The Red Drift ///Machine - 2026 NASA TT4 adventures

[bigjae46]

Leafblower? Should at least give you a good idea of what the air is doing.

tried that and an industrial fan. The tufts don’t start moving until about 40mph.

[heinzboehmer]

I think I could get by with a smaller radiator and less oil cooling by increasing the airflow efficiency - also reduces weight with less radiator, fewer lines and hoses.

That sounds like an interesting exercise in finding the optimum point. Decreased effective surface area with the tilted radiator will likely play a big role as well. Although you could offset a good chunk of that with a properly designed shroud.

I need to figure out how to capture flow on the front bumper. Thinking of using a gopro on the front straight pit wall.

Leafblower? Should at least give you a good idea of what the air is doing.

[bigjae46]

Jae, I feel like I've seen you talk about wanting a slanted radiator setup before. Was just recommended this video, which shows a carbon piece that does just that: https://youtu.be/uUSk5w5G4W8

Maybe you could even recreate (improve?) it...

Yes, I have! It has been something that I've been brainstorming but haven't been able to figure anything out that doesn't require major modifications. Ideally, I could make something and sell a couple of parts to replenish the slush fund.

That's an interesting way to mount the radiator - to a shroud and then the shroud to the frame rail. Ultimately, I'd like to try and close off the kidney grills for aero efficiency and take the intake air from the foglight ducting and headlight if needed.

I think I could get by with a smaller radiator and less oil cooling by increasing the airflow efficiency - also reduces weight with less radiator, fewer lines and hoses. BUT...I've got a lot of learning to do. The first step I'm taking is to learn more about aero - specifically air flow patterns and what effects the air pressure differential across the radiator and how it affects cooling.

The part I haven't figured out is the ducting on the back of the radiator. The airflow needs to be laminar to lower the pressure. Right now, the air needs to make 3 90 degree turns which will result in flow detachment and turbulence - higher pressure and reduced cooling performance. The real challenge is how to maximize laminar flow. The first step I've taken is to do some wool tuft testing. I understand the flow across the hood and windshield. I need to figure out how to capture flow on the front bumper. Thinking of using a gopro on the front straight pit wall. Once I get a better understanding of the flows on the front and sides of the car, I will start making some changes. Not sure what those are yet.

Thanks for the thinking of me! That video has given me more options to think about.

[heinzboehmer]

Jae, I feel like I've seen you talk about wanting a slanted radiator setup before. Was just recommended this video, which shows a carbon piece that does just that: https://youtu.be/uUSk5w5G4W8

Maybe you could even recreate (improve?) it...

[bigjae46]

Not a PR, but close. 1:40.9. PR is a 1:40.5.

I have a deal with myself. No fast, sticky tires until I get into the 1:39s on these RRs. I might have to break that deal. I think I can get there but its going to take the moon, stars, god, heaven, hell, and everything in between to align.

I'm learning more from the aero testing. Someone brought up using a rear mounted radiator. Also seeing how a gurney can make such a big difference with air extraction...its got me thinking.

[bigjae46]

Forgot to post the carbon fiber doors that were finished

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/280794-carbon-fiber-doors-finally-finished-almost

[bigjae46]

Here we go. OEM slick top roof panel. Only
took 3 attempts and then 3 months to get it.

[bigjae46]

See you in December!

Hell yeah! See you there!

[bigjae46]

Is the engine losing power after a few hard laps? How many miles does it have on it?

The engine has about 110k miles on it I think...its a used replacement. The loss in power when its 90+ is noticeable but it also loses a lot of grip. Hard to say how it compares to the rest though. Could be the driver. As I get older, driving in the TX heat gets less and less fun. Even with a cool shirt. Also the track in the video, MSR Houston, is in terrible shape. The surface grip seems so temperamental.

Interesting piece of data from this past weekend. I was running 1:47s with near dead NT01s. Throw on relatively fresh RRs (a year old but with 2 heat cycles) and I'm 4 seconds faster the next session.

[samthejam]

See you in December!

[Slideways]

Finally...back on track! Did some aero testing, learned a bit from that. I'll be more prepared for the Dec PCA event.

The track was not in good shape, weather was far from optimal. I feel like my car loses a lot of time in warmer weather, more than other cars. I need to investigate that.

Is the engine losing power after a few hard laps? How many miles does it have on it?

[bigjae46]

Finally...back on track! Did some aero testing, learned a bit from that. I'll be more prepared for the Dec PCA event.

The track was not in good shape, weather was far from optimal. I feel like my car loses a lot of time in warmer weather, more than other cars. I need to investigate that.

[bigjae46]

Carbon fiber doors are done. At 2598 with brake ducts and 2nd oil cooler which adds about 11 lbs - so about 2588 in min weight trim. Disappointed, thought it would be lower.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/280794-carbon-fiber-doors-finally-finished-almost

[bigjae46]

Let's see how this left door turns out. Learned my lesson from the hood, this one is going to be twice as thick. Planning to do the infusion tomorrow and then I'll start on the inner half.

[bigjae46]

Well...blew up my transmission. Just driving and heard a loud bang followed by rattling. The tranny shifted fine into all of the gears. First step, drain the oil and see if there's a clue.



So something broke. Found a used ZF310 locally. As per usual they come covered in oil and clutch disc material. Got it cleaned up. It was from an E46 and shifts great! Only downer is the output shaft seal leaks. I needed to get the car ready for COTA so in it went. I'll deal with it later.




Ran Circuit of the Americas with Chin Track Days. Went well. Had a wire to the fuel pump come off due to vibrations...luckily a buddy noticed it after getting towed off the track.

Ran a 2:28.9 on NT01s in traffic. Finally figured out a couple of turns - T2/3 and T18/19. Don't see why I can't get into the 2:27s on NT01s. NT01s are fantastic for hooning but braking is its weakness. Braking makes a big difference at COTA. I think I could cut an easy 2 seconds with some Hoosiers or scrubs. I also really need to get a power dip at 3.5k rpms tuned out and my dampers rebuilt.

Maybe a low 2:26 could be in the cards?

As always, difficult to get a clean lap at COTA.