Welp, I neglected this thread for a very long time, because honestly I'm not very good at keeping up with things like this.
I had been daily driving the car and abusing it on the track for months, and put around 20k miles on the car since I last posted in here.
Final modifications list was:
EQT Vortex Standard Housing turbo
3" Custom exhaust
Titanium Intake
Walbro 450lph with Torqbyte PM4
Precision Raceworks MPI kit with 1400CC injectors
Cobb Protuned by EQT for E85
Ebay Majesty Intercooler
EQT Boost piping kit
Spulen Throttle Pipe
Spulen V2 catchcan system, modified with EVAP/Purge bypassed
Throughout that time period, I had to replace the thermostat housing (warranty), and all DI injectors because #3 had defected and stuck open, flooding the cylinder with raw fuel. Beyond that, I was having fueling issues with the Walbro 450lph pump. What felt like, and looked like boost cut issues, were actually fueling issues. At the top of any gear (above 6500rpm), after a few back-to-back pulls, the car would start to cut and dump boost. I had replaced the diverter valve and re-adjusted wastegate actuator to no avail. Couldn't quite put my finger on it at the time, because there were no tell-tale signs of fueling being the source of the issue, aside from STFT jumping a tad bit (nothing insane). A couple weeks ago, this all came to a head, when I had a track day for SuperLap Battle. After the first session which went smoothly, my co-driver took his laps, and in the first lap he started experiencing the fuel cut issue. Assuming it was still a boost cut issue by an electrical gremlin, we kept pushing the car, but not at 100% so as to keep the boost cut from happening. We ended up running a total of 5 sessions, and then I drove the car home 1.5hrs away. We did some datalogs during the course of his session and one of my sessions, and the datalog reviews at home were alarming. STFT was up to 34%, and in some instances we were pushing the car at 30psi and 14.1:1 AFR!
Surprisingly, she didn't spew guts all over the track, but the damage was done.
After seeing these fueling issues manifest, it was time to pull the 450lph pump out and re-install my 525lph into the tank, with a new(er) basket assembly from an '18 GTi. I removed the tophat from the R and installed on the GTi assembly, since the connections are different. After installing, I took it out for some basic driving to ensure there were no issues with the installation, and all seemed fine when pushing the car about 50%. Decided to go get a log of a 3rd gear pull to check fuel trims and pressures, and at about 6krpm, the motor went limp and sounded like a boxer. Great, 3 cylinder action. Checked codes, and had a Cyl 4 misfire, and hide cylinder. Called a wrecker and had the car taken back to the house so that I could see the damage. At home, I pulled the plug and it was oily, but not terrible, so I pulled the other plugs as well. By now, it was already 10:30 and I didn't want to lose any sleep over the potential damage, so I waited until the following morning to do a compression test.
I was extremely nervous, but hopeful. The result of the compression test was the straw that broke the camel's back, though. My heart sank into my stomach, and I knew there was no other choice but to tear down and rebuild.
Cylinder 4 was CRACKED IN HALF. The only part of the cylinder still intact, was the bottom of the wrist pin area. Best guess is that there was a stress crack or fracture from the track day, and my final pull on the stock motor opened the crack enough that it dropped compression and sent all combustion events into the crankcase. I've been counting my blessings since the mishap, because there's zero damage to the block and head.
I wasn't planning on doing a rebuild just yet, but there was no other option, so currently this is where I stand:
JE 9.6:1 asymmetrical pistons ordered
IE Tuscan I beam rods ordered
IE Springs/Retainers ordered
ACL race bearings ordered
ARP Head studs ordered
All gaskets and seals and hardware (bolts/nuts) ordered
OEM main bearings and main bolts ordered
"Upgraded" to steel oil pan
Once all the parts come in, and the motor is back from the machine shop, my long time friend and builder will assemble the rotating assembly, saving me some time from doing it myself.
