Effects of piston speed.
#61
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Originally Posted by DavidNJ
I believe Ti is a good spring material, and the higher strength of Ti should make it a good pin material also.
It is my understanding that coated Ti pins and Ti valve springs are used in high level racing. Obviously F-1 uses pneumatic valve springs.
The Ti springs especially seem like they would be a good fit for the small spring LS1/2/6 heads.
Does the LSx have any oiling problems?
It is my understanding that coated Ti pins and Ti valve springs are used in high level racing. Obviously F-1 uses pneumatic valve springs.
The Ti springs especially seem like they would be a good fit for the small spring LS1/2/6 heads.
Does the LSx have any oiling problems?
Ti springs aren't the best for reliability but are used in some all out drag racing. The same goes for the coated Ti pins as they do see time in many drag cars but not endurance engines really.
The LSx has a mediocre at best oiling system with horrible drainback problems at high rpm. ALL oil in the LSx family of engines must pass through the spinning crank to return to the pan. This is what causes the problems. Aerated oil does not work really well basically. This is why GM went full dry sump on teh LS7 with it's stroke and rpm.
#62
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Originally Posted by SStrokerAce
I've even taught a few guys more about camshafts in a hour than they said they learned the whole time they were there.
OTOH I have not had any problems with any of the camshaft advice I've heard you say so far or that I can remember. To me camshafts are pretty simple devices to understand when you break everything down but any good engine builder can usually pick a good first cam but then you really have to start testing.
I've certainly had probably my fill of supposed cam gurus that know all these supposed secrets! We know and teach at the school that that's a bunch of BS! If anyone could pick a perfect cam WJ wouldn't have 30 of them sitting on a table to run.
#63
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Originally Posted by racer7088
David,
Ti springs aren't the best for reliability but are used in some all out drag racing. The same goes for the coated Ti pins as they do see time in many drag cars but not endurance engines really.
The LSx has a mediocre at best oiling system with horrible drainback problems at high rpm. ALL oil in the LSx family of engines must pass through the spinning crank to return to the pan. This is what causes the problems. Aerated oil does not work really well basically. This is why GM went full dry sump on teh LS7 with it's stroke and rpm.
Ti springs aren't the best for reliability but are used in some all out drag racing. The same goes for the coated Ti pins as they do see time in many drag cars but not endurance engines really.
The LSx has a mediocre at best oiling system with horrible drainback problems at high rpm. ALL oil in the LSx family of engines must pass through the spinning crank to return to the pan. This is what causes the problems. Aerated oil does not work really well basically. This is why GM went full dry sump on teh LS7 with it's stroke and rpm.
Pins; If they're coated, as I believe most dry sump induced-vaccum pins are, why would there be a wear problem with Ti vs steel? They should have a higher fatigue limit and reach any specific yield strength or fatigue strength with less weight.
Springs: Ti has a higher yield strength, higher fatigue limit. Why wouldn't it make a better, lighter spring?
#64
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David,
The LS7 still areates oil but the dry sump scavenges it to a settling tank with a cone shaped bottom so that all the air and bubbles can rise out of it and the pressure side pump only receives liquid oil. Thw windage is bad but as far as what we are talking about at least you don't run out of oil to the bearings at high rpm with the dry sump.
The Ti pins are weaker and flex more and gall. They HAVE to be coated or they will gall very bad. With some more advances maybe they will be seen some day in more endurance engines.
Ti springs break fairly quickly in reality David and there are many reasons why. They don't last too long and I can't think of them getting used anywhere outside of drag racing right now but I just do not know that much about Ti springs. At times many PS teams used them and a few still do at times.
The LS7 still areates oil but the dry sump scavenges it to a settling tank with a cone shaped bottom so that all the air and bubbles can rise out of it and the pressure side pump only receives liquid oil. Thw windage is bad but as far as what we are talking about at least you don't run out of oil to the bearings at high rpm with the dry sump.
The Ti pins are weaker and flex more and gall. They HAVE to be coated or they will gall very bad. With some more advances maybe they will be seen some day in more endurance engines.
Ti springs break fairly quickly in reality David and there are many reasons why. They don't last too long and I can't think of them getting used anywhere outside of drag racing right now but I just do not know that much about Ti springs. At times many PS teams used them and a few still do at times.
Originally Posted by DavidNJ
Oiling: The LS7 scavenges the pan. How does that help drain back? Other aftermarket pans (i.e., Harrop, ARE) also seem to scavenge the pan. Do some setups also scavenge the lifter valley and valve covers?
Pins; If they're coated, as I believe most dry sump induced-vaccum pins are, why would there be a wear problem with Ti vs steel? They should have a higher fatigue limit and reach any specific yield strength or fatigue strength with less weight.
Springs: Ti has a higher yield strength, higher fatigue limit. Why wouldn't it make a better, lighter spring?
Pins; If they're coated, as I believe most dry sump induced-vaccum pins are, why would there be a wear problem with Ti vs steel? They should have a higher fatigue limit and reach any specific yield strength or fatigue strength with less weight.
Springs: Ti has a higher yield strength, higher fatigue limit. Why wouldn't it make a better, lighter spring?
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"I see you have the same stellar opinion of Mr. Bauer & his father as I do. I have a shop, a real shop located in NY about 4 hours away from Bret & his fathers wanna be shop. Which consists of a residential 2 car garage with basic tools and an old SF600. I love the use of BS theory and regurgitated Reher Morrison information on these forums to snow job people into thinking he is a engine god and camshaft wizard. I got a good laugh out of this thread. Especially the challenge to build a fast LS1. He couldn't do it with an LT1, so I doubt he will have much luck with a new platform. Keep up the good work"
Posted originally by JnJSpdShop?
Not sure if this is in reference to me, but I'd like to reply to "Mr. JnJSpdShop"
if he was quoting me.
Thanks.
P.S. If anyone can read back to my previos post and comment, I'd like to
get on track with my ideas.
#66
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Quote:
"I see you have the same stellar opinion of Mr. Bauer & his father as I do. I have a shop, a real shop located in NY about 4 hours away from Bret & his fathers wanna be shop. Which consists of a residential 2 car garage with basic tools and an old SF600. I love the use of BS theory and regurgitated Reher Morrison information on these forums to snow job people into thinking he is a engine god and camshaft wizard. I got a good laugh out of this thread. Especially the challenge to build a fast LS1. He couldn't do it with an LT1, so I doubt he will have much luck with a new platform. Keep up the good work"
LOL! I must have missed that one originally. I'm "his father" in the quote.
Evidently the poster doesn't have much first hand knowledge or he toured another establishment.
My guess is that original posts like that might have been "sanitized". They do give me a laugh, however.
I'm not picturing what you mean here, Z. It's always the surrounding atmospheric pressure that pushes the air into the engine. The piston creates a pressure lower than atmospheric on it's down stroke. Ma Nature hates a vacuum so she tries to fill it. It there is some good intake tuning going on that adds to the filling.
Rotating inertia retards the acceleration of the engine so less power gets to the flywheel. Yes, that would have an effect on BSFC. You could see that on an engine dyno by comparing steady-state (step) tests to accelerating tests. Intuitively, the faster you accelerate the engien (1000 rpm/second vs. 300 rpm/sec), the less power you'll get at the flywheel (or the dyno or "brake").
Overall heat going into the piston certainly depends on how often you fire the cylinder (rpm). Endurance engines are designed to reject enough of that heat so that the piston doesn't overheat. There are ways to aid this like coatings and oil spraying onto the underside of the piston crown. A Cup Daytona (plate) engine is a good example of an engine running at hp peak for long periods of time, especially if it's the lead dog or running out of the draft.
"I see you have the same stellar opinion of Mr. Bauer & his father as I do. I have a shop, a real shop located in NY about 4 hours away from Bret & his fathers wanna be shop. Which consists of a residential 2 car garage with basic tools and an old SF600. I love the use of BS theory and regurgitated Reher Morrison information on these forums to snow job people into thinking he is a engine god and camshaft wizard. I got a good laugh out of this thread. Especially the challenge to build a fast LS1. He couldn't do it with an LT1, so I doubt he will have much luck with a new platform. Keep up the good work"
Originally Posted by Adrenaline_Z
Where is this post? I can't see it after a refresh, or cache clear?
Posted originally by JnJSpdShop?
Not sure if this is in reference to me, but I'd like to reply to "Mr. JnJSpdShop"
if he was quoting me.
Thanks.
P.S. If anyone can read back to my previos post and comment, I'd like to
get on track with my ideas.
Posted originally by JnJSpdShop?
Not sure if this is in reference to me, but I'd like to reply to "Mr. JnJSpdShop"
if he was quoting me.
Thanks.
P.S. If anyone can read back to my previos post and comment, I'd like to
get on track with my ideas.
LOL! I must have missed that one originally. I'm "his father" in the quote.
Evidently the poster doesn't have much first hand knowledge or he toured another establishment.
My guess is that original posts like that might have been "sanitized". They do give me a laugh, however.
Originally Posted by Adrenaline_Z
It's tough to speculate on this level, but I'd like to throw out my ideas:
I'm thinking valve control at high RPM is a definite concern - especially upon
closing. Any sort of bounce is going to kill combustion pressure.
I've seen huge benefits of spring changes, or REV kits on street motors in the
5000-7000 RPM range, so I can believe there is power to be made with valve
control at 10,000 +.
There are several articles claiming power gains by eliminating mass at the valve,
retainer, upper spring area, etc. so I'll agree valve control is a limiting factor.
I have no idea how fluids/gas react at extreme piston speeds, but I would
assume a gas under vacuum will behave better than a gas which is 'pushed'
into the cylinder due to its viscosity.
I'm thinking valve control at high RPM is a definite concern - especially upon
closing. Any sort of bounce is going to kill combustion pressure.
I've seen huge benefits of spring changes, or REV kits on street motors in the
5000-7000 RPM range, so I can believe there is power to be made with valve
control at 10,000 +.
There are several articles claiming power gains by eliminating mass at the valve,
retainer, upper spring area, etc. so I'll agree valve control is a limiting factor.
I have no idea how fluids/gas react at extreme piston speeds, but I would
assume a gas under vacuum will behave better than a gas which is 'pushed'
into the cylinder due to its viscosity.
When it comes to piston mass and high RPM, I think it's equally as important
as valve mass. 300+ grams at 10,000 RPM can certainly exceed tensile limits
of rod caps in a hurry I'm sure, and increase the maintenance period.
All the talk about Inertia can't be ignored. The time it will take to accelerate
the piston with a heavier mass will change how the air flows through the port.
Having 8 pistons slugging around is certainly going to reduce the efficiency of
the motor (energy required to turn rotating assembly). This would result in
poor BSFC correct?
as valve mass. 300+ grams at 10,000 RPM can certainly exceed tensile limits
of rod caps in a hurry I'm sure, and increase the maintenance period.
All the talk about Inertia can't be ignored. The time it will take to accelerate
the piston with a heavier mass will change how the air flows through the port.
Having 8 pistons slugging around is certainly going to reduce the efficiency of
the motor (energy required to turn rotating assembly). This would result in
poor BSFC correct?
My last thoughts are RPM brings heat. Oil cooling, heat transfer from the pistoncrown to the cylinder walls must be considered.
Ring flutter and crankcase pressures and pressure above the piston increase
as the piston speed/RPM increases. Gas porting is probably a good idea.
How about the profile of the ring itself (contact area)?
All I have to say is, I've brainstormed for about 20 minutes and I'm sure these
engine builders have days of considerations beyond what we're coming up with.
Cheers to you both in this discussion!
Ring flutter and crankcase pressures and pressure above the piston increase
as the piston speed/RPM increases. Gas porting is probably a good idea.
How about the profile of the ring itself (contact area)?
All I have to say is, I've brainstormed for about 20 minutes and I'm sure these
engine builders have days of considerations beyond what we're coming up with.
Cheers to you both in this discussion!
#68
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To everyone else.... my personality doesn't let me not write this crap, so just bear with my waste of bandwidth for a change. I'm hoping my good posts make up for ones like these in the grand scheme of life.
Eric,
Before I get into this.... I'm going to preface this last part of my argument, since you want to make this personal. My own mother has called me an *******, I paint with a very broad brush, and frankly I don't take **** from anyone. I've never been afraid to be wrong and take risks... but that's what separates those of us in the world from each other. Don't be afraid of who you actually are, that's the key to being a man. Yet in our world few of us learn to do that.
I'm going to give you a Pee Wee Herman esque quote for the day
"Don't confuse me with the facts my mind is already made up"
nah forget a day, lets apply that to every post you make. Now as long as everyone remembers to stand up and shout when you post everything we will be all good. (sorry if your too old or too young for pee wees playhouse, and no it didn't envolve nudity back then)
and let’s add on to that a good rip off from the NAACP (I'm a equal opportunity offender here)
"A closed mind is a terrible thing to waste"
I am by no means the cam guru, but to the average guy I might be. I'm not a megalomaniac such as yourself. I just have a very good talent for finding the commonalities in systems extremely efficiently. So camshafts are relatively easy.
Tell Judd, hell have him call me up and I will tell him myself if he wants to discuss it with me.
From my IM log FWIW
Former SAM Student: "I really wish Judson would've gone over this stuff more, I honestly didn't learn very much at all from his camshaft talk."
One of the joys of a very good liberal arts education Eric is that you learn to take and give out constructive criticism. Yes I got that 4 year degree in 4 years. Being well rounded has pretty much let me learn on my own accord studying closely in 5 years what you have done over the last 20, Good Job! I've been studying engines for 20 years but doing it religiously for about 5, I still don't see where you are ahead in terms of anything other than a over inflated ego. Flip that jealously switch around, I sure as **** would be a little miffed if someone 10+ years junior to me had the grasp I did on the workings of the internal combustion engine. Only difference is I would be glad to know them.
Actually I'm quite glad that I didn't do SAM.... I do much better learning things on my own than being impregnated with the fallacies and shortcomings of others. I don't learn as well that way. Then again I was lucky... I was born with a thirst to learn this AND a teacher at my disposal 24/7. I guess the alternative is you. It's better than nothing.
In reality SAM is a very good education for guys who want to learn this stuff. I'm not putting it down at all; I'm just being a dick to Eric.
Now if you hand assembled Ricks motor yourself, well I might have been impressed with that whole ordeal. I really think that if you want to take credit for the motors you need to build them YOURSELF.
The only thing I've ever asked out of you is to answer a direct question that I pretty much know that you don't know the answer too.... guess what your EGO is too big to let you do that. I mean come on there are all these SAM students watching you and you have to live up to their expectations so they respect you. I mean how else are you going to learn anything when they get real jobs in the field, lord knows the saint of original thought isn’t going to come down and bless you anytime soon. Life is pretty easy when you have a bunch of followers.... if you’re right or not is another thing entirely.
Go start studying flat crank 90° V8 harmonics at 18,000+rpm and maybe you can answer the question you have been eluding.
I'll leave you with this....
That's probably one of the best compliments I have ever had. This comes from a guy who had a Sonny Leonard built 500 cube SBC that did extremely well in Comp Eliminator (think he actually had some records with it), has more than a few 1.7 Hp/Cube street motors under his belt and doesn't consider 9.0's to be fast.
So I guess in closing.... stop taking credit for others. The pronoun WE means that YOU actually had something to do with the accomplishment at hand. You might have done some good accomplishments in your life, but how about you just refer to those YOU actually put your mitts on.
This WOULD have been a great discussion on the topic at hand IF you ERIC could have been open minded enough to go along and feel things out. Kind of shows how little of a team player you are even as smart as you are, you’re just not one of the guys on the teams that wins the major championships every year. I give you a lot of credit for your mental capability, but your lack of interpersonal skills and personality problems pretty much leaves you in the realm of an idiot savant.
TTYL, Rainman.
Bret
The shame in all of this is that if we sat down and had a beer we would probably have a good conversation.... who gives a rat’s *** if we disagree.
PS I realize your name is spelled with a K as well, but then again why should I give you any respect at this point?
Originally Posted by racer7088
HAHAHAHAHAHAHAHA! I'll be sure to pass that along to Judson as I'm sure he'll have quite a good time with that one!
Before I get into this.... I'm going to preface this last part of my argument, since you want to make this personal. My own mother has called me an *******, I paint with a very broad brush, and frankly I don't take **** from anyone. I've never been afraid to be wrong and take risks... but that's what separates those of us in the world from each other. Don't be afraid of who you actually are, that's the key to being a man. Yet in our world few of us learn to do that.
I'm going to give you a Pee Wee Herman esque quote for the day
"Don't confuse me with the facts my mind is already made up"
nah forget a day, lets apply that to every post you make. Now as long as everyone remembers to stand up and shout when you post everything we will be all good. (sorry if your too old or too young for pee wees playhouse, and no it didn't envolve nudity back then)
and let’s add on to that a good rip off from the NAACP (I'm a equal opportunity offender here)
"A closed mind is a terrible thing to waste"
I am by no means the cam guru, but to the average guy I might be. I'm not a megalomaniac such as yourself. I just have a very good talent for finding the commonalities in systems extremely efficiently. So camshafts are relatively easy.
Tell Judd, hell have him call me up and I will tell him myself if he wants to discuss it with me.
From my IM log FWIW
Former SAM Student: "I really wish Judson would've gone over this stuff more, I honestly didn't learn very much at all from his camshaft talk."
One of the joys of a very good liberal arts education Eric is that you learn to take and give out constructive criticism. Yes I got that 4 year degree in 4 years. Being well rounded has pretty much let me learn on my own accord studying closely in 5 years what you have done over the last 20, Good Job! I've been studying engines for 20 years but doing it religiously for about 5, I still don't see where you are ahead in terms of anything other than a over inflated ego. Flip that jealously switch around, I sure as **** would be a little miffed if someone 10+ years junior to me had the grasp I did on the workings of the internal combustion engine. Only difference is I would be glad to know them.
Actually I'm quite glad that I didn't do SAM.... I do much better learning things on my own than being impregnated with the fallacies and shortcomings of others. I don't learn as well that way. Then again I was lucky... I was born with a thirst to learn this AND a teacher at my disposal 24/7. I guess the alternative is you. It's better than nothing.
In reality SAM is a very good education for guys who want to learn this stuff. I'm not putting it down at all; I'm just being a dick to Eric.
Now if you hand assembled Ricks motor yourself, well I might have been impressed with that whole ordeal. I really think that if you want to take credit for the motors you need to build them YOURSELF.
The only thing I've ever asked out of you is to answer a direct question that I pretty much know that you don't know the answer too.... guess what your EGO is too big to let you do that. I mean come on there are all these SAM students watching you and you have to live up to their expectations so they respect you. I mean how else are you going to learn anything when they get real jobs in the field, lord knows the saint of original thought isn’t going to come down and bless you anytime soon. Life is pretty easy when you have a bunch of followers.... if you’re right or not is another thing entirely.
Go start studying flat crank 90° V8 harmonics at 18,000+rpm and maybe you can answer the question you have been eluding.
I'll leave you with this....
Originally Posted by - Mindgame
"I know I've poked at Bret more than a few times because he's a young guy.
Fact is... because he IS capable of thinking outside the box... I'd send my stuff to him before I'd pay one of the big name drag engine builders whose set in the "old" way of thinking about engines. If for nothing more than the simple fact that he'd be willing to give it a TRY. "
Fact is... because he IS capable of thinking outside the box... I'd send my stuff to him before I'd pay one of the big name drag engine builders whose set in the "old" way of thinking about engines. If for nothing more than the simple fact that he'd be willing to give it a TRY. "
So I guess in closing.... stop taking credit for others. The pronoun WE means that YOU actually had something to do with the accomplishment at hand. You might have done some good accomplishments in your life, but how about you just refer to those YOU actually put your mitts on.
This WOULD have been a great discussion on the topic at hand IF you ERIC could have been open minded enough to go along and feel things out. Kind of shows how little of a team player you are even as smart as you are, you’re just not one of the guys on the teams that wins the major championships every year. I give you a lot of credit for your mental capability, but your lack of interpersonal skills and personality problems pretty much leaves you in the realm of an idiot savant.
TTYL, Rainman.
Bret
The shame in all of this is that if we sat down and had a beer we would probably have a good conversation.... who gives a rat’s *** if we disagree.
PS I realize your name is spelled with a K as well, but then again why should I give you any respect at this point?
Last edited by SStrokerAce; 01-22-2006 at 01:17 AM.
#69
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I read Erik's "we" as he said it was used. He was not taking credit for anything at the EMC. The English language is a very clear one. StrokerAce, you jumped on something that wasn't there and you need to relax.
The truth is the truth. Some choose to suffer fools, other don't. An automotive tech forum is one of the last places I would go looking for emotionally intelligent people. To learn something and leave with a new fact is good enough.
No need to put down SAM or Judson's cam class either. As with any school or class, there are interested and disinterested students.
The truth is the truth. Some choose to suffer fools, other don't. An automotive tech forum is one of the last places I would go looking for emotionally intelligent people. To learn something and leave with a new fact is good enough.
No need to put down SAM or Judson's cam class either. As with any school or class, there are interested and disinterested students.
#70
FormerVendor
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Bret, you have to stop taking this stuff so seriously. Just because you are wrong about something doesn't mean you have to do this much soul searching! It's a bulletin board for christ's sake!
As for your wierd F1 question I still don't even know what you're talking about? I don't follow it that closely right now but I know they are going to have to go V8. What is your exact question as I may or may not have any idea?
Also when people attack one of your ideas or theories and you can't fight back you start with all of your personal garbage just like you have in this thread. I attack your ideas and you have to attack me personally because otherwise you have no leg to stand on.
You are not even close to being half as knowledgable about the internal combustion engine as you think you are or you wouldn't routinely come up with these wierd statements that are false.
I also know two students that HAVE talked to you and were shocked at how LITTLE you knew about cylinder heads at least in their opinion. They did think you were trying to learn or you wouldn't have asked them so many questions but they considered it entirely one-sided.
Coming in here and giving us gems like how "you have learned far more on your own than you could have elsewhere" shows what a delusional paranoid LA-LA land you are in. Not everyone has a father that plays with cars and engines and thinks that just because of this they also already know everything.
I have students like you all the time that think they know everything and can't hardly tie their own shoes in the engine building world. Thankfully most of our students are here because they KNOW there is always more to learn. We have guys that grow up in racing and have even had direct family experience in NHRA Pro classes and they come to SAM and they learn.
I have been relearning everything I know about pistons and rings again lately as I talk to everyone I can. NO one knows everything so you have to talk to quite a few "experts" and then make your own decisions. I am ALWAYS looking for new info as is anyone in the competitive engine building world.
How about YOU coming up with some original thought like I do in every damn one of my posts instead of simply regurgitating every damn Reher-Morrison tech talk paragraph like the guy said(and yes WE have some students there too!). I know that you read more than that Bret but I see you on these boards and I do NOT see much understanding at all so why don't you try and impress ME with some of YOUR knowledge for once!
As for your wierd F1 question I still don't even know what you're talking about? I don't follow it that closely right now but I know they are going to have to go V8. What is your exact question as I may or may not have any idea?
Also when people attack one of your ideas or theories and you can't fight back you start with all of your personal garbage just like you have in this thread. I attack your ideas and you have to attack me personally because otherwise you have no leg to stand on.
You are not even close to being half as knowledgable about the internal combustion engine as you think you are or you wouldn't routinely come up with these wierd statements that are false.
I also know two students that HAVE talked to you and were shocked at how LITTLE you knew about cylinder heads at least in their opinion. They did think you were trying to learn or you wouldn't have asked them so many questions but they considered it entirely one-sided.
Coming in here and giving us gems like how "you have learned far more on your own than you could have elsewhere" shows what a delusional paranoid LA-LA land you are in. Not everyone has a father that plays with cars and engines and thinks that just because of this they also already know everything.
I have students like you all the time that think they know everything and can't hardly tie their own shoes in the engine building world. Thankfully most of our students are here because they KNOW there is always more to learn. We have guys that grow up in racing and have even had direct family experience in NHRA Pro classes and they come to SAM and they learn.
I have been relearning everything I know about pistons and rings again lately as I talk to everyone I can. NO one knows everything so you have to talk to quite a few "experts" and then make your own decisions. I am ALWAYS looking for new info as is anyone in the competitive engine building world.
How about YOU coming up with some original thought like I do in every damn one of my posts instead of simply regurgitating every damn Reher-Morrison tech talk paragraph like the guy said(and yes WE have some students there too!). I know that you read more than that Bret but I see you on these boards and I do NOT see much understanding at all so why don't you try and impress ME with some of YOUR knowledge for once!
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I have no idea how fluids/gas react at extreme piston speeds, but I would
assume a gas under vacuum will behave better than a gas which is 'pushed'
into the cylinder due to its viscosity.
assume a gas under vacuum will behave better than a gas which is 'pushed'
into the cylinder due to its viscosity.
The mixture entering the chamber is at a lower pressure than the intake
manifold. I would think the flow of air/fuel would travel through the port
with less turbulence than a gas which is pushed through the port.
Exhaust gas is traveling from high pressure in the cylinder to lower pressure
out to the atmosphere.
Whether these pulses are mixing with friendly, or destructive reflected waves
isn't my focus. My focus is more about how a pulse propogates through a tube when it is under vacuum, as opposed to pressurized.
#72
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Originally Posted by Adrenaline_Z
SS, what I meant by the above is:
The mixture entering the chamber is at a lower pressure than the intake
manifold. I would think the flow of air/fuel would travel through the port
with less turbulence than a gas which is pushed through the port.
The mixture entering the chamber is at a lower pressure than the intake
manifold. I would think the flow of air/fuel would travel through the port
with less turbulence than a gas which is pushed through the port.
Whether these pulses are mixing with friendly, or destructive reflected waves isn't my focus. My focus is more about how a pulse propogates through a tube when it is under vacuum, as opposed to pressurized.
#73
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Originally Posted by Old SStroker
I'm still confused, Z. I guess I'm just not seeing your point.
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
I'll have to draw up a little graph to illustrate what I'm seeing in the brain.
Maybe I should just leave it alone because it's not a critical part of this
discussion, or making power in particular. It's just me wanting to know how
a gas behaves as it comrpesses and rarefacts.
It would seem exhaust tuning would bring more gains than intake tuning in
general, and this is what my thought was based on initially.
Here are a few links to share:
http://kr.cs.ait.ac.th/~radok/physics/e5.htm
http://myfwc.com/boating/airboat/Section3.pdf
http://www.physics.utoronto.ca/~phot...n%20Primer.pdf
#74
TECH Fanatic
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Z, this might be a good book for you. It'll keep you busy for a while and out of your wife's way. ![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
It's the best one I've come across. I first read it when it was the first edition before the start of the muscle car and pony car era.
http://www.amazon.com/gp/product/083...lance&n=283155
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
It's the best one I've come across. I first read it when it was the first edition before the start of the muscle car and pony car era.
http://www.amazon.com/gp/product/083...lance&n=283155
#75
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Bret said:
If F1 could stay unrestricted in terms of bore size for a given displacement then they would develop the ports to move the wind they need to increase RPM.... they have the capability to go over 20K but not the durability, and the V8's give them even more of a problem with increased RPM. I want to see if anyone else here knows why?
The information to answer the question (I hope) is in the thread. PSa= rpm * stroke/6.
So with a 2.4 liter V-8 and a max bore of 98mm, the most oversquare, highest revving engine they can build has a bore of 98mm and a stroke of 39.7mm (egads!! 1.56 inch stroke, 0.7815 crank throw). At 21k rpm that gives a PSa of 5460 (I believe that is feet per minute)
So to rev any higher while keeping the PSa under 5500 the only two options are to bend time or shorten the stroke, which requires widening the bore, which is forbidden by the rules.
Yes?
EDIT: I guess they could keep the bore and shorten the stroke to trade displacement for rpm, but a 2.4 liter V8 is hardly a torque monster to begin with.
If F1 could stay unrestricted in terms of bore size for a given displacement then they would develop the ports to move the wind they need to increase RPM.... they have the capability to go over 20K but not the durability, and the V8's give them even more of a problem with increased RPM. I want to see if anyone else here knows why?
The information to answer the question (I hope) is in the thread. PSa= rpm * stroke/6.
So with a 2.4 liter V-8 and a max bore of 98mm, the most oversquare, highest revving engine they can build has a bore of 98mm and a stroke of 39.7mm (egads!! 1.56 inch stroke, 0.7815 crank throw). At 21k rpm that gives a PSa of 5460 (I believe that is feet per minute)
So to rev any higher while keeping the PSa under 5500 the only two options are to bend time or shorten the stroke, which requires widening the bore, which is forbidden by the rules.
Yes?
EDIT: I guess they could keep the bore and shorten the stroke to trade displacement for rpm, but a 2.4 liter V8 is hardly a torque monster to begin with.
#76
FormerVendor
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Yeah you won't see anyone in F1 truly destroking their engines. By this I mean true destroking which is reducing the stroke WITHOUT increasing the bore. Big bore / short stroke engines make more power and more power per inch because of the bigger bore at the same displacement and not because of the shorter stroke. The shorter stroke is just necesary since they are not allowed above a given displacement. If they could add stroke they would make more power even at the same bore as all engines routinely do. When they use these older F1 engines with "stroker" cranks they do routinely pick up large amounts of power and of course their rpm is reduced. That's why they never only have a bore limit in racing but also a displacement limit every single time from the NMCA to F1.
#77
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Some sanctioning bodies not only limit MAX displacement, they limit MIN displacement. IOW, there is a range you can use, say 350 to 358 cubes. Sounds strange, doesn't it?
#78
FormerVendor
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Originally Posted by Old SStroker
Some sanctioning bodies not only limit MAX displacement, they limit MIN displacement. IOW, there is a range you can use, say 350 to 358 cubes. Sounds strange, doesn't it?
You are free to build as small an engine or use as short a stroke as you can in most classes but people ALWAYS max out their inches. If you destroke these engines as they are built (no bore increases now but only true "destroking") they will simply slow down since they will lose cubic inches and power.
Now if I add stroke to either engine either F1 or PS I will gain cubic inches and power and lose at least some rpm as well in both cases. You cannot do this though as the rules will not allow engine over the written CID limit and that's why. The larger engines will go faster in a heads up situation.
The bore is the single biggest thing in the way of power when you are rpm unlimited as you get all your airflow through the head and the heads work best when set up for the bigger bore. Again the big bore is making the potential for power not any "destroking" action!
Also if I have a 434 chevrolet engine with 350 cfm 23 degree RR heads and I drop that stroke to 3 inches from 4 inches so now I only have a 311 CID what will happen to my power and how fast I can accelerate now in that same car?
#79
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I never heard that the min cube rule was about "huge lying and cheating with and about the restrictor plate engines". I thought perhaps some experimenting was being done on how to get better BMEP from a limited amount of air, and maybe a slightly better BSFC.
For example if you only lost 3 indicated hp from a shorter stroke same bore (smaller) engine, but decreased friction hp by 5, you'd be 2 up at the flywheel (brake hp). Something like that. It sure would escalate the plate development costs trying to find the best combination of displacement and friction. My take was that the min. displacement rule was to minimize plate development costs.
Live and learn. I've lived a long time, and am still learnilng.
For example if you only lost 3 indicated hp from a shorter stroke same bore (smaller) engine, but decreased friction hp by 5, you'd be 2 up at the flywheel (brake hp). Something like that. It sure would escalate the plate development costs trying to find the best combination of displacement and friction. My take was that the min. displacement rule was to minimize plate development costs.
Live and learn. I've lived a long time, and am still learnilng.
#80
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Originally Posted by racer7088
Also if I have a 434 chevrolet engine with 350 cfm 23 degree RR heads and I drop that stroke to 3 inches from 4 inches so now I only have a 311 CID what will happen to my power and how fast I can accelerate now in that same car?