Not to glaze you dude, but holy hell. That amount of work would not be something I'd want to tackle in a single week *between* events haha. So sick. Bummer about the G80 LSD limitations. What's your projected necessary top speed in this thing?

If 146mph with a 3.23 isn't enough... got damn son.

 

The overall goal for CMP was not to shatter track records or win, but more to turn laps. The last time I was really able to turn multiple laps in this car was the K24 at RRR April 2025. Every event since then was plagued with issues, or was 1-2 laps on A7's before everything was cooked. So needless to say I was sooooo rusty.
The first two sessions at CMP were soaking wet. I had a set of A7's and a set of RC-1's on hand(both treadless, "slick" tires) so obviously I did the smart thing and... ran every single wet session on slicks! whooooo that was an exciting handfull for sure. The open diff actually wasn't terrible in the wet. Instead of spinning both wheels and sliding the car, it would just spin up one wheel and bounce off limiter. So when I felt the acceleration stop and heard "bap bap bap" I knew it was time to pull an upshift. Not fast, but certainly much more controllable and less drama then running with an LSD in the wet.
Yup... open diff things


Third session saturday there was a dry line so got a better feeling for the car then. Even on 7psi(wastegate spring, approx 320whp) car boogies. Had a few corner workers hunt me down during lunch break to ask me what on earth was in the car "yooo that sounded like a viper!" and pretty much everyone that stopped by my paddock slot expressed how damm good it sounded. 10/10 noises. The open diff revealed itself to suck here(shocker) pretty much the whole way through a corner. Not being able to rotate the car with a light throttle feather during entry/mid corner was sooo weird, and it really nullified it trying to dig on exit. One wheel peels "BAP BAP BAP" *upshifts*

Saturday morning it was cool and dry so I threw the A7's on and went out for 2 laps of glory. Kicked the car up to 14PSI(~400whp) and went for it. I know I said this was a "turn laps" weekend, but I did kinda want to match/beat my PB 1:36.8 with the K here....

Not quite a PB. Going through the data later, I was driving the A7's like an RC-1, the min speeds were basically identical, so I need to readjust to how much more grip the A7 should afford. In comparing to last years K24 lap, the 07K/8HP setup MATCHED the K24 in top speeds, despite running about 5psi less boost and having slower corner speeds(second part is a driver issue, not a car issue). So this setup shows potential to be faster then the K24 with an H pattern installed.

The downsides: This motor pushes a LOT of oil into the catchcan at higher boost levels. At 7psi I could go 2 sessions of 8-9 laps each before the 1qt catchcan would be greater then 3/4th full. At 14psi it was overflowing after 2 fliers. I think this motor was a claimed 220K mileage from the junkyard? I might be able to improve the baffling some, but I think this is mostly an "older, more worn OE engine" issue than anything else.


But the cooler part... GLOWING ROTORS OH YEAH



Oh yeah that's cool as ****... broad daylight, bright red rings.

Oh yeah, thats cracked as ****... damm really putting Bronson's brake kit though the ringer


These rings had a handful of laps at Pittrace, then 7 sessions at CMP this weekend, and they were DONE when I pulled them off afterwards. Half a dozen good sized cracks though the edges on each, and plenty of crazing as well. Hawk DTC80's were also crumbling on the edges so **** was hoooot. I'd get 5-6 flyer laps at 7psi before I would feel the brakes start to soften and I'd take a cooldown. I know its half a meme as often as I've said it in the past, but now it actually needs some brake ducts. I was never able to turn more then 1-2 laps at pace before anyway so it wasn't a priority issue, but as reliability seems to be trending upwards it will actually get addressed now.

I turned the car back down to 7psi, put the RC-1's back on, and ran all the rest of the sessions at CMP like that. Just. Turn. Laps. At some point both my ABS sensors in the front melted so I lost ABS and mann... ABS is so good. This car/me sucks under braking without it. These did have heat tape over them, this was what I found after I pulled it off.


I'll probably move to a different style sensor that keeps the wiring/sensor farther away from the glowing hot rotor, but brake ducts will also help with this part. Not a huge deal.

Uhh oh right oil pressure... well the good news is that there is zero starve/oil pressure dip during lateral turns. It *does* still dip heavily under braking though. I'm seeing it drop from a nominal 70psi to 12psi, even with the accusump. Unsure if I needed to get a larger accusump(have the 2qt, figured that would be enough?), but the pan baffling for oil pan V2 will definitely be improved to help with this as well. There wasn't an appreciable amount of metal in the oil after dropping it after the weekend, so I don't think this is a fatal issue in the short term since it's only during braking and recovers before throttle.

Won the TTU class. Was a pretty soft class this weekend so not a huge accomplishment, but winning is winning baby.



Other then the ABS melting... made it through the entire weekend with ZERO mechanical issues.

Which is why, 18hrs after turning its last session at CMP, the engine was already out...

 

Have you opened up that engine and pulled the pistons? When I got my "130k" Ecotec, I pulled the pistons and the second and oil rings were stuck. I threw the pistons in ATF in an ultrasonic cleaner until they were cleaner, the rings were not stuck, and slammed them back in the block. I am not forced air like you, but zero oil burning my first race.

Do you have a drain on your catch can that drains below the oil line?

Love the build.

 

That's a simple question with a really complex answer that keeps me up late at night.
For starters, here's the gearing with my current 3.42, and a forecasted Ford 3.08 or 2.73, assuming a 7500RPM redline. Note these calculations were done with a 245/40/15, while the 275/35/15 I run for competition is a little shorter.




I'm sure there's a way to plug in the estimated drag of the car, and calculate a theoretical top speed with XYZ horsepower. I haven't gotten that complicated yet, but I'd guess gearing the car for mid to low 160's would be reasonable. 170+ might be needed for fast tracks like Road Atlanta/Road America, but that prospect terrifies me.
The lower end of the gears with the 2.73 is ideal, with the longer 1st. From 3rd up, its basically the same gearing as the 3.42 but with every gear moved up one(2.73's 3rd is ->4th with a 3.42, 6->7th, ect). Driving on track using 3-5th at CMP felt really good, but it wasn't quite fast enough a track to get a feel for 6th on. I think this is *probably* the ratio I'll end up going with but this isn't set in stone.

Only downside is 6th with the 2.73 is reaaaaly long. Engine is still well in the powerband, but its just such a long gear when aero drag is hitting the hardest.

The 3.08 is slightly less ideal for the lower gears(being shorter), but probably has a more useable 6th. I'd be OK bumping the redline up a few hundred RPM if needed for 6th. It's definitely between those two options for me.

Shoutouts to @Padlock and @thebeerbaron for the tractive force calculators.
Nope, never touched the inside of this motor. It doesn't smoke and doesn't fill the can at low/no boost, so I don't think the rings are stuck, just pure combustion blowby.
The Radium can I have does have a port on the bottom for a drainback. I could tap the pan for a return(no return setup currently), but I haven't yet. I'd honestly been mulling that idea over since everything is out right now anyway, but I think that's more a bandaid solution. I probably have enough 6AN line/fittings hanging around I could make it happen...

 

We have been trying to figure out the blowby with our Volvo racecar for years. We have a drain, so at least we don't overflow the can, but it still vents a ton of oil vapor that gets everywhere. We tried venting to the intake, but at tracks with long straightaways our air filter would drip oil.

 

These guys have a very entertaining, aesthetic and informational series for CF mold-making, for sure worth a watch.

 

Just for a reference point, my full aero/interior NB (2230lbs) with n/a K24 (231whp/186wtq) was hitting 135mph before T1 at Road America. For right or wrong, I like using C6 Z06 lap times as a point of reference for top speed ranges that I believe I could be close to for future planning now that I'm going down the LSx path. Most videos I review with 450-500whp C6's are hovering between 155-160mph in the same sections of Road America. The miata is lighter, but at those speeds aero drag impacts top speed more than vehicle weight and a miata likely has a higher drag coefficient with aero than a slippery C6 would have, so I'd like to think this very crude method of using another car at similar power level will get your top speed estimate close.

 

Stef's may sell you the rubber baffle doors if you call them. I'm local and was able to stop by, and they handed me a pile of helpful kit when I made my oil pan. Pickups, tubes, windage screens, etc. They didn't have the rubber doors back then but they do now.

Who's electric power steering is that?