Scotthatch wrote: ↑Fri May 18, 2018 2:31 pm
Not saying that is a bad thing but maybe you can do that on all out race stuff but in my world sometimes it's the headers that fit that get used and most of the time what I get is a box of parts from a guy with heads he got from a swap meet and intake from his buddy and a carb from the back of the garage that has not run in years ... I do my best to sort out the parts and make it the best I can ... my point is not this is wrong just that you have gotten out of touch with a big chunk of how regular guys build engines.
Actually, the 1D software is great for piecing together an engine from piles of parts.
It helps you figure out what a mismatched part will cost you performance wise.
I'm not sure if this was stated already and I overlooked it or not: Is the expected result of this effort to come up w/ "the" cam specs for a given engine combination, or a more robust approach to establish a baseline spec from which to test other cams as the baseline is refined?
BradH wrote: ↑Fri May 18, 2018 3:23 pm
I'm not sure if this was stated already and I overlooked it or not: Is the expected result of this effort to come up w/ "the" cam specs for a given engine combination, or a more robust approach to establish a baseline spec from which to test other cams as the baseline is refined?
It is a process for continuous improvement.
You repeat the cycle until the value of the returns are less than the cost of the cycles.
The challenge with sims (and yes, I've used EA Pro for years) is that you have to input intake runner dimensions when there could be 4 of them for a given manifold design. Same thing with headers and if you go out to the shop to measure all the primaries and average the length, the sim throws a giant hole in the torque curve that doesn't show up on the dyno.
I already know this argument and here's my reply: not everyone can get/fit equal-length primaries nor are they interested in an 8-speed transmission that doesn't even exist for the car they're building to keep the "optimized" engine in that narrow power band.
Another is collector length. I could change the length by two inches and it would throw another big hole in the torque curve that wasn't even close to what happened on the dyno (real-world experience as opposed to whitecoat theory). And as several who have far more clout here than I do (I've clearly been pigeonholed but oh well) have pointed out, you have to have real results to know where and how far to tweak the program to make it match and then you have to change that valve event back to what you know is true to order the cam.
Now how in the world can you learn something when you know right out of the gate that it won't match reality? How does looking at waves on a single cylinder help you see what's needed when all 8 are connected on the intake and often on the exhaust side?
I know full-well there are a lot of things a guy can learn from looking at CFD and 1D but neither of those two programs can evaluate common sense and real-world experience.
RevTheory wrote: ↑Fri May 18, 2018 4:17 pm
The challenge with sims (and yes, I've used EA Pro for years)
I have use EAPro a couple times, it is not in the same league as EngMod4T.
I think that if you would put some effort into EngMod4T, most of the discrepancies will be reduced to a range that you know what to expect based on experience.
A lot of people get on the wrong track when they think 1D software is to be used like a dyno and CFD software is to be used like a flow bench.
If you take that approach, you will miss the major advantages they offer.
Yeah, my 1D simulation software wasn't right. Didn't see that coming! I thought physics was physics. And sure, the only possible excuse is my lack of effort and/or intellegence.
I thought the whole idea was to eliminate empirical data so we could improve and move into the future. Now I have to buy several different ones to see which one closely matches reality and then use empirical data to fine-tune the end result anyways? Do you see why so many of us have a problem with what you're saying?
Are you unable to see that you're caught up in a never-ending loop? Please, no more condescension and talking in circles.
RevTheory wrote: ↑Fri May 18, 2018 5:16 pm
Yeah, my 1D simulation software wasn't right. Didn't see that coming! I thought physics was physics. And sure, the only possible excuse is my lack of effort and/or intellegence.
I thought the whole idea was to eliminate empirical data so we could improve and move into the future. Now I have to buy several different ones to see which one closely matches reality and then use empirical data to fine-tune the end result anyways? Do you see why so many of us have a problem with what you're saying?
Are you unable to see that you're caught up in a never-ending loop? Please, no more condescension and talking in circles.
Neels (engmod4t) often gives out free trials as does eapro. It was easy to see eapro is a pos when you look at the limited inlet and exhaust inputs amongst other things
digger wrote: ↑Fri May 18, 2018 6:06 pm
Neels (engmod4t) often gives out free trials as does eapro. It was easy to see eapro is a pos when you look at the limited inlet and exhaust inputs amongst other things
RevTheory wrote: ↑Fri May 18, 2018 5:16 pm
Yeah, my 1D simulation software wasn't right. Didn't see that coming! I thought physics was physics. And sure, the only possible excuse is my lack of effort and/or intellegence.
I thought the whole idea was to eliminate empirical data so we could improve and move into the future. Now I have to buy several different ones to see which one closely matches reality and then use empirical data to fine-tune the end result anyways? Do you see why so many of us have a problem with what you're saying?
Are you unable to see that you're caught up in a never-ending loop? Please, no more condescension and talking in circles.
Some physics models are more complete than others and will be accordingly more or less accurate.
If you are correct about simulation, the leading engine development organizations are wrong.
