Chamber Grooves - what do you guys think?

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bc
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Chamber Grooves - what do you guys think?

Post by bc » Wed Aug 03, 2005 12:23 pm

Here is a site that I found, just wondering what you guys think about doing this kind of thing?
http://www.somender-singh.com/

Do you think that there really is something to cutting grooves into the combustion chamber like this?

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Post by airflowdevelop » Wed Aug 03, 2005 2:29 pm

"Do you think that there really is something to cutting grooves into the combustion chamber like this?"

ABSOLUTELY!

Detonation and loss of charge managment! :roll:

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Post by 67RS502 » Wed Aug 03, 2005 6:48 pm

I was thinkin the same thing with detonation.
Also the testing had too many variables along with the cut grooves,
like raised comp. and porting.
On that camaro its hard to believe they were running
45deg. of timing with Pro Action heads, even with 13:1 domes.
I'd like to see a back to back dyno test of these groves:
dyno without, heads come off, cut grooves and dyno again;)
Maybe theres a reason why they havent done that...
Wheres some real documented R&D on this?
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Post by Ape » Thu Aug 04, 2005 4:28 am

Looks to me from the principle a lot like the golfball texture pistons or chambers that mcfarland developed.
He supposedly has good results

I think it could work but why cutting them logitudinal in a two stroke chamber???
There is always advancement to be made.

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Post by Fkned » Thu Aug 04, 2005 9:31 am

My only thought on this is-If it really worked wouldn't the teams that spends millions a year in r&d have found this long ago :roll: -.I don't believe it for a second,and was laughing at my comp the first time I heard of this guy.

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Post by joe » Thu Aug 04, 2005 1:15 pm

he's made a heatsink outta the piston . that much is sure whether it creates beneficial "turbulence " or not I can't say. I have my doubts...
It's quite easy to increase the surface area of a piston or chamber and it will catch more heat , but that's a problem as much as it is a solution !

I was thinking about quench geometry the other day though and was wondering if it wouldn't be worthwhile to experiment with a chamber that had quenches on either side of the valve that had EXACTLY the same dimensions.
It occured to me that if one side had a greater quench area than the other side that it might "overpower" the other side and tend to concentrate air/fuel into a localized region . That may be beneficial if you can get it where you want it , but can you ?

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Post by bob cook » Thu Aug 04, 2005 1:27 pm

I saw the article when it first came out. I tried to contact him but, had no luck. I think the best way to check it out is a back to back comparison. I just can't afford to do it. There must be something there. I wonder how it would work in a forced induction application.

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Post by ClassKing » Thu Aug 04, 2005 10:59 pm

How many years ago did Jim McFarland dimple the @#$ outa the chambers and run 17:1 Cr. on 94 octane?

Answer? 20? at least. So what - It WASN'T efficient enough to make decent, useable power, but,.... it ran. And made for a magazine story.
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Post by gas » Wed Aug 10, 2005 10:31 am

airflowdevelop wrote:"Do you think that there really is something to cutting grooves into the combustion chamber like this?"

ABSOLUTELY!

Detonation and loss of charge managment! :roll:
I take it, you've substantiated your above statement by duplicating the machining
mod, and followed it up with actual tests that disproved claims in above link?
67RS502 wrote:Also the testing had too many variables along with the cut grooves, like raised comp. and porting.
According to link, not all test cases included other variables.
Fkned wrote:My only thought on this is-If it really worked wouldn't the teams that spends millions a year in r&d have found this long ago :roll:
You make it sound as if they would HAVE to be the ones to come up with anything different?
These 'teams' are obviously infallible. :roll:

Guys, can we occasionally think 'outside of the box', in lieu of playing 'follow the leader'?
Learning stops when breathing stops.

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Post by Darin Morgan » Wed Aug 10, 2005 11:47 am

gas wrote:Guys, can we occasionally think 'outside of the box', in lieu of playing 'follow the leader'?
There is thinking out side the box, then there is thinking of ignorant inventions because you have no real world experience or knowledge. This is one of those cases. What he is doing is ignorance plain and simple and it does not work. Just because some new Widget gets some press does not lend to its validity! The journalists are often totally ignorant about the topics they cover!
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Post by kdrolt » Wed Aug 10, 2005 1:23 pm

The notion of a squish pad wasn't ignorant when it was invented, it was just a new concept that might have appeared outlandish to those that didn't first think about "what it was?", and "why it was there?" Ricardo wasn't ignorant by trying a new idea, although you could argue that his critics were certainly ignorant.

If I THINK about what a channel cut into the cylinder head, pointed twds the spark plug, should do, empirically:

A. it seems would have no real effect as the piston climbs from BDC because the column of mixture is tall compared to the tiny channel; the squish region, btw, also has no effect during the climb from BDC for exactly the same reason;

B. when the piston slows, as it approaches TDC, the squish region begins to have an effect -- pushing the mixture out into the chamber (by squishing it). We assume some level of turbulent eddies. The channel, meanwhile, provides a low-resistance path in which the mixture might follow (Why? To seek the path of least flow resistance);

C. so some portion of the mixture that would be squished out is now guided by the channel, and jetted to the plug region. Presumeably the plug has already ignited (some 28 to 40 deg before TDC) so this has the effect of increasing the percentage of mixture burned early in the combustion cycle (making delayed spark a good idea) BUT it also increases the amount of possibly unburned hydrocarbons (in the channel) late in the combustion cycle.

Think of this as increasing the crevice volume (which is bad) in order to speed combustion (and reduce the so-called "negative torque" of pressure rise before TDC, which is good). If the "jet" (my term btw) were aimed properly, it might also enhance dual swirl if the chamber had a heart-shape... and that might help combustion along the cylinder crevice.

There may be more to this than I can think of, but the simple logic in A-B-C above is reasonable so there may be merit in his idea. THAT'S why I am also an advocate of thinking outside the box, rather than just casting it aside.

FWIW I don't work for any firm that markets or sells the idea btw, so I'm not shilling the product. The idea may have actual merit but more controlled tests would have to be done to convince people (including me).

The idea might also be old.... and abandoned... so just because it got a patent doesn't mean it's a useful idea or a new idea. Multiple elctrode spark plugs are older than dirt, yet people manage to get new patents on them. This idea might not be much different, but it was worth reading about and thinking about, IMO.
Just because some new Widget gets some press does not lend to its validity! The journalists are often totally ignorant about the topics they cover!
True and true.

AND it also means you shouldn't just outright trash a new idea just for being new. It might just be another overly-hyped idea (like the Tornado!), or it might be a useful evolution of the squish region.

I'm reminded that the world used to be flat... My $0.02, FWIW.

joe

Post by joe » Thu Aug 11, 2005 1:16 pm

I like to think of the old "room full of basketballs" analogy .

You've got a big room full of bouncing basketballs ( just like a cylinder full of molecules when the intake valve goes shut)

You shrink the room and what happens ? The motion of the basketballs becomes faster ,more intense, and most certainly more chaotic.

Now would cutting grooves in the walls affect the flight of the basketballs ? Probably so ! Would it do so in a predictable ,planned fashion so that the course of the wild bouncing balls can be "steered" ? HIGHLY DOUBTFUL !

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Post by gas » Thu Aug 11, 2005 1:43 pm

joe wrote:I like to think of the old "room full of basketballs" analogy.
How 'bout a bit of psychology?
Have any here, after seeing a positive result from 'whatever' (flow testing may come to mind), and remarked, "gee, would not EVER have thot that would have worked!" If the facts, or the correct solution were ALWAYS apparent, we would ALL (funds notwithstanding) be competing at the same speed.

Reminds me of children, when they won't eat a particular food. Why? They don't like it. How can they not like 'it' when they haven't even tried it first? Because, the decision was made beforehand, the mind is CLOSED! Will/does it work? :shrug: My mind is OPEN. That means I am NOT blindly stating it will... or that it won't. :) FFT.
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kdrolt

Post by kdrolt » Thu Aug 11, 2005 4:32 pm

joe wrote:I like to think of the old "room full of basketballs" analogy .

You've got a big room full of bouncing basketballs ( just like a cylinder full of molecules when the intake valve goes shut)

You shrink the room and what happens ? The motion of the basketballs becomes faster ,more intense, and most certainly more chaotic.
That's exactly what happens when pressure rises, in a container, in a UNIFORMLY distributed manner. That's not what happens between two squish surfaces, with an adjacent chamber volume.
Now would cutting grooves in the walls affect the flight of the basketballs ? Probably so ! Would it do so in a predictable ,planned fashion so that the course of the wild bouncing balls can be "steered" ? HIGHLY DOUBTFUL !
You skipped two important items.

Let the room be the combustion chamber. Let the shrinking walls be the piston crown and the roof of the head chamber.

What happens when the piston approaches, or reached, TDC? Specifically, what happens to the basketballs in the squish region?

Because the volume between the "walls" has shrunk severely, then the local pressure, and density, between the walls must increase significantly (via conservation of stuff). Does the stuff stay there, or will it move out of the squish region?

The universal answer is that the stuff between the wals does, in fact, move in a manner to seek a lower pressure, so the squish volume convects (flows) into the the chamber. The pressure gradient drives the flow in a preferred direction. So the pressure in the whole chamber is not uniform (that's the 1st item you missed in your room analogy) while the piston rises to TDC. And the direction of the flow out of the squish region is one form of steering, it's just not very uniform.

So to conclude the argument, why is it so hard to imagine that the steering be accomplished in a channel so that the plane-plane squish region has an escape path into a channel, a channel that happens to be directed twds the spark plug? That's the 2nd item you missed.

There is always some level of chaotic molecule motion in the cylinder (it's called pressure in a macroscopic sense), but when you have an imbalance of pressure you get a flow that attempts to equalize the pressure. In air we call it weather, where high pressure will induce flow (wind) to low pressure. That's why the self-descriptive squish region works --- it jets a planar (flat) slug of mixture back into the chamber which in turn speeds the burn (once ignited).

The notion of using a channel cut into the squish region merely helps direct a greater percent of the flow stream twds the spark plug rather than just thrusting the flow into the chamber in a less controlled way.

joe

Post by joe » Thu Aug 11, 2005 6:43 pm

I wonder if I'm making a mistake responding to this :D

Yeah the basketballs were a little simplistic compared to a chamber and cylinder , but I was hoping this slight trespass might be allowed in order to help people visualize.
Because the volume between the "walls" has shrunk severely, then the local pressure, and density, between the walls must increase significantly (via conservation of stuff). Does the stuff stay there, or will it move out of the squish region?
The universal answer is that the stuff between the wals does, in fact, move in a manner to seek a lower pressure, so the squish volume convects (flows) into the the chamber. The pressure gradient drives the flow in a preferred direction. So the pressure in the whole chamber is not uniform (that's the 1st item you missed in your room analogy) while the piston rises to TDC. And the direction of the flow out of the squish region is one form of steering, it's just not very uniform.
The stuff moves outta the squish region by way of velocity overwhelming a HIGHER pressure in the chamber . When the piston makes a close approach to the head the velocity between the head of piston and quench area can go supersonic ,at which point it is impossible for sonic waves to pass back into the quench.
The notion of using a channel cut into the squish region merely helps direct a greater percent of the flow stream twds the spark plug rather than just thrusting the flow into the chamber in a less controlled way.
Do we want to aim it at the plug ?

I'm not close minded I have been grinding chambers today in a way that I had never done before , in an attempt to help improve wet flow characteristics but I ground a groove part way AROUND the plug to stop any fuel deposits from collecting there !
The approach I'm using is modelled after a chamber mod I have seen that made best power with only 29* of total timing which means things are more efficient in the chamber and less negative torque has to be undone.

I'll just stick with what I'm doing for the time being and you try that "jet" piston and get back to me when you figure out what is being accomplished.

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