Setting timing on dyno

[TopMountGSR]

Hey everyone, I hope this has not already been covered but I want to make sure I am doing this the way it should be done. I start at say 1 degree retard per pound make a pull, record the max tq set it to: .9 per pound make a pull, record max tq set it to: .8 per pound ect.. ect.. When the tq doesn't increase as much as before I stop, maybe pull a degree or so out to keep it safe. Pull plugs and check for specs. Am I on the right track with this? With d series engines I have been starting this process at 1 degree per pound, and b series .75. Some times I do .1 increments, sometimes .05 increments Thank you for your time, dk Any tips suggestions or comments are more than welcome.

[Adam Hopkins]

No, thats not how I do it. I usually start with 1.25 to 1.5 retard per psi. Once im on the dyno I start to look at the torque curve. You do not want to just add timing to the whole map, you have try and add timing where the power curve looks like it is dipping down goes flat or does not look right. I never add timing by changing the degree per psi. I always look at what RPM it \"needs\" timing and add some there. Also you want to try and not add too much timing at peak torque. Peak torque is peak cylinder pressure. You may also want to run a little richer there to help prevent knocking.

[Bugermass]

I do both.. I start off with the standard retard, then once fueling is good I'll add 2 deg at a time globally to the WOT/Boosted area, then compare graphs to see where TQ is increasing and where its not, then if theres any areas where there wern't good gains I'll pull back timing in those areas.. The areas where there were good gains I'll add another 2 deg. I usually repeat this process untill there are minimal gains all over.. Now this is on race gas tunes.. On pump gas tunes, most times I\"ll do a standard retard, then do the add 2 degress to see where I\"m at timing wise, then decide depending on the gains if I wanna push it or not. Most times I leave timing super conservative on pump gas motors unless they are built, and I'll make up power with boost

[FACETUNED]

I do both.. I start off with the standard retard, then once fueling is good I'll add 2 deg at a time globally to the WOT/Boosted area, then compare graphs to see where TQ is increasing and where its not, then if theres any areas where there wern't good gains I'll pull back timing in those areas.. The areas where there were good gains I'll add another 2 deg. I usually repeat this process untill there are minimal gains all over.. Now this is on race gas tunes.. On pump gas tunes, most times I"ll do a standard retard, then do the add 2 degress to see where I"m at timing wise, then decide depending on the gains if I wanna push it or not. Most times I leave timing super conservative on pump gas motors unless they are built, and I'll make up power with boost

x2

[ckretvix]

Im trying to find out if .65deg per psi is safe enough for pump gas (93). Its about 19deg at 12psi (7000) on a stock LS motor. From the tunes I've seen that were done by xenocron, the timing was a little more across the board.

[Bugermass]

well you really can't base your timing off somone elses maps.. Differnces in air, weather, alititude, and especially quality of gas in different areas can really affect how much timing you can run.. Your best bet is if you don't know and can't get it on a dyno to find out, just keep it conservative and use the boost to make power.. Every motor will want somthing different, even if you have 3 identacal setups back to back, they will all want different maps..

[ckretvix]

I gotcha. It will be dynoed saturday, but I wont have time to tune, just do a few runs to see what it puts down.

[TopMountGSR]

Thanks for your replies guys! So can I adjust the timing throughout the rpm range in the WOT/boosted columns smoothing the tq line, Once its smoothed can I just highlight the whole wot/boosted column adding a degree of timing a pull till tq diminishes? Then pull a degree to be safe? Am I sort of on the right track here? If there is a downward dip in the tq graph, it needs a little timing there to make it smooth fading it all into the peak torque area. I've noticed on my tunes my timing tends to flatten out till redline in the boosted/wot column and I've always had a weird feeling that wasn't right. This would be on a built engine with race gas. I pull plugs and check for specs constantly. Thank you guys for your time, I've always wondered about this. I'm so scared of dynos and I know there is more power to be had in my setups.

[ckretvix]

From what Im getting, what you say will work, but you need to read the graph. If theres bumps anywhere, you smooth them out first (adding/subtracting) timing to individual cells, and then move on to applying more timing across the WOT area?