Engine Sim - Lotus keeps crashing

[BLSTIC]

I've been having trouble with my lotus engine simulation. It appears when certain values come up it crashes the solver portion of the program, which is really annoying considering there's no rhyme or reason to it. I can have a functioning model that gives legitimate looking outputs and it crashes when I do something simple like alter a diameter to another feasible value for the same part. However I can run the same functioning model again and again.

Has anyone else experienced this? Could you solve it? It's kinda annoying because I'm trying to model a new exhaust for a mates racecar and I'm spending 4-5 times longer trying to avoid the crashes than I am actually modelling parts.

Thanks
Ben

[PackardV8]

Is there actually a Lotus engine simulation software? If so, dunno.

If an aftermarket , which/whose program?

[BLSTIC]

It's a (now freeware) engine simulation done by lotus engineering. Probably similar in capability to EngMod4t but basically unsupported by lotus anymore. Unfortunately the only information I can find on the net says it was crashing randomly on some PCs 5 years ago too

[modok]

Back in the day I had to get a computer with ECC memory to run that. The average computer would not make it an hour without an error.
I would assume any modern computer would be ok tho.

megaphone tapers in the exhaust system can be very taxing on it also.

[BLSTIC]

Back in the day I had to get a computer with ECC memory to run that. The average computer would not make it an hour without an error.
I would assume any modern computer would be ok tho.

megaphone tapers in the exhaust system can be very taxing on it also.

Megaphone is one of the things it crashed on, but it also crashed on a primary length change, a secondary length change (but not on other lengths), a step, an anti-reversion chamber, a change in valve timing, a change in firing order, a change in primary diameter. Complexity of the system doesn't matter, it's almost entirely random, it will probably crash on a 4-1 with no steps if I choose the wrong length and diameter. But it might only crash on the 4500 and 7000rpm steps and not the other 500rpm increments from 2500-7500.

It's super frustrating...

[modok]

If it's random then I'd be blaming the computer. The calculations are very taxing on the memory and processor.
I have run it on at least 6 different computers, the difference in stability is huge. I still have the one computer that did best, an antique now, still working perfect after 20 years, Dimension 8200 with ecc ram.

[BLSTIC]

So do you currently have a computer that is running on? If I send you a file that I know to crash mine, could you run it yours as a test? I don't have another computer to test with

[BLSTIC]

Because I'm dangerously close to dropping a month's savings on EngMod4t. Lotus has opened my eyes so much to the information available from a good sim and I'm not willing to give up my newly found research ability

[modok]

Sure, lets do it.
Yeah it's a really cool tool. Second or third most challenging video game I've ever got into. I still don't really understand all of it but I've learned a lot from it.

[modok]

Nothing wrong with your computer, the sims crash like clockwork every time.
I've back-tracked and simplified the model until it works, and I'm going to see how close I can get without crashing and send that back to you.