I'm curious if you have dyno tests to back up that amount of advance as optimal. It would be more than I have seen.

Rich

 

Wen we dynoed last spring (p1sc 11psi twin ic 383 ported stock heads cc305) we started at 11-11.5 A/F and 25-26 degrees timing (tabells)=510rwhp we started to adjust A/F to 12-12.5 dont remember how much gain but when we were finished it ended up at 28-30 degrees from 4-6000rpm= 570rwhp, we tried to add more timing widh negative respond.
Whats important to think of is that a dyno run takes less time than a run down the 1/4 so count whith a higher IAT down the way and pull 1 or 2 degrees extra for saftey...
dont have all the dyno sheats to prove every change, the dyno could only storage 4 runs at the time and we didnt save beatween the runs, just deleted the old ones when we got improvment .

 

If you have lower CR (my will be 8:4.1) will this let me add 1-2* more if i was @9:1cr....

would someone post there timing curve (wot tables)

 

When doing timing tables do you lock in the hole table at 24* in the 95-100kpa.

With the stock timing tables at what rpm do you start add in the timing....

 

What I have seen with timing tables is the lowest value of the table occures at the RPM of peak torque, as the cylinder pressures will be highest at that point. Usually the timing will decrease as you approach peak torque, and increase a little there-after.

 

Sure with less compression you might be running a good amount of timing depending on boost and fuel.

Personally, I would never run the AF leaner than 12:1 in a FI car, so I consider Lisa's 12.5 to be on the edge of safe with that timing, assuming pump gas.

What is stock LT1 timing at WOT?

 

rich,
in response to the dyno info. i did indeed dyno it many times and settled on 29. it would make more power @ 30-31 but not enough to justify the risks. i often wondered if it was a timing problem but a verified it many times against a timing light. i plan to pull the motor shortly and will post if i find anything wierd. comp. ratio is just under 8:1 also

 

Did you ever check to ensure your timing marks are in fact true TDC?

I also never run leaner than 12:1

 

Slightly off from the topic, but when I had a 11.5:1 ARE 422 setup I tried four different timing amounts one day on the dyno. Keeping in mind that stock is like 26, we tried 25, 27, 30, and 32. Made most power around 28-29 but the gain from 25 degrees to 30 degrees was like 4rwhp.

 

I was wondering that myself?

 

i checked true TDC several times. i was seeing large jumps in hp (20+) until i got to around 28 then very little from there. pretty sure we backed off at 31 maybe 32

 

I'm running 31 degrees in my SS and 34 in My TA and I have several dyno pulls to back up these numbers all of my tunes are on Race gas! All boosted cars are different in the amount of timing they like. My SS makes the most power with 32 degrees and and around 11.2AFR not sure why it likes it so rich but it does. My TA likes 34 and I set it at around 11.8 AFR it makes more power the leaner I take it but I'm scared

Jeff
96 SS BLOWN
96 TA 396 D1

 

Oure 98oct (RON) is a little higher than youre 93 it also has a 5% etahnol in it from the pump.
The A/F were between 12.15 to 12.4 on the dyno if i remember correct, and than i added +/- .1 for diffrent wether conditions.
Only used that tune on the strip, for ordinary driving -2degrees+and not so much WOT driving
Comp were 9.0
But yes i agree it was a little aggresiv tune, dont think im gonna aim for the last HP on the new setup.
Ake

 

anyone care to post the timing tables(wot)