jake
with searoy's new toy I've been searching a little about Jim Feuling. Anyways I found that he also experimented with something called a pluse cam. The cam would have a bump on the intake lobes that would kick the valves a little to knock off some fuel droplet that gathers around the valves. He claimed that this gave a more homogenious fuel/air mixture. and this gave him various good results.
So I figured with the exploration into roller cams for type IV, maybe given some time have you concidered looking at a pluse cam or some of the other oddities that Feuling was getting into?
I mean the whole AR exhaust thing could be easy to do. Use a cone insert between the stub pipes and the exhaust header.
just a thought
rip
pluse cam
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MASSIVE TYPE IV
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HAM Inc
- Posts: 591
- Joined: Wed Jan 14, 2004 7:33 am
In the late seventies my father did a great deal of exhaust development for TypeI engines. He first dyno (Stuska) tested an ass-load of quality "tuned systems" then began building his own systems. What he learned was that every system available was to large (both primaries and collectors) for his application (1.7l any way you can get it, 7200rpm, 13.5:1) The only system that made as much power as his own and had an acceptable torque curve for circletrack racing was an anti-reversion system built by Fueling. Contrary to the thinking at the time, the cones don't have to be right up at the port, they can be spaced anywhere between the collector and port (according to Fueling). A popular system for Formula Atlantic cars a couple of years ago was an interference system(commonly known as Tri-Y's) with anti-reversionary cones.
Fueling is a clever guy. He thinks outside the box. He designed a combustion chamber that is effecient at high revs with something like 10 degrees of timing. I totally stole his ideas regarding valve shrouding, and chamber shapes. His idea about breaking-up condensed fuel by popping the valve is very interesting. I would expect it to apply more to lower speed situations where fuel fallout between cycles is more of a problem, but I'm making an educated guess.
Len
Fueling is a clever guy. He thinks outside the box. He designed a combustion chamber that is effecient at high revs with something like 10 degrees of timing. I totally stole his ideas regarding valve shrouding, and chamber shapes. His idea about breaking-up condensed fuel by popping the valve is very interesting. I would expect it to apply more to lower speed situations where fuel fallout between cycles is more of a problem, but I'm making an educated guess.
Len
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MASSIVE TYPE IV
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raygreenwood
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- Joined: Wed Jan 22, 2003 12:01 am
Ham....you can also stop or alter reversion in plenum EFI systems by adding divisions/diverters in the plenum. Not quite as severe as say a dual plane carb manifold, but more of a berm to both split the incoming air "toward" where it needs to be on each bank, and also to deflect or buffer potential untuned intake reversion waves. If you dig around in FI plenums out in the junkyard....there are and have been a lot of "subtle" things going on in FI plenums in the last decade or so. Especially on some of the more advanced japanese and german cars.
Another potential piece of equipment that can be used to keep micro-droplets from adhering to valves....at least in injection.....are extended and shaped nose pieces for injectors. There are a few cars I have been studying lately that use very peculiar noses on the injectors to act......like a combination of a laminar flow device (using the area principal....classic coke bottle shape)....to create a venturi effect that further sub-atomizes the fuel droplets. The smaller the droplet is, the less surface tension it has...and the less chance it may condense or adhere to a surface. I ahve been playingwith a few designs lately, that may help the injector flow to bypass the valve stem and the guide boss with much greater atomization...and no striking on the pocket wall...before it enters the valve.
I have seen at least one design (in production) that uses uses the equivalent of a pitot tube inside of the runner, to a keyhole slot that dumps in right at the injector...atomizer!.
I realize you are talking carbs and exhaust here...but reversion is reversion and a venturi is a venturi. Looks of interesting thoughts here. Ray
Another potential piece of equipment that can be used to keep micro-droplets from adhering to valves....at least in injection.....are extended and shaped nose pieces for injectors. There are a few cars I have been studying lately that use very peculiar noses on the injectors to act......like a combination of a laminar flow device (using the area principal....classic coke bottle shape)....to create a venturi effect that further sub-atomizes the fuel droplets. The smaller the droplet is, the less surface tension it has...and the less chance it may condense or adhere to a surface. I ahve been playingwith a few designs lately, that may help the injector flow to bypass the valve stem and the guide boss with much greater atomization...and no striking on the pocket wall...before it enters the valve.
I have seen at least one design (in production) that uses uses the equivalent of a pitot tube inside of the runner, to a keyhole slot that dumps in right at the injector...atomizer!.
I realize you are talking carbs and exhaust here...but reversion is reversion and a venturi is a venturi. Looks of interesting thoughts here. Ray
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raygreenwood
- Posts: 11878
- Joined: Wed Jan 22, 2003 12:01 am
Ham....you can also stop or alter reversion in plenum EFI systems by adding divisions/diverters in the plenum. Not quite as severe as say a dual plane carb manifold, but more of a berm to both split the incoming air "toward" where it needs to be on each bank, and also to deflect or buffer potential untuned intake reversion waves. If you dig around in FI plenums out in the junkyard....there are and have been a lot of "subtle" things going on in FI plenums in the last decade or so. Especially on some of the more advanced japanese and german cars.
Another potential piece of equipment that can be used to keep micro-droplets from adhering to valves....at least in injection.....are extended and shaped nose pieces for injectors. There are a few cars I have been studying lately that use very peculiar noses on the injectors to act......like a combination of a laminar flow device (using the area principal....classic coke bottle shape)....to create a venturi effect that further sub-atomizes the fuel droplets. The smaller the droplet is, the less surface tension it has...and the less chance it may condense or adhere to a surface. I ahve been playingwith a few designs lately, that may help the injector flow to bypass the valve stem and the guide boss with much greater atomization...and no striking on the pocket wall...before it enters the valve.
I have seen at least one design (in production) that uses uses the equivalent of a pitot tube inside of the runner, to a keyhole slot that dumps in right at the injector...atomizer!.
I realize you are talking carbs and exhaust here...but reversion is reversion and a venturi is a venturi. Looks of interesting thoughts here. Ray
Another potential piece of equipment that can be used to keep micro-droplets from adhering to valves....at least in injection.....are extended and shaped nose pieces for injectors. There are a few cars I have been studying lately that use very peculiar noses on the injectors to act......like a combination of a laminar flow device (using the area principal....classic coke bottle shape)....to create a venturi effect that further sub-atomizes the fuel droplets. The smaller the droplet is, the less surface tension it has...and the less chance it may condense or adhere to a surface. I ahve been playingwith a few designs lately, that may help the injector flow to bypass the valve stem and the guide boss with much greater atomization...and no striking on the pocket wall...before it enters the valve.
I have seen at least one design (in production) that uses uses the equivalent of a pitot tube inside of the runner, to a keyhole slot that dumps in right at the injector...atomizer!.
I realize you are talking carbs and exhaust here...but reversion is reversion and a venturi is a venturi. Looks of interesting thoughts here. Ray
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HAM Inc
- Posts: 591
- Joined: Wed Jan 14, 2004 7:33 am
Hey Carpe Diem where did you find those cones?
One of the big challenges of building an effective anti-reversion header is that (according to research literature on the subject) the cones have to be perfectly centered, meaning they must be perfectly aligned with the outgoing tube to be effective. There's torgue to be gained.
One thing my experience and my fathers experience has revealed is that most conventional sytems are to large for their application, and oversized collectors are more harmful than oversized primaries. Short collectors where the primaries tubes are simply shoved in and welded are particulary offensive to torgue. As in ports, turbulence in collectors is a killer. That's why the most effective systems have hand fabricated, not stamped, collectors. Very pricey. Some hand built stainless collectors with blended convergent cones sale for as much as a $1000.00! (see Burns) As engine combinations change, the need for exhaust development never ends.
Len
One of the big challenges of building an effective anti-reversion header is that (according to research literature on the subject) the cones have to be perfectly centered, meaning they must be perfectly aligned with the outgoing tube to be effective. There's torgue to be gained.
One thing my experience and my fathers experience has revealed is that most conventional sytems are to large for their application, and oversized collectors are more harmful than oversized primaries. Short collectors where the primaries tubes are simply shoved in and welded are particulary offensive to torgue. As in ports, turbulence in collectors is a killer. That's why the most effective systems have hand fabricated, not stamped, collectors. Very pricey. Some hand built stainless collectors with blended convergent cones sale for as much as a $1000.00! (see Burns) As engine combinations change, the need for exhaust development never ends.
Len
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dstar
- Posts: 3733
- Joined: Tue Feb 25, 2003 12:01 am
http://www.the-biker-toy-store.com/sys- ... RCone1.JPGHAM Inc wrote:Hey Carpe Diem where did you find those cones?
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Len
Hey Len, do you have any tools to look inside the intake tract while
flowing a head? Either running or with a smoke gen will be fine.
Don
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Guest
http://www.the-biker-toy-store.com/sys-tmpl/arcones/
heres where I found the pic, a bike store. They only want about 20 bucks for them maybe if you can find where they get made or the tooling nessicary to make them.
rip
heres where I found the pic, a bike store. They only want about 20 bucks for them maybe if you can find where they get made or the tooling nessicary to make them.
rip
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JohnConnolly
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dstar
- Posts: 3733
- Joined: Tue Feb 25, 2003 12:01 am
I'm having a pair of manifolds *copied* in acrylic as we speak so I canHAM Inc wrote:At the moment I do not have a method of viewing flow. I will at some point. Ultimately, a wet flow system is what I want.
Len
see it better. My video camera has a 1/600th sec shutter, so I can
see the charge rotating and moving very well.
I was using clear straight, plastic pipe and a smoke generator, and
was concerned that I was not duplicating the *real world* very well.
As to John's post, since PR engines don't like that little bump,
I have found that a few *whoop-de-do*s, in the right places do WONDERS
for mixture. Kinda like a coke bottle, if you know what I mean!
Properly spaced for stroke and bore, it acts like the same thing mentioned above, just in reverse.
Instead of pre-opening the valve, it delays the first intake charge,
then the next one pushess it into the back of the valve just as it starts
to open. Almost doubling the charge density!
I'm sure you can imagine what I am talking about.
It is a totally WRONG approach from all I've read and heard, but you can
actually see the difference in the density,
even with my *vacum cleaner* setup.
Heh, Heh, Heh!I am not looking for high flow numbers that can't be achieved with
the castings we have available now, I just want a more homogenous mixture
and cleaner burn.
Then I can "bump it up and hear it thump!" without fear of detonation.
More CR=More POWER!You can see the *rich* areas on an old piston, as carbon buildup will
occur more in the *wet-est* areas.
I guess if you see any *white* areas on a piston, then I know WHY
you tore the engine down to start with.....
Ya'll have a good weekend!
Don
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raygreenwood
- Posts: 11878
- Joined: Wed Jan 22, 2003 12:01 am
Ham...I did some D-jet plenum/smoke pictures a couple years ago. Not very good...but instructive. The plenums need an air striaghtener assembly in them after the TB....as well as a lengthener tube between plenum and TB to cut down on the plume of turbulence from the throttle plate. I have one design I am playing with that uses no plate...but a plug instead....shaped like the center hub on a jet engine or a propellor. I have the outside casts made of a 1.7 plenum, in plaster. The plan was to do the same...to make a polyester shell version of the plenum with correct inside. The easiest method I came to was to make the inside correct...and the outside "blocky"....and not true to shape. If you try to so that, the poyester distorts too much when it cures...ruining the inside. A wax buck will work the ebst on the inside so it remains until after curing...then is melted out in hot water. Its all on hold until late fall. Cool stuff! Ray
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HAM Inc
- Posts: 591
- Joined: Wed Jan 14, 2004 7:33 am
Dstar you're work with a clear intake is interesting. But what would be even more revealing would be a clear cylinder to get a look at wet flow characteristics.
The idea of storing a gas charge in the intake port between cycles requires a somewhat different approach to port shape than pure flow numbers. Same is true of mixture quality. Many tuners approach engine design with the idea that the I.C. engine is just an air pump. Big mistake. With that logic the ideal port sizes would be the same as the bore. Obviously that doesn't work. The truth is a 10% improvement in fuel mixture quality will yield a bigger torque gain than a 10% improvement in flow where mixture quality is not improved. A 10% improivement in quench characteristecs yields more increases as well. To properly store a charge behind the valve, velocity must be high and the shape of the bowl is critical as well. When done properly the torgue curve flattens out and the RPM range is extended, because as engine speed extends past the intake valves closing point (meaning the cylinder is still filling when the valve closes) the inertia of the incoming charge bottles up behind the valve. When the intake eases off the seat next time the charge gets yanked in by the depression created by the exhaust during the overlap phase. Another reason going to large on the exhaust is harmful. Without proper exhaust velocity this effect is lost. The whole system must be tailored for this. The engine Jake built using my heads recently that made peak torque with just 20degrees of timing indicates he got the combo just right . It's much harder to do than you might tihink. Requires lot of experimentation.
Reading residue patterns in chambers is a very useful tool. Many of the washed down areas in a chamber can be traced to poor mixture quality as a result of poor port shaping, not chamber shape problems. I couldn't begin to guess how many professionally ported race heads I've seen that had residue lining certain areas of the port. Knock down the sharp turn under the intake valve, run a couple of races, tear down the head and you'll see what I mean. Lots of fuel fallout. This liquid fuel dribbles into the chamber where it causes all kind of problems! Better to limit flow a little and improve mixture quality than the other way around.
Ray I've long thought that a simple deflector vane placed on the floor of the FI plenum to direct the airflow towards the runners rather than allowing it to impinge on the plenum floor would help a bunch. You guys keep trying new approaches and let us know what you find.
Len
The idea of storing a gas charge in the intake port between cycles requires a somewhat different approach to port shape than pure flow numbers. Same is true of mixture quality. Many tuners approach engine design with the idea that the I.C. engine is just an air pump. Big mistake. With that logic the ideal port sizes would be the same as the bore. Obviously that doesn't work. The truth is a 10% improvement in fuel mixture quality will yield a bigger torque gain than a 10% improvement in flow where mixture quality is not improved. A 10% improivement in quench characteristecs yields more increases as well. To properly store a charge behind the valve, velocity must be high and the shape of the bowl is critical as well. When done properly the torgue curve flattens out and the RPM range is extended, because as engine speed extends past the intake valves closing point (meaning the cylinder is still filling when the valve closes) the inertia of the incoming charge bottles up behind the valve. When the intake eases off the seat next time the charge gets yanked in by the depression created by the exhaust during the overlap phase. Another reason going to large on the exhaust is harmful. Without proper exhaust velocity this effect is lost. The whole system must be tailored for this. The engine Jake built using my heads recently that made peak torque with just 20degrees of timing indicates he got the combo just right . It's much harder to do than you might tihink. Requires lot of experimentation.
Reading residue patterns in chambers is a very useful tool. Many of the washed down areas in a chamber can be traced to poor mixture quality as a result of poor port shaping, not chamber shape problems. I couldn't begin to guess how many professionally ported race heads I've seen that had residue lining certain areas of the port. Knock down the sharp turn under the intake valve, run a couple of races, tear down the head and you'll see what I mean. Lots of fuel fallout. This liquid fuel dribbles into the chamber where it causes all kind of problems! Better to limit flow a little and improve mixture quality than the other way around.
Ray I've long thought that a simple deflector vane placed on the floor of the FI plenum to direct the airflow towards the runners rather than allowing it to impinge on the plenum floor would help a bunch. You guys keep trying new approaches and let us know what you find.
Len