simonrhart wrote: ↑Thu Jun 11, 2020 10:30 am
Nice! I bet it will feel crazy to drive, but a lot of fun I am sure. You can see just how linear those engines are in terms of power delivery. Can you explain the silicone hoses, what was the problem here?
I bet it's loads of fun! The power to weight is somewhere between a Veryon and a Chiron. Will take it to Laguna Seca this weekend. Will I lift of over the crest, fly, or keep the throttle pinned and trust the aero? Exciting times!
The heads on these true VTEC 4 port Honda engines flow like no other. I have to add that torque would have climbed much much more aggressively and therefore power too if I didn't use a tripple pass muffler. I'm robbing the engine of at least 30hp up top by using this in order to pass 90db @60ft regulations. Honda engines love a straight through muffler but I couldn't get it anywhere near 96db let alone 90db with a straight through design. I even tried a massive truck long straight through muffler.
The intake had to make a 90 degree bend to clear the engine cover and the only way to do that was to use a silicone coupler for the intake pipe. That's to make it all accessible at track days for inspection and all. Although I chose a custom massive Jim Wolf pop charger matched to the Rotrex inlet size, it was apparently still very restrictive for the amount of air the engine was inhaling. When I would go full throttle the air demands would overwhelm the filter and collapse the intake couplers. With the intake pipe shut by the couplers the engine would try to get its air from the blow off valve port. Sometimes even the blow off valve was shut due to vacuum. Hence, all the engine could do is keep the RPM steady. The lesson here is to try to use as few of those couplers as possible, they are weak unlike the aluminum pipe and can shut off the airflow.
So what we did now is to cut the engine tray to have a simpler intake that is 99% aluminum tubing. We also replaced the filter with an enormous one.
