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Any info on lean burn & swirl (in combustion)?
- Thread starter JamesMcD
- Start date
MaxRaceSoftware
Automotive
Info on Swirl ..tumble..votex-generator ??
i've done a little research into these subjects
over the years i've played around with combustion chamber shapes and swirl-measurements
done a pair of Chrysler Pro Stock Truck heads
for a 358 CID engine made 940+ HP @ 9300 RPMs
qualified in top 16
can Email you a few Hi-Resolution digital pictures of the vortex generator in the intake bowl
and some flow , swirl, velocity-profiles on the ProStock
358 cid heads that made 2.63 HP/CID
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
i've done a little research into these subjects
over the years i've played around with combustion chamber shapes and swirl-measurements
done a pair of Chrysler Pro Stock Truck heads
for a 358 CID engine made 940+ HP @ 9300 RPMs
qualified in top 16
can Email you a few Hi-Resolution digital pictures of the vortex generator in the intake bowl
and some flow , swirl, velocity-profiles on the ProStock
358 cid heads that made 2.63 HP/CID
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
- Thread starter
- #3
Hey, I'd like to see those pictures. (mcdonald@clas.net)
I guess I'm mostly looking for info on shaping the combustion chamber to induce/encourage/accelerate a swirling fuel mixture (piston dome shapes?), as well angling/shaping intake ports to point the mix in a direction that will get it spinning.
My understanding is that once you get the mixture spinning, it has a given amount of kinetic energy, and as the piston compresses it, there is less room for that energy to be comtained, and thus the swirl accelerates. I'm trying to better understand how various piston top and bowl shapes will affect this motion, and thus the quality of combustion.
I guess I'm mostly looking for info on shaping the combustion chamber to induce/encourage/accelerate a swirling fuel mixture (piston dome shapes?), as well angling/shaping intake ports to point the mix in a direction that will get it spinning.
My understanding is that once you get the mixture spinning, it has a given amount of kinetic energy, and as the piston compresses it, there is less room for that energy to be comtained, and thus the swirl accelerates. I'm trying to better understand how various piston top and bowl shapes will affect this motion, and thus the quality of combustion.
MaxRaceSoftware
Automotive
Hi Jim....my mistake, the ProStock Truck heads with the vortex-generators are on Hi Resolution video and .MPEG files
..what i'll do is take "snapshots" of video segments and
enhance further and shrink to 640 x 480 .JPG picture
closeups ...to keep sharpness !! Will Email you a couple of pictures around 9:00 pm CST
to do any "work" on heads as far as swirl, tumble, and velocity profiling you will need a serious flowbench,
write or buy your own software, buy swirl and tumble meters, ..and be prepared to live like a "hermit" for the next 5 or 10 years of your life !!! go to College Libraries and go to SAE -papers & book sections , ETC.
Theres stuff on swirl probably as far back 1920 and 1940s
i first "noticed" swirl effects back in 1975 with a Chevy
337 cid small block with 492 cast-iron heads
this engine had gas-port holes in piston domes..and i noticed that there were swirl patterns /trails coming out of the gas port holes ..on one cylinder the swirl pattern was clockwise, on the next cylinder the swirl pattern was counter-clockwise !! later when i got my digital swirl-meter hooked up to my flowbench i varified long ago what i was seeing !! Much to say on this subject later !
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
..what i'll do is take "snapshots" of video segments and
enhance further and shrink to 640 x 480 .JPG picture
closeups ...to keep sharpness !! Will Email you a couple of pictures around 9:00 pm CST
to do any "work" on heads as far as swirl, tumble, and velocity profiling you will need a serious flowbench,
write or buy your own software, buy swirl and tumble meters, ..and be prepared to live like a "hermit" for the next 5 or 10 years of your life !!! go to College Libraries and go to SAE -papers & book sections , ETC.
Theres stuff on swirl probably as far back 1920 and 1940s
i first "noticed" swirl effects back in 1975 with a Chevy
337 cid small block with 492 cast-iron heads
this engine had gas-port holes in piston domes..and i noticed that there were swirl patterns /trails coming out of the gas port holes ..on one cylinder the swirl pattern was clockwise, on the next cylinder the swirl pattern was counter-clockwise !! later when i got my digital swirl-meter hooked up to my flowbench i varified long ago what i was seeing !! Much to say on this subject later !
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
MaxRaceSoftware
Automotive
MazdaJim...
Whats your "BEST" expectation and hopes/dreams
as to the "number" of HorsePower you hope to achieve from
the very best you can accomplish in the swirl and tumble department , after about 10 years of effort ??
On a 4 cyl ...on a 8 cylinder ????
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
Whats your "BEST" expectation and hopes/dreams
as to the "number" of HorsePower you hope to achieve from
the very best you can accomplish in the swirl and tumble department , after about 10 years of effort ??
On a 4 cyl ...on a 8 cylinder ????
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
MaxRaceSoftware
Automotive
MazdaJim.....
In 10 years from now, you'll tell me you found
approx. 10 to 15 HP gains with swirl or tumble in an 8 cylinder engine !! ..during a full-load acceleration dyno test ! about half that gain on a 4 cylinder
i'm talking only about cylinder swirl rotation on cylinder tumble research efforts .
If you have too much swirl, you can "centrifuge" and wet cylinder walls..causing some fuel/air separation
If swirl is OK , but spark plug is in wrong spot, swirl
will not have the effects you seek. (Hemi-head example)
in general heads with tall-short-turns will have hardly any swirl till higher valve lifts..tall short-turn heads have more tumble than swirl.
Low-Short_Turn heads are easy to achieve swirl in and depending on intake port direction , such as a small block Chevy engine two adjoining port pairs ..one has clockwise swirl and the other port has counterclockwise swirl.
Vortex-generators...in intake bowls..these generate very localized swirl instead of cylinder-swirl ..the vortex-generators increase the ports flow coefficient(increase airflow)..this can be worth as much as 25+ HP ..way better than messing with cylinder swirl in modern type chambers !!!
With computerized modern-fuel-injection , and combustion chamber designs, swirl is not going to be worth a ton of HP
..its good to prevent lean-rich spots in chambers at low rpm and low port velocities..and give you the ablility to completely burn "leaner mixtures" than you could normally burn completetly otherwise, increase gas milage and reduce emissions.
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
In 10 years from now, you'll tell me you found
approx. 10 to 15 HP gains with swirl or tumble in an 8 cylinder engine !! ..during a full-load acceleration dyno test ! about half that gain on a 4 cylinder
i'm talking only about cylinder swirl rotation on cylinder tumble research efforts .
If you have too much swirl, you can "centrifuge" and wet cylinder walls..causing some fuel/air separation
If swirl is OK , but spark plug is in wrong spot, swirl
will not have the effects you seek. (Hemi-head example)
in general heads with tall-short-turns will have hardly any swirl till higher valve lifts..tall short-turn heads have more tumble than swirl.
Low-Short_Turn heads are easy to achieve swirl in and depending on intake port direction , such as a small block Chevy engine two adjoining port pairs ..one has clockwise swirl and the other port has counterclockwise swirl.
Vortex-generators...in intake bowls..these generate very localized swirl instead of cylinder-swirl ..the vortex-generators increase the ports flow coefficient(increase airflow)..this can be worth as much as 25+ HP ..way better than messing with cylinder swirl in modern type chambers !!!
With computerized modern-fuel-injection , and combustion chamber designs, swirl is not going to be worth a ton of HP
..its good to prevent lean-rich spots in chambers at low rpm and low port velocities..and give you the ablility to completely burn "leaner mixtures" than you could normally burn completetly otherwise, increase gas milage and reduce emissions.
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
MaxRaceSoftware
Automotive
Do you want swirl orientation horizontally ???
or do you want swirl to "spiral -downwards" ???
Sometimes it depends, but for all-out . max-effort racing engines with larger intake/exhaust valves with plenty of overlap...you would need "spiral-downward" swirl..to keep
flow direction "away" from the partially open exhaust valve during overlap period ..this will prevent too much overscavenging , and on some single 4 barrell restricted type max-effort engines it can be worth more HP....its like why NASCAR Chevy SB2 heads "point" the intake port direction like FORD did..away from the exhaust valve for gas efficiency and HP on other applications .
Look closely at the current state-of-the-art combustion chambers and intake port directions..or even production Camaro and Corvette LS-1 and LS-6 chambers , they bias the intake swirl downward away from the exhaust valve instead of too-much horizontal type swirl.
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
or do you want swirl to "spiral -downwards" ???
Sometimes it depends, but for all-out . max-effort racing engines with larger intake/exhaust valves with plenty of overlap...you would need "spiral-downward" swirl..to keep
flow direction "away" from the partially open exhaust valve during overlap period ..this will prevent too much overscavenging , and on some single 4 barrell restricted type max-effort engines it can be worth more HP....its like why NASCAR Chevy SB2 heads "point" the intake port direction like FORD did..away from the exhaust valve for gas efficiency and HP on other applications .
Look closely at the current state-of-the-art combustion chambers and intake port directions..or even production Camaro and Corvette LS-1 and LS-6 chambers , they bias the intake swirl downward away from the exhaust valve instead of too-much horizontal type swirl.
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
MaxRaceSoftware
Automotive
MazdaJim...
i can make an "honest" 940 to 960 real Horsepower
with Edelbrock Victor Race heads on a Chevy 500 cid engine size
(this engine could easily dyno 1050 HP on other dynos,
not all dynos are honest)
...but the current state-of-the-art ProStock Car engines dyno on honest dynos at 1260 to maximum of 1280 HP would be the best !! this means between the Edelbrock Victor race heads and a all-out ProStock head on the same size 500 cid engine there is approx. 320 HP difference to be gained in
head design ....why spend years with swirl trying to maybe find 20 HP when you missing 320 HP or could be finding ways to gain 320 HP ???????????????
Makes swirl not so important,, you should learn how to make heads flow more in quality and quantity ..and leave the swirl efforts for later on ...it will take years of experience to learn the flow part much less the swirl part ,
either way you will have to buy a flowbench, dyno, engine parts, software, swirl and tumble meters, velocity probes, etc, valve and valve seat grinding equipment, etc.
its a great undertaking of money and time
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
i can make an "honest" 940 to 960 real Horsepower
with Edelbrock Victor Race heads on a Chevy 500 cid engine size
(this engine could easily dyno 1050 HP on other dynos,
not all dynos are honest)
...but the current state-of-the-art ProStock Car engines dyno on honest dynos at 1260 to maximum of 1280 HP would be the best !! this means between the Edelbrock Victor race heads and a all-out ProStock head on the same size 500 cid engine there is approx. 320 HP difference to be gained in
head design ....why spend years with swirl trying to maybe find 20 HP when you missing 320 HP or could be finding ways to gain 320 HP ???????????????
Makes swirl not so important,, you should learn how to make heads flow more in quality and quantity ..and leave the swirl efforts for later on ...it will take years of experience to learn the flow part much less the swirl part ,
either way you will have to buy a flowbench, dyno, engine parts, software, swirl and tumble meters, velocity probes, etc, valve and valve seat grinding equipment, etc.
its a great undertaking of money and time
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
MaxRaceSoftware
Automotive
A long time ago , i went to Brodix Cylinder Heads in Mena, Arkansas....i was talking with J.V. Brotherton about
moving the ports and water jackets around in a set of custom aluminum SBC heads..and about angle-machining the heads before they drilled the headbolt holes ..anyways,
i spotted a a sectioned piece of cast-iron SBC head on a table and went over and picked it up and started checking it out really careful...what was a cast-iron GM head doing in Brodix's aluminum head foundry ???
it turned out the cast-iron piece was a prototype of the 1st "Bowtie" SBC head...it was somehow smuggled out of GM's plant and made its way to Arkansas ??
It had a much higher intake port roof and floor than the current #292 Turbo SBC head......when this head finally was released by Chevy to racers, headporters could get higher flowbench numbers than the 292 Turbo heads, but
less HP on the dyno ....this puzzeled a lot of headporters ,
but mainly it was from cross-sectional area at short-turn's peak causing a combination of "sonic choked-flow" and a reduced swirl in inch/ounces .......
so sometimes all the vortex-generated swirl may look good on a flowbench and increase the flow coefficient, but on a live engine the flow at that part is in sonic-choke !
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
moving the ports and water jackets around in a set of custom aluminum SBC heads..and about angle-machining the heads before they drilled the headbolt holes ..anyways,
i spotted a a sectioned piece of cast-iron SBC head on a table and went over and picked it up and started checking it out really careful...what was a cast-iron GM head doing in Brodix's aluminum head foundry ???
it turned out the cast-iron piece was a prototype of the 1st "Bowtie" SBC head...it was somehow smuggled out of GM's plant and made its way to Arkansas ??
It had a much higher intake port roof and floor than the current #292 Turbo SBC head......when this head finally was released by Chevy to racers, headporters could get higher flowbench numbers than the 292 Turbo heads, but
less HP on the dyno ....this puzzeled a lot of headporters ,
but mainly it was from cross-sectional area at short-turn's peak causing a combination of "sonic choked-flow" and a reduced swirl in inch/ounces .......
so sometimes all the vortex-generated swirl may look good on a flowbench and increase the flow coefficient, but on a live engine the flow at that part is in sonic-choke !
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
- Thread starter
- #10
Larry,
I really appreciate you taking all this time to help me.
Honestly, I don't have a firm enough grasp of these concepts to answer your questions about my expectations, or "Do you want swirl orientation horizontally ???" or "do you want swirl to "spiral -downwards" ???"
My main interest, I suppose, is using these ideas to be able to run higher compression ratios in a forced induction engine.
Have you heard of Larry Widmer before? It is my understanding that he's the guy who shook up the NASCAR world by using his knowledge of these concepts to run engines with previously unheard of compression ratios...like over 16:1, and this lead to the limiting of compression ratios in NASCAR rules. (Maybe I'm a bit off on this info...)
Larry W. is now heavily involved in the import scene, among other things, and he runs a message board where he helps out enthusiasts. It's He's known as the "The Old One", or "TOO" on there.
There are also archived articles he's written on various subjects from the past:
I'm sure you're really busy but if you get the time you might check out the "Soft Head", "Talking Heads", and "Swirl Power" article series in the link above...Maybe you are already familiar with them?
This guy now does most of his import work with Hondas. I'm trying to understand these things better because I wan't to apply these ideas to my car at some point in the future, and I'm pretty sure he's never going to do any work with Mazda's.
Here's a link to his "rollerwave" Honda piston series which you'll probably find interesting:
I believe Larry Widmer is the real deal...his daily driver/ parts getter is an 11 sec Civic with full interior which gets over 30mpg.
If you get a chance to wade through all those articles about heads, I'd like to hear your take on them.
Thanks a lot again
Jim
I really appreciate you taking all this time to help me.
Honestly, I don't have a firm enough grasp of these concepts to answer your questions about my expectations, or "Do you want swirl orientation horizontally ???" or "do you want swirl to "spiral -downwards" ???"
My main interest, I suppose, is using these ideas to be able to run higher compression ratios in a forced induction engine.
Have you heard of Larry Widmer before? It is my understanding that he's the guy who shook up the NASCAR world by using his knowledge of these concepts to run engines with previously unheard of compression ratios...like over 16:1, and this lead to the limiting of compression ratios in NASCAR rules. (Maybe I'm a bit off on this info...)
Larry W. is now heavily involved in the import scene, among other things, and he runs a message board where he helps out enthusiasts. It's He's known as the "The Old One", or "TOO" on there.
There are also archived articles he's written on various subjects from the past:
I'm sure you're really busy but if you get the time you might check out the "Soft Head", "Talking Heads", and "Swirl Power" article series in the link above...Maybe you are already familiar with them?
This guy now does most of his import work with Hondas. I'm trying to understand these things better because I wan't to apply these ideas to my car at some point in the future, and I'm pretty sure he's never going to do any work with Mazda's.
Here's a link to his "rollerwave" Honda piston series which you'll probably find interesting:
I believe Larry Widmer is the real deal...his daily driver/ parts getter is an 11 sec Civic with full interior which gets over 30mpg.
If you get a chance to wade through all those articles about heads, I'd like to hear your take on them.
Thanks a lot again
Jim
MaxRaceSoftware
Automotive
Hey Jim..i guess you got the pictures i emailed you..
i pasted them inside an email instead of attaching them as .BMP or .JPG files ..you will have to configure MS OutLook for HTML view of Email ??
just check the HTML box to view if you have trouble i'll resend pictures as attachments.
i will checkout your links to Larry Widmer and let you know
Somebody came into my shop once and made the comment
"Are all heads porters named Larry ?"
He told me theres Larry Widmer(EnDyn), Larry Eicke (Dale Eckie), Larry Woodward (BrandyWine) ,Larry Lackey (Yates),
and a bunch of others ....strange around here if your last name is Duhon, you are most likely a Automotive Paint and Body guy
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
i pasted them inside an email instead of attaching them as .BMP or .JPG files ..you will have to configure MS OutLook for HTML view of Email ??
just check the HTML box to view if you have trouble i'll resend pictures as attachments.
i will checkout your links to Larry Widmer and let you know
Somebody came into my shop once and made the comment
"Are all heads porters named Larry ?"
He told me theres Larry Widmer(EnDyn), Larry Eicke (Dale Eckie), Larry Woodward (BrandyWine) ,Larry Lackey (Yates),
and a bunch of others ....strange around here if your last name is Duhon, you are most likely a Automotive Paint and Body guy
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
- Thread starter
- #12
Yep, I got the pics. Thanks.
In the link I gave you for EnDyn's rollerwave pistons, notice the "turbulators"...
I didn't really understand what these were for, but now that I've talked to you I'm guessing they prevent the fuel from dropping out of the mix and wetting the cylinder walls when the mixture is swirling aroudn the circumference of the bore, (as you mentioned was a problem with too much swirl.) I find this to be quite fascinating, and I'm now having the *eureka* feeling of having learned something
-Jim
In the link I gave you for EnDyn's rollerwave pistons, notice the "turbulators"...
I didn't really understand what these were for, but now that I've talked to you I'm guessing they prevent the fuel from dropping out of the mix and wetting the cylinder walls when the mixture is swirling aroudn the circumference of the bore, (as you mentioned was a problem with too much swirl.) I find this to be quite fascinating, and I'm now having the *eureka* feeling of having learned something
-Jim
MaxRaceSoftware
Automotive
Jim. i took a quick look at the
link.... everything about the pistons i see Widmers' doing is OK..its on the money !! ..but its sort of old stuff NHRA Comp Eliminator pro racers having been doing for decades
..the anti-detonation grooves , the oil ring holes half diameter into the groove and the other half diameter out of the groove in the skirt,.........the "rolling-action" from generated squish of two different squish areas colliding
in the valve relief troughs and the indentions in the corners where the end-gases are to prevent detonation.
the rolling action occurring in the valve troughs are about the only new concept he calls "Roller-Wave" , but even some of this naturally occurs in some types of piston domes when you machine valve reliefs and raduis the notches .
..don't misunderstand me, i'm not knocking the guy, all the stuff is great and on the money , but some of the stuff that looks new is really old news .
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
link.... everything about the pistons i see Widmers' doing is OK..its on the money !! ..but its sort of old stuff NHRA Comp Eliminator pro racers having been doing for decades
..the anti-detonation grooves , the oil ring holes half diameter into the groove and the other half diameter out of the groove in the skirt,.........the "rolling-action" from generated squish of two different squish areas colliding
in the valve relief troughs and the indentions in the corners where the end-gases are to prevent detonation.
the rolling action occurring in the valve troughs are about the only new concept he calls "Roller-Wave" , but even some of this naturally occurs in some types of piston domes when you machine valve reliefs and raduis the notches .
..don't misunderstand me, i'm not knocking the guy, all the stuff is great and on the money , but some of the stuff that looks new is really old news .
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
- Thread starter
- #14
He's supposed to have been one of the main inovators for the last 30 years...Those pistons are probably old news to some, but they are new to the import scene, better tech. than other pistons out there for similar applications, and more reasonably priced.
One of the things he mentions some times is how much more expensive import hop-up parts are compared to domestic, and that he is trying to bring hi-tech products to market with prices that are actually within reach of a normal person. The Japanese stuff out there like HKS, Mugen, Spoon, etc. mostly doesn't give much value per dollar.
I have a $550 HKS cat-back on my MX6 turbo. Sure it's mandrel bent and looks nice, but it's not stainless and not really worth the price. (getting off topic...)
-Jim
One of the things he mentions some times is how much more expensive import hop-up parts are compared to domestic, and that he is trying to bring hi-tech products to market with prices that are actually within reach of a normal person. The Japanese stuff out there like HKS, Mugen, Spoon, etc. mostly doesn't give much value per dollar.
I have a $550 HKS cat-back on my MX6 turbo. Sure it's mandrel bent and looks nice, but it's not stainless and not really worth the price. (getting off topic...)
-Jim
MaxRaceSoftware
Automotive
One of the things he mentions some times is how much more expensive import hop-up parts are compared to domestic, and that he is trying to bring hi-tech products to market with prices that are actually within reach of a normal person.
--MazdaJim
-----------------------
Jim , you and Widmer are correct !! i have a friend who helped wire my shop for 3-phase electricity for the pumps and fans for the SF-901dyno...he has a Land & Sea computer dyno he uses on Briggs/Stratton 14 CID Jr Dragster and GoKart engines ....it amazes me to see how much some of those guys get to port and flowtest those heads , also the costs of each of those Briggs parts compared to like a small block Chevy are also very high ...so whatever can be done to make racing cheaper will be better for the sports future ! Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
--MazdaJim
-----------------------
Jim , you and Widmer are correct !! i have a friend who helped wire my shop for 3-phase electricity for the pumps and fans for the SF-901dyno...he has a Land & Sea computer dyno he uses on Briggs/Stratton 14 CID Jr Dragster and GoKart engines ....it amazes me to see how much some of those guys get to port and flowtest those heads , also the costs of each of those Briggs parts compared to like a small block Chevy are also very high ...so whatever can be done to make racing cheaper will be better for the sports future ! Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
One paper I read recently stated that a "clockwise" swirl was superior to an "anti-clockwise" swirl, and proceeded to explain why, but never convinced me!
Sorry, but maybe in a symmetrical engine layout (where each cylinder is a carbon copy of the one next to it) but many engines are mirror images of each other, the small block Chevy and Mopar “A and B” engines for example.
The terminology of a horizontal swirl describes a rolling effect parallel to the crankshaft axis. This is widely used now in direct injection gasoline engines, where a jet of high pressure gasoline is injected at various piston positions. The piston dome is used to help shape the swirl pattern to focus the richest portion of the fuel mixture directly at the spark plug. GDI engines may operate at AF ratios far outside the normal range, and may very well be the next generation of internal combustion engines.
Vertical swirl patterns are parallel to the cylinder bore, and what are common on almost all engines today.
Larry Widmer is quite a character and has a good following. I recently spent a couple of hours reading up on him and I must confess that his ideas are refreshing. His one statement of “visualize the piston dome as the bottom of the combustion chamber” sticks with me.
Franz
Sorry, but maybe in a symmetrical engine layout (where each cylinder is a carbon copy of the one next to it) but many engines are mirror images of each other, the small block Chevy and Mopar “A and B” engines for example.
The terminology of a horizontal swirl describes a rolling effect parallel to the crankshaft axis. This is widely used now in direct injection gasoline engines, where a jet of high pressure gasoline is injected at various piston positions. The piston dome is used to help shape the swirl pattern to focus the richest portion of the fuel mixture directly at the spark plug. GDI engines may operate at AF ratios far outside the normal range, and may very well be the next generation of internal combustion engines.
Vertical swirl patterns are parallel to the cylinder bore, and what are common on almost all engines today.
Larry Widmer is quite a character and has a good following. I recently spent a couple of hours reading up on him and I must confess that his ideas are refreshing. His one statement of “visualize the piston dome as the bottom of the combustion chamber” sticks with me.
Franz
MaxRaceSoftware
Automotive
Sorry, but maybe in a symmetrical engine layout (where each cylinder is a carbon copy of the one next to it) but many engines are mirror images of each other, the small block Chevy and Mopar “A and B” engines for example.
Yes Franz ...in the Chevy SBC 23 deg heads with mirror
image left and right port directions in orientation to
cylinder bores , you will have clockwise swirl in one cylinder and counterclockwise swirl in its "mirror-image"
sister port
Franz do you remember the Number of that SAE paper ??
i wonder what that guy would say about the small block Chevy
....do you remember any of his reasons ???
kind of like why a toilet flushes oneway or a hurricane rotates oneway ?
How much power difference would it be if it rotated the opposite direction ? Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
Yes Franz ...in the Chevy SBC 23 deg heads with mirror
image left and right port directions in orientation to
cylinder bores , you will have clockwise swirl in one cylinder and counterclockwise swirl in its "mirror-image"
sister port
Franz do you remember the Number of that SAE paper ??
i wonder what that guy would say about the small block Chevy
....do you remember any of his reasons ???
kind of like why a toilet flushes oneway or a hurricane rotates oneway ?
How much power difference would it be if it rotated the opposite direction ? Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
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The direction of swirl is obviously dependant on the geometry of the intake/head/chamber/etc.. Disregarding this, the direction is arbitrary...
I don't think the laws of nature/physics provide for a clockwise swirl to have some strange talent for atomization that an anti-clockwise swirl lacks...
I CAN NOT believe that a clockwise swirl in a given combustion chamber would make more or less power than an anti-clockwise swirl in a combustion chamber that was a mirror image of the first.
So yeah, I'd like to hear his reasons as well.
I don't think the laws of nature/physics provide for a clockwise swirl to have some strange talent for atomization that an anti-clockwise swirl lacks...
I CAN NOT believe that a clockwise swirl in a given combustion chamber would make more or less power than an anti-clockwise swirl in a combustion chamber that was a mirror image of the first.
So yeah, I'd like to hear his reasons as well.
When I first heard the CW/CCW comment, my reaction was that I should post some sort of a joke about how CW works in the northern hemisphere and CCW is better for the southern hemisphere, but I restrained myself. Unfortunately, I can't hold it back any longer. 
Gotta start marketing "Coriolis" brand intakes.
Gotta start marketing "Coriolis" brand intakes.
MaxRaceSoftware
Automotive
i come from the land down under ?
just joking, Franz might reply with that guy's SAE paper and make us all humble ??
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
just joking, Franz might reply with that guy's SAE paper and make us all humble ??
Larry Meaux (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
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