Speaking of individual throttle body (ITB) sizes, apropos hardly anyone. As I mentioned earlier, using my superpower to ignore important facts, I ordered 45mm ITBs for my 1776 that are probably 10-11mm too large, each. Based on my similar experience putting a Mustang 5.0 75mm throttle body on a supercharged Miata, I knew it would work, but I also knew that if I was way off, there would be drivability downsides. In the Miata case, this was easily solved because everybody and their 3rd cousin sell a progressive linkage wheel for the Mustang that makes most of the pedal travel control the very lowest portion of the throttle opening. As I discovered today, that is not the case for Weber ITF style crossbar linkage - huh, big surprise.
Now don't get me wrong, it's not terrible at all. In fact, the only time I notice it is when I'm driving over speed bumps and slight movements of my throttle foot creates noticeable jerking as the throttle cracks open and closed. I'll have to PERFECT this problem with a little home fabrication, but that's in the future. To prepare for this, I wanted some data about what part of the pedal curve was getting the most use.
I've been doing tons of data logging of every engine event over the last 2 weeks while tuning and playing around with settings. Megalogviewer (MLV) lets you load multiple datalogs at one time and just stitches them together into one big log. The only thing I was interested in was how much pedal (throttle position sensor - TPS) I was using during the majority of the time. Once I'd loaded several megabytes of detailed engine logging, I went to the Scatter Plots function and asked MLV to plot the throttle position against the engine load (MAP) and to just count the number of hits in each cell. The resulting scatter plot shows I spend at least 70% of driving time in the lower 35% of the pedal. So, that means I will need to try to fabricate a cam action that gives priority to the lower 35% of the TPS. I'm thinking of building an aluminum cam that lies on the face of the bar that the cable attaches to to reduce the travel of the bar during the first 35% of the pedal press. At least that's my current thinking... Change my mind or give me a link to someone who's already fixed it :-)
Here's the scatter plot:
