Brandon@Forged

Oh, I was referring to the zero silicon pistons.

Aquineas

Just out of curiosity, would there be any benefit to going with the same high-silicon aluminum forged piston with a thicker ring land? If your goal was 600whp, which would be fine for most I'm sure, you could maintain the benefit of a quiet motor yet still strengthen the ringland (which was the obvious failure point in Todd's car).. Just wondering..

G3po

iTrader: (8)

By properly shaping the crown and taking quench area into account you can also shroud the vulnerable ring land areas and distribute heating, without necessarily droping down the top ring o thinkening the lands even more. Note the failures occured only on the intake side of the cylinder, not on the sides. There is good reason why newer OEM FI configurations are playing close attention to the squish and the quench areas. FI on pump gas is far different than a full race configuration.

Sharif@Forged

iTrader: (92)

Without moving to a button design, and shortening the skirt, there isnt much room availble to enlarge the top land. The total length of the piston must remain identical, so you a fixed amount of real estate to work with. If you thicken a ring land, then you need to shorten something else.

It is my understanding that Arias is always refining their shelf piston design, so it wouldnt surprise me if the begin using thicker second ring lands on all of their VQ pistons. Like everything, its a constant learning process, and the best manufactures will work closely with vendors and other shops, to improve their products over time.

Sharif@Forged

iTrader: (92)

Good point....most true racing engine builders will be shocked to learn of the power we are making with pump gas...its just incredible, how the technology has progressed, but there is a material element of risk involved with boosting this much on pump gas.

The low CR dish design actually improves squish/quench...I always confuse the two....areas.

G3po

iTrader: (8)

A simple low CR dish attmepts to maintain the OEMs squish volume (flat lip around) the perimeter; however a perfectly circular dish does not improve upon the OEM's quenching properties. And actually the further you drop the top ring the less effective the squish effects perform. In order to maintain the queching properties of the OEM one would need to fashion the crown to take into account the actual combustion chamber shape. The simple symmetric dish design does not accomplish this .

Sharif@Forged

iTrader: (92)

but the high lip remains...just just the center portion that remains. The ring land hasnt moved....in relation to the combustion chamber...nor has the edge of the piston.

G3po

iTrader: (8)

I don't want to come across as dissing these new pistons, they certainly have there place (it is primarily a race design) But , from the pics , the top ring position was moved down from the top along with the second ring. Obviously this makes for stronger overall lands and helps shroud the top ring from the direct shock and heat of the combustion process and the unplanned short duration detonation.

However; the top ring being moved down does "reduce" the squish effectiveness intended by the OEM. If you measure the volume around the perimeter (lip out) down to the top ring , you should note that the volume has been increased, thus making squish less effective. What I want to convey is that there are other more street effective ways to help shroud the top ring and lands without necessarily dropping the top ring to such an extreme.

For example by making note to the OEM CC design and were the quench pads are positoned , one can more effectively shroud the first most vulnerable land postions which appear to be the land areas above the skirts. Taking this into account, one can see how lighter more detonation tolerant , more street fuel optimized design can be made while not going to such extremes.

I will note even with these extreme design pistons a few seconds worth of detonation under full load can still result in destruction. Maybe last a few more seconds , but none the less destruction. They can't make up for improper timing of poor assembly.

Sharif@Forged

iTrader: (92)

All very good points G3..its all about compromises. When you have a set amount of real estate to work with, sacrificies have to be made, if you want thicker ring lands, and ultimately, and much stronger piston.

Here is the stock OEM piston vs. Arias Extreme Duty.

G3po

iTrader: (8)

shariff , what would be an even better pic would be all three side by side.

OEM , Arias shelf 9:1, Arias Extreme 9:1 , pin side view and top (crown views). So basically six pic shot shown together.

Thanx

G3po

iTrader: (8)

Oh yeah and the "full Rolex". Your slipping , I can only see a fraction in this pic

Sharif@Forged

iTrader: (92)

I dont have a 9.0:1 shelf here

I do have an 8.6:1 shelf piston, but not be a totally accurate comparison

Sharif@Forged

iTrader: (92)

lemme see what I can do for the next series of shots....I still havent had lunch yet...

G3po

iTrader: (8)

That would be better than not. At least it would be a good comparo for the side view. Even though I have noted that the shelf 8.6 shelf version dropped the rim a little , as noted due to the total lack of valve clearance notches. The custom 9:1 etc versions all have valve clearances in the rim area , indicative of a higher rim and more attention to squish volume reduction.

Sharif@Forged

iTrader: (92)

Not really....the lack of valve pockets is simply becuase the lower CR pistons have a deeper dish, and less edge to them, that are in no danger of hitting the valves.

G3po

iTrader: (8)

No, I didn' t mean to imply that there is a valve clearanace issue on the 8.6 or that the sky is falling .

What I am implying is that the 8.6 could have been designed a little better if the rim were raise , dish lowered, valve pockets cut in the rim (like all the custom CR versions. The 8.6 IMO was done the way it was to reduce production time on the CNC machine and hence make it the least costly alternative. Basically if there aren't pockets on the rim , squish volume was not "optimally" minimized.

ALright now time for me to get abck to my yob.