Quote from z3r0c00l :

Last time I checked the only serious factor regarding how much horsepower you get from the engine for any given fuel/air ratio and ignition mapping is how much cash you spend sorting it out.

edit: £5 on tristan, because he's british.

Well, actually cash helps engine to last longer too, it is possible to make engine that does produce 1000hp for 0.0001seconds, trick is how to make it last on race conditions two seasons or more without opening it and that does cost a lot.

Quote from tristancliffe :

Yes, it might be more than a couple of degrees, but it's a figure of speech. It's rarely going to be more than 5 degrees from 'Best Torque'.

There are many situations in which the detonation margin will be dozens of degrees one way or the other from MBT.

Look at a typical ignition map for a large engine with two valves and old combustion chambers. There may be fifty degrees or more difference between the smallest and largest advance value. Yet aircraft engines are certified to run without detonation in all conditions with a fixed timing value.

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You don't just plug in a computer and let it magically sort it all out

Oddly enough this is, in a nutshell, the purpose of closed loop ignition control.

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And before mappable ignition became as advanced as it is now, then the compromises were a lot bigger.

Certainly. See the few hundred thousand non FADEC piston aircraft engines in service. Huge compromises.

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Best torque is found at best torque. Lean of best torque is where you get a small decrease of torque (perhaps negligable), but a large improvement in BSFC. To state that best torque is found at LBT is simply wrong.

Why do you insist on semantic arguments? I already said I've seen no formal definition of LBT/RBT, have you? Let me know what text it is in. The obvious non handwaving point of the two terms is that torque is more or less constant over a certain range of lambda values. Going richer than LBT is not typically done for extra torque, but for extra life of things like exhaust valves.

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Sounds interesting. I'd love to see some of your work.

I'll post YouTubes in the forums when I get it running and sorted.

Quote from JTBo :

Well, actually cash helps engine to last longer too, it is possible to make engine that does produce 1000hp for 0.0001seconds, trick is how to make it last on race conditions two seasons or more without opening it and that does cost a lot.

Cash is important indeed for reliability, because cash means you can test extensively. Another big problem is quantity. Even with ample cash for development, you simply can not in practice build things with the quality control production manufacturers are attaining when you are building a handful of units.