Alternate title: The $6 Cooling System Upgrade
My 37mm Koyo aluminum radiator is doing great with my spiffy new turbo. Sharka is staying pretty cool. Except for at highway speeds. When cruising around on the freeways at 75 mph, the coolant temps seem to hover in the 200-205 *F range. That… bothers me.
Cruising around the city streets at 40-50 mph, I see 190-195 *F coolant temps. That’s where they should be with my 180* thermostat. Clearly, something was going on with the faster air on the freeway. Perhaps more of the air was going around the radiator instead of through it? That seemed like a good theory, so that’s where I started.
So, it was off to Target for some radiator ducting material!
My material requirements:
1: Flexible. So as to be able to bend it into position in the mouth.
2: Easy to cut.
3: Would not eat into my silicon intercooler pipes horribly if a zip tie happened to snap.
5: Available in town.
Bonus #6: If there was some sort of natural bend in the material, that would be awesome.
The storage bin from Target fit all of these requirements. It looks a bit low-rent, but it is not anything that you can see without the car being on jack stands with the wheels off. And this is version 1. I intend to revise and upgrade, so spending $6 on a storage bin sounded perfect.
Onto the fabrication! (I am embarrassed using that word to describe this quicky project.)
The failure in radiator efficiency is pretty obvious here. The passenger side shows a HUGE area for the air to scoot right through, totally bypassing the radiator. See, air is lazy. It would much rather go through a nice opening like this than through an intercooler, a/c, and radiator. Anything at all in this gap should be a big upgrade over the nothing currently in there.
Small bonus: You can see how my RS Factory Stage tow hook attaches in this shot.
High tech eh? I think so. Using both cardboard AND duct tape? Yes. I spare no expense with my prototype materials.
And that’s what I came up with. The natural curve of the storage box gives me a fastening point at the top. The bottom is supported by the factory undertray quite nicely. A few extra zip ties on the back edge (with the foam) will hold it in place pretty well.
You can see how the top is held in place a bit better in this shot. I used the bolt that supports the little bumper spar. After shooting this, I added the zipties. And considering the low cost and quick snip job, this thing fits pretty well. It looks pretty low rent in this shot, but for a first version, I’m not disappointed.
This side doesn’t show quite the gross opening in front of the intercooler that the passenger side did, but air still escapes from here just the same. This side was actually easier to seal. Less interference from the a/c condenser pipes.
This one had a small gap at the top against the frame, so I added a piece of airbox insulation. I think I also added a piece of this to the far back edge in an attempt to seal as well against the side of the radiator as possible.
Again, I used the bumper spar bolt to hold the top edge in place. An a single ziptie at the bottom edge holds it in the rest of the way. Simple. Easy. Not too much work in case I was barking up the wrong tree and my freeway airflow problems were not due to ducting.
It’s nice and dark back there. Dark is good. That means there’s no light shining through, showing a nice hole that air could zip around.
A little light can be seen here, but it’s a decent seal. And this is a huge upgrade from the vast open hole that used to exist here on the passenger side.
So how does it work? Excellent! Cruising on the freeway now gives me about the same coolant temps as cruising on city streets. 190-198 *F. Never above 200. I’m very happy about this. And a recent track day showed me a maximum of 210*F after multiple laps in boost. That also makes me very happy.
I will be upgrading the mouth ductwork sometime in the future. I’d like to get a perfect seal around those intercooler tubes, perhaps with some more airbox insulation. I’d also like to upgrade the material to something other than Target storage box. When this happens, I’ll come back to this post and update it with the link.
Anyone out there done anything similar? Got pix or a link to share? Please do so! I’d love to see other solutions to this problem.