Does anyone know how much the ignition timings should be with 91 octane?

I have an EMU and my car has no knock sensor. I will not damage my engine. I will drive my 91er 1.6er Miata with 10PSI and safe ignition settings.

 

Assuming your base timing is set to 10 degrees BTDC, the usual convention is one degree per PSI, however there are many variables from car to car.

Originally, I found that even with my FMIC I had to pull somewhat more timing than this to avoid pinging. There was no carbon fouling of the chambers and the fuel was spot-on, so I've never been able to explain this. Now that I am using water/alcohol injection however, I am pulling considerably *less* timing than this, and have not experianced any ill effects from it.

 

yeah make up a map that takes out 1 degree per PSI in the 3000 to 5000rpm zone.....BUT then add in i degree per 1000rpm above5000rpm,evry 500rpm below the 3000.....so at 10 psi youll have -8at 2000rpm,-9 at 2500 -10 at 3000-5000 then -9 at 6000 and -8 at 7000....

adding in those 2 extra degrees at high rpm makes a BIG BIG difference on top end power

 

You do realize that, even on the stock ECU, the timing does not stay at 10°BTDC all the time, right?

 

Jonny, I wouldn't even consider to use the grappy 91Octane Gasoline,
use "Superplus-98 Octane" if you like your engine...

for the others- I'm from Germany, he's from Austria, we do have a different measurement system for the OCTAN numbers,

what he calls "91 Octane" is actually " 87 Octane " in the United States.

So what would you consider as a safe Octane number for running 10PSI?


German-------------------US:

normal (91)------------ 87 Octane
super (95) ------------ 90 Octane
Super Plus (98)--------- 93 Octane
Optimax (100)---------- >95 Octane

 

yes joe i do realise that..i was talking about the amount of retard to use from the stock timing curve..if you keep it at -10 below stock curve youre missing out on power ...putting back in a few degrees above 5000 unleashes A LOT of HP

 

<BUTTHEAD>Hehe. You said retard.</BUTTHEAD>



Assumes a stock 10°BTDC @ idle base timing, and WI. Could probably bump it a few more points with decent gasoline.

 

I'm interested in a timing map also. If anyone has one to post I'd be a happy camper.

 

It'd help if you told us what engine the timing map will be for. Otherwise, I'd be happy to share with you the timing map from my lawnmower.

 

Here is my ignition map. JRSC, 8 psi, 93 octane fuel, 14* static initial timing. Timing was set on the dyno by a professional.

 

soflaric: That's not a timing map it's a compensation map.

Joe: I have a '94 1.8l turbo. My map runs to 18psi and 8000rpm. If you could provide the base map for that engine I can go from there. Thanks.