Intake manifolds seem to be a far less popular mod than...almost everything else. Especially on the 10th Gen Honda Civic Si or any 1.5T, it's not necessarily the first modification that comes to mind when you think of your next modification once you've got all the bolt-ons. And for those that go big turbo, it's still far from a 1:1 ratio of big turbo cars getting manifolds.
Skunk2 recently released their intake manifold kit for the 10th Gen L15B7 engines and we were curious about it. Here's why.
Okay, now you know why we're excited. You should be too. We took it upon ourselves to install the Skunk2 Intake Manifold on our own 2017 Civic Si shop car. We always want to give you as much info so you know if this is a path you'll want to go down too. We did a back to back test. We baselined our Civic Si with a Hondata off-the-shelf map. This is the +6psi, high octane map. Then we installed the manifold and did another run using the same map. We know that tuning for any hard part modifications is the best way to maximize a setup but we're always curious about what happens when you bolt something on. Here is a graph with the back to back runs.
The thicker line represents our original baseline before the intake manifold. The thinner line represents post-install. Peak torque just barely reached higher than baseline but the difference is negligible. The most noticeable part of the changes are around 4500rpm to 5500rpm where we lose a little bit of power and torque. This isn't unexpected to be honest. The plenum size increase is typically designed to aid with high rpm horsepower, which is where the engine lives when you're doing any sort of racing. Along with that, the intake runners are bigger which causes a decrease in air velocity.
You can see that no power is lost up top at all. Remember, we're on the same OTS map from Hondata, the +6psi High Octane map. It's important to know that because of our altitude here in Denver, CO, the atmospheric compensations built into the Hondata maps simply won't allow us to make more boost. Regardless of whether we use a +6psi or a +9psi map, we only see about 2psi more than stock.
Overall, we're not disappointed. Sometimes, much bigger losses are seen when doing a modification like this so it's encouraging for when we get a bigger turbo on the car.
Now that our wastegate actuator is fixed, we went back to customizing our tune so we can get more power and control our boost a bit more. In hindsight, we really should have tried to custom tune the car with the stock manifold first before doing a back to back. Oh well. Maybe we'll mess with it more when the time comes for a bigger turbo. Because I really do want to see what the difference is with this manifold using our custom mapping and also with a big turbo. Once we do that, we'll definitely put out more info.
So if you're curious to see what we were able to achieve after dialing in our own tune after the manifold was installed, here you go!
Significant improvements were made after dialing back some of the altitude compensations which allowed us to push the turbo a little further. Improvements can be seen at every point in the curve.
Ready to take the plunge on the Skunk2 Racing manifold? Go ahead and click here to get it on the way. If you still aren't sure and you're looking for some guidance on the installation process, we have you covered. Check out our full installation guide right here.