Meen95z

iTrader: (26)

I have a solid roller 385 lt4, 11.6-11.8 compression and always ran 36* degrees at WOT. Starting to see some run upwards of 40*. What are most you guys with a good aggressive tune running? Just curious.

96capricemgr

iTrader: (1)

Shouldn't need that much with a good chamber.

bowtienut

iTrader: (1)

Is that 37* in the timing tables? If so, that sounds like way too much.
If the 37* is what's reported with a datalogger like Datamaster, it's probably still on the high side.
I run 29* WOT in the tables, which is 33 to 34 degrees total, as reported by Datamaster. Ported LT1 castings. 12:1 CR

Mystery Bird

iTrader: (7)

Stock tables are 35 correct?

moehorsepower

iTrader: (3)

You cannot ask an across the board question, it depends on a lot of things, Like 96 stated, depends on chamber efficiency. then there is quench, how efficient you heads are ect. I have seen as little as 33* and upwards of 39* on a setup with that compression..

bowtienut

iTrader: (1)

....and also depends on the mechanical variations/ tolerance stackups of every part from crank to cam to opti. That's why we have to dyno tune or track tune to find the sweet spot
Moe, is that 33 to 39 range actual total advance? not what's entered in the timing tables?
Mine at 29* is the extreme low number AFAIK. The other few that I personally know of with compression, quench, and heads similar to mine range from 30 to 33 in the tables for best power, not limited by octane.

moehorsepower

iTrader: (3)

Thanks for asking that question, That is whats entered in the tables, actual vary as you say, due to DA?, Humidity? ect dont know. I have not seen actual as low as yours, but in the 31-33 range...Again maybe Octane limited or type of fuel.

Mystery Bird

iTrader: (7)

Frankly I was scratchin' my head trying to figure out how you're running 29*.

moehorsepower

iTrader: (3)

Are you saying as in a lot of timing? Because even on a 13.1 motor I have not seen as low as 29*. But again a lot of variables.

Mystery Bird

iTrader: (7)

No, I meant low, sorry.

DUDCOUPE

Read the plug, one way to tell if you need less timing or if you can add more

96capricemgr

iTrader: (1)

I use 29* programmed max in my car too.

bowtienut

iTrader: (1)

You won't necessarily find best power with that method. But it's safe if you know how to read them.

noice

I ran 41 degrees timing on the distributor, with a weak advance spring to allow for starting but essentially the distributor was locked. Dart Pro 1s ported, ~13:1, flat top pistons, 396ci.

It was on methanol though. I was aiming at mixing nitro with the methanol which would require even more timing.

Was running high 30s with 150 shot nitrous, race gas, and methanol. Never did start leaning out the shot or playing with advance while reading the plugs. Could have really worked towards the edge. Just would look at the plugs to see if any problems and would take EGT readings every run.