Engine simulation programs ??

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GARY C
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Re: Engine simulation programs ??

Post by GARY C »

hoffman900 wrote: Sat Jun 23, 2018 10:17 pm
GARY C wrote: Sat Jun 23, 2018 10:12 pm
mekilljoydammit wrote: Sat Jun 23, 2018 6:28 pm If you get the sim to where it represents one configuration pretty well, you can try a bunch of variations and see if you can improve on it, even stuff that's counterintuitive and seems like it would be a waste of time, or weird stuff where you don't want to pay for one-off parts until you have a pretty good idea it's going to work.

Not everything is as well proven out as American V8s - not every engine are you going to be able to talk to someone who did it already and find something off the shelf that gets you the result that you want. It's nice to be able to narrow the list down from thousands of potential things to try to the best half dozen or so.
I understand that but you still have to choose what models your going to test and they have to be tested but it still doesn't confirm that any of those half dozen ideas are better than the other thousand unless you test them all against each other.

If you get wrapped up in believing the model knows best you may never test what is actually better because the model says it wasn't, you would need to test best and worst models and some in between to baseline your models and could actually increase the amount of testing needed.

Regardless of the name plate on the engine you are still dealing with the same dynamics.
Do you know you made the correct change on the dyno though?

If I change a camshaft and it does worst, was it the cam? Maybe I have to change three other parameters and then I'll realize a gain with that camshaft that I couldn't realize before.

Without giving away details, an engine builder I chat with told me he changed a camshaft and it did nothing but burn more fuel and made about the same power. He developed a whole new intake set-up, and the cam made a quite a bit more power than what the other two could provide (and he tested them all with both intake set-ups).

Kevin Cameron wrote a great editorial recently about the fallacy of testing and changing one thing at a time. When you have a validated simulation, you can change things at a much greater speed (and less expense) and get a snapshot into the engine that may make you realize what needed to be changed in addition to, to realize the full potential of that change.

Everyone needs to watch this: https://www.youtube.com/watch?v=rBZCnG1HwDM&t=1369s

If you've watched it already, then watch it a hundred times. Listen to what he's telling you about how to think about engine development. Go listen to what he says at 26:00. Simulators help with realizing the "modern way".

I've posted many links over and over again, showing simulation used to help realize development in Formula 1, FSAE, and Grand Am competition. I don't know if people read them or what, but everyone can search out my posts.
Theses examples are based off of motorsports with decades of real world testing with data to go off of long before sims were part of it, I agree that recording your test results will help you down the road but even the top teams in F1, NASCAR and NHRA with multi car teams have said that you can't transfer the data from the winning car to the loosing car and make them equal, you can test pieces of that data and see what works but that still requires testing everything that you have logged and none of it may transfer at all, so your back to square 1.
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Re: Engine simulation programs ??

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hoffman900 wrote: Fri Jun 22, 2018 2:45 pm
Stan Weiss wrote: Fri Jun 22, 2018 2:34 pm One problem with most dyno testing is the method used. For how long or where on the track or at what engine RPM is the engine actually seeing lets say a 600 RPM / Sec acceleration rate?

Stan
So it’s a simulation? Huh. :wink: :D
Well that depends,
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Re: Engine simulation programs ??

Post by Dave Koehler »

Cu the blue wire, Cut the blue wire!

To the OP's original question.
FWIW, I have always gotten along and got decent results from Performance Trends products.
Started with the basic version and worked up to the pro version once I had more questions than answers.
I look for a trend, don't you know.
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Re: Engine simulation programs ??

Post by Frankshaft »

Dave Koehler wrote: Sun Jun 24, 2018 6:40 am Cu the blue wire, Cut the blue wire!

To the OP's original question.
FWIW, I have always gotten along and got decent results from Performance Trends products.
Started with the basic version and worked up to the pro version once I had more questions than answers.
I look for a trend, don't you know.
Same here. I don't use them anymore, but I did have the performance trends ones. The regular engine analyzer program was actually quite good, and was reasonably priced. The pro version was more complicated with more specific inputs, and worked good too. Suprising though how close the regular version would be. Not even sure if they still sell them.
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Re: Engine simulation programs ??

Post by SchmidtMotorWorks »

GARY C wrote: Sat Jun 23, 2018 11:00 pm
Theses examples are based off of motorsports with decades of real world testing with data to go off of long before sims were part of it, I agree that recording your test results will help you down the road but even the top teams in F1, NASCAR and NHRA with multi car teams have said that you can't transfer the data from the winning car to the loosing car and make them equal, you can test pieces of that data and see what works but that still requires testing everything that you have logged and none of it may transfer at all, so your back to square 1.
Can you tell me who says this?
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Re: Engine simulation programs ??

Post by rebelrouser »

I use the performance trends cheap program. I have had good results with engines being within the advertised 10% accuracy. I use the program as a tool just like all the other tools in building an engine. My issue is, I have a lot of customers bring me a pile of parts they have collected and they say make me 800 HP. I can tell them they are crazy, but putting the parts into a simulation program, and it tells them they are crazy, really helps with my arguments. I always tell them, you decided how much HP when you bought the parts, I don't have magic wrenches to make more.
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Re: Engine simulation programs ??

Post by David Redszus »

Having worked with various high end simulation programs for many years, including dyno validation testing, I have concluded that the value of a sim program is not to predict how much power can be produced, but rather to help understand what effect each tunable parameter has on performance. It allows the quick testing of combinations of parameters to eliminate those that move in the wrong direction.

Accuracy is much less important than proper direction.

Dynos are not accurate but hopefully they are consistent.
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Re: Engine simulation programs ??

Post by Turbo231 »

Frankshaft wrote: Sat Jun 23, 2018 3:51 pm
mekilljoydammit wrote: Sat Jun 23, 2018 2:27 pm The turn this thread took is really weird. Why wouldn't you use every tool you have at your disposal?

So, I'm an engineer... I call engineering the science of laziness. All engineering is, is a bunch of tools to not have to build a real version of whatever to see if it will work. So everything, flowbench, cam checker, dyno, software simulation, whatever... it's all tools to try to do better without having to run down the track. Have a dyno and a 1d sim package? Use one to refine the other! A dyno is less of an abstraction, 1d sims can tell you more of what's going on and let you try more things more cheaply. Neither substitutes completely for the other without a pile of money and time.
Summed up well.
Ditto
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Re: Engine simulation programs ??

Post by Turbo231 »

I am not looking at a simulation program to just tell me the torque and power of a combination. I can't imagine, with so many variables, that any simulation can get these right to within the accuracy most engine builders need. I am looking for a simulation program that can predict when flow may be reversing at the valves (intake or exhaust) which then allows me to better pick cam points. The only real world testing that might give us clues on what is happening at this level would be cylinder pressure testing.
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Re: Engine simulation programs ??

Post by Ron E »

EA-pro does show the "when" of reverse flow on both sides. And, you can input your flow at the lifts in question. How accurate it would be is hard to quantify. Hellish dynamics going on for sure.
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Re: Engine simulation programs ??

Post by 4vpc »

englertracing wrote: Sun Jun 24, 2018 1:01 am
hoffman900 wrote: Fri Jun 22, 2018 2:45 pm
Stan Weiss wrote: Fri Jun 22, 2018 2:34 pm One problem with most dyno testing is the method used. For how long or where on the track or at what engine RPM is the engine actually seeing lets say a 600 RPM / Sec acceleration rate?

Stan
So it’s a simulation? Huh. :wink: :D
Well that depends,
It is if you took the red pill
But if you took the blue pill, if your erection lasts more than 4 hours consult a doctor.
No that's about stimulation, not simulation. =D>
There is no S on the end of RPM.
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Re: Engine simulation programs ??

Post by mk e »

Turbo231 wrote: Thu Jun 28, 2018 9:00 am I am not looking at a simulation program to just tell me the torque and power of a combination. I can't imagine, with so many variables, that any simulation can get these right to within the accuracy most engine builders need. I am looking for a simulation program that can predict when flow may be reversing at the valves (intake or exhaust) which then allows me to better pick cam points. The only real world testing that might give us clues on what is happening at this level would be cylinder pressure testing.
Then you want a 1d sim....
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Re: Engine simulation programs ??

Post by smeg »

I use engine analyser pro and pipemax, work back and forth between them and then test on our dyno, dam close all the time.
Used to use DM but found a problem in the lobe seperation calcs. It always likes wide LS when the engine doesn't.
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Re: Engine simulation programs ??

Post by MadBill »

Don't know about later versions, but my circa 1996 vintage Dynomation has a problem with the speccing of the EVC event. DM 'wants' a ridiculously early closing to maximize power, e.g. 25-28°, when I know 45° is more in the ball park. The ~20° too early closing increases the exhaust CL by 10° and thus spreads the LSA by 5°.
My fix is to humor the program by developing all the engine specs with the EVC it likes, then when selecting an actual cam, correcting it back to a realistic value, usually a few degrees more than the IVC°.
Incidentally, I originally intended to have CamKing do me up two solid rollers for my BBC; one to my DM-developed numbers and one specced by Mike, however the valve events were so close to each other, I just went with his choice.
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Re: Engine simulation programs ??

Post by smeg »

Bill,
I did test two cams at the nationals over 3 days back to back, one with 109 LS that we were using and the other with 114 LS DM called for.
The 114 DM was slower but not by much.
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