Datamaster DA Timing Question
Thread Starter
Race Director
Joined: May 2001
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Datamaster DA Timing Question
The value that datamaster dispalys for spark advance, is that the value commanded by the computer, or is it an actual calculated value?
I ask because I'm having trouble with a friend's car. I can randomly pick points out of a datalog can look at the RPM and MAP value and find that his timing is consistently reported to be about 3 degrees less than what the computer is commanding.
I posted another thread asking why the data log doesn't match the chip and I didn't get much of a response. I got to thinking that maybe I'm chasing my tail. If the value is an actual value instead of a commanded value, perhaps I should look at some other reasons why the timing would be different, such as the opti reporting incorrectly, etc.
Is that even possible? Could the opti somehow be "skewed" so as to report a different timing value than is commanded?
I ask because I'm having trouble with a friend's car. I can randomly pick points out of a datalog can look at the RPM and MAP value and find that his timing is consistently reported to be about 3 degrees less than what the computer is commanding.
I posted another thread asking why the data log doesn't match the chip and I didn't get much of a response. I got to thinking that maybe I'm chasing my tail. If the value is an actual value instead of a commanded value, perhaps I should look at some other reasons why the timing would be different, such as the opti reporting incorrectly, etc.
Is that even possible? Could the opti somehow be "skewed" so as to report a different timing value than is commanded?
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by Nathan Plemons
The value that datamaster dispalys for spark advance, is that the value commanded by the computer, or is it an actual calculated value?
I ask because I'm having trouble with a friend's car. I can randomly pick points out of a datalog can look at the RPM and MAP value and find that his timing is consistently reported to be about 3 degrees less than what the computer is commanding.
I posted another thread asking why the data log doesn't match the chip and I didn't get much of a response. I got to thinking that maybe I'm chasing my tail. If the value is an actual value instead of a commanded value, perhaps I should look at some other reasons why the timing would be different, such as the opti reporting incorrectly, etc.
Is that even possible? Could the opti somehow be "skewed" so as to report a different timing value than is commanded?
I ask because I'm having trouble with a friend's car. I can randomly pick points out of a datalog can look at the RPM and MAP value and find that his timing is consistently reported to be about 3 degrees less than what the computer is commanding.
I posted another thread asking why the data log doesn't match the chip and I didn't get much of a response. I got to thinking that maybe I'm chasing my tail. If the value is an actual value instead of a commanded value, perhaps I should look at some other reasons why the timing would be different, such as the opti reporting incorrectly, etc.
Is that even possible? Could the opti somehow be "skewed" so as to report a different timing value than is commanded?
It is possible although I can't tell you why. I do know that in the ZR1 ECMs and if you are scanning with either a TECH2 or using Datamaster, what is reported is a 6 degree difference. For some reason neither scan tools can pick up the offset. It could be the same thing with what you are seeing. I would need to verify that with my TECH2 and a my scope to see the difference between what we see on the balancer and the scan tool.
Thread Starter
Race Director
Joined: May 2001
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What is strange to me about this is that my '92 LT1 reports exactly what the chip commands. What would make one incorrect vs the other?
Also without any marks on the balancer to base off of, how in the world do you determine what the car is really running at?
Also without any marks on the balancer to base off of, how in the world do you determine what the car is really running at?
