When Ray speaks sometimes I think he's speaking a foreign language so I've been determined to get some skillz!! I've decided to start posting what I learn. Let's see if you are SMARTER THAN A GIRL?? ;) For the "Racers" out there... here are some SPEED SECRETS you may or may not know. For the "Average Joe" and I... I've translated Ray's opinion into NORMAL people words ;) on Donut Dome Pistons....
Advantages of the Donut Dome Piston in high boost applications:
RACER NOTES: So why is this Donut Dome better than the rest…...it provides low compression for your high boost application!!
AVERAGE JOE & I NOTES: How about a 427 cubic inch with 8.1:1 compression? Sound good? Apparently that is very good. The lower the compression the more boost you can throw at it. Upon boosting an engine, with boost, you can increase the compression of the air over the pistons by double or triple the original atmosphere. That is a lot of stress on parts. You wouldn’t want to double or triple a compression of 14:1, your engine will leave a trail of pieces behind.
RACER NOTES: These forged pistons are perfect for a high performance LS engine. The Asymmetrical Forged Side Relief design is engineered to handle high power normally aspirated and forced induction LS engines. An exclusive asymmetrical skirt maintains a larger skirt area on the heavily stressed major thrust side, while reducing friction with a smaller skirt on the minor thrust side.
AVERAGE JOE & I NOTES: A few advantages of the Donut Dome design include the asymmetrical skirts.
The skirts are indicated as “minor” or “major” and are asymmetrical to fit the job they are required to do. The “minor” can be smaller to reduce friction but the “major” is larger to withstand the stresses placed upon it. The “struts” between reinforce the overall piston and give added strength to the skirts that most pistons don’t have.
The R/D packed into this piston results in a high strength, lightweight, piston that will outperform the competition!
The bowl shape of the Donut Dome piston reduces the compression because of the added volume of the bowl to the combustion volume. This reduction in compression reduces detonation risk in boosted applications. The distinct bowl shape controls air and fuel movement as the piston comes up for the compression stroke. A vortex of air and fuel swirls creating a better mixture inside the piston bowl before combustion takes place. A better fuel/air mixture will result in a better and more efficient combustion, which leads to more power.
RACER NOTES: Pistons also feature:
AVERAGE JOE & I NOTES: Pistons also feature:
• Accumulator Grooves - is a small groove machined between the top and second ring. It provides additional volume where residual combustion gases that have “blown by” the top ring can collect. This additional volume helps to reduce pressure between the top & second ring, thus aiding in top ring seal and minimizing ring flutter.
• Offset Wrist Pin - Offset of the wrist reduces piston slap. Offset pins can also change the angle the rod is positioned on the crankshaft affecting torque.
• Double Pin Oilers - deliver twice the amount of oil to the wrist pin as compared to the standard single pin oiler. These are oil passages that connect oil scraped off the cylinder wall directly to the wrist pin bore.
I'll be adding more "Average Joe & I" tech talk to our website at www.RaymacRacingEngines.com. If you have a speed secret or engine building topic you would like "translated" shoot me a message and I'll see what we can learn!