7747-7427 Swap

[89RCLB]

So just curious...does it run noticeably better? What does the SOTP dyno tell you?

I would love to do this to my C1500.

 

[Scooterwrench]

So just curious...does it run noticeably better? What does the SOTP dyno tell you?

I would love to do this to my C1500.

Acceleration is definitely improved and less pedal input at 70 MPH cruise. Exhaust system is holding it back. 70 MAP at 70 MPH. Factory logs, restrictive 2 into 1, probably the cheapest Discount Auto Parts muffler they could buy and judging by the burrs they left on the tailpipe I'm guessing all the welded joints have big burrs choking the exhaust flow. I'll be dancing a jig when I'm toting that crap to the scrap iron pile.

 

[L31MaxExpress]

I was playing with buttons on the history table and clicked on the spark advance table and found this,

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ICM? Setting?

The math is wrong in the scanner program, causing it to display values like that when the timing advance goes negative. I corrected the math a while back in the $OD definition file I have and it reads negative values when applicable now.

 

[Scooterwrench]

The math is wrong in the scanner program, causing it to display values like that when the timing advance goes negative. I corrected the math a while back in the $OD definition file I have and it reads negative values when applicable now.

Sounds like I need to add more timing in high MAP/lower RPM regions. I was getting so much spark knock I basically threw the timing table away I was working with and plugged in a stock table and added 6deg across the board to get it back on the road again. That log was with no PE or PE advance.

 

[Scooterwrench]

OK, Tell me about "Main Spark Bias" and how little of it can I run. Right now I have the knock sensor turned off but something is still pulling all my timing out. If I try to add timing I get audible spark knock.