Timing vs Load - General Question
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Timing vs Load - General Question
I've been reading a lot of timing threads (here and at TGO) / gathering information as I approach that part of my tuning. I am comfortable with timing vs. load vs. RPM and why timing would generally be increased or decreased as load and RPM change. I will start conservatively (stock table in the apyp bin) and work from there.
In a lot of the threads I came across, people had posted about having the total timing advance in at a certain RPM (i.e. 38 degrees by 3000 rpm, 39 degrees by 2800 rpm, etc) but did not specify at what LV8 value this was for. I'm assuming it's not 38 degrees for all LV8 values at that rpm (which wouldn't make much sense).
So my question is, when something like that is posted, is it generally for a specific load, or lower variables? Just curious how you guys generally talk to timing figures with respect to load.
Hopefully my question makes sense
In a lot of the threads I came across, people had posted about having the total timing advance in at a certain RPM (i.e. 38 degrees by 3000 rpm, 39 degrees by 2800 rpm, etc) but did not specify at what LV8 value this was for. I'm assuming it's not 38 degrees for all LV8 values at that rpm (which wouldn't make much sense).
So my question is, when something like that is posted, is it generally for a specific load, or lower variables? Just curious how you guys generally talk to timing figures with respect to load.
Hopefully my question makes sense
Melting Slicks
Joined: Aug 2003
Posts: 3,399
Likes: 394
From: Lakeville MI
If I were to talk in terms of total timing say 34 degrees, I'd be referring to the timing at the loads encountered during WOT while accelerating through the rpm range.
In my case I see the load LV8 hovering around 230 from something like 2800 rpm - 4500 rpm while at WOT, above 4500 rpm load decreases somewhat proportionally with rpm up to 6200rpm where it is at 180 or so. Load is essentially torque, or airflow/rpm.
In my timing table I have 34 degrees in nearly all of the high load (LV8 > 180) mid-high rpm cells. There is more timing elsewhere in the light load areas, but this is not usually worth talking about.
In my case I see the load LV8 hovering around 230 from something like 2800 rpm - 4500 rpm while at WOT, above 4500 rpm load decreases somewhat proportionally with rpm up to 6200rpm where it is at 180 or so. Load is essentially torque, or airflow/rpm.
In my timing table I have 34 degrees in nearly all of the high load (LV8 > 180) mid-high rpm cells. There is more timing elsewhere in the light load areas, but this is not usually worth talking about.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Thanks tequilaboy - I appreciate it!
The stock apyp timing table has only about 24 to 27 degrees of advance at loads > 176 (around 2800 - 3200 rpm), so I'll be taking those numbers up (in small increments). The cam manufacturer recommended around 38 degrees ttl advance by 3000.
Thanks again!
Dan
The stock apyp timing table has only about 24 to 27 degrees of advance at loads > 176 (around 2800 - 3200 rpm), so I'll be taking those numbers up (in small increments). The cam manufacturer recommended around 38 degrees ttl advance by 3000.
Thanks again!
Dan
