[DonWG]

Sunday the race was cancelled due to high winds, which led to fires all over California. I packed up the car and when I got back to the shop, decided to do some tuning, since the wind was not bad at all at the shop. The car was still on methanol and I needed to work on the return road tuneup (light cruising up to 2800 rpm). After working on that in front of the shop, I pulled the car into the shop and started to play with the tuneup at converter stall on the transbrake.

After studying some recent datalogs and doing some experimenting I found that this engine really likes the a/f ratio under boost that I had assumed was too rich. My readout is set for gasoline and I guess I was thinking too much of what good a/f numbers would be for gasoline. I was assuming those lambda values would also work for methanol. I was wrong. During recent track testing, I was starting to realize that as I tried to lean the a/f ratio under boost to my target of 11.3 to one, my mph started to drop off or at the least was not getting any better. I always felt that as I leaned toward 11.3 the mph should increase. A sure sign that HP was coming up. It didn't.

In the garage, as an experiment, I setup the a/f table to target 12.4 at 2440 rpm, which is converter stall at 0 boost, and ramped the target a/f ratio to 10.2 to one by 135 kPa boost. The results of the test was interesting. After going WOT, the rpm would go to 2440 rpm as usual, but then slowly climbed to 3400 rpm, which is when I got out of the throttle. Not sure how high it would have continued to go. As a check, I went back to the a/f table and set the target a/f to 12.4 at converter stall at 0 boost, ramping it to a different value at 135 kPa. I used 12.4 for this test. The result was, the engine rpm stalled at 2440 rpm and did not increase as before. I couldn't go back and do a retest because I ran out of methanol. Grrr. More testing to continue. What would going richer still bring?

After getting this result I decided to look up some old notes that I had taken on safe best power and rich best power for gasoline versus methanol.

Safe best power for methanol is 5.5 to one.
Rich best power for methanol is 4.5 to one.

5.5 methanol = .85 lambda = 12.48 gasoline.
4.5 methanol = .70 lambda = 10.21 gasoline.

I guess it's a good idea to dig up old notes and read over them every once in awhile.