For a Flawless Return - Direct-Fit Catch Can R&D, Part 2 - Design and Test Results

For a Flawless Return - Direct-Fit Catch Can R&D, Part 2 - Design and Test Results


Just about every major launch these days is complemented by some unforeseen bug in the system. It's just the way of the world, and manufacturers are quick to solve these small hiccups with a recall or a software update. Some bugs aren't easily remedied with a code revision or swapping for updated parts. For many vehicles, including your A90 Supra, blow-by will be an issue no matter the measures taken by Toyota and BMW to prevent it. When it comes to protecting your intake components, the solution requires a hardware upgrade, and we have that hardware.

Even with the help of some technical documents from BMW, determining which line to tap for our catch can requires some hands-on science.

It's taken a few months of poking, fabricating, and testing, but our engineering team has struck oil. If you remember back to our first post, our engineer, Dan, was in the process of equipping the Supra with a trio of catch cans to cover all possible routes that blow-by could take to the engine. To find which of these routes was the primary contributor of blow-by, Dan took a two-pronged approach, starting on the dyno.

Dan fitted a network of tubing to monitor the pressure readings from each potential avenue for our catch can kit.

It should come as no surprise that a modern vehicle like the Supra comes equipped with highly calibrated emissions sensors throughout the car. Changing the airflow through emissions sensors by, say, adding a catch can could lead to a very stubborn check engine light. This is something that we've dealt with before and wanted to avoid on the Supra. To prevent a check engine light on the Supra, Dan monitored the pressure through each line at various engine loads. If any line showed a significant variance from stock, that would give us an early indication that one of our cans could cause an issue. From this initial test, we only started running into a problem after the installation of all three cans. Luckily, we didn't need the full set.

The next step was to determine what, if anything, each can would collect under real-world conditions. For this test, Dan installed all three of our catch cans and drove the Supra for 750 miles. This test accounts for factors that dyno testing cannot, including road-going load and weather conditions, both of which affect blow-by collection. Our initial collection will also indicate the service interval for our kit. Let's take a look at what we captured in our road testing.

We did see some fluid in the can mounted on the PCV system but found that it was primarily condensation.
The CCV breather was the culprit for the Supra's blow-by. This initial run might not seem like much, but without the catch can, this much oil is feeding directly back into the intake tube every 750 miles and maybe more depending on the weather. As the vehicle ages, this amount of blow-by will also increase.
You can see that even on a brand-new car, the effect of blow-by is already visible. This is a closeup of the outlet on the Supra's turbo compressor outlet. Why was the turbo out of the car? More on that coming soon.

From our testing results, we concluded that the Supra requires a catch can on only the CCV system. The next challenge was mounting the catch can in the vehicle. Even with the Supra's long snout, space under the hood is limited. The line that we're tapping into is also much more accessible from under the car. For those two reasons, Dan decided to explore possible mounting locations under the vehicle. In the end, Dan decided to mount the catch can on the front cross member of the sub-frame.

The cutout in this cross member provided Dan with the opportunity to get a little extra creative when it came to his bracket design. Typically, we would search for a location where another component is mounted and piggyback off of that or utilize unused mounts. However, the Supra did not present us with many of those opportunities. So, the bracket includes a mounting plate, that keys into the cutout, and squeezes the main bracket firmly into place.

Admittedly, mounting the can underneath the vehicle isn't an ideal location when it comes to draining the system. Dan thought so too, which is why we also opted to include a draining system. In cases like these, we would ship our catch can with one of our petcock drain kits, but we decided the Supra deserved a special touch. Dan created a hard line drainpipe, complete with a threaded drain plug routed to a more accessible location.

Even though the Supra's return was close to flawless, there were still some bugs in the system. Bugs consisting of fuel and oil vapors that will make their way through the intake system and could eventually slow your Supra down. Consider our catch can as your latest security update.


Thanks for Reading!