In cylinder turbulence/ burn rate

[automotivebreath]

Originally Posted by Cammer

...Notice he machines grooves in pistons as well as in valves.

Last weekend I grooved the chamber of this head for Scott Sheen. In addition
to the modifications done he will be adding Metric Mechanic valves as well.
Unfortunately his "butt dyno" will not be able to determine what is responsible for
the performance or heaven forbid lack there of.

[big block fiero]

Butt dyno?

[automotivebreath]

Originally Posted by big block fiero

Butt dyno?

"butt dyno" - Having the ability to measuring mechanical power, esp. the
output or driving torque of a rotating machine by the seat of the pants.

[Cammer]

My experience with dimples in the combustion chamber indicates they often contribute to unwanted vortices.

IMO, keeping the mixture homogeneous throughout the process is key to engine efficiency.

_________________________

[big block fiero]

Originally Posted by Cammer

My experience with dimples in the combustion chamber indicates they often contribute to unwanted vortices.

IMO, keeping the mixture homogeneous throughout the process is key to engine efficiency.

_________________________

But those dimples on the back side of the valves, I'm real glad you guys spilled the beens on that one. Even the wizard seemed a little interested. I still haven't dyno'ed it yet but I will in a couple weeks.

[mpgmike]

Originally Posted by Cammer

My experience with dimples in the combustion chamber indicates they often contribute to unwanted vortices.

IMO, keeping the mixture homogeneous throughout the process is key to engine efficiency.

_________________________

In an area that there is plenty of action, you would be correct. Furthermore, dimples increase the surface area of the chamber, which is not a good thing. I've found it difficult to do anything constructive with this recessed area that keeps it from accumulating all the heavies and creating detonation issues under higher boost. The dimples solve a problem, not accentuate an already great combination.

Mike

[Dusty]

Heres a thought i have no idea if it has been tried before. What about a little ski jump on the piston that would direct the swirling mixture at the exhaust valve as the piston approaches tdc and possibly aid in vaporization

[Pinhead]

Originally Posted by Dusty

Heres a thought i have no idea if it has been tried before. What about a little ski jump on the piston that would direct the swirling mixture at the exhaust valve as the piston approaches tdc and possibly aid in vaporization

Do you mean like with these pistons??

[Dusty]

figures someone thought of that already

[automotivebreath]

Here's a good shot of the "Hi-tech" swirl quench design. GM did something similar
in the combustion chamber of the LT1 head (below to the right of the plug).
The question is, does this actually improve combustion?