I drove the car several times over the last couple weekends. It has some quirks I have to work out but overall feels pretty good. I did a lot of tweaking and I feel like I have a decent sense for how things move.
Here's the engine in its current running state. I got new carbon fuel rail covers from Shad at driving ambition, they look good and really pop in the sun!
As a refresher, a number of things changed; the big chunks:
* The supercharger was rebuilt
* There is a 1" insulating plate between the supercharger and intake manifold
* The water meth nozzle was moved from before the throttle body to now spray after the supercharger
* A new Masiv radiator
Because of the new plate, the supercharger is now really prominent in the rear view mirror:
I also replaced some smaller things like new VTEC solenoids, new knock sensors, and all new coolant sensors. All that little stuff works. The knock sensors are less noisy than the old ones. It looks like it's going into VTEC and has the same oil pressure behavior in VTEC as before. Coolant sensors all work and appear to be the same scale as the prior sensors. Coolant level has stabilized, likely no more air bubbles. Also no leaks!
Air temps
A major goal of all this work was improving the air temps.
The supercharger tended to heat soak. For example: let it sit in a parking lot after driving then start it back up, air temps would be close to coolant temp. Then it'd be tough to get them down. The new insulating (phenolic) plate under the supercharger is supposed to solve this, it should keep the intake manifold heat from transferring to the supercharger.
I already have water / meth injection (WMI), but it seemed pretty inefficient with the nozzle in front of the throttle body. It used a lot of water and it was slow to reduce the intake temps. I'd go through a couple gears where the temp would spike pretty hard before it finally came down. Not great for a street car that is only in boost occasionally
You can read all about there air temp woes in
this post in the build thread.
The pic below shows all the air temp issues from the previous setup. It was a hot day, I had stopped and started the car several times so the sc was fully heat soaked, and it took a while for the WMI to actually affect the air temps:
Soooo, is it better now??
Yes! It uses significantly less water and has a much larger and more immediate effect on air temps. I have it set up to use about 40% of the water it was using previously:
And some partial throttle action, you can see it has a huge effect bringing the temps pretty immediately down from 150 to 125
Heat soak tho
The promise of the phenolic plate is insulating the supercharger from the engine heat. I was hoping that it would totally eliminate heat soak, keeping the baseline cruising temp down in the 120s or 130s or so. For example, the pic of the new setup above shows the baseline temp at 125deg, then a lot lower after the pull. That was my expectation! I was pretty excited after seeing that.
Does that mean the heat soak is gone?! Nope, It's still there, but it does seem to be a little better.
After taking the 125F baseline logs above, I started and stopped the car several times to adjust the belt tension and tinker with other stuff. It would sit in the sun for 20 minutes, then I'd take it back out.
Baseline air temps with the new setup would hover right around 150 when heat soaked, then they'd come down during a pull. Better than 170-180, but still not amazing. Check it out:
Why? Over time, the supercharger itself seems to get really hot. No matter the belt tension, my temp gun would read around 180-185F on the gearcase and around 175F on the rotor housing.
Note in the pic above that after the pull, the temp pretty quickly returns to baseline, in this case 150. This feels like one downside to spraying water after the supercharger. When I was spraying before the supercharger, water would cool the sc and other parts down, reducing the baseline after the pull. I'm considering adding a second tiny nozzle in the old location in front of the throttle body just to cool the sc itself down a bit.