Well, time for an update!
Turns out the SR25X does indeed have a pinion depth 10mm deeper than a stock SR18x. So, had I known this when I first did my transmission swap, a stock SR25X is the perfect combination for Type-1 Beetle engine and Porsche 901 transmission. No machining necessary, and you'll get full starter / flywheel teeth engagement. Unfortunately, for me at least, the way Bosch did this is exactly the same way I made the SR17X work...they simply made the nose & mating surface thinner. There is no meat left to machine the SR25x thinner, to make up for my new 10mm spacer.
Hmmmm
After thinking about it for a while, I went with the only option I knew I could make work. Chris at Hi-Torque starters and I exchanged a number of emails and and phone calls, to ensure that we were on the same page and understood the required measurements exactly. A rather expensive shipping charge later, and this arrived in two days. It's setup to have the pinion depth a full 20mm deeper than a stock beetle starter, which makes it perfect for my current configuration. Dropped it into the car, hit the key and the motor turned over perfectly.
I spent a few days buttoning up various things on the car, while I worked out getting my Mac laptop ready for tuning. Interior is back in, trunk is back setup, burned up my BN2 gas heater and then installed another one, and finally hooked up the laptop to the ECU. Everything checked out, I loaded my starting map, primed the oil system and started the car. Or, rather, I would have started the car if it actually fired up. I had fuel pressure, but no spark. Solved that problem and then spent two hours trying to work out a no start problem. I had fuel pressure, there was fuel on the plugs when I pulled to check for spark. I had spark, there's obviously air...compression? Check the valve timing, all good. Bad fuel? Drive to go and get fresh fuel...and that's when it dawned on me.
You see, the carbureted setup had two fuel pups. FP1 was the primary fuel pump, and FP2 was simply a back-up. If the first pump ever failed on an event, flip the switch and keep going. Except, I removed the second pump to make room for the surge tank. I flipped the switch to the FP2 position, shutting off the pump, while I was setting up the initial timing the night before. So yeah, all that time diagnosing the no-start issue, and I literally didn't have the fuel pump turned on. Oops!
With that sorted, I turned the key and fired it up. On the current map the cold start and initial warm-up is terrible, worse than with the IDF carbs. But needing a base of understanding and settings to start from, I worked the pedal to keep it running and got the engine warmed up to the point where it was running off the O2 sensor and the fuel map part that I know enough about. From there I could set the idle on both the idle speed screws, and in the fuel map. Idled quite nicely, and called it a night.
I cut work short today, headed to the shop and dropped the car down off the axle stands. After torquing the wheels, I opened my garage door, put the car in first gear, stood on the clutch and turned the key. S**t. The car crept forward on the starter, not quickly...but enough that I knew the hydraulic clutch setup was not disengaging fully. S***! While I warmed up the engine I considered my options, and weighed the possibilities. After the initial panic / thoughts of tearing it all down, I realized that I may have enough adjustment in the pedal stop I welded in. A few wrench turns later, and I can officially call the hydraulic clutch conversion a success!
Well, time for a road test, eh?
The fuel map is rough, and the A/F ratios were all over the place in the first 15min. A combination of a couple of tweaks by me, and the "Quick Tune"'s self-learning program saw things improving over the next two phases of the drive. Did some in-town driving, and then up to the Alberni Summit and back. The in-town section on the way home was significantly smoother and better than on the way out. Quite driveable, I'd even take it out on a road trip right away. Some of the drivability issues are definitely the 009 distributor I'm currently using. It drives like the car did on carbs, before I tuned out as much of the "009ness" as I could. No worries, the CB Blackbox is ready to go on the ignition side, so that will help out. I figured I might as well get the car running and somewhat useable on fuel mapping alone, before adding in the ignition side of things.
Sigh...do I have to work tomorrow? Maybe it's "tuning Friday"?
-Dave