I ran across this article on the innovate motorsports website on tuning a turbo engine, and wanted to know what the rotary community's take on it is. It seems valid from a thermodynamic point of view, at least to me.

http://www.innovatemotorsports.com/resources/rich.php

So... possible?

 

Nice theory, but in real life i have prooved it to be without merit and 100% fatal when applied to any rotary engine

The ONLY rotary engine that responds to 0.85 lambda or leaner is a NA one, all turbocharged units need to be made to live v's following any text book ideas that will end in guaranteed misery.

Its preferable to run richer and more conservative levels of ign advance, trust me

 

Correct me if I'm wrong, but wouldn't any benefits of running the closer to stoich mix be offset by the massive amount of retard you'd need anyways?

Also, I believe the main point in our engines is that we get pre-ignition more so then typical detonation ignitied by an early spark. So mixing closer to stoich would make pre-ignition more possible since if it were to cause a ping, it would be from spontaneous combustion, not an early spark event.

 

biggest problem is heavy apex seal wear, fuel is used to cool the engine its a very overlooked aspect amoung newbies and internet theorists

I have run cars on my settings, rich and with low spark advance v's others from other shops that are on better fuel, leaner and with lots of timing and run same MPH in same vehicles (shape, size, weight) + the engines tuned properly last v's hand grenades that are tuned to *ideals*.

basicaly the innovate recomendation is crap ! try it at your own risk/expence

 

Like Rice said.
How long do you want the motor to last? Even with the use of exotic materials there are limits. I've done a lot of testing for instance with different types of apex seals etc. and I know the limits of many. You'll be surprised as to what you can get away with. But in actuality it always boils down to the same question. Durability vs power.
Rotaries also don't respond to a lot of ignition advance . If you need to run a lot of advance to make decent power then you did a really hack porting job. Good port work would not even benefit from advance timing no matter what the AFR is at. The 10 to 15 hp even if that much is not worth breaking the motor in my opinion.
Total horsepower goals and it's intended operation use also affects AFR's and timing. The higher the power the higher the BTU's involved given the same application and setup for both piston and rotary motors. Anyone who's going to sustain very high power levels for any length of time is going to be required to do what it takes to keep operation temps down something which advance timing and lean mixtures normally results in the opposite.

 

Ok, Thanks for the responses, I wasnt planning on doing this cause i'd like to keep the motor thats in my car intact for a while (using it as a DD), and dont have the resources to experiment.

 

I just wanted to say a few things, not having any pratical experience with tuning an engine yet, but with plenty of technical knoledge.

The end of the article is saying to run a leaner mixture, and less ignition advance. So as you said Rice Racing, it is better to run more retarded timing, even more than you would with an even richer mixture which you claim success in reliable power with. Good to have experience pratical input to this.

Second, I agree with the ideas of the fuel cooling the rotary, and being that these tuned engines you speak of are operating at the limit, the 4 degree or so cooling from the richer mixture probobly contributes to reducing knock when you run so close to the limit.

I do think, that the argument made in this article, is that if you ran a water injection for equal cooling of a richer mixture, you could effectivly lean your mixture and retard your timing(because of faster moving flame fronts), and make equal or comparable power to a richer slower burning mixture, providing cooling from the fuel directly, with slightly more advanced timing (because of the slower burning rich mixture).

Tho the author of that article tends to stray from the cooling effect of the extra fuel or water replacement, using his theory with correct timing and water injection would yield better fuel consumption under WOT conditions.

So the net idea is to run water injection strictly for the purpose of better fuel consupmtion at full power.


On a side note, unlike what the author of the article states, everything i've read states that it is not fully known all the sub-reactions that burning fuel undergoes before forming the end products. Some theory involves as many as 6 and others, more than 6 intermediate steps for the sub-reactions of cumbustion of hydrocarbons, some involving the oxidation of portions of the fuel molecule, still assembled in its original chain, such as forming hydroxides.