MS guys- is there a rough engine model available?

Raze wrote: Isn't this just parameterizin a basic pump fluid flow problem?

It is, but the parameters also involve how cam timing interacts with piston motion and intake and exhaust resonance effects... at WOT. At less than WOT it gets more tricky.

I remember a thread on rx7club where a guy was insisting that tuning empirically was the crude way, and Real Tuners just plugged in calculated data and out popped a perfect map without an engine (running or motored) having turned a single revolution.... Wish I could find it.

Knurled wrote:

Raze wrote: Isn't this just parameterizin a basic pump fluid flow problem?

It is, but the parameters also involve how cam timing interacts with piston motion and intake and exhaust resonance effects... at WOT. At less than WOT it gets more tricky. I remember a thread on rx7club where a guy was insisting that tuning empirically was the crude way, and Real Tuners just plugged in calculated data and out popped a perfect map without an engine (running or motored) having turned a single revolution.... Wish I could find it.

That was my point...definitely going to be crude unless a lot of data exists...we used to joke in the combustion lab how poor the 'best' models and sims were...they kept a Saturn V injector plate out front explaining how higher order vibration coupling had to be overcome with manual empirical testing which led to a very unsymmetrical pattern...tailored to that particular engine on that vehicle...

And the way you get that data is rather crude It's not calculating from first principles, it's calculating based off of SWAG approximations of the difference between the new product and a known prior attempt.

I think I've seen one of those injector plates. The amount of by-guess-and-by-gosh in those rockets is heartwarming.

Ok, so with some searching tonight- I found that there is a free version of a Lotus Engineering one cyl model- which is here- http://www.lotuscars.com/engineering/engineering-software

Part the way down the page is this:

A freeware single cylinder version of Lotus Engine Simulation is also available to download , with associated documentation here.

Where there are actual links to the software and documentation.

While a multi will breathe a little different than a single cylinder, without any data for your engine, it would be a good basis for developing a desktop calibration.