After some careful dialing in of the fuel map in the area where the nitrous first hits and starts the initial spooling of the turbo, I was able to get the 60 foot down to a 1.35 over the weekend. This paricular area of the fuel map is very tricky to work with since the ALS masks the O2 reading with a very lean reading. I made sure this section of the fuel map was rich to cover any mistakes and have been slowly leaning it out to find the best mixture to allow the quickest turbo spool up during the ALS affect. Between the last testing session and this one, I've leaned that area about 4% now. What I've noticed is that the O2 reading through the ALS affect is becoming much more stable as I lean that section of the fuel map. Where the reading would go to 14.64:1 at the beginning to the nitrous hit, it would only maintain a flatline reading for a short period of time, and then the reading would bounce to a richer reading, such as 13 or 12 to one and then back up to 14.64 for a short period, until the ALS was cancelled. What I'm trying to say is that the 14.64 O2 reading was not a flatline reading throughout the ALS affect, where in past smaller nitrous shot sizes I've played with, it did give a flatline 14.64:1 reading throughout the ALS affect.
Soon after switching to this latest nitrous shot size and seeing the O2 readings bouncing off the 14.64 reading, I realized that the mixture might not be just right to maintain the best ALS affect and hence the quickest turbo spoolup. The big question was, is it too rich or too lean through that section? To be safe I first tried to richen that section and the results were that the O2 reading became more erratic through the ALS affect with no noticeable change in the performance of the car. I then began to lean that section of the fuel map and the more I leaned it out, the more the O2 reading stabilized towards the target flatline 14.64:1 reading. Also, the turbo was creating a better boost level in relation to rpm through the ALS region, and giving better 60 foot times, as evidenced by the latest best 60' with the car and the 91mm turbo.
The ALS O2 reading is still not perfectly flatline yet, although, it is very close, so there may still be a little more improvement in the 60 foot to be had. We'll see what happens.
I'm also going to try lowering the rear tire pressure from the current 8.75 psi to 8.50. The passes have been very stable with the 8.75, and I want to see what 8.5 might do.
Soon after switching to this latest nitrous shot size and seeing the O2 readings bouncing off the 14.64 reading, I realized that the mixture might not be just right to maintain the best ALS affect and hence the quickest turbo spoolup. The big question was, is it too rich or too lean through that section? To be safe I first tried to richen that section and the results were that the O2 reading became more erratic through the ALS affect with no noticeable change in the performance of the car. I then began to lean that section of the fuel map and the more I leaned it out, the more the O2 reading stabilized towards the target flatline 14.64:1 reading. Also, the turbo was creating a better boost level in relation to rpm through the ALS region, and giving better 60 foot times, as evidenced by the latest best 60' with the car and the 91mm turbo.
The ALS O2 reading is still not perfectly flatline yet, although, it is very close, so there may still be a little more improvement in the 60 foot to be had. We'll see what happens.
I'm also going to try lowering the rear tire pressure from the current 8.75 psi to 8.50. The passes have been very stable with the 8.75, and I want to see what 8.5 might do.
