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Any info on lean burn & swirl (in combustion)?

Any info on lean burn & swirl (in combustion)?

Any info on lean burn & swirl (in combustion)?

(OP)
I'm interested in finding more info on these concepts.  I know about Larry Widmer and read everything he says on his Endyn board, but I'm wondering if there are any books or other experts in this area I might be directed to...

thanks

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

(OP)
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.






RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

(OP)
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 www.theoldone.com
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:

http://www.theoldone.com/articles/

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:
http://www.theoldone.com/articles/expanded_pistons/

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

(OP)
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

RE: Any info on lean burn & swirl (in combustion)?

Jim. i took a quick look at the
http://www.theoldone.com/articles/expanded_pistons/

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

RE: Any info on lean burn & swirl (in combustion)?

(OP)
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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

(OP)
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.

RE: Any info on lean burn & swirl (in combustion)?

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.

RE: Any info on lean burn & swirl (in combustion)?

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

RE: Any info on lean burn & swirl (in combustion)?

Hmmm, I read it on-line, and I think it the author was either Japanese or Chinese.  I will try to do a search and dig it up, but I remember that the author was VERY emphatic about it!  I think it MIGHT have an SAE number too, it was about a year ago.  I was doing some intake manifold research profiles at the time (still) and it turned up during a search.

Coriolis intake?  Sounds like a brand of diet food!

I have heard the looniest reasons for toilet swirl and hurricanes, but still has me baffled.  Something with the earth rotation, equator position, moon juxtaposition, and who is in office at the time.

This is the subject of one of the greatest threads yet! ! !

Best regards,
Franz

RE: Any info on lean burn & swirl (in combustion)?

i didn't want to mention it to MazdaJim , but how much
"in cylinder" swirl can you be getting in that Honda chamber with 4 valves (2 Intakes) ???

Nothing really significant under full load tests
..maybe some "tumble" ...but hardly swirl !!

i think too many head shops make swirl a tremendous deal
because just about everyone has some kind of flowbench,
....so to be competitive ...you push the swirl and tumble
to make the customers come to you ???

swirl and tumble are good for some HP and letyou do things to make more HP...but like i said..how much HP was just the swirl part worth of of say..Warren Johnson's
1260 HP 500 cid ????????   maybe max 25 HP maybe less??
that still leaves 1235 HP being made by something else
puts swirl and tumble into perspective ??????

waste too much time playing with this ..unless you have exhausted every other possible gains for HP

Larry Meaux  (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

RE: Any info on lean burn & swirl (in combustion)?

From reading those articles, it sounds like they're just saying that clockwise tumble is important in their particular engine, because of the relative positions of the spark plug, injectors, and valves.  

To make their statement more generally applicable, perhaps they should have said something like "If the air tumbles towards the spark plug, it will carry a directly injected fuel spray into the spark plug, creating a soot buildup that leads to misfires."

It's silly, to me, that they're even calling the tumble "clockwise" as it's only clockwise in the particular view they're showing.  If one were to look at the cyl from the other side, it'd be a CCW tumble, and (presumably) nothing would change.

RE: Any info on lean burn & swirl (in combustion)?

Once, a long time back, I tried to emulate Suzuki and build "swirl" into my combustion chamber/piston design (hemi, two valve straight in and out porting).  The odd thing about all this is that the smaller the cumbustion chamber and the closer to flat top I made the pistons ,ie, more'squish' & less swirl, etc, THE MORE POWER IT MADE!!!  I am not an advocate of spending too much time on swirl and tumble any longer, not enough time for me, but if someone else gets it nailed down, I'll listen.  


Rod

RE: Any info on lean burn & swirl (in combustion)?

Suzuki later on changed from 2 valve to 4. Intrestingly enough this engine was called TSCC. Twin Swirl Combustion Chamber . What they did to induce this was make one floor of the intake port higher than the other (up close to the valve,where the port split to feed both intakes.This caused a downward swirl,towards the piston top,towards the exhaust side. This made great power and a very efficient engine.In many drag race versions they are on the order of 300 H.P.for a 86 cu.in. engine. Now with the advent of aftermarket M/C race heads the 2 valve design has made a great return. Huge ports , very high flow. Versions in Prostock on the order of 325 H.P. with a 92 cu.in. engine.      Craig

RE: Any info on lean burn & swirl (in combustion)?

Interesting Craig..thats basically the same HP
my program calculates

15.4 HP gain from Ram-Air Scoop
Peak HP=319.3  Torque=140.6  (600 RPM/SEC -Acceleration)

Peak HP=335.3  Torque=147.7  (Steady-State non-Acceleration)
Carb CFM=418 to 492 at 1.5 inches Hg.
 60= 1.090    63.103                  0 to 30 mph=0.362
  330= 3.024    122.873               0 to 60 mph=1.008
  660= 4.620   154.682  to  155.364   0 to 80 mph=1.551
1000= 5.990   180.131                 0 to 100 mph=2.183
1320= 7.150   193.878  to  193.027    0 to 120 mph=2.909

 Ft    ET    MPH
-1  - .155  0.000 = Rollout ET @ 12 inches
 0   .000   8.822 = Rollout MPH @ 12 inches
 1   0.096   11.655
 2   0.145   15.775
 3   0.184   18.672
 4   0.219   21.018
 5   0.250   23.029
 6   0.278   24.811
 7   0.305   26.422
 8   0.330   27.900
 9   0.354   29.271
 10   0.376   30.554

Year 2001 Typical HorsePower ranges= 290 to 320 Peak HP
Year 2001 Typical ET= 7.15 to 7.25   MPH= 185 to 193+

Engine size= Suzuki 1500cc 92 cubic inches InLine 4 cyl.
Bore= 3.300 in.    Stroke= 2.600 in.
16:1 Compression Ratio  (Typical)    114+ octane gasoline
315 Peak HP at 13,000 RPM

5-Speed manual transmission and Maximum of 6-Speeds
Drive-Gear ratio= 5.88:1

Weight=550 to 600 Lbs. including Driver depending on engine
WheelBase= 70 inches         Width= 26 inches
Overall length= 140.0 inches including wheelie bars

Slicks= M/T ET Drag 26 in. diameter  x 10.0 in. wide  - 15 rim

Larry Meaux  (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

RE: Any info on lean burn & swirl (in combustion)?

just to clarify a little...
when i say "swirl" i'm always referring to
"horizontal" mixture motion/direction ..or
horizontally spiraling downward in either clockwise or counterclockwise direction

you could look at a "side-view" at tumble and call it "swirl" , but i name "tumble" as almost purely
"vertical-swirl" motion in either direction.

maybe that clarifies what i mean ??

Larry Meaux  (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

RE: Any info on lean burn & swirl (in combustion)?

Craig...Email me a .JPG picture of your bike and/or shop
and i'll send you a Windows ET_Analyst for DragRacers
HorsePower prediction program

i'll put the picture inside the program to give a personal look !

No strings attached..completely free....offer expires
December 23,2001

it will calculate ET MPH GForces Aero & Rolling Resistance
HP losses each foot down 1/4 mile
and generate all your
1/4 mile progressive time increments

Larry Meaux  (meauxrace2@aol.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers

RE: Any info on lean burn & swirl (in combustion)?

re:  when i say "swirl" i'm always referring to
"horizontal" mixture motion/direction ..or
horizontally spiraling downward in either clockwise or counterclockwise direction  you could look at a "side-view" at tumble and call it "swirl" , but i name "tumble" as almost purely "vertical-swirl" motion in either direction

I think the pics in that article that Franzh linked to get the point across pretty well, but I'll take a stab at putting into words what may be better represented graphically (perhaps because I like to hear myself type):

* swirl motion is rotation of the in-cylinder fluid about an axis nearly parallel to the cylinder axis.

* tumbling motion is ... about an axis nearly perpendicular to the cylinder axis.

RE: Any info on lean burn & swirl (in combustion)?

Larry, You hit the nail on the head with your program. Thank you very much for your offer,I do not as of yet have a scanner.Maybe soon. The very latest Pro Stock version is now 1640 cc , 89MM PISTON , instead of 85mm. So they drop E.T. down into the 7.0 range. If you would like to see the current cylinder head used go to www.wardperformance.com ; This is a new head that has 160 cfm as cast!! Remember we are only "feeding" a 23 cu.in. cylinder... Check it out. What have I built in the past? My true speciality. Hilborn injected / alky / Turbo.. 86 cu.in./ 485 H.P... 10:5.1 comp / with 38p.s.i. boost.. Talk about cylinder pressure. To MazdaJim, sorry for getting off subject here.. Larry,just some info , I work at Rockdale Cycles Racing in Georgia and we specialize in Dragbike Engines And Chassis,Electronics,etc.   Craig

RE: Any info on lean burn & swirl (in combustion)?

i m interested to make the project about mpfi engine.

RE: Any info on lean burn & swirl (in combustion)?

What is "LEAN"? Does anybody really know?  I've got gasoline engines happy at 30:1!  As for swirl and tumble..they WILL make you stumble!

RE: Any info on lean burn & swirl (in combustion)?

HEY!!!....Isn't Larry Widmer the guy with the SOFT HEAD?  

RE: Any info on lean burn & swirl (in combustion)?

(OP)
Yes, he's the soft head guy.  Are you familiar?

RE: Any info on lean burn & swirl (in combustion)?

Stroker, "Swirl and tumble will make you stumble"???? Could you elaborate on this ? I am not clear as to what you are saying...  Appreciate your reply..   Craig

RE: Any info on lean burn & swirl (in combustion)?

Mazdajim...I recall the Pat Ganal,Jimmy MacFarland stories heralding the "revolutionary new technology" in cylinder head design..and then there's the Coates Spherical rotary valve head and the Crower "STEAMOLINE" engine!

RE: Any info on lean burn & swirl (in combustion)?

Craig..Actually the  "stumble" quote belongs to Steve Bozso(I wish I had said it first).I believe swirl,tumble/Piatti effect etc. are weak band-aids that attempt to treat a symptom..not cure the problem. Sorta like putting pre-cats on top of main cats ..more money,more weight,more BAND-AIDS!

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