We seem to go through a lot of rubber intercooler boots. Not sure if it’s a function of higher temperatures from heavy track use, or just normal for a boosted car with a top mounted intercooler. So this time we decided to try to replace them with Silicone boots from Alta which are about a quarter of the cost of stock rubber boots.
The silicone boots are usually sold to people who want to dress up their engine. Given the rat-rod nature of this car, that really isn’t a consideration. We’re looking for function over form. Do they last longer than stock? We know installation has a reputation to be much more difficult than the stock ones, but is it worth it? Let’s find out.
My first thought when I opened the box, was, “I could make these….” You just need two pieces of silicone hose cut to 1-5/8 inches wide (40mm), one with an inner diameter of 3.25 inches (80mm) and the other 4.25 (100mm) inches. Now to figure out how to cut them cleanly to size…. (That’s probably why it’s worth just buying them.)
Do the research. You can’t just slide these on like the rubber ones. According to the wisdom of the internet, the preferred method is three-fold: Warm them up to make them more pliable; install them on the intercooler first, using a bent awl to (carefully) pull them on to the horns; and lastly, swear profusely. The process will suck — just embrace the suck. Surprisingly, this was not our experience.
We simmered them for about 10 minutes until they were about 200 degrees F (93 C), dried them off and they slipped right on to the intercooler. We pressed the smaller end on to the horns first, then wrangled the larger end on, using the awl to ensure it wasn’t caught on the edges. All-in-all it was no more difficult than installing new rubber boots in the past.
The bent awl made it easier, but probably wasn’t required. The top tip we discovered: read (and follow) the instructions. Next would be to check the edges of your brackets before tightening them. The stock brackets are reused with the silicone couplers. One half slides into the other and the receiving end has a cut-out on the side to receive the upper half. The edge of that cut-out may be sharp and will cut into the outer surface of the couplers, creating a weak-point that may eventually leak. Also, when you install the stock brackets, be sure to push them out to the edge of the couplers to avoid leaks.
October usually marks the end of track season here in the Mid-Atlantic. Since the first event of the new year is normally in April, we like to swap out some of the go-fast bits that will take a needless beating during the winter months. That generally means swapping out track pads, removing the cold air intake and splitter, and eventually putting on winter tires. Since we removed the stock fog lights to use the openings for brake ducts, this also meant we would drop the bumper cover, remove the wheel liners and put the lights back. But this year, we thought we’d try something different. Since we had a few of the Alta Rally Light Bars in the shop, we thought we’d see how difficult they are to install. (Feb 17 update: Unfortunately it appears Alta has stopped making these. We’re working on making our own instead. Check back soon.)
The Alta Rally Light Bar mounts to the rear of the bumper and protrudes through the lower grille. It has four light mounting points, but we only used the two outer positions. If you’re adept at removing the bumper cover and bumper, this project could be completed in about an hour if you are using the exiting fog light wiring. Double that if you are wiring up a new switch, and double that again if you’ve never removed the bumper.
Follow the instructions included with the bar, though you can probably use a smaller drill than the 7/16 inch bit they recommend. Just be sure your bit is slightly larger than the bolts used. Also note that the bumper is curved. Once installed and tightened, you will need to use a large philips screwdriver to get leverage to bend the mounting points back toward each other in order to fit the cross member. Do this before you place the bumper back into the cover to decide where you need to cut the grille for them to pass through.
Since we know we’ll be removing the lights to install the splitter again in the Spring, we added quick-connects near where the wire comes through the grille, and attached the other end of the wire to the connectors for the stock fog lights. This way we use the stock fog light switch, and the fogs dim when the high-beams are activated. The Hella lamp kit includes mounting brackets, wire, a relay, and a switch. The lamp kit is available with either fog lamps (short, wide beam) or driving lamps (long, narrow beam). We chose the fog lamps and also optional yellow lens shields.
For about $200 plus a couple hours of your time, this kit provides ample lighting and is quite a bit less expensive than the stock kit. You do have to remember, however, that the lamps sit a couple of inches in front of the front bumper.
Driving on the track in the extreme cold, I noticed how the supercharger really responded to the cold. I did some research and found that the stock intercooler and diverter has a thermal efficiency (TE) of only about 65%. Before paying a lot of money for more surface area, why not try to improve TE?
There are a number of design compromises that affect TE. First is the location of the intercooler on top of the engine, left of the centerline of the car. You pick up ambient heat from the lump itself and the flow through the intercooler is compromised by forcing the air to make a 90 degree turn from the mail-slot in the hood.
To solve the heat gain, I’ve placed some heat shielding on the intake manifold, and along the interior surfaces and edges of the intercooler. My semi-scientific tests found about a 20 degree reduction in surface temperatures between the insulated and uninsulated parts. The next step was to replace the stock air diverter with the Alta Diverter. The Alta diverter seals better to the hood and channels the air from the right side more efficiently than the stock set-up. I removed the stock heat shield and used some thermo tech which increased the volume of space between the intercooler and hood, but still sealed well with the Diverter
I always new the MINI intercooler wasn’t in the center of the car, but it wasn’t until I made this composite image that I knew how far off-set it really is.
In this side view, you can see how far forward the diverter actually sits on the engine. You can also see how high the air filter sits. I’m also getting a good seal from the CAI box against the hood. I added some insulation to the outside of the CAI box as well. As measured inside the box when the engine was up to temperature, the side that was insulated was significantly cooler than the front that wasn’t insulated where the difference was about 50 degrees (so I added some heat shielding there as well).