If you can write the above, and have the intelligence to safely operate a modern high performance engine, you can handle a 1D software.B Original wrote: ↑Fri May 18, 2018 6:04 am
Jon do you consider yourself a high-functioning sociopath? Or is this an engineers attempt to torment the lesser educated by posting when he gets drunken bored after midnight? An engineering version of a prank phone call lol.
What do you recommend the other 99.76% of us do that don't have your level of Education to understand simulation isms
How to develop cam specs
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Re: How to develop cam specs
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Re: How to develop cam specs
Thanks for ALL of the great technical information / help.Vincenzo wrote: ↑Fri May 18, 2018 4:43 am I believe that the majority of members of this forum are V8 engine enthusiasts, so what follows is specifically for their interest.
Any 1D software package has an inherent problem when simulating such an engine - it simulates a static valve lift design, whereas the engine running at the speed of the sim will be experiencing a dynamic valve lift design.
Because there is considerable difference between the two, most notably in a delayed exhaust valve opening, unless this can be effectively made allowance for, the result of the simulation may well be far different when compared to the measured output from a running engine.
This can be very effectively handled by combining the results from program 10 in Blair's software 4StHead, using a feature which enables the user to save a dynamic valve lift file, and then import it into Vannik's EngMod4T software, into the Dat4T section.
Of particular note might be the result from the program 10 in Blair's 4StHead, which are extremely accurate when compared to those from a Spintron for the same engine.
The delayed exhaust valve opening mentioned above, can be as great as 20 crankshaft degrees, and possibly even more. This delay is almost completely absent in a DOHC engine, so in this latter case the dynamic valve lift file is not as important
Stan
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Re: How to develop cam specs
I don't know how he's still BS'ing people to pay him.SchmidtMotorWorks wrote: ↑Fri May 18, 2018 12:30 am The most experienced person alive working in engine development that I know of; Hans Herman, does 1D engine simulation as a consultant job for leading OEMs and race teams all over the world.
Every project. where we both designed cams, he wasn't even in the same ballpark.
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Re: How to develop cam specs
This is an example of a industry standard optimization or continuous improvement loop. It is used the world over. It is what the Japanese applied, most notably at Toyota (Toyota Production system) to kick our industrial asses in the 1980's.SchmidtMotorWorks wrote: ↑Fri May 18, 2018 12:19 am (actually most major dimensions)
1. Get a 1 D software and learn how to use it.
2. Design the best engine you can based on where the 1D software leads you
3. Build an engine based on #2
4. Plan a dyno session with the variety of parts that you can afford to test.
a. Cams
b. Cam index
c. Intake manifolds
d. Headers
Note, make the tests with both single-part changes and reasonable matching sets of parts.
5. Make 1D models for each combination planned in #4
6. Dyno test to the plan in #4:
7. Compare the dyno results to what the 1D models predicted
8. Understand the "simulationisms" (how the tests vary from the simulation)
Repeat steps 2-8 until you are satisfied.
I train HS drop outs on its application and I have yet to find one that can't comprehend and apply it. It is also called the Deming cycle after its first advocate William Edward Deming, a US statistician. It's most basic format is Plan, Do, Check, Act...repeat.
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Re: How to develop cam specs
Then people should focus on fitting larger cam cores, finding ways to run less valve spring, etc.Stan Weiss wrote: ↑Fri May 18, 2018 9:58 amThanks for ALL of the great technical information / help.Vincenzo wrote: ↑Fri May 18, 2018 4:43 am I believe that the majority of members of this forum are V8 engine enthusiasts, so what follows is specifically for their interest.
Any 1D software package has an inherent problem when simulating such an engine - it simulates a static valve lift design, whereas the engine running at the speed of the sim will be experiencing a dynamic valve lift design.
Because there is considerable difference between the two, most notably in a delayed exhaust valve opening, unless this can be effectively made allowance for, the result of the simulation may well be far different when compared to the measured output from a running engine.
This can be very effectively handled by combining the results from program 10 in Blair's software 4StHead, using a feature which enables the user to save a dynamic valve lift file, and then import it into Vannik's EngMod4T software, into the Dat4T section.
Of particular note might be the result from the program 10 in Blair's 4StHead, which are extremely accurate when compared to those from a Spintron for the same engine.
The delayed exhaust valve opening mentioned above, can be as great as 20 crankshaft degrees, and possibly even more. This delay is almost completely absent in a DOHC engine, so in this latter case the dynamic valve lift file is not as important
Stan
In all seriousness, Billy Godbold brought this issue up. He said what you can do, is you have Spintron data, is to input that into your model.
The user defines the parameters and must recognize the limitations of what they’re doing and be able to I repeat the information.
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Re: How to develop cam specs
Man, what's the intended dividing line between "advanced engine tech" and "engine tech" on this forum anyway? If you are happy just plugging one cam in it's "engine tech" if you want to test stuff rigorously it's "advanced"?
Kind of joking, but also not really. Maybe it's my age, but I've found dinking with some of the less sophisticated 1d sims (at least I'm pretty sure that's what EAP is anyway) at least as easy as the various rules of thumb like the Blair one laid out. Which reminds me I really need to cut Vannik a check next payday.
I think what people really need to do is apply design of experiments to this stuff, though that basically slots into what Jon is suggesting in the OP of this one.
Kind of joking, but also not really. Maybe it's my age, but I've found dinking with some of the less sophisticated 1d sims (at least I'm pretty sure that's what EAP is anyway) at least as easy as the various rules of thumb like the Blair one laid out. Which reminds me I really need to cut Vannik a check next payday.
I think what people really need to do is apply design of experiments to this stuff, though that basically slots into what Jon is suggesting in the OP of this one.
Re: How to develop cam specs
If the discussion uses terms like "3/4 Race", "Full Race", "Lopey Idle", "Sounds mean", or "max effort", it shouldn't be on the Advanced Engine Tech forum.mekilljoydammit wrote: ↑Fri May 18, 2018 10:36 am Man, what's the intended dividing line between "advanced engine tech" and "engine tech" on this forum anyway?
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Re: How to develop cam specs
The project he did for us last year was as close as the two dynos it was tested on.CamKing wrote: ↑Fri May 18, 2018 10:08 amI don't know how he's still BS'ing people to pay him.SchmidtMotorWorks wrote: ↑Fri May 18, 2018 12:30 am The most experienced person alive working in engine development that I know of; Hans Herman, does 1D engine simulation as a consultant job for leading OEMs and race teams all over the world.
Every project. where we both designed cams, he wasn't even in the same ballpark.
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Re: How to develop cam specs
There are no rules or formulas.
The best bet is to gain experience with a specific engine, or talk to someone who has.
I've had custom camshaft grinders offer me cams that trailed by more than 25 hp compared to ones that I have spec'd. But 99% of my engines are SBF's or FE's.
The biggest issue I've found with most grinders is that they think that they have nailed it on the first lick. The best scenario is to grab a hand full of cams and swap them out on the same engine, on the same day, on the same dyno.
The best bet is to gain experience with a specific engine, or talk to someone who has.
I've had custom camshaft grinders offer me cams that trailed by more than 25 hp compared to ones that I have spec'd. But 99% of my engines are SBF's or FE's.
The biggest issue I've found with most grinders is that they think that they have nailed it on the first lick. The best scenario is to grab a hand full of cams and swap them out on the same engine, on the same day, on the same dyno.
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Re: How to develop cam specs
Another method i found for typical pushrod v8
Intake duration
Int dur = 148.1+ (3.8 * comp ratio) + (12 / (rpm at tq peak * stroke / 33002.4) ) + 0.007 * ( rpm at tq peak ^ 0.77) * (bore diam ^ 0.27) * ( stroke ^ 1.47)
Exhaust dur = int dur * ( 1 + ( ( 0.348 / rod stroke ratio)^1.99)) + 12
Now that 12 seems arbitrary for a drag race na engine for long powerband after peak but who knows
Let me dig up the lsa part
Intake duration
Int dur = 148.1+ (3.8 * comp ratio) + (12 / (rpm at tq peak * stroke / 33002.4) ) + 0.007 * ( rpm at tq peak ^ 0.77) * (bore diam ^ 0.27) * ( stroke ^ 1.47)
Exhaust dur = int dur * ( 1 + ( ( 0.348 / rod stroke ratio)^1.99)) + 12
Now that 12 seems arbitrary for a drag race na engine for long powerband after peak but who knows
Let me dig up the lsa part
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Re: How to develop cam specs
You’ve created a database in your head.blykins wrote: ↑Fri May 18, 2018 11:28 am There are no rules or formulas.
The best bet is to gain experience with a specific engine, or talk to someone who has.
I've had custom camshaft grinders offer me cams that trailed by more than 25 hp compared to ones that I have spec'd. But 99% of my engines are SBF's or FE's.
The biggest issue I've found with most grinders is that they think that they have nailed it on the first lick. The best scenario is to grab a hand full of cams and swap them out on the same engine, on the same day, on the same dyno.
Create a working computer database, and you can reverse engineer why what you spec’ed worked better.
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Re: How to develop cam specs
Now that's funnyCamKing wrote: ↑Fri May 18, 2018 10:43 amIf the discussion uses terms like "3/4 Race", "Full Race", "Lopey Idle", "Sounds mean", or "max effort", it shouldn't be on the Advanced Engine Tech forum.mekilljoydammit wrote: ↑Fri May 18, 2018 10:36 am Man, what's the intended dividing line between "advanced engine tech" and "engine tech" on this forum anyway?
I may giggle about that line all day
Re: How to develop cam specs
I really don't need a computer to tell me that a port is big and slow, or an exhaust side is poor.
Too many variables for a database or formula to work correctly. May get you close, but there's sometimes a big difference between close and optimal.
Too many variables for a database or formula to work correctly. May get you close, but there's sometimes a big difference between close and optimal.
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www.lykinsmotorsports.com
www.customfordcams.com
Custom Ford Windsor, Cleveland, and FE Street/Race Engines
brent@lykinsmotorsports.com
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www.customfordcams.com
Custom Ford Windsor, Cleveland, and FE Street/Race Engines
Re: How to develop cam specs
Thank you!Orr89rocz wrote: ↑Fri May 18, 2018 11:36 am Another method i found for typical pushrod v8
Intake duration
Int dur = 148.1+ (3.8 * comp ratio) + (12 / (rpm at tq peak * stroke / 33002.4) ) + 0.007 * ( rpm at tq peak ^ 0.77) * (bore diam ^ 0.27) * ( stroke ^ 1.47)
Exhaust dur = int dur * ( 1 + ( ( 0.348 / rod stroke ratio)^1.99)) + 12
Now that 12 seems arbitrary for a drag race na engine for long powerband after peak but who knows
Let me dig up the lsa part