Is anyone familiar with this or is it internet poppycock... http://somender-singh.com/content/view/7/31/
If this was an industry recognised invention that could improve economy (better combustion efficiency = better fuel economy), it would have been in every magazine you could name, and it would be in car engines. Just like CVCC technology, V-tech technology, and the like were discussed years ago in many circles.
Subtle changes to combustion chamber shapes can make big differences and every chamber is different. One mod does not effect all the same way. Not to mention the fact that India has hardly been recognized as a hotbed of innovation in automotive technology.
I had a 350 GM engine built by a guy in Austin that was Nursemaid to some pretty hot bike racers.... He was really heavy into swirl ramps and piston mods of this nature, "shark skin" surface treatments in the intake runners and fuel flow at the molecular level.... As Brian states it gets a lot harder on multiple cylinder engines as design complexity increases.. That guy came back to mind though, as Speedo introduced those new high tech swimsuits that were used to break swimming records this Olympics. He fastidiously rebuilt my Pontiac motor to stock specifications though, almost insistent on it for longetivity....
The shape of a combustion chamber is a very complex thing.. so doing something like this may have optimal effect for small rpm ranges, but i doubt it is something that could provide a increase across all operating ranges of an engine. Additionally, tuning of the engine would have as much to do with how much unburnt fuel is left as HOW the fuel was burned. A good tuner would be able to see via Air fuel ratio coming out the tail pipe that the engine was getting too much gas. Most engines are also tuned to run a little rich anyway for safety. The guy also claims it eliminates "ping" or pre-ignition, which is very much a consequence of tuning as much as it is combustion chamber design. I think it might work on something like a large power generator or engine that runs in a somewhat narrow rpm range, but for something that revs anywhere between 500rpm to 9k, i don't think it would have much effect without some serious development time. If the groove is shaped wrong, it might direct a lot more energy to a particular spot on the head gasket, causing premature failure. One of my friends spent years designing a combustion chambers to get better gas mileage, and i have talked to him quite a lot about it as it is one of my interests. Ill have to talk to him to see what he thinks about it, but i think it is safe to say it is more internet fable than actually useful, at least without your own computer cluster to simulate combustion events and chamber shape interactions.
This type of deal is used in one way or another in many types of racing. The slotting technique is typically used in engines using very large piston domes to increase compression. It effectively helps the ignition of any fuel "cut off" from the rest of the combustion process. I use generous radiuses on the piston domes without regard to the compression losses, to allow the flame front to "flow" over the piston dome, as dyno testing has shown that quality combustion far outweighs any losses in compression. The more modern deal is to use dimples or ramps to affect the combustion process vs. slotting. I've used piston and chamber dimples in plenty of racing engines and many custom piston makers offer these options on their upper end pistons. Car makers and engine builders all have researched the advantages of "swirl and tumble" techniques to increase horsepower and fuel economy. Too smooth of a surface can lead to fuel falling out of suspension - fuel in large droplets instead of fine atomization. In upper end racing engines, I use a roughing technique under the valve job that promotes good atomization of the fuel, without hurting the overall flow numbers of the head. Anyway, what Mr. Singh has here as been done and used by engine builders for years.
The website is global warming based and the modification has to do with increasing fuel economy. Regardless, the point is that you cannot simply place these devices into any combustion chamber simply because it worked well in another. Only analysis with flow benches, dynomometer work and road tests could confirm where, or if, to place any of these devices into an engine. I think it would be very foolish to allow your engine to modified by these people without a great deal of information regarding your particular engine application. My gut feeling is that they zero testing outside of one or two engines to support thier work. Caveat Emptor.
Hi all, Can someone provide pictures of the combustion chamber and piston top of a Ferrari engine? I have years of experience with grooved cylinder heads, much different application. I'm interested in Ferrari design features used to enhance combustion efficiency. AB
Can someone let me know where I can find pictures of the combustion chamber and piston top of a Ferrari engine?
Here - if you do some searching and put a little effort into it You should be able to find examples of the 2-valve, 4-valve, and 5-valve heads and pistons For example -- the 308 2-valve hemi head: http://ferrarichat.com/forum/showpost.php?p=137918007&postcount=117 and some good shots of a 5-valve 355 head: http://ferrarichat.com/forum/showpost.php?p=137716430&postcount=32 also try word combinations like "308 pistons" or "pistons rings" or "cylinder head cc", etc.
Thanks Steve, The link to the 2V chamber shows a hemi configuration and the pistons I found have a dome and what appears to be a squish band. Am I correct to assume this piston squish band matches the flat portion of the chamber? If so what's the piston to head clearance at assembly? Also, what's the RPM range of the 308 2V engine? http://ferrarichat.com/forum/attachment.php?attachmentid=797022&stc=1&d=1220362128 http://ferrarichat.com/forum/attachment.php?attachmentid=778466&stc=1&d=1217870701
The piston you show I believe is an aftermarket higher compression piston -- IIRC, the stock 308 pistons are actually dished concave on the top (8.8:1 CR). The 308 redline is 7700 RPM (71 mm stroke).
Is there a squish band? How wide, like this? http://www.nicksforzaferrari.com/forzaferrariwebsite1007003.jpg
It might be the 308QV stock pistons (4-valve heads) that are dished in the center -- this thread: http://ferrarichat.com/forum/showthread.php?t=188138&highlight=308+piston+mahle&page=2 shows the stock 308QV piston (which seems to match the jpeg you posted) -- although the FChatter was having trouble with there being two different types of the same part. Unfortunately, some of the stock 308 2-valve piston pics got lost in the crash a few years ago -- hopefully someone will repost. They might just be flat-topped with two angled valve reliefs.
Thanks again..., I found this flat top, it looks like there is a small squish band. Do you know if these engines run well at idle/ low speed operation? http://autovolante.tripod.com/sitebuildercontent/sitebuilderpictures/ep001.jpg
the stock and most aftermarket 2V pistons I've seen have an even larger squish band . . . and on the stock motors the pistons don't come to the deck by about .03" from memory . . this is something I changed when I had pistons made . .. these engines idle fine but everyone wants more bottom end tq . . . seems like these "grooves" would help turbulance which is the advantage of the 4v had yes? cheers, Sean
Hi Sean I'd like to see the 308 head with a gasket overlaid to get an idea of the squish area on the head deck. I get the feeling that it's very small plus with the piston 0.030" in the hole and the thickness of the head gasket puts the piston to head clearance very wide, I'm sure your engine liked the custom pistons tightening up the squish clearance. As for the advantages of 4 valve heads, I feel the benefits come from increased valve area and ideal spark plug location (shorter burn distance). The squish location is good especially if effective side squish areas are used. Turbulence is provided with tumble and squish with both the hemi and the pent roof design. I don't see much place for grooves in the 308, the squish area is just too small. Perhaps with the 4 valve head the squish area is larger. The engines I groove (V8s) have very large squish pads allowing plenty of room for grooves. Do these grooves create turbulence? I suppose its more about redirecting the energy where it can be more useful.
