??

Next is cam choice. . . I've never built a turbo motor so the requirements are new to me here. What lobe center is best for turbo?? Again conventional wisdom leads me to a fairly mild grind since it will be force fed anyway, but I defer to turbo experts on this.

For heads, I'm leaning toward a more stock rebuild w/ stock sized S/S valves, HD springs, chromoly retainers and light, Manton push rods. Again having never built a turbo specific motor, I'm open to any and all suggestions. What do you turbo experts suggest??

I'm planning to retain the SSI heater boxes and Sebring 4 into 1 header so that I can retain heat (this is a street car that routinely carries my wife) and plumb the exhaust forward to a turbo outside the engine sheet metal.

I plan to run an intercooler either under the car with a ducted dedicated fan, or in the engine compartment. I would prefer to have less "stuff" in the engine compartment and have heat sources away from the cooling air, but I'm pretty flexible at this point.

EFI will be the latest MS w/ EDIS ignition. I already have made some turbo end-castings and plan to connect them with a custom "T" and have a late model car TB (around 50-60mm in size). Any suggestions on what car to get said TB??

Well that's enough for now. Any suggestions folks can give would be appreciated.