Dimpled Pistons

[LBZ]

Might have missed this discussion if it already happened but if not, found this for an interesting read:

Dimpled Pistons Use Golf Tech to Improve Diesel Power, Efficiency

Speed of Air claims their dimpled pistons make more power and reduce particulate emissions of diesel engines, and have the data to back their claim up.

www.motortrend.com

 

[2004LB7]

Looks interesting but I'm betting that they are stretching the numbers a bit

"In that report, there was a 15.5 percent increase in horsepower and a 15.2 percent increase in torque. That's not where the good news stops, either, as this report found that the Brake-Specific Fuel Consumption was reduced by 3.2 percent, the opacity of the exhaust was reduced (meaning less particulate matter) by 77.6 percent, NOx levels reduced by 61 percent, exhaust hydrocarbons dropped by 32.5 percent, and CO2 levels dropped by 41.4 percent."

If CO2 levels dropped by 41.4% wouldn't that mean less complete combustion and thus increase in carbon monoxide? Thay don't list that. Probably because it went up. This would explain the reduction in NOx. But they also say they got a 15+ % increase in HP and torque along with a reduction in fuel use. Seems almost like the combustion temperature went down, hence the NOx & CO2 reduction but also a reduction in particulates would have to mean more complete combustion which should mean more CO2. But since the CO2 is down I doubt there would be in increase in HP/torque

Something doesn't add up to me

 

[juddski88]

I think Tony Burkhard tried this idea, but I haven't seen any data posted about it.

 

[MAXX IT OUT]

I have heard of dimpling the runners of cylinder heads for increase in CFM, but with some mixed results. Wouldn't the main effect of dimpling aside from the "boundary layer"on a piston be to lower the CR and increase surface area for heat adsorption.

 

[gmduramax]

I have heard of dimpling the runners of cylinder heads for increase in CFM, but with some mixed results. Wouldn't the main effect of dimpling aside from the "boundary layer"on a piston be to lower the CR and increase surface area for heat adsorption.

Now I could be totally wrong. I don’t think dimpling on cylinder heads help. I have seen it increase power but the reason was the runners were too large and slowed velocity. By dimpling it essentially created a layer of stagnant air against the runner making the runner smaller and helping velocity.

 

[TheBac]

Just seems to me that those dimples would create more hotspots that would promote detonation than help with combustion. But then, Im no engineer....

 

[MAXX IT OUT]

Now I could be totally wrong. I don’t think dimpling on cylinder heads help. I have seen it increase power but the reason was the runners were too large and slowed velocity. By dimpling it essentially created a layer of stagnant air against the runner making the runner smaller and helping velocity.

Yes, that's why I said with mixed results, from basic understanding I have, the effect it only useful at a high velocity. A golf ball travels at 200+ mph, but a baseball that travels at 80+mph wouldn't get the same benefits due to the lower velocity.

 

[1FastBrick]

Funny the are reporting this like it's new.

I read this older article recently. It states the pistons are manufactured by UEM for SOA. I found the Dualoy pistons from UEM and it looks like the put a steel ring land in like the Mahle race cast pistons. I was curious if any one had used the regular Dualoy pistons from UEM. I couldn't find anything about them. The SOA version has to be purchased through SOA.

Speed of Air Engine Technologies' Delivers Performance Breakthrough - Engine Builder Magazine

Speed of Air (SOA) Engine Technologies has found a way to optimize combustion that delivers several startling performance benefits. A significant increase in power is just one among many.

www.enginebuildermag.com

Edit:

haha, I found Enginebuilder published the same article from Motor trend 2 weeks earlier...

Speed of Air Engine Technologies Breakthrough Piston Technology - Engine Builder Magazine

Speed of Air® (SoA) Engine Technologies has developed patented technology to enhance the efficiency of medium-duty Cummins®, Powerstroke® and Duramax® engines, providing measurable performance and fiscal benefits. SoA’s patented piston treatment on its Hyperformance Pistons™ provides increased...

www.enginebuildermag.com

 

[Bdsankey]

I think the theory has some merit to it but I don't know of enough people that have used them. The gentleman who had the 7.3 pistons from SoA I have spoken to at length and he seems like a stand-up guy (IE not fudging anything) but who knows?

I'd love to see more testing on them that's for sure. I do believe DHD was building a motor with a set but I don't know if they've completed it yet or done any testing if they have.

 

[MarkBroviak]

Stay away from the Dualoy pistons, they do not hold up at all!

 

[1FastBrick]

Stay away from the Dualoy pistons, they do not hold up at all!

What has your experience been with them?

My understanding is they are just a factory type replacement.

 

[Bdsankey]

Stay away from the Dualoy pistons, they do not hold up at all!

Good to know. I know Evan @ DHD has said they've gotten decent luck out of them in an OEM type application and not as a Motorsport replacement.

 

[MarkBroviak]

What has your experience been with them?

My understanding is they are just a factory type replacement.

A dealer of mine has a couple of engines on the floor with cracked ones in it when they tried to use them as a motorsport replacement because they were advertised as just as good and they definitely aren't!

 

[1FastBrick]

A dealer of mine has a couple of engines on the floor with cracked ones in it when they tried to use them as a motorsport replacement because they were advertised as just as good and they definitely aren't!

Thanks for the info.

 

[kidturbo]

Way I see it, MythBusters confirmed the golf ball effect conclusively, many moons ago. Ranks up there with busting the myth of better fuel mileage with your tailgate down.

Dimpled combustion chambers dates back to my juiced gasser days of the early 90's. First recall seeing pictures of a Hemi head someone had done in a magazine. And #'s made were impressive. Back then effective gain was based around mixing the un-atomized air/fuel, normally pouring into the combustion chamber like gas dumped from a funnel. So combustion efficiency wasn't hard to improve upon back then. With introduction of sequential port injection offered better A/F mixture, power, and fuel mileage. Which put the dimples idea into that final 2% possible gain potential.

Reading the diesel piston article, first thing I saw was an upside down hemi head.. So am down with more dyno data. Also found it interesting that the exact Mythbusters gain on mileage in the golf ball car, from 26mpg to 30mpg is 15.38%

 

[Dozerboy]

Source: https://youtu.be/_030AnLt0Ko