3D printed cold air intake

Intake temperature has a direct correlation with engine power. For every 10°C rise in air intake temperature, engine power will be reduced by 2%. Last season I logged intake temperatures over 40°C on a 20°C day, which is really a waste of power.

So I need to duct cool air. I've been googling for different types of air scoopes and naca ducts but prefer not to cut a hole in either bonnet or nose cone. So I decided to try to get some air from in front of the radiator.

As I've written before, my 3D modelling skills suck. But where I work I have access to a 3D printer and wouldn't it be nice with an air duct that goes in the small space between the radiator and nose cone?

I started with a lot of measuring.  I used my kids' clay for the space between the nose cone and radiator, that I cut in pieces and measured. Then I modelled the constraints in the CAD program. I used the loft feature for a nice flow-friendly air duct and started printing.

3D printing is a slow process, and they can only print small objects. I had to split the part in five smaller parts and glue them together with epoxy. Each part took about 8-12 hours to print in medium quality! And it took a few tries before the outcome was good enough.

3D printing, first attempt.
I quickly learned that support stays should be avoided as much as possible.

I also did some CFD analysis to get a design that flowed all right.  I admit it is not perfect, but the first versions was worse...

CFD analysis of an early version

The theory is that the  higher air pressure in front of the radiator will force air into the duct. I've never had problems with high coolant temperatures and I hope it will still will be ok.

The parts glued together with epoxy.

Some filler and black spray can paint. As I didn't want to ruin the existing radiator alu frame I manufactured a duplicate and cut a hole for the duct. When I look at the result I'm amazed that I didn't put just a little more effort to make the end result better looking. But I just wanted to get it finished...

This duct has taken a lot of effort to produce. I've learned the hard way that 3D printing is not a mature technology and have a long way to go. The printer I used was far from a cheap entry level model.

Next step is a better suited air hose and how it will integrate with the filter. I have a temporary solution that works but could be much better. Also some back to back testing and see if there is any improvement.


References:
1. Comparison of Engine Power Correction Factors for Varying Atmospheric Conditions