Using engine simulating software as a guidance tool

[berkut]

Dear Guy Croft,


I would like to ask you what do you think of using engine simulation software to predict engine characteristics ?

I know about two such programs, one is Engine Analyzer Pro that i am using and the second one i know of is the one developed by Lotus. Unfortunately the EAP side doesn¢ž¢t work right now (still it can be googled), the Lotus software page is http://www.lesoft.co.uk/ .

As far as i have read this kind of software is good as a guidance tool, some tuners say if the engine data is typed precisely enough the results for the inlet manifold length for example are within 2-3cm in the real world.

As far as i have tested EAP this is true to some extent, it matches the Toyota 1UZFE stock power output and characteristics, the Ford Zetec (stock and with some modifications) and my modded CVH Turbo engine (although i have some problems with setting up turbocharger characteristics).

I would like to discuss this program on the Toyota 1UZFE example as this is the engine i am building right now. As i said earlier the stock engine dyno plot matched the one generated by EAP, as well as the mild modifications peapole perform.

After obtaining data of a mildly ported head from www.1uzfe.com i started to fondle with cam settings, inlet manifold lenght and type, exhaust, compression and port size.

After a few hours of playing the results went from 270bhp to 500bhp @ 8000rpm (this is about the maximum rpm the engine can take while being stock with uprated con rod bolts and modified heads). As far as i know no one except Australians and Japanese (JTCC Supras) use these engines as naturally aspirated units and they don't show any dyno-run or rolling road results so there is no chance for me to compare.

I personally find this result optimistic, especially is almost everyone around me say that without 9500-11000rpm there is no chance this engine will produce more than 480bhp, on the other hand there is always hope ;)

I have almost none experience with building engines, as far as it goes for the building process i have no problems performing it. I can only rely on books, mathematical simulations and rule of the thumb i can find around the net. I would like to simulate everything as far as possible and gather a knowledge base before building my engine rather than build and cry when theres no horsepower...

Guy, what do you think about it ? Is this any good ? I added attachments with my current settings and how the program looks for your viewing pleasure.

[Guy Croft]

It's OK is my short answer - you can learn quite a bit from these types of programmes about engine behaviour but I would not depend on it or use it for determining absolute characteristics.

The best programmes are iterative (Virtual 4T took 20 years to develop and has to be one of the finest) and mostly the much-lower-budget ones are just full of presets which is why they give puch-button response.

Cannot speak for the Lotus simulation - you'd have to buy the full package rather than just the free one-cylinder download to get a handle on its capabilites. Probably it's brilliant, Lotus are a top-drawer firm, but I don't personally know anyone who has it.

GC