Car A/F totally different on dyno and track
Posted: Sat May 29, 2010 7:17 am
This is on a race dc2 with b18cr 11.5:1 with toda cams.
The car was tuned on dynojet to 13-12.8:1 A/F on dyno with water temp above 81'c.
1st test on track showed that water temp was hovering just below 81'c. about 79-80'c. And A/F was like 11.8-12.2:1. Then noted water compensation shows add over 20% fuel at 75'c.
So when back to dyno to touch up a/f further and try using 0% compensation at 75'c. On dyno it shows that it work and a/f consistent.
back to track for testing, water temp throughout datalogs shows water temp was 79.7'c consistent. And a/f once again drop to 12-12.2:1 instead of 13-12.8:1 that we set on dyno.
Could this be low water temp problem??? But even i set 0 compensation at 75'c and 81'c will the ECU some how still override and add fuel to a cool engine?
I'm now thinking of changing to a higher temp themostat but wanted to get some idea/suggestion from here before burning more money on parts, dyno time and track fee testing...
The car was tuned on dynojet to 13-12.8:1 A/F on dyno with water temp above 81'c.
1st test on track showed that water temp was hovering just below 81'c. about 79-80'c. And A/F was like 11.8-12.2:1. Then noted water compensation shows add over 20% fuel at 75'c.
So when back to dyno to touch up a/f further and try using 0% compensation at 75'c. On dyno it shows that it work and a/f consistent.
back to track for testing, water temp throughout datalogs shows water temp was 79.7'c consistent. And a/f once again drop to 12-12.2:1 instead of 13-12.8:1 that we set on dyno.
Could this be low water temp problem??? But even i set 0 compensation at 75'c and 81'c will the ECU some how still override and add fuel to a cool engine?
I'm now thinking of changing to a higher temp themostat but wanted to get some idea/suggestion from here before burning more money on parts, dyno time and track fee testing...
