Most of my driving is now pretty local - surface streets with round trips of 5-10 miles... almost no freeway driving. I think the reason I got a better improvement in fuel economy is that I can now use fifth gear on typical 35 MPH boulevards.

I don't have to downshift until below about 30 MPH, which is about 1100 revs. Below this I can feel the engine labor and response is sluggish - probably due to lack of sufficient spark advance. Given the torque peak of 4600, the engine is not designed for low rev torque, but it has excellent torque bandwidth with the R16/1 resistor removed from 1500 to the rev limiter.

My engine system engineering requirement for a responsive high performance road engine is 80 percent peak torque at 2000 with a manual trans and 90 percent with an automatic. Back in the nineties I had my car on a chassis dyno, and it actually made 80 percent at 2000, which surprised me because it felt pretty soggy down low. With the R16/1 removed it must make 90 percent at 2000, which is excellent for such a high torque peak engine!

I actually just use 87 PON, and if ambient is below 70 and coolant at the usual 80C it doesn't detonate, even if I drag it down to about 700 in second gear at a stop sign and then go without declutching and going to first. Since I usually only drive it during the cooler months, 87 is okay, and if ambient is over 70 and coolant is over 80C I can "drive around" any slight transient detonation by shifting at higher revs. Usually I shift at 2000-2500.

You've got a 300E, right? Where's the R16/1 resistor located?

Duke