Modify squish zone groove, get 20% more HP

[Karl]

Check out this article....... www.rexresearch.com/singh/singh.htm

[90GTVert]

It's an interesting idea. What I wonder is why it really is so hard to test. It says no government funded lab can test without approval from the manufacturer. It says no manufacturers show interest. O.K.... what about AFR, Holley, Edelbrock, Brodix, Canfield, Trick Flow, etc.... There are tons of perfomance companies out there. You would think that it would be worth the effort to test the idea. If for example AFR tested the idea and it worked, everyone would buy AFR heads instead of Edelbrock because they would make more power and use less fuel. I have to wonder why no company shows any interest.

[rallyrrr]

Interesting read. I found it curious, though, the need for two types of channels/grooves on the combustion chamber surface. Also unclear is the number of channels/grooves utilized. It will be interesting to see if this innovation takes hold. There may be long term issues of carbon build-up. Also, this may not pan out for extreme operating parameters in racing applications especially in the area of the passeges due to high heat surrounding a small parcel of aluminum on two sides. It could melt and fall out. This innovation, as stated in the article, seems to favor low speed operation. The anti-knock characteristics and lowering of octane requirements could be very important in third world countries.

I wouldn't be surprised if we are able to buy Indian built Tatas here in the U.S. in 3 - 5 years. Wouldn't a lot of girls love a new pair of Tatas?

[90GTVert]

Aug 16, 2008 16:32:46 GMT -5 rallyrrr said:

Also, this may not pan out for extreme operating parameters in racing applications especially in the area of the passeges due to high heat surrounding a small parcel of aluminum on two sides. It could melt and fall out.

Looking at that side view diagram made me think the same, especially for a little minarelli or something. The way they show it, the area between teh passage and the chamber would be terribly thin. Then again, look at the upper illustration of the cylinder etc... It's this monster piston approaching little baby valves, spark plug, combustion chamber. It's like Godzilla attacking Japan or something.

[rallyrrr]

I'm sure that was just for the purpose of making room for the labels. I noted that too.

[Karl]

I have an extra head but don't have the tools to make those cuts. Brent, you're pretty handy with stuff, you wanna give it a go if I mail it to ya?

[90GTVert]

I've got an extra MRP head. I don't think I'm gonna mess with it myself. All you'd need is a drill and dremel to do something similar if you wanted to.

[Karl]

Can you tell the orientation of the cuts and holes? I'm sure it would make a difference how it's oriented, wouldn't it? It does in the 4-stroke configuration.

[motomech]

I saw this post in the General section, but didn't respond.

Engine builders have long understood the importance of promoting flame front propagation with turbulence and keeping the quench tight.
Judging from the picture of the cyl. head he is holding, it appears to be a rather dated design, 2 valve, large included angle of the valves, etc. So there might be a significant gain by notching the piston crowns, etc. But not 20%.
Modern cyl. heads accomplish this by design. Maintaining port velocity, proper angles and, within the limits of mass production, keeping the piston to cyl. head clearances(deck height) tight.

Nothing to be gained by doing that with a 2 stroke.
Transfer port shape is the key to a good Schurle loop and in my past days building 2 strokes, the drill was to remove the head after enough time/carbon had built up on the piston crown to observe the loop pattern. Often, the action taken to improve this was to "flatten" the transfer port floor.
Care must also be taken not to get the distance between the transfers and the exh. port too close and have the mixture "short-circuit".

[rallyrrr]

The Schurle loop is old school two stroke technology. Today's xfer theory aims the aux. and main xfers horizontally across the crown of the piston in somewhat opposing flows instead of in a 60ish degree upward angle of the Schurle loop theory. Today's lower cylinder is virtually filled with xfer ports and the resulting low velocity flow collides against itself resulting in a slow and fairly gentle rise of the mixture. This can result in a small amount of residual exhaust gases remaining in the head area taking away valuable space for fresh mixture. From the factory most manufacturers have boost and xfer ports opening at approximately the same time. Some tuners, therefore, raise the upward aimed boost ports (close to 75 deg. and located opposite exhaust port) to open first by around 1-1.5 mm in order to get this static pocket of gases displaced immediately. I did this when performing port mods on my Airsal single ring kit.

I fear, however, this procedure very adversely affected my fuel mileage.