Lots has happened with this project so I feel like I should give an update. Things are moving back in a positive direction, thanks to blood sweat and tears.
I took the head off the engine, with the engine still in the car. Made the following changes when I had it apart:
- Knocked down high spots with some 800 grit on some unfortunate scuffing that happened on cylinder 2, the one that had a clogged injector and ran lean early on
- New rings on cylinder 2, they saw some minor accelerated wear from the above issue, despite fine leakdown numbers. We're crossing our fingers boys, otherwise fully fixing this calls for starting all over again. I know this is not ideal but we're in damage control mode at this point
- New rings on cylinder 4, the piston with the bad leak down numbers. The original rings all looked fine, including their gap, but I threw new rings at it regardless since something clearly wasn't right. I did notice that one of the top two rings was EVER SO SLIGHTLY not flat, possibly from my machine shop bending it while installing it. That's my best guess as to why it wasn't sealing properly and I was seeing a ton of oil in my pcv line.
- +10 thou cometic head gasket to compensate for the material removed during head/block decking. My theory was that the CR may have been increased too high (I had 190PSI of comp on some cylinders which is almost unheard of high) causing our shitty 91 octane fuel to predetonate even easier
- I fired my machine shop and lapped all of the valves myself. They did a dogshit job that resulted in almost every valve not making 360 degree contact. I reached out to them about this. They got me to ship it over to inspect it. They did some type of vacuum test on it, said there was nothing wrong with it since it "held" 30psi of vacuum, decked it again for some reason (apparently they saw some knick I was unaware of), put it through the parts washer, and sent it back. Since the head did not have assembly lube or oil anywhere, this washing filled the head's nooks and crannies with water. This rusted my valves into their guides so badly I had to beat them with the end of a screwdriver to get them out. Good thing I planned on going over them for lapping (since I did not trust their diagnosis that it was fine) anyway. I ripped them a new one over the phone and will never be back.
After re-assembly, we basically went from 2-3+ kr on every pull to ~1.6 - ~1.8 kr. Noticeable and repeatable improvement, where Will D went from saying "you have a huge issue you gotta fix" to "I can't go any further with this tune but it's stable". This was good enough for us to move on to introducing my methanol kit.
First, I tried running methanol that I have had sitting in a container for over a year. It didn't even affect the AFR it was so stale! Picked up some fresh stuff, got another two revisions done with Will, now running 24psi, and hit a ~1.8 KR wall yet again. My favourite.
Chatted with Will about options, and we decided to try a 1500cc/min spray up from 1000cc/min. I set the car up for 1500cc/min, did a pull, and the AFR was IDENTICAL to before. What? Did I put the same pintle back in by mistake? How is it behaving identical to before?
Then I removed one of my nozzles and tested it inside a bottle. Holy shit, it's shooting more meth back out of the push fitting than is coming out the nozzle! That explains it, and I am lucky I never had an engine bay fire with this happening.
The tubing was installed fully. The tubing is cut perfectly square and it not deformed in any way. I tested this nozzle with brand new tubing from my stash, fully properly inserted, and it leaked like a sieve.
It seems to me like the O ring inside the push fitting has expanded and is no longer making reliable contact with the OD of the tubing. Since stupid problem call for stupid solutions, I did the right thing and shoved the stem of a valve inside the end of the tubing to increase its size where it meets up with said O ring. It's now a huge pain to install and remove, but it's sealing perfectly now. Will this fix last? I dunno man, probably. Fuck push fittings.
I switched the car back to its original 1000cc/min nozzle set up now that all the fuel is actually entering the engine, and the car is now running super rich in the early RPMs which Will is currently adjusting for. Now that that's fixed, we are now well under one degree of KR at 24PSI. We're so back. With the car running this well, I am hopeful that we can now get to the end of the tuning process without any further hair loss. We just need another two or three PSI worth of tune revisions and then it's drag strip time in the spring
Massive shoutout to Will D for putting up with me and my car through all of this, we are about to reach a full year that this tune has been in progress and it has not been easy.
