So a few weeks ago I posted about my car not really running the times and mph expected given the number of mods. Here is the thread: http://www.turbobuick.com/forums/th...-why-is-my-car-not-quicker-than-it-is.406377/.
Following some of the advice received, I started creeping up on WOT timing. I added 2 degrees of timing over what was in the Turbo Tweak alcohol chip already. The car did not knock at all at 26-27 psi with the added timing, so I added 2 more degrees of timing at WOT for a total of 4 degrees over what is in the tune already. Still no knock. So I added more timing for a total of 7.7 degrees over what is programmed into the chip, which I believe is around 21 degrees for an alcohol tune. Finally I got a slight bit of knock. The Powerlogger file showed 31 degrees of timing with 27 pounds of boost and 2 degrees of KR, which went away quickly. Obviously, something is not right...
So I decided to check the base timing with a timing light. I jumped the A & B pins at the ALDL connector to put the car into ALDL mode. Timing measured at the balancer with a timing light showed a perfect 15 degrees, but spark advance measured at the same time with the Powerlogger showed 25 degrees.
Why would the ECM/Powerlogger see timing as 10 degrees higher than actual timing measured with a timing light? Is this normal? If not, what do I need to do to correct it?
Thanks.
Following some of the advice received, I started creeping up on WOT timing. I added 2 degrees of timing over what was in the Turbo Tweak alcohol chip already. The car did not knock at all at 26-27 psi with the added timing, so I added 2 more degrees of timing at WOT for a total of 4 degrees over what is in the tune already. Still no knock. So I added more timing for a total of 7.7 degrees over what is programmed into the chip, which I believe is around 21 degrees for an alcohol tune. Finally I got a slight bit of knock. The Powerlogger file showed 31 degrees of timing with 27 pounds of boost and 2 degrees of KR, which went away quickly. Obviously, something is not right...
So I decided to check the base timing with a timing light. I jumped the A & B pins at the ALDL connector to put the car into ALDL mode. Timing measured at the balancer with a timing light showed a perfect 15 degrees, but spark advance measured at the same time with the Powerlogger showed 25 degrees.
Why would the ECM/Powerlogger see timing as 10 degrees higher than actual timing measured with a timing light? Is this normal? If not, what do I need to do to correct it?
Thanks.