Heat Containment

Update by Alan Cesar to the Subaru Impreza WRX project car
Nov 8, 2013

Heat turns plastic into smoking, molten plastic.
Our radiator fan support and other nearby plastics were getting hot enough to melt.
A bit of Thermo-Tec header wrap did great things for our under-hood temperatures and dramatically improved spool-up.
Our MAF sensor and ignition coil wire looms were starting to melt.
Thermo-Tec's Express Sleeves go on easy and should protect them from further damage.
The sticker proved prophetic. This is the exhaust tip proximity after we adjusted the hangers.

After one particularly spirited drive, we came to a stop and noticed smoke coming from under the hood. It accompanied the distinct smell of hot plastic. A quick look underneath revealed melting plastic bits. Wire looms, electrical connectors and the radiator fan support, mostly. We called up Thermo-Tec and ordered some of their header wrap as well as some Express Sleeves to wrap around our wiring.

We wrapped the stock header as best as we could, using Thermo-Tec’s Snap Straps to secure it. One 50-foot roll of 2-inch-wide wrap left us with plenty extra, but it was a little tough to work around some of the tighter bends. If we were to do it again, we’d use the 1-inch-wide stuff.

Still, it’s effective. We noticed a difference when we opened the hood after a bit of a drive. Keeping the heat inside the manifold also helps the turbo spool faster. This was something we’d heard would be an effect, but figured it would be minor or hardly noticeable. It’s not. The change was fairly dramatic, and put a smile on our faces.

We had also applied a hyperbolic upgrade sticker to the rear bumper, near the exhaust. We didn’t think it would be prophetic. Our TurboXS exhaust was a bit too close to the bumper, and it was starting to show signs of its heat and proximity. We had to tweak the hangers a bit to get the tip away from the bumper. We don’t like fires.

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