Timing at 8.5 or 9.5 degrees BTDC?

ROCK HARVEY

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I have a Kent Moore timing setup on the way, so I was reading the tech article on how to to set the timing on our trucks. The article mentions how some people prefer to set their timing at 9.5* BTDC rather than 8.5. What’s the advantage to this? Does slightly advanced timing give more power, or is this intended as a buffer for the timing slowly becoming more retarded as the injection system wears out? Or is it just people adapting to low-cetane fuel?
 

Big Bart

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From what I have read some felt they get more power at 9.5*.

As I recall there was a thread about a meet and they timed and dyno’d and I believe there was a increase in hp or torque at 9.5*.

But personally I run at 9* and did not notice any difference over 8.5*.

I wish I had a dyno it would be interesting to know what the dyno would show at 8.5* and 9.5*.
 

Clb

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The loss of the actual GOOD **** "sulfer" caused the btu and or flame spread to alter timing....
Check mels stickies on timing. Amgen
So 7.5-10.0 degree spread.
mine runs hot retarded.
don't advance it to the point of clatter
 

IDIBRONCO

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From what I've seen on here, trucks with turbos seem to like their timing more retarded than the N/A ones do. That aside, each engine/pump/injector combination is it's own creature. They all like slightly different timing settings. You can get close by setting your timing at "X"*. It may be spot on or your engine may like a little bit more or less timing advance. The pump builder's recommendations are a good place to start. Experimentation is the key here though.
 

ROCK HARVEY

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It sounds like I’ll have to just play around with the timing every couple tanks and see where I get the best performance/mpg. Good idea on asking the pump builder.
 

Booyah45828

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Mine is at 7, NA 6.9 in a school bus. I tested from 6 all the way to 10 in 1 degree increments. Being in a heavy bus, the differences between the tests were pretty noticeable in acceleration, heat, clatter, and black smoke produced. 6 was smokey and seemed to be hotter temps then 7-10. 7 was quickest with only a haze of black smoke. 8+9 were slower, but with no smoke. 10 was slowest, with no smoke and kind clatterish. So I reset it back to 7, got 6.6, and said good enough. All done with a j33300. Then I dug out the mt257 and snap on dial adjust light to confirm the end result, and it showed 7.

One might get different results in a lighter truck at a different settings. I'm just listing what I found.
 

ROCK HARVEY

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Thanks that’s good data. I’ll probably do something similar and try to measure my mpg at various settings.
 

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