The Red Drift ///Machine

[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]

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.

[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]

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]

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]

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.

[bigjae46]

Not sure if I mentioned it but the goal for 2025 is to set TT4 NASA track records for the TX region. I'm 90% confident that the car can do it as is. But I do want to run TT3 where my car is at a significant tire disadvantage. My car is lighter (duh) but there will be a HP and tire deficit. So I have to out drive other cars with stickier tires and more power. The power disadvantage becomes obvious on long straights - the car just runs out of steam over 120mph due to drag. So I will continue to optimize the weight - first step is to get below 2500lbs. I'm getting closer, an estimated 2525lbs right now (2615 minus 15g of gas - 90lb = 2525). 2nd half of the year - work on drag reduction and hopefully a suspension upgrade.



Lots to do before the first NASA event that I can attend this year. Detune, ballast installation, and test, test, test.

First step is to get some laps in at MSR Cresson and Eagle's Canyon. So event #1 - MSR. Previous PR is a 1:20.1. I'm very happy to say that I was running consistent 1:18's, PR 1:18.4. There are things I need to do to optimize for MSR since it is a smooth track compared to MSR Houston. Virtual best was a 1:17.1 which is a massive delta to the reference lap. I need to close that up and be more consistent sector to sector before I can start fine tuning. Running 2 year old Toyo RRs with a bunch of heat cycles. So an easy extra .5 second gain with just tires.

It was going really well. Mid 90's through Riccochet, happy with the speed everywhere else except for Big Bend.

Then this happened...

Came out as good as I could expect. Car was still drivable, no noises or issues but the car felt sick. Got it home, found a damaged splitter mount and control arm. The ball joint blew up yet it made zero noise. Fixed and ready for more!