Has anyone ever tuned their rotary engine for stoichiometric ratio? I know that is insane but so are some of the people on this forum lol

If not what is the highest A/F ratio anyone has tuned for?

 

Under what conditions?

If you do not have a catalytic converter it is advantageous to tune it very lean under highway cruise conditions.

Stoich is only important if you have a catalytic converter and you need it to work. Cats don't work at rich or lean mixtures.

 

As peejay said, the conditions mean a lot. I've gotten a rotary to run under very light load about about 16.2:1, but it made very very little power and lean-surged a lot. Best cruise mixture I've found is about 15.2:1 for a car with no cat. If it's got a cat, I tune for 14.7:1 under all steady-state low-load conditions, richer under accelerative load.

Brandon
BR7 Racing

 

Making little power is actually a good thing for cruise conditions. You have to open the throttle more which means less manifold vacuum which means less pumping losses from the engine trying to draw a high vacuum. End result - better fuel economy.

Popping open the EGR valve can do the same thing... reduces manifold vacuum, meaning the engine has to work less hard on the intake stroke.

 

Intresting, I haven't thought about the high vacuum causing a load on the engine while cruising. Once I get a WB I'll have to play with that. Thanks.

 

Thanks guys that answered the more questions i had. No7Yet what ratio would you tune for under race conditions? WOT with wide open exhaust?

 

There's no way to say... it simply depends on too many factors. The short answer is "whichever ratio makes the most power while still being reliable enough". Vague, but that's about as good as it gets.

Brandon
BR7 Racing

 

it really depends on how long you want your motor to last. Im sure the people out there that tune for every little bit, run the car on the egde.
The leaner you get the less life you will get out of the motor. Not sure about cruising though

 

Na's make the best power right before 14.7. Besides, all a rich mixture does is add fuel to cool the intake charge with (thus deterring detonation and preignition). Water injection can do the same exact thing.

 

14.25 is where my car made peak power. After that it started falling off. BTW, this was on a dyno. CJ

 

That makes perfect sense. Has anyone grenaded their motor with a super high AF ratio? (accident on tuning, wrong calculations) if so did you guys use a knock sensor like the J&S?
Rob

 

Haven't grenaded but didn't make any power and ran really hot. By no power I mean about 100hp for a street ported 12A.

 

14.6 on a dyno with Dyno Jet's muffler **** probe. I don't know how accurate it was but my tunning read 14.6 flat across from 6,500-10.500 rpm WOT.

 

mine was so lean it would ping and stop running at about 4500in 3rd, engines fine

mike