Nashco wrote:Sounds like a bunch of bull-crap to me. Might work to introduce turbulence/tumble on a crap head with tons of safety factor built in, but on a well designed head will reduce flow at high RPM and will introduce hot spots in the head.
The few I have seen that worked as advertised were usually way too expensive/complex to make it worth the while.
Bryce
After I explain this it will make perfect sense but before I do that and spoil it, lets look at the variety of ways people perceive this and how this speculation leads to the creation of wise tales, urban myth, hocus pocus and all that stuff because that is sort of fun too.
Grooves will induce turbulence and tumble?
Gee, I suppose it could and who could argue that it doesn't at all or even a little bit. But thats not really it.
Grooves will reduce flow at high rpms?
Again, I suppose it could especially if it sets up rotation on overlap that is counter productive to the existing flow and swirl but then again it can help induce earlier rotation and swirl that is beneficial to increase flow as well, but again, thats not the overwhelming reason for the gains that people are seeing. Many back to back dyno tests have shown no peak hp loss as a result of adding quench chamber grooves.
Grooves will introduce hot spots in the head?
It was common for people to say that chamber sharp edges must be deburred to prevent preignition from hot spots but look at a stock hyabusa chamber, alot of sharp edges and isn't a problem unless were talking about a long distance endurance event and even then the deburing is only possibly nessasary near the plug and exhaust valves. The valves will usually glow before a sharp edge of the chamber will. Many race engines are now built with sharp edges on the intake side of the chamber on purpose to provide a sheering edge for incylinder fuel vaporization and Quench walls are now usually left sharp. At the location where quench grooves occur, this isn't going to be a preignition source.
Nashco quote
"The few I have seen that worked as advertised were usually way too expensive/complex to make it worth the while".
I would like to see a "worked as advertised" chamber.
If you look at all these groove threads you will notice that the experts you would expect to give profound explanation never do but that doesn't mean there isn't something positive going on, its just that they dont agree with whats being said. When I prompted darin morgan for an explination his answer was quite vauge but very accurate altho he didn't find isolation for the reason for the improvements.
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