Timing Tuning ?

[V8_Club]

How do you guys do it ? Do you :

1- Add a number to the entire table nad keep going until you get KR then reduce timing in the affected areas ?
OR
2- Tune specific areas/rpm ranges ? For example > .76 gm/sec & > 3000 rpm ? Then smooth the transition to those cells ?

Also , from experience what are :

1- Best Timing Values on LS1s ? Stock ? With Bolt ons ?
2- Best Timing for LS1s on N20 ?

Thanks Guys

[12secSS]

I like adding timing at specific locations, but I would have to strongly recommend this be done on a dyno to verify that the target timing produces the most HP.

As for what timing is the best ... it really depends on the vehicle for that. And as for nitrous ... I am not a nitrous guru, so I wouldn't know. ???

[V8_Club]

Cool. I will be doing so on a Dyno . Note Chevy Perfomance mag suggests the following :

Add a couple of degrees of timing to the 0.76 g/cyl row and copy this data to the higher g/cyl rows. Use the 0.72 and 0.74 g/cyl rows to smooth the transition to the 0.76 g/cyl and higher rows.

I've seen people add +6 to the whole table to start with then add 1* as they go along.

I would like to know something though, to better decide between both approaches. Is their any advantages/disadvantages to adding timing to the low load cells ? i.e. below .72 ?

Also the reason I'm worried about the Nitrous is in general I heard people RETARD timing for Nitrous so a setup for max NA performance might not be what the doctor ordered for N20 ???

[S2H]

I transitioned the theoretical timing table into my stock table with very good results...
when I have some time for a dyno run or 7 I'm going to check and see where teh best timing is....
I seem to remember on my old car it was at 27*...
so after I pasted that table(and saw no knock except for 1* in just a few spots)
I decided to reduce the table until I saw 27 on teh top end...
I did notice that under heavy load...and low low rpm..I had some knock....so I pulled that out...
and teh car feels extremely powerful in all ranges....
I put back in teh stock tabel to feel it..and it feels liek a slug compared to the new values...

things to remember..the max theoretical timing table does not exactly match the high and low octane #'s..you have to do a little interpolation between rows and columns.

[WS6FirebirdTA00]

timing is based on your package, has a lot to do with valve events and the combustion chamber design. best way is the dyno for sure, you dont want to flatline your timing, you want a dip around max torque. AFAIK that is to create more pressure, also with added fuel, to make more timing in the car. i dropped my timing from 29* to 25* at 4400 rpm-4800 rpm and noticed a big difference in power, mainly because i couldnt keep the tires hooked in 2nd no longer, before it wouldnt spin in 2nd on accel until high rpms, sometimes. i also compaired values such as dynamic airflow (which will get scrwey with wheel spin as well so if you are spinning you cant compair) also compaired various acceleration times.

[WS6FirebirdTA00]

also, .72 g/cyl is high load, i see about 0.88-0.90 g/cyl WOT on my car, take a log of the timing advance and you will see what cells you hit when

[chrisj6]

My timing table right now reads 25-27* WOT timing in most places and I still consistently see 30* on the scanner, whats up with this?

Chris

[WS6FirebirdTA00]

Check out the spark corrections, If you are in SD make sure that both high and low have been set. Sometimes I forgot to go back to the low octane to make changes, when I didnt have 1 bar sd package. also check out the correction tables and make sure it isnt adding anywhere. Just double check WOT cells and confirm they are WOT cells with a log and see waht g/cyl you are at

[chrisj6]

Yeah I am now using a start of the stock Z06 timing table with a bit of smoothing out done. I am now commanding 23-24* and still consistently hitting 28-29* at WOT. I am looking at the adders now, will let you know.

Chris

[chrisj6]

My AFR adder was kind of aggressive. It added alot of timing quickly so i backed that off some and smoothed it out.

Chris

[SMOKINV8]

I transitioned the theoretical timing table into my stock table with very good results...

things to remember..the max theoretical timing table does not exactly match the high and low octane #'s..you have to do a little interpolation between rows and columns.

Why did you transition the theoretical table into the stock (high octane?) table? I'm assuming the theoretical table is another parameter we can modify in the editor?

What interpolation is it that you're referring to? Averaging the values?

[chrisj6]

Yes he means the values were somewhere in between neighboring cells. The Max Torque table should NOT ever be modified, but it has worked for alot of people as a timing start.

Chris

[WS6FirebirdTA00]

i have changed my max torque timing table, i dont really see why you shouldnt change it. although we really dont have a full understanding of what this does. i got help on timing from a guy that used the dyno to build the octane tables, he also modified this table. i would like abetter understanding of it though

[4.8t]

Yes he means the values were somewhere in between neighboring cells. The Max Torque table should NOT ever be modified, but it has worked for alot of people as a timing start.

Chris

what if you put in a bigger motor then do you not change it??

[Greenpea]

For those of us that don't have access to a dyno, a drag strip or long flat highway works, while logging some runs, you can see what cells to use for increased timing. Make some soft runs through the gears, and full throttle blasts. Then after making changes to these cells, you can log again and check for KR and back off those cells that record some KR. May not be as acurate as a dyno, but worked for me.

[chrisj6]

I would think you would probably want to use the max torque timing table of a motor close to the size you put in.

Chris

[408GOAT]

what happens if you max out the cells on the timing table?

Logging last night I was hittin 1.16 g/cyl on the timing table and I didn't even bring it past peak hp (~6500rpm) It only goes to 1.20 g/cyl right?

[WS6FirebirdTA00]

hmm good question. that would mena you are moving 72 #/ min of air if you were at about 6500. are you n/a? and what kinda power are you putting to the ground?

[408GOAT]

hmm good question. that would mena you are moving 72 #/ min of air if you were at about 6500. are you n/a? and what kinda power are you putting to the ground?

Yep NA. Not sure about power, haven't had it dynoed yet. Been doing all my tuning via wideband.

FWIW it'll spin the tires from a roll at any rpm >3k in third and lights em up at the torque peak in 4th. It's a monster. Scott (soundengineer knows)

What calc did you use to convert g/cyl to #/min ?

[WS6FirebirdTA00]

its in the editor, i bet thats a beast, its what i want to go with, i got a price now i just need money! haha id like to see what you make iwth that cam as i want to go with something that has similar lift and around that range of duration (right now its all a dream though lol)

i would imagine if the table goes above 1.20 it just uses the last values in the table, which is fine for WOT anyway. im suprised i havent read about this before though, hell my little motor will read 0.92 WOT those big motors must be at the limit all the time.