Timing Table

[BLG355]

I've been looking for a good timing table for some time, and I ending up using one Brian617 posted a while back, but modified it to suit my needs. Basically, at certain points while driving the truck just felt flat, so I made the timing more aggressive and increased it overall and more so at certain spots. I looked at a lot of timing tables all over the place, and a bunch here, and they just don't seems to have near the timing I am using. I tried a bunch but the engine feels very weak midrange, and I modified brian617's table and was able to eliminate the flat spots almost completely, I am thinking about tweaking a degree or more in a few spots and see how it feels.

Most other timing tables I tried, even the Vortec one, just don't have the throttle response or the feel I was looking for. I am looking for some input and thoughts from you guys, do you think I am way to aggressive on the table or is it ok? Should I tame it down a little...or a lot. The truck runs and pulls great, I was thinking about trying more to see if I can find some knock and then back it off a few degrees. Any thoughts, comments, anything at all...is greatly appreciated. Thanks.

BLG

[steveo]

that isn't a very aggressive table, but then again it's a truck.

I was thinking about trying more to see if I can find some knock and then back it off a few degrees

you're better off increasing it in a reproducable range, and monitoring for an increase in vacuum (or decrease in KPA, whichever way you want to look at it). when vacuum stops increasing, you're at the ideal point, just stop.

once you've determined a few points in the table like that, you can usually interpolate the rest of the table and figure out how the curve should be, and do fine tuning if there's any resulting knock.

[BLG355]

Thanks for the reply. I was being conservative at first because of the weight, but i started slowly increasing timing to roughly where it is now, and have since brought the timing in a lower rpm's with good results. It seems like most of the tables I found max out under 20 at WOT and the part throttle stuff was almost 15-20* less than what i am at now. I have very crisp throttle response now and it feels very good driving it.


BLG

[brian617]

Been to busy lately to fiddle with mine, although I keep thinking about adding or changing mine too. Glad to see that the same basic shape is working for you, makes me want to throw some more timing at mine. I'm constantly looking at other maps eyeballing the shapes trying to understand more about them.

[BLG355]

Been to busy lately to fiddle with mine, although I keep thinking about adding or changing mine too. Glad to see that the same basic shape is working for you, makes me want to throw some more timing at mine. I'm constantly looking at other maps eyeballing the shapes trying to understand more about them.

It really worked good for me, especially compared to some others I have tried. For my build, bringing the timing in at a lower RPM really makes the truck feel more responsive. I'm currently swapping out 7.4 TB and injectors so I want to get that nailed down before I change too much else at the moment.

BLG

[Fast355]

It really worked good for me, especially compared to some others I have tried. For my build, bringing the timing in at a lower RPM really makes the truck feel more responsive. I'm currently swapping out 7.4 TB and injectors so I want to get that nailed down before I change too much else at the moment.

BLG

I noticed the same thing bringing in timing earlier on the Vortec head engines I have tuned.

[BLG355]

Fast355,

I noticed 30 degrees at idle on your one table...is that really at idle or is there a separate table for that?

BLG

[Fast355]

Fast355,

I noticed 30 degrees at idle on your one table...is that really at idle or is there a separate table for that?

BLG

Separate table, but I use the same values in that table. Never seen a need for different values as it makes the transition pretty abrupt to go from no timing to full timing off-idle. Same reason I do not use ported vacuum on the older carb setups. Idle generally ends up best around 26-34* depending on the heads/cam/compression ratio.

[BLG355]

ok, I'm going to try this with mine. I have two different tables and my idle never feels very good. I've tried it from 18 to 23, but never any higher. I am going to bump it up and see how it goes. Thanks.


BLG

[Fast355]

ok, I'm going to try this with mine. I have two different tables and my idle never feels very good. I've tried it from 18 to 23, but never any higher. I am going to bump it up and see how it goes. Thanks
BLG

I usually advance the timing at idle until the IAC/MAP stops dropping and then retard the timing 2-4* from that setting. One thing I have noticed is the idle timing variation has less effect the more closely optimized your idle timing is for the setup.

[PJG1173]

WOW, I have always been reluctant to advance mine more than 19 ~ 20* at idle. might have to try it too.

[Fast355]

WOW, I have always been reluctant to advance mine more than 19 ~ 20* at idle. might have to try it too.

The last LT4 Hotcam Vortec 350 that I messed with, liked about 30* of timing at idle.

[rsicard]

The last LT4 Hotcam Vortec 350 that I messed with, liked about 30* of timing at idle.

Have the same setup Vortec 350 with LT4 Hotcam. Also have 454 throttle body. Question, do you check the timing on the balancer or just ignore it and use Tuning Software to set the timing table/map? Have compared balancer with TunerPro ECM commanded timing and found no relationship between the two. Maybe should just set the tables in TunerPro according to you tune and then set the distributor to attain the desired values. Please advise. Thanks.

[steveo]

idle timing should be set just like the rest of timing map, to the point of maximum vacuum and no more.

[brian617]

Fast, any chance you could screen shot your MAP vs RPM table in 3D view so I can eye ball the shape?