dvcn

What are the stock ecu timing maps for NA's?

I looked at the factory manual and it only shows the baseline CAS setting of 5 ATC L / 20 ATC T. I want to know what the maximum total timing is under various parameters (load, map, etc).

I did a search and I found various carb vs efi arguments, ecu vs 1st gen distributor arguments and a thread talking about turning the CAS until there was power loss, but no real numbers were given.

j9fd3s

iTrader: (3)

i doubt anyone actually knows, its not like air fuel ratio where you can stick somthing in the tailpipe and find out. you need someway to datalog the stock ecu

mike

dvcn

All these people with modded 2nd gens and no accurate and exact ignition advance information?

Do so few people advance the timing? It makes such a huge difference on performance (acceleration and economy).

scathcart

Its a common mod for NA owners to advance their timing.

It is an uncommon thing for TII owners to do so. Detonation is a bad enough problem as it is.

And those of us who have REALLY modded RX-7's get their accurate and exact ignition advance information by running an aftermarket ECU.

If you want a better ignition map, either get an aftermarket ECU or get a chip. You can't alter the ignition map on the stock ECU anyway, and ANYONE can figure out how to advance the timing over the entire Map. Just get a timing light and add 5-10 degrees (if you have an N/A)

dvcn

I searched again and read another 10-20 posts. Not one answers the question.

The initial timing is clearly stated in the factory manual. I fully understand that you can advance total timing by advancing the initial timing by rotating the CAS.

Not one post distinguishes between total and initial timing.

I currently run 26 BTC L / 16 BTC T total timing in an 84 6port. 87 octane only. The engine is now at 217k miles and has been at this setting for the last 20k miles.

I was hoping that someone could tell me what total timing the ecu actually gives under various conditions so that I could properly set the initial timing so I can accurately hit the number that I want.

NZConvertible

How do you actually know the number you want? There are lots of factors that influence the max timing you can run without detonation. The only way to really find out is to have the ignition tuned on a dyno, with the operator listening for detonation using a proper auditory detonation detector.

dvcn

When swapping an 81-85 distributor into an 86-92, Racing Beat suggests 23 BTC L / 8 BTC T total timing )@ 5000rpms). They are generally conservative and this makes it a good and safe starting point.

To achieve these numbers using the ecu/CAS it may take more than just revving the engine to 5000rpm and setting the CAS to reflect the total timing. There might be other factors like MAP, temp inputs. Maybe not. The only way to be sure is to know what the ecu does to modify the timing signal.

To just set the CAS on the dyno is fine, for the condition on that particular day. Given altitude or temperature changes I don't currently know what gross alterations the ecu may or may not do to the timing. That is what I am trying to find out.

The question still remains: What are the ignition maps of the various NA ecu's?

dvcn

For those who are NA, dyno tuned and have a stand alone ecu or piggy back:
What was your timing map? Please list mods and conditions.

peejay

This is something I find funny too... people screw around with the CAS advancing timing and they don't even know exactly what they're doing.... it's meatball surgery tuning IMO.

Sure it might not detonate... but just because it's not detonating doesn't mean it's not too advanced for best power.