Trash

I (we) weren't trying to rain on your parade but base timing is basically used for idle control and baseline ignition mapping for the spark table. Any change to base timing affects global timing and often not in ways you'd prefer. With both set to 8 degrees at least you'll have a solid baseline from which to work. If one motor is lazy there may be other issues (throttle rigging?).

Best of luck and let us know. Feedback on success OR failure is important.

92nsx

This is what the computer is doing at idle to make it idle smooth. this is why the base timing is set in diagnostic mode. Granted this was 502 but 454 is prob doing the same thing.

https://www.youtube.com/watch?v=tgBYh_IFMyU

Trash

Yes, part of the spark stabilization built into the TB ignition. It tames down the idle fairly well, even with a healthy cam. That stabilization is removed to fixed tabular values around 1200 rpm (don't remember the exact rpm off hand).

Cap'm Kurt

my 1999 mefi 3 "enables" the stabil mode according to engine temp, which is set kind of low so basically it is active all the time. In my opinion factories set things fairly conservative. I bumped up the timing 4 degrees on a trial by just resetting the base timing and it felt noticeably better. Gained 2-3 mph with wot timing set at 34 vs 30 factory. so i reprogrammed the timing tables to get to the same spot at wot and around idle but the mid range i had to retard back to factory because factory was already quite high at around 37 degrees cruising.

However, i do run 91 premium.... always have and always will.... it's not worth a motor from detonation.

Trash

I think that's what a lot of people don't realize what the Merc timing tables look like. They tend to be conservative or at least reasonable at WOT / high MAP/ RPM (say greater than 3600 rpm). However, the midrange cruise advance numbers can be quite high. Decel advance is over 40 degrees. So if people start tweaking base timing they can inadvertently send the midrange timing through the roof and hurt the motor.