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This has about the same AFR to lambda mapping as regular 93 unleaded pump gas, whereas E85 has a very different mapping. So E85 is not useful in tuning a pump gas car. Plus feeding this engine with enough E85 using a reprogrammed LH would be a bit of a challenge.
In contrast, we can tune the car with this race gas safely first, and then step down the octane level by blending in pump gas and pull boost and/or timing. Alternatively, we can start very conservatively with pump gas and then blend in the race gas while adding boost and/or timing. Fixing the AFR to the predicted ultimate richness across all these tests regardless of the octane level, say 12.0 AFR, is going to be close enough for government work in the first pass.
In my opinion, yes. Opinions vary, of course. Although it's rarely done in a formal optimization way, tuning is just a simultaneous estimation-optimization problem. Race gas makes the knock constraint less binding and therefore allows the functions to be estimated more easily. What this means in practice is that it's easier to figure out the torque produced as a function of ignition timing for given boost setting and rpm, because you can sweep a larger area of alternative ignition timing settings without having to worry about the knock. Now, I'm not a professional so someone more experienced may think that this is wrong/irrelevant/waste of time.
In my opinion, yes. Opinions vary, of course. Although it's rarely done in a formal optimization way, tuning is just a simultaneous estimation-optimization problem. Race gas makes the knock constraint less binding and therefore allows the functions to be estimated more easily. What this means in practice is that it's easier to figure out the torque produced as a function of ignition timing for given boost setting and rpm, because you can sweep a larger area of alternative ignition timing settings without having to worry about the knock. Now, I'm not a professional so someone more experienced may think that this is wrong/irrelevant/waste of time.
Think this is good thinking - interesting the startup is on the go.
Åke
How much mass does all this add to the front end? (Thinking weight balance and likely the need for Big Big brakes on the front. Might need more spring too.)
How much mass does all this add to the front end? (Thinking weight balance and likely the need for Big Big brakes on the front. Might need more spring too.)
While I'm having a rough month traveling, John's testing the fuel system. Everything seems to pressurize correctly, no smell, no leaks, and pressure holds well downstream of the check valve.
Personally, in November I've done two World Series games in Chicago, long weekend in Disney World, some private clubs in London, a week in Cape Town, and now Thanksgiving in St. John. This was supposed to be my vacation month, and I feel like I need a vacation when I get back from vacation! How do the Europeans do this every year with their seven week holidays???
The European holiday is an acquired taste and takes a little to get used to... Once you acclimate to the lifestyle, changing to the American one becomes impossible...!
How much mass does all this add to the front end? (Thinking weight balance and likely the need for Big Big brakes on the front. Might need more spring too.)
We've got to see where it lands. The earlier system added maybe 50-75 lbs to the front, this system should probably be pretty close to that. Then again, I'm about 40 lbs lighter myself compared to the previous iteration...
12-01-2016, 07:11 PM
