Can you explain why it's not worth the trouble? Safety related, tuning or?
To add methanol, you need to add either a pre-throttle or direct-port injection system. Pre-throttle, you add risk from all of the normal meth failure points (tank emptying, leaking lines/fittings, pump failure, clogged nozzles, as well as uneven cylinder distribution and damage to the throttle body.
Direct-port is much better in that you avoid the last two, at least. However, the only safety mechanism is monitoring a flow-sensor, we don't know if each meth injector is actually working without monitoring EGT per cylinder, which is essentially impossible with this cylinder head (if you look at serious V8s with nitrous, there will be an octopus of EGT probes running to a standalone). Also, the proper way to add direct-port on these cars is via an aftermarket intake manifold, which introduces further cost, fitment, drivability and tuning issues.
The ECU doesn't "know" if each OE injector is working either, it just knows how much it's commanding from each one and has labcoat models allowing it to infer when each cylinder is misfiring and then shut it down. With meth injection, we're at the mercy of the aftermarket safety patches, which are great, but not at the level of a proper standalone ECU. And due to the headifold, even if we are running an EGT probe, it's not going to have per-cylinder resolution.
The goal of adding monitoring for oil pressure, EGT, etc. is increased reliability. Methanol decreases the risk of detonation, but so does high-quality fuel, colder spark plugs, a good intercooler, and a safe tune. One oil pressure sensor is a single added leak point vs. many points of failure for a meth system. I'm comparing those since I
think we have the option of using an extra ECU input pin for one 5v sensor on SP, and I think logging/correlating oil pressure is far more valuable.
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It'll be a while before I can get the motor out, but I've had several experienced folks tell me it's pretty unlikely the crankcase is reusable. I'm leaning towards building an Alibaba shortblock as simply/cheaply as possible. 9.3:1 Mahle pistons, forged rods, ACL bearings, ARP head studs. Re-use my head since the chinese heads seem to be where quality issues creep in. Keep the iabed oil pan, fluidampr. Send all the injectors out to get tested just in case that's somehow a contributing factor to the combustion temperature issue. Probably get a fresh OE R oil pump just in case.
I'm torn on a few things. One, whether it's worth even trying to make this car competitive given the motor failures. It's been expensive as fuck just keeping this thing on the road and doing casual HPDE, much less at a point where it's in a competitive environment.
Given the car isn't that streetable, it'd probably make sense to ditch the cat. Another potential failure point that could have caused this issue, and it makes sense to mitigate that while rebuilding.
I like having MPI, but it isn't strictly necessary on a stock turbo. Another set of injectors that can fail compared to dealing with the HPFP instead. I don't think I've seen any evidence that the fuel system contributed to any failures since ditching the aftermarket HPFP and continental DI, though.
Lastly, the elephant in the room, the tune. My logs are somewhat public, as is the tuner I've used and my engine failure. Not going to blame him, since there's no indication in the logs that the motor was hurt until the last pull or so. I should have been checking plugs regularly and doing a pre-season compression test and boroscope inspection. This may have given me more of a heads up that it was running a bit too hot (hence thinking about EGT sensors), but in my noob mind, moderate oil/coolant temps = motor isn't having heat issues. No one I've talked to has looked at my logs and said "oh, yeah, that's your problem." No fuel pressure or trim issues, timing and boost is what I'd call a stage 1 tune. There are dudes
toasting their pistons with Unitronic tunes without apparent issues.
For now, I've made the initial e-acca purchase of all the new OE seals, gaskets, and bolts for the inevitable rebuild. Still shopping for everything else, always a bunch of extra costs you forget about. Not sure the rs3 filter is replaceable, so some sort of new LPFP. At least 8 quarts of break-in oil. A bunch more synthetic and oil filters. Fresh injector seals. Trans/flywheel bolts. Definitely new spark plugs. Turbo seems fine but it would be a great time for a new wastegate actuator. If I ditch the cat, it's way easier to swap a downpipe without a motor in the way. Also the best time to re-seal the weeping bevel box and DSG case. Maybe I will start a gofundme...