More power from any engine?
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57rto
- Posts: 115
- Joined: Sun Nov 03, 2002 12:01 am
More power from any engine?
Heres a new idea. Is anyone willing to experiment with this? MASSIVE? The dyno doesnt lie. Ive been reading this, and asking myself if this will actually work for the past year now. Any input?
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57rto
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yilon
- Posts: 173
- Joined: Mon Apr 15, 2002 1:01 am
Let's take a look at the 'horsepower secret' of smaller ports. I am a systems analyst by profession and I will guide you through the thinking process.
1. 'High velocity intake is good.' The idea is fine. In fact, ram intake basically uses this method. Now, what factors influence intake velocity? High velocity fluid flow is first achieved by insuring laminar fluid flow. Laminar fluid flow is when the fluid flows smoothly with no turbulence. (You can read books on fluid flow mechanics, but if you do not accept the idea that laminar fluid flow is good, you may as well stop reading right here.) What negatively affects laminar fluid flow? Surface roughness negatively affects laminar fluid flow. (Of course, a certain amount of roughness also improves fuel air mixing (carbs, not direct injection). We have two ideas fighting each other.) The shape of a port also has a great deal of influence on laminar fluid flow. A discussion of optimal shape of a port quickly gets into PhD math. However, a long time back I had an engine ported by a guy who had been delivering results for the racers in the area. The porting guy was an illiterate hillbilly. When I asked him a question about why he had left a certain amount of material inside of a port, illiterate boy gave me a short explanation of the phenomena of cavitation in fluid flow. Don't expect me to explain cavitation, it is a PhD level subject. Where did illiterate boy learn about cavitation? It sure as hell wasn't in school, the sumbitch couldn't even read. Some guys got it, some don't. The motion of a poppet intake valve (trust me, all the intake valves you have ever seen are poppet valves) creates pressure waves in the port serving the valve. Said pressure waves also influence laminar flow (as well as pressure in the port). The effect of pressure waves in a laminar flow fluid stream is yet another PhD level subject. If horsepower boy understands fluid flow better than PhD engineers, then he gonna get more horsepower; else less horsepower.
2. If you want higher velocity due to a smaller port, you have to restrict the port. If you just make the port smaller you may get more velocity, but (trust me on this one) you aint gonna get more flow through the port. In order to get more flow through a smaller port, the port designer has to understand fluid flow mechanics better than PhD engineers. Is this last possible? Of course, I actually dealt with an illiterate who could do this. However, if there is a person who intuitively understands fluid flow mechanics better than PhD level engineers, he is doing porting for the guys who are winning championships (there is no other damn way!). Is the guy in the article porting for champions? If not, he aint for real.
3. Well then, why don't I just go to a champion racer and ask who is doing his porting and how? If you don't already know the answer to this question, you need to have a long talk with your daddy about the secrets of earning money, etc. If I know how to win races let me assure you it is only because of the lucky scarf my lady love ties about my neck before each race. HONEST!!!
1. 'High velocity intake is good.' The idea is fine. In fact, ram intake basically uses this method. Now, what factors influence intake velocity? High velocity fluid flow is first achieved by insuring laminar fluid flow. Laminar fluid flow is when the fluid flows smoothly with no turbulence. (You can read books on fluid flow mechanics, but if you do not accept the idea that laminar fluid flow is good, you may as well stop reading right here.) What negatively affects laminar fluid flow? Surface roughness negatively affects laminar fluid flow. (Of course, a certain amount of roughness also improves fuel air mixing (carbs, not direct injection). We have two ideas fighting each other.) The shape of a port also has a great deal of influence on laminar fluid flow. A discussion of optimal shape of a port quickly gets into PhD math. However, a long time back I had an engine ported by a guy who had been delivering results for the racers in the area. The porting guy was an illiterate hillbilly. When I asked him a question about why he had left a certain amount of material inside of a port, illiterate boy gave me a short explanation of the phenomena of cavitation in fluid flow. Don't expect me to explain cavitation, it is a PhD level subject. Where did illiterate boy learn about cavitation? It sure as hell wasn't in school, the sumbitch couldn't even read. Some guys got it, some don't. The motion of a poppet intake valve (trust me, all the intake valves you have ever seen are poppet valves) creates pressure waves in the port serving the valve. Said pressure waves also influence laminar flow (as well as pressure in the port). The effect of pressure waves in a laminar flow fluid stream is yet another PhD level subject. If horsepower boy understands fluid flow better than PhD engineers, then he gonna get more horsepower; else less horsepower.
2. If you want higher velocity due to a smaller port, you have to restrict the port. If you just make the port smaller you may get more velocity, but (trust me on this one) you aint gonna get more flow through the port. In order to get more flow through a smaller port, the port designer has to understand fluid flow mechanics better than PhD engineers. Is this last possible? Of course, I actually dealt with an illiterate who could do this. However, if there is a person who intuitively understands fluid flow mechanics better than PhD level engineers, he is doing porting for the guys who are winning championships (there is no other damn way!). Is the guy in the article porting for champions? If not, he aint for real.
3. Well then, why don't I just go to a champion racer and ask who is doing his porting and how? If you don't already know the answer to this question, you need to have a long talk with your daddy about the secrets of earning money, etc. If I know how to win races let me assure you it is only because of the lucky scarf my lady love ties about my neck before each race. HONEST!!!
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porsche_914_freak
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MASSIVE TYPE IV
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raygreenwood
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While watching my brother port heads a while back (he is a process engineer with a specialty in airflow) that is one of the things he was saying...is that when velocity is the issue, many times shape and texture are much more important than large changes in size and volume. There are some heads that he actually added material into, to gain a higher flow rating at a specific velocity/rpm level. He went on to say, unless you can view the cavitation, or document it with photographic evidence inside the manifold in situ....it comes down to a combination of knowlege, experience, a lot of time on the flow bench and dyno...and of course intuition based on the preceding info. Ray
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MASSIVE TYPE IV
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raygreenwood
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No problem Jake. If you did not get the E-mail with his #'s a while back...I will re-send. He has also been busy, so he may be neglecting to call you.
There are a few things to remember about this gentlemans work. Motorcycles are a bit different in some ways. Also, in racing designs like those he is working on, many have less issuesthan a steetable engine. The compromises that are being made on a street engine are many. Yes...in the name of not slackening the charge velocity during initial charge fill...a smaller valve and port may help. This is precisley why Audi, on their long stroke vehicles has done so well with a muti-valve design. Several smaller valves can help keep the velocity up...AND overall flow volume across a wide range. Still others do it with multiple valves and variable valve timing.
If the port becomes too restrictive in the name of velocity....heat can rise. The compromises we need may very well have to do with keeping good temps, and making certain FI systems work. Lots of issues. I cannot see this as a universal formula. Restriction "steering" would be a good name for what he is doing. Its also precisely what I have been ranting about as of late in various FI forums...to control cavitation and turbulence in various parts of a slightly mis-sized plenum system. For example restricting or further opening up TB sizes ...can have great affect on turbulence and reversion damping in the plenum, conversely, plenum sizing can have the same damping effect on runners that are mis-sized...on down to valve sizing affecting what is upstream. Your "logic" says go large to get volume on valve sizing. But the turbulence the slamming of too large a valve causes...may well upset metering and replenishment air for the runners...then, even though the valve port flows high...it is fed too slowly to make a difference. Also most very experienced people do not used te flowbench in quite the haphazrd method described by this guy. It is but one tool..showing one particulare set of paramteres. Thats where experience, intuition and a lot of headwork comes in. Ray
There are a few things to remember about this gentlemans work. Motorcycles are a bit different in some ways. Also, in racing designs like those he is working on, many have less issuesthan a steetable engine. The compromises that are being made on a street engine are many. Yes...in the name of not slackening the charge velocity during initial charge fill...a smaller valve and port may help. This is precisley why Audi, on their long stroke vehicles has done so well with a muti-valve design. Several smaller valves can help keep the velocity up...AND overall flow volume across a wide range. Still others do it with multiple valves and variable valve timing.
If the port becomes too restrictive in the name of velocity....heat can rise. The compromises we need may very well have to do with keeping good temps, and making certain FI systems work. Lots of issues. I cannot see this as a universal formula. Restriction "steering" would be a good name for what he is doing. Its also precisely what I have been ranting about as of late in various FI forums...to control cavitation and turbulence in various parts of a slightly mis-sized plenum system. For example restricting or further opening up TB sizes ...can have great affect on turbulence and reversion damping in the plenum, conversely, plenum sizing can have the same damping effect on runners that are mis-sized...on down to valve sizing affecting what is upstream. Your "logic" says go large to get volume on valve sizing. But the turbulence the slamming of too large a valve causes...may well upset metering and replenishment air for the runners...then, even though the valve port flows high...it is fed too slowly to make a difference. Also most very experienced people do not used te flowbench in quite the haphazrd method described by this guy. It is but one tool..showing one particulare set of paramteres. Thats where experience, intuition and a lot of headwork comes in. Ray
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Wesayso
- Posts: 232
- Joined: Fri May 16, 2003 4:21 pm
I wondered about those valve-sizes.... he does not mention them, apart from the relation to the mentioned 65% rule he made for the porting job.raygreenwood wrote:...a smaller valve and port may help. This is precisley why Audi, on their long stroke vehicles has done so well with a muti-valve design. Several smaller valves can help keep the velocity up...AND overall flow volume across a wide range. Still others do it with multiple valves and variable valve timing.
If the port becomes too restrictive in the name of velocity....
What if you were to make a head the way he describes, and experimenting with the intake shape only, on a currently big sized intake-valve-head.
It would be interesting to know what it would do.
All it really takes is the epoxy on the right spot and some serious work with a dremel to know what the real potential is. If proven right it would change a lot of polish jobs on those ports! (rough surface as opposed to smooth and the way the ports are build up, to prevent a backdraft...)
If I had the means to test it I would I guess
, doesn't sound like that much of an investment to see if the power could build up in the entire bandwidth from low to high rev's....In other words, it does seem to make sense to me... (maybe it's time for me to quit reading his articles now, it is getting rather late here
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Bobby74
- Posts: 1747
- Joined: Wed Feb 21, 2001 12:01 am
Thank you for finding this website... This is exactly what I have been trying to explain for a while now.
An idea I've always used was; If the port is inverted like this / \ ... you create a low pressure area right behind the valve (by bottle-necking the top of the port). It should keep the high velocity for low RPM drivability and have more flow in general. Now having a winding path, is not something I really thought about, but it would make sense for allowing you to tune for a specific RPM or range. Interesting stuff...
An idea I've always used was; If the port is inverted like this / \ ... you create a low pressure area right behind the valve (by bottle-necking the top of the port). It should keep the high velocity for low RPM drivability and have more flow in general. Now having a winding path, is not something I really thought about, but it would make sense for allowing you to tune for a specific RPM or range. Interesting stuff...
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Billyisgr8
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Shad Laws
- Posts: 1605
- Joined: Fri Aug 24, 2001 12:01 am
Hello-
Would it be to late to run this idea by Shad for his upcomming Heads?
(maybe he allready is aware of it's gains)
Intake velocity is old news. The fact that over-sized ports (without the rest of the engine configuration to back it up) is a loss of power is also old news. Taking advantage of high intake velocities via inertia tuning is also old news.
He's just adding hype to the whole thing and calling it new again. Whoopie!
Small ports have a lower potential for horsepower. Always. However, like anything else, to get the full potential, you need the whole engine configuration to be in tune with itself. If you have huge heads, but no engine to back it up, then you have less power than if you had smaller heads and the correct engine to back it up.
The largest porting level of our upcoming Porkies cylinder heads are friggin' huge. The intake and exhaust ports and valves and chamber are all designed together to be appropriately sized for one another. If you put these heads on a little 2056-2270cc engine, you will have a horrible engine combination that will make less power than if you used a smaller porting level of Porkies. But, if properly configured with the cam, intake, exhaust, and enough cc's to bring the redline back below the stratosphere, hold on tight!!!
Take care,
Would it be to late to run this idea by Shad for his upcomming Heads?
(maybe he allready is aware of it's gains)Intake velocity is old news. The fact that over-sized ports (without the rest of the engine configuration to back it up) is a loss of power is also old news. Taking advantage of high intake velocities via inertia tuning is also old news.
He's just adding hype to the whole thing and calling it new again. Whoopie!
Small ports have a lower potential for horsepower. Always. However, like anything else, to get the full potential, you need the whole engine configuration to be in tune with itself. If you have huge heads, but no engine to back it up, then you have less power than if you had smaller heads and the correct engine to back it up.
The largest porting level of our upcoming Porkies cylinder heads are friggin' huge. The intake and exhaust ports and valves and chamber are all designed together to be appropriately sized for one another. If you put these heads on a little 2056-2270cc engine, you will have a horrible engine combination that will make less power than if you used a smaller porting level of Porkies. But, if properly configured with the cam, intake, exhaust, and enough cc's to bring the redline back below the stratosphere, hold on tight!!!
Take care,
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Wesayso
- Posts: 232
- Joined: Fri May 16, 2003 4:21 pm
Shad, that sounds logical enough....
But the ports mentioned in those article's are all ported to have a relationship with the valve-size... (his 65% rule)
http://mototuneusa.com/the_2007_superbike.htm
They're also all reduced in the same way and seem to increase power that way, so I'm not saying to put smaller valves in the heads but would "Motoman" be right about the shape and size compared to the valves used or is this also depending on the sort Cam beeing used...
(e.g. cam lift height, duration and form)
Just trying to learn something here
I realized he has to work with engines of a certain spec, beeing in the Superbike class, he has rules to follow. The most interesting thing for me (and I suppose others as well) is to see if he has a point with the shaping of the porting of the Inlets and Outlets in a relation with the valve-size. The rest would be up to what kind of other spec's are beeing run. It would be interesting to get an insight to proper porting a 2 valve head.
I know more than enough people are porting themselves, or want to know how it's done. It is surpricing (at least to me) to see the changes he made to several heads do gain power as opposed to "good flowing" heads. If he has a point there (as to the relation of the ports to the valves) we could all learn from that.
Those that really want power will go out an buy a "power head" from LNE or another firm but those that work with modified original heads might learn from this to optimize their porting shape to gain a few HP's in a wide bandwidth.
But the ports mentioned in those article's are all ported to have a relationship with the valve-size... (his 65% rule)
http://mototuneusa.com/the_2007_superbike.htm
They're also all reduced in the same way and seem to increase power that way, so I'm not saying to put smaller valves in the heads but would "Motoman" be right about the shape and size compared to the valves used or is this also depending on the sort Cam beeing used...
(e.g. cam lift height, duration and form)
Just trying to learn something here
I realized he has to work with engines of a certain spec, beeing in the Superbike class, he has rules to follow. The most interesting thing for me (and I suppose others as well) is to see if he has a point with the shaping of the porting of the Inlets and Outlets in a relation with the valve-size. The rest would be up to what kind of other spec's are beeing run. It would be interesting to get an insight to proper porting a 2 valve head.
I know more than enough people are porting themselves, or want to know how it's done. It is surpricing (at least to me) to see the changes he made to several heads do gain power as opposed to "good flowing" heads. If he has a point there (as to the relation of the ports to the valves) we could all learn from that.
Those that really want power will go out an buy a "power head" from LNE or another firm but those that work with modified original heads might learn from this to optimize their porting shape to gain a few HP's in a wide bandwidth.