hi there. I am a newbie, so please take it easy if you want to flame me

Anyway, I am new to the rotary world. I did a lot of search on this forum, I read something about decrease the timing split from the trailing and leading plug. So they will fire "together" and give a better air/fuel mixture burn.
And I know that there are some argument about this tuning.
My question is, how can you adjust your timing split? Can it be done without using aftermarket ECU or burn a complete new ignition map?
Also, what is the ideal "best" setting (ignition timing wise) for a N/A 89 rotary?
I will have basic bolt on like intake, high flow cat and full cat back. Anyone of you please give me some direction about the timing split, also some suggestion on timing spec. Thank you so much.

 

I read somewhere that it's best to set leading a little ahead of trailing, but I'm not sure.....

 

you can not change the split, the leading and trailing are aways the same apart. if you move the CAS to advance or retard the timming. they both move the same amount.

however there is no need to change it...

you could probably advance your total timming by a little.

 

Is there a way to tell if your timing is a little off? At idle my car "farts". I know its supposed to with a custom exhaust a little but mine does it a whole lot even when I hold it at 2k it still "farts". Any answers???

kleach

 

Can't be done. You can only adjust overall timing on a stock ECU.

To adjust, get a timing light and follow the instructions in the Haynes manual...

Basically, warm up the car, connect timing light to L1, and adjust CAS so timing marks line up. Pretty simple. Then rev the engine and verify the advance is working properly (it will be).

 

Yep, those of us that write about adjusting the timing split have an aftermarket ECU.

Don't worry about it. Until you need an aftermarket ECU, you don't need to worry about the split.

 

thanks guy... that's help a lot.

But one more question. If I advance the CAS.. will it throw off the fuel timing too?

 

dont advance it...leave it alone it will do what needs to be done on its own...as for the "fart" you may want to check for a leak ... thats often the cause when its really bad.

 

So is this what a modified ECU changes on our N/A cars to make more power? Or am I thinking of something else?

 

As far as the "farting" - on the '86-88 cars, sometimes if the idle mixture is a bit rich (set by the idle mixture screw on the passenger side shock tower) you'll get a rich spit at idle.

This can also sometimes be helped by doing some throttle body adjustments.

Dale

 

Is your car a n/a or a TII? N/a's run zero split from 2000 rpm up under WOT to increase power. The timing split is mainly for emissions.