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?

 

I've tried a handful of solutions at this point but the can keeps filling up pretty rapidly with additional boost. Changed vent locations, added mesh/screen material to the inlets, same deal. I'm absolutely not going to vent it to the intake, that's just asking for additional issues/oil burn.
I also looked at doing an oil drainback, but the drain fitting on the bottom of the radium can is only setup to accept a -4 fitting, which is waaaay to small to have any real effect as an oil drainback, or at least wouldn't be anywhere near enough to combat the inflow amount I'm seeing. For the time being I'll have to limit full power to 1-2 laps worth, and if I want to do extended lapping turn the boost down. Annoying, but not the end of the world. I expect this issue to go away once I get an actual built/fresh motor in the car.

I added aluminum trap doors from improved racing. Easier to buy them premade then fabricate. I've seen a handful of reports of people receiving knockoff rubber doors instead of legit vitron and seeing degradation over time, and I don't see any benefit of the vitron flap style over aluminon trap doors anyway.
The column was out of a chevy... equinox I think. Its Epower steerings kit for control, and then all the mounts are custom fabbed.

Alright, going back to this high RPM power dropoff. I was hoping this was caused by valve float. There was a... very small amount of glitter in the oil after that dyno session, and that combined with power going down the more boost I threw at it, made me think that perhaps I was floating valves. Seemed a reasonable guess, and putting valve springs into this motor would be far less costly then cams/porting.

For the first time, I was able to take advantage of Audi parts for engine internals. The Audi RS3 valve springs are a 1:1 part for the 07K valve springs, and are much stiffer, coming in a factory turbocharged application. It's also several hundred cheaper to buy factory style, aftermarket springs/retainers then to buy aftermarket springs for the 07K(these are Kelford beehive springs from Iroz).


Of course because VW, timing chain in the rear, blah blah blah, entire engine comes out to be able to pull the cams out and get access to the valves. Yay!
These aftermarket springs are definitely waaaaay heavier then the 200K mile factory springs... even with the proper tooling this wasn't a particularly fun job.


And the end result... no change in VE curve, numbers, or butt dyno. Poo. So I think this is going to need aftermarket cams to address. Issues for future me.

A little bit more pressing of a change was fixing how the front ABS sensors mount. How I have them now sits them in very close proximity to the brake rotor, which...does get rather hot. Even with some reflective heat tape these sensors will die over time.



Looooong time ago @rdb138 sent me the PN for an alternate style BMW sensor that's both omnidirectional(doesn't need seperate right/left sensors) and works with the E5 magnetic tone rings. Instead of reading from the tip of the sensor they read from the side, so they can be mounted horizontally in plane with the wheel hub instead of 90* to it. New style(P/N 34526870077) vs old melted style.


These sensors I moved from ontop of the wheel hub to behind it, freeing up the forward side of the hub for ducting purposes and making the packaging/routing for these very nice and neat, as well as turning the brake adapter bracket into a giant heatsheild to keep these sensors from melting like their predecessors.


To mount them I drilled a hole through the bracket, tapped it for an M6 bolt, and used an aluminum spacer to set the proper distance. Bolt got a healthy amount of locktite to hopefully keep the sensor clamped in place.



With the sensors moved out of the way to the backside of the hub, I had a clear shot to the inside of the rotor for ducting. This doesn't mean that ducting was easy though...

The BIGGEST hurdle of adding ducts to this car, and why it always got kicked down the road, was once you slap an 11" wheel, and the tire to match it on the car, there's zero room at steering lock to run a 3" tube to the front of the car. This is with 15mm worth of rack limiters and the swaybar moved out of the way... WHERE DO YOU FIT THE TUBE????



So basically the ducts can't run to the front of the car/bumper. They just don't fit unless I cut holes into the frame rails and do weird internal brake ducts. Instead I ran them to the heat exchanger ducting and have them grabbing air just off the front of the radiator. Looks easy once its done but its a lot of work to get them to fit here. This area does still does get good airflow, when tested with a fan in the front grill I can feel air coming through the scat tube and the fins in the rotor. So hopefully that's enough to keep brake temps in check.



This upcoming weekend is a brand new hillclimb in TN, Brushy Mt. Looks like the course will be very fast with no switchbacks, from the limited video and scouting reports I've seen the pavement looks very smooth, so I anticipate this will be a fast, flowing course like Dragon, just much better pavement. Its also only ~4hrs away, instead of the 5-6hr tows most of the KY/VA events are. I anticipate the car being very well suited for this course, and to have a shot at the overall season championship, is a must win event. Fingers crossed.

 

Looking forward to more hillclimb content. Bummah that the valve springs didn't have an impact on the top end, but you said the engine pull on this thing is pretty quick at this point, right? How quick are you able to yank that thing now?

 

Awesome first few events with the new package!

1. Consider guiding some diffuser air to the brake package as well as the 3''+ ducts. I dropped caliper temps by ~20F doing this and also noticeably smaller microcracks on the rotor.
2. Nonetheless, I'm still edge cracking the GT48s after about 2 hours of runtime. I'll be testing a set of bolt on floating AP 60 vanes in a month to help remedy this. We're also looking to go to a 6 pot radial mount to combat taper wear in the same 7420 pad shape.
3. Not sure what you are running for the rear, but with stock NB pads on sport rotors and cooling guides, I can overheat and bending the pads in a15 minute session which are also carving grooves into the rotors. I'm going to a Superlite vented 11.75'' in the back as well. Beyond motorsports offers a kit.
4. I recommend considering a dry sump. I recently did one for my BP and I can't believe how much time (and sanity) I wasted pretending the wet sump was fixable at these power and grip levels. I primarily starved braking as well and even with minimum pressures of 30+ psi the bearings would be torn up after a few hours. I had all the baffles and a full open accusump. The dry sump also ends all the venting issues with a 2+ gallon AOS with the tank.

-Chris

 

Not to hijack, but I gotta ask about your dry sump BP build. Got a thread? I couldn't find one

 

Lowly N/A K24z3 here but that drained Radium dual inlet VTA "race" can solved everything on my K and the current owner hasnt had to touch it in his year and half of consistent running so far. I would think the latter part of your statement is true and you might need corrective action on both the input and output of that equation. Fresher/healthier motor and a drained can both.

As always, love this thread and you give me motivation to keep mine updated...

 

@cwatson in for BP drysump information as well.

 

@redursidae @Fireindc

Shoot me a message with your gmail address on FB for BP integration specifics @ chris.watson.1840 . I'll note it is a motorsport solution with corresponding price tag ($8k+), but you can piece together something for less. Here is some performance data to highlight the impact, but I don't want to hijack with BP specifics.
.
I think there is still a general discussion that applies to any high power motor on track. You can search the same problems and solutions and find them for many applications. In general, track-capable cars this quick come with a dry sump, scavenge pumps, and/or AOS centrifuges with drain back (some external, some integrated into the valve cover). The essential functions of the dry sump is getting de-aerated oil to the pickup location. The external tank system is just one approach to achieve that.
.

1. Starvation on braking is still starvation. A minimum gallery pressure is required to prevent vacuum (cavitation) bubbles from forming in the crankshaft passages.
2. Supply pressure alone is not sufficient, the oil should be de-aerated as well. You can quantify aeration by dividing the actual pressure by reference (usually straight line) pressure at that oil temperature and RPM. I measured increased starvation events increasing over the course of a session that would reset for the next one, showing the impact of having oil foam instead of liquid in the crankcase.
3. My GEN1 Radium AOS was a condensing type. Combined with a drainback (check valve required) it worked okay until about ~300whp/15psi on a fresh motor. Any more was marginal. ~400whp/25psi+ never really worked. I'm not sure if the GEN2 has a centrifuge, but that element is essential. The Mann ProVent (beware of knock offs) and Improved Racing are both centrifuges (as is a proper dry sump tank).
4. Any oil in the AOS is not in the sump (another case for drain back).

-Chris

 

Little over an hour, give or take. Having drybreaks on every fluid line makes the entire process a breeze. Expensive, but 10000% worth it. Most annoying part is undoing the driveshaft bolts as its tight access allen headed bolts into the transmission. Everything else is pretty straight forward.
I have the NB2 sport rotors with the adapter brackets for NB1 pads/calipers. I noted that the piston rubber dust boot had melted away on one side, and the rears have an evvver so faint red glow from track photos, so yeah this might need attention at a later point.

I'd love a drysump. But it's a lot of additional complexity, engineering, and cost I'm not quite ready to dive into. At some point(probably around the time I actually build a motor for this thing) I'll dive into drysump things with a DIY kit but I've got enough on my plate as is currently.

This last weekend was the first Bushy Mt hillclimb in TN, brand new hillclimb site for us this year. The video I had of it made it seem like a fast, flowing course, but the wide angle, low perspective video was deceiving. It still lacked the tight hairpins that dominate Norton or Pine, but was much tighter and steeper then expected- some areas have to be maximum grade, it felt near vertical when driving.
Friday night we had HEAVY storms roll through. Like catastrophic heavy rain. The very road we were using washed out about 2 miles past our finish line, the grass paddock turned into a swamp, and the sedate, 3" deep stream near paddock turned into a 6ft deep raging deluge. I was told by a local it was the most rain they'd seen over 20 years. It was heavy enough to completely collapse my canopy overnight, despite it having been tied down and secured quite well.


Saturday morning the rain was still coming down heavy enough to delay start by over 3 hours- the first time I've ever seen a weather related delay at a hillclimb event. By the time first cars began runs around 11am it had lessened to a light shower, but needless to say the course was a few steps beyond damp. I did two runs in soaking wet conditions, but by the time I lined up for 3rd run in the afternoon it was a 90% dry course with a few damp patches.
Halfway up run #3 I was red flagged- a non-insignificant tree had fallen across the road, doubtless from the soaked ground. I was turned around for a re-run, but this gave me a good opportunity to scout the conditions on the lower half of the hill, and make quick go again with hot tires. Lured into a false sense of security by the fairly dry bottom end of the hill, I got a little caught out by the last quarter of the hill still having lots of patchy wet spots. On literally the second to last corner before course finish, I applied power on corner exit over a very damp spot, lost all rear traction, fishtailed twice, then nosed off the side of the road, glancing off a rather large and unmoving tree which spun me 180* backwards down a very steep embankment, bouncing off trees until I stopped some 50ft off the road and well below its surface.



This was halfway through the recovery effort... it was so far off the road we had to wait till after competition runs at end of day to have enough time to extract it.


This was far beyond weekend ending damage.

All things considered it could have been much worse- had I gone off 2ft earlier I would have plowed headfirst into that tree instead of glancing off the side of it, and the long ride down the hill dissipated energy pretty well. I walked away from the incident under my own power and 36hrs later the only remaining sign were some light marks on my collar bone from the hans/harnesses.
The damage to the was both not as bad as I expected, and pretty bad. Front left corner sheet metal was completely crushed into the frame rail, and said frame rail seems like its tweaked in ever so slightly- maybe a 1/16th or so, as I had to remove the nose crossbar with some hammer blows, and it's normally a slide in/out affair. The intercooler has a substantial dent into it and the radiator is dented/punctured/twisted in several locations, rendering the entire heat exchanger stack unserviceable. Front left fender, hood, the 3D printed bumper are all crushed/broken beyond use, and both wing mounts are torn out of the body and off the airfoil itself, alongside a nice dent in drivers rear quarter. Transmission has a hole in the pan, but engine still makes oil pressure and runs. Both frame rails underneath are pretty badly dented and torn, but these are mostly cosmetic to start with anyway.
The car as a whole is salvageable, it's just... a LOT of work I created for myself now, and much of it is body work. I think we all know how I feel about body work at this point.

Two days after this incident I did one of the Porsche driving experiences in a GT3. Porsche has their east coast HQ/dealership just a few miles from where I work, complete with a fairly small but fun track, skidpad, autoX, and water hill on site. 2hrs in a GT3 with a qualified pro driver in the right seat was a pricy, but worthwhile experience. I felt very comfortable going 8/10ths as the raw speeds/acceleration honestly felt very comparable to my car... except we were doing it with the AC on, while talking at a normal volume, with a flat 6 howling at 9K behind us. Man, why would I bother rebuilding my car when I can buy one of these???


*looks at quarter million dollar price tag* Oh... right. Back to ball'in on a normal person budget...

 

I feel like this should be the default response for any updates to this thread at this point.



Glad to hear you're doing alright and the car's not a complete loss. Major bummer though.

 

F*ck. I will say, that looks like about as well as it could have gone for sending it 50 feet down a hillside. Least she landed feet down... Glad you weren't hurt dude.

 

Geeze, I knew you must have been ok because you were posting, but it sure looked bad. Glad to see that confirmed, too bad about the car but as you say, it could have been worse.

Are you/have you considered a reshell, that avoids a a big spell of panel work, but also requires the firewall mods to be done again?

It might be irrelevant now, but I got one of these for a specifc difficult-to-reach location, and was surprised to find how handy it has proved.

 

Damn Dude, scared you into a german machine eh?
You'd get bored with one quite quickly. nothing you're ALLOWED to touch.

Glad it wasn't worse. Makes you realize how much a cage (and all safety gear) is worth the weight.

Maybe it's my low HP turbo tuning experience talking here, but it seems watching the vid that you were out of spool rpm, and then when the turbo kicked it blew the tires off and you were done.
Have you considered antilag to maybe keep the difference between "out of boost" and into boost less (ie, less engine braking when off throttle, and quicker/more consistent into boost).
and considering you have the MK60, did you have traction control setup?
Either (or both) might have changed this outcome.