Mark B's Build Thread

[Mark B.]

I tackled my most ambitious carbon fiber project so far -- made air ducts for the radiator (both in and out). I'll post a video going through the process, but in the mean-time here are the basics and some pics.

I made plugs by layering up foam boards to get the overall shape, sanded them to clean up the shape and round the corners, then used spackle and primer for a final clean-up. After that packing tape to help with the mold release then a few coats of mold-release wax.

Here's the inlet plug ready to lay up:

I followed the same process for the exit / hood vent but that shape was much more complicated of course. I wet-laid the carbon/epoxy with 4 layers at 45* angles for strength. My epoxy has a pot life of about 30 mins with our high humidity so I had to do 2 batches for the inlet duct and 4 batches for the exit duct just because of the size and how long it was taking me to get the carbon fully wetted and remove excess epoxy.

After a 24 hour cure, I de-molded them. The inlet came out no problem since it's 3-sided. The exit duct not so much since it's 4-sided and a pretty complex shape. Unfortunately I had to destroy my plug to get it out. I need to find someone with a 3D scanner to make a file just in case it ever gets damaged, and I have to re-make it (the mold process took forever; I don't ever want to do that again).

Here are some shots of them both complete. The inlet screws in to my front clam brackets. The outlet bolts to a bracket on the floorpan just behind the radiator with the top bolted to my radiator shroud, and the back rests on a carbon tube that replaced the factory steel cross-bar. So far they work great. I wasn't having any overheating problems before, but was getting a lot of heat coming up the sides of the window/doors with my crude ABS heat deflector. Now there's absolutely none. I have my next track day at COTA on May 11 so that will be the real test.

 

[Joel K]

Awesome work Mark, beautifully integrated into the front clam.

 

[Mark B.]

Awesome work Mark, beautifully integrated into the front clam.

Thanks Joel!

 

[Howard Jones]

Ya, you could sell those as a set. Two options. Fiberglass or CF.

 

[Mark B.]

I've never been thrilled with the performance of the Vintage Air system in the SLC. In Texas heat it couldn't keep up on 100+ summer days particularly with the canopy acting like a greenhouse in the sun (even with tinted side windows). I have the factory vent locations and also opened up the top of the monocoque like most builders do. I always noticed that even with the blower cranked up it just made more noise, but didn't increase flow that much. I didn't build my car to be comfortable, but I also don't want to be sweating like mad cruising around in the afternoon .

I decided to try drilling some more vent holes in the front of the evaporator plenum. I drilled 4 x 1.25" holes, so they're aimed right at the passenger's stomach. Then I bonded 45* PVC bends on two of them to aim them at the driver.

The difference is HUGE! Surprisingly, it didn't take much flow, if any, from the main vents at all since the fan flows a lot more than those vents can handle anyway. It now keeps the whole cabin nice and cool (that's 100* ambient in direct sunlight for 1.5 hours in my test drive). Also, I can crank the fan all the way if I want and you can really feel the difference. Side benefit is the fan is much quieter at all levels.

Because of the location under the dash, you can't see any of this while seated in driver or passenger seats.

(the box on front of the plenum is the controller for my electric water pump)

 

[Ken Roberts]

Cooler and quieter......that's a win win. Thanks for sharing this tip Mark.

 

[Jeff W]

This is the Vintage Air setup?