Ah damn, I forgot to mark the oil level today and add the extra quarts. On the list for later tonite, or maybe tomorrow.

I did get the cooling system burped, I hope. I think next time I open up the cooling system, I’m going to remove the thermostat. It took way too long to get hot water flowing through the radiator. It’s not like this car ever sees less than what, 50f? At least, during the season.

Oil pressure is good and the engine sounds perfectly fine. No leaks so far. I may do a test drive tomorrow.

 

You'll want to keep the thermostat. Removing it can cause issues with coolant flow.

What many people have done is drilled out a hole at the top of the thermostat to held any small bubbles make their way through.

I went with a remote swirl pot which made it far easier to bleed, but it was still doable with the stock setup on a Z3.

 

x2 on keeping tstat

I've said it multiple times, rear water necks with integrated fill ports (and/or a swirl pot) are the bee's knees on kmiatas.. how/why KPI hasn't just built their kits that way, I will never understand. It makes bleeding the system infinitely more convenient.

 

When you have limited time to prep for a race weekend, it absolutely makes sense to refactor the accelerator pedal that was not great, but functional. I should really just figure out how to mount whatever GM pedal everyone else uses.

I was hoping to drop the car and take it for a test drive, but work kept that from happening. Tomorrow, I hope (for real).

 

@Wingman703 and @Roda I hate to tag you directly, but I’ve got oil pressure questions for the K-series.

I saw really low pressures yesterday with 5w30 so I changed the oil to 5w40 last night. Rotella T6 both times.

i was 40s-50s in oil pressure yesterday with the 5w30, now 60s-70s with 5w40, at track rpm. Temps 230-250.

idling in pits after a session, 230-2(0f oil temps, I’m super low, like 12psi.

All - do I pack it in or is this OK?

 

On track, my oil pressure is generally around 80psi, never drops below 50, highest temps a little over 200. I went back and found a log that had some pit driving and it was 21psi at idle hot (208). 50 psi at 2k rpm.

I'm running 15W40 Rotella T6. I don't know what difference (if any) there would be to a Z3 from my A2, especially when both are running the K20 pump.

I'm not qualified to say if it's time to pack it in, but your numbers seem a bit low. Temps seem high to me, but my oil temps have been lower than most Kswaps I've seen data for... no idea why. Not running a cooler...

 

I should note that my main/rod bearing clearances are the +1 size, so it increases the oil clearance by… I forget if it’s a thou or a tenth. Whichever. Stock crank, measured perfect. See above for details

 

Spoke with a K motor guru at the track and I’m done for the day. Pressure not right.

FML

 

I have standard size ACL mains and King "High Performance" rod bearings which are .01mm smaller for extra clearance, running VR1 which is a 20W-50. I don't remember my exact spec sheet and I'd have to walk downstairs to the garage to dig it up.
At 150*-180* oil temps I see ~50ish PSI on track and 15-20PSI at idle. 12 PSI is definitely on the lower end at idle, but the oils also pretty warm so might be normal, and is a 5w not a 20w so a little thinner.
I know I'm a little late to the party at this point, but personally I wouldn't be thaaat freaked out about 12psi with 230* oil temps. 12psi cold... yeah ***** fucked, but I wouldn't throw in the towel at those hot numbers. FWIW I've never had glitter in the oil even at ~15psi idle. I'd let it cool down a bit and keep running it. Or bump the idle up to ~1500 for some more flow.

 

Not gonna claim to have any pertinent knowledge base on the K series motors. However, Roda's 80PSI @ ~200*F vs your 60's-70's @ 230-250*F seems to track, given you're both on "40" oils from the same manufacturer. 21psi @ 208* vs 12psi @ 230* is a larger delta, but still kinda tracks. Do you have oil pressures logged? Wondering if you're hitting 80PSI at 200*F like he is.

FWIW, my current motor, running 5W30, will hit 90PSI around redline with oil temps under 190*F. Once temps are up to 220*, that number drops to about 65PSI. Not saying those numbers are applicable to your platform but that pressure drop vs temperature increase seems to correlate almost perfectly with the temps/pressures you and Roda are seeing on track.

What's manufacturer spec for oil pressure at idle on these motors? Sh*t, my NC's 2.0L idled at 9psi @ 200*F, which I later found out to be normal for those motors.

Drop the oil and filter and check for anything offensive, then send it if no shiny stuff found?

 

If you are concerned, get one of those filter cutters, and cut the filter open when you change it. That should catch the tiny flakes/bits that are small enough to get through the strainer, maybe see signs before the bigger bits come out the drain plug into the bottom of the drain pan?

 

where are you measuring pressure from?

I'm not looking at 12psi idle with 230*F oil as an issue based on my experiences. My K24A2 always idled at a pressure in that ~15psi range, so much so that my longacre oil pressure gauge would ALWAYS flash at me to warn me of an "issue". The moment I got off idle, pressure came up and I tracked the car that way for years. I'm with the other guys here... change oil and check for glitter in pan and cut apart filter. If you don't find a reason to be alarmed, put new oil in it and keep sending it.

 

This right here means that you aren't going to align with anyone else when it comes to oil pressure data, especially running a thin oil at elevated temps. Cut open your oil filter and look for debris and bump up to a 5w-50 and see what happens.

 

Data logs, for those interested...

I like the idea of cutting open the oil filter and seeing if there's anything interesting in there.

Thanks for all the feedback, I'm processing and being neurotic...

 

Neurotic data point, from the service manual:




I've already dumped out $70 worth of brand new 5w30 T6, maybe I'm being...


and pound-foolish, but I think I'll keep the current 5w40 in there and siphon a sample out of the sump and send it off for analysis. I'll definitely cut open the current oil filter and examine for


Now, after looking at the logs, I just have to figure out why I felt like I was hitting the redline cut when I clearly wasn't...

Also looking at the logs, my driving sucks. I'm not sure if I included the channel in the logs I uploaded, but I'm using very little throttle for the most part, like less than 50%. I know I only go WOT in a few places at Sonoma, but I thought I was using way more throttle than my ECU says I am...

 

I’ve been dealing with some non-car crises that have been emotionally and physically exhausting. The final event of the NASA NorCal season is this weekend and I’m slammed with professional work until Friday afternoon.

So I’m doing the minimum possible to get ready and hoping it’s enough. I pulled the oil filter and cut it open. No sparkles, just a couple small pieces of what looks like RTV in the folds. Oddly this is not the color of the RTV I used this time around (Permatex Black).



I’ve been away for a week and a half and forgot I’d ordered this amusing bit of bling. Not an actual plate, FWIW.

We’ll see if I make it to the track this weekend.

 

Fingers crossed for you! Glad to see you didn't find anything noteworthy in the filter and am loving the faux-plate lol

 

I made it to Thunderhill!

The car ran great all weekend!

The car drove onto the trailer at the end of the weekend and all that was lost was some fuel and tire.

Tony Zwain drove my car for a session on Sunday and scorched my best lap of the weekend by 12 seconds. He turned in a 2:06 on very slippery tires. Two sessions later I cut a 2:14. I’m still slow, but learning.

Sadly there is no audio in these clips.



The car is stored inside the trailer for now so that I can take a break and work on some other projects. I was thinking about adding aero over the winter, but after talking with Tony and others, I’m going to learn to drive the car I have now faster, on 200TW tires.

Riding with Tony really gave me the experience of what it feels like to be on the edge of grip. I swear the only time he wasn’t sliding the car was when we were on the straights. There’s a moment in his video where he gets a little loose going through T5, that was the only time he actually had to “catch” the car; the rest of the time he was just driving the edge. I really wish I had video of his hands throughout the drive. It was amazing to watch him pushing the car to the edge and keeping it there.

Tony had no complaints about the car’s behavior under him. It took him a few laps to get used to the 6 speed (missed 5th a couple times, grabbed 6 instead of 4 a couple times). The car did what he asked of it and there were no surprises. That gives me a lot of confidence in the setup - I’m not going to spend any more time worrying about whether I’ve screwed something up or that the car is somehow not up to what I’m asking of it.

So yeah, after feeling what the car can do, I started pushing it more in safe places - T2 especially. I wasn’t sliding the car as much as he did, but I slid it a hell of a lot more than I ever have before, and it worked!

It was a great weekend with my NASA family and the adrenaline/dopamine of track driving - exactly what I needed after a few really difficult weeks of my dad being super sick, my work being crazy, and flying back and forth across the country on zero notice. The track is one of the few places where my mind has a singular focus, and it’s wonderful. A bit expensive, but wonderful.

 

I'm going to be there with Lucky Dog in a couple weeks, so your timing is great for the video! Tony does indeed look like he's hucking it around, shame about the camera placement. We have a lot of HOD customers with Garmin's, that's my biggest complaint is the common place to mount it is right in front of the rear view mirror.

I agree on the aero, aka, wait. You did the best thing for your continued learning, which was get a fast driver to show you what the car can do. Now your homework is just study his video and a data log if you've got it, sign up for a bunch of track days, and work on one corner at a time. I'd start with 1/2, you're losing about a second in each, and go from there.

 

Stoked to hear the car worked great. Agree with Tony, Captain Slow, and others - driver mod is best mod for now. It's always fun to put a great driver in your car to give you something to work towards. It's one of my favorite things about working here - Sonny or Emilio go out and set a lap, then hand me the keys and I get to see how slow I am haha

That singular focus is what it's all about. Getting in the zone. Good stuff.