Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

beatr911 · 07-11-2012, 05:55 PM

No mpg gain? Hmmm. Maybe this myth is busted?

Anyone else want to test? More than one data point is always important.

As far as atomization is concerned, I understand that GDI is better partially because of the very high injection pressures and fine atomization. MPG isn't the benefit though, it's more power.

Also on some high performance motorcycles they use 12 hole injectors for ultrafine atomization. MPG is not a concern, HP is. These are 12,000+ rpm engines where a fast burn is essential.

Maybe the gain is due to a faster burn requiring less ignition advance resulting in less combustion pressure rise before top dead center, hence more power. Intuitively it still seems like it would also help MPG, but maybe it's a negligible gain compared to HP.

BackroadBomber, did you notice a power gain with the 4 holers?

07-11-2012, 05:55 PM	#33 (permalink)
beatr911 Master EcoModder Join Date: Feb 2008 Location: West Coast, USA Posts: 516 B2300 - '96 Mazda B2300 SE Focus - '05 Ford Focus ST The red car - '00 Honda Insight Thanks: 6 Thanked 77 Times in 56 Posts	No mpg gain? Hmmm. Maybe this myth is busted? Anyone else want to test? More than one data point is always important. As far as atomization is concerned, I understand that GDI is better partially because of the very high injection pressures and fine atomization. MPG isn't the benefit though, it's more power. Also on some high performance motorcycles they use 12 hole injectors for ultrafine atomization. MPG is not a concern, HP is. These are 12,000+ rpm engines where a fast burn is essential. Maybe the gain is due to a faster burn requiring less ignition advance resulting in less combustion pressure rise before top dead center, hence more power. Intuitively it still seems like it would also help MPG, but maybe it's a negligible gain compared to HP. BackroadBomber, did you notice a power gain with the 4 holers? __________________ Good design is simple. Getting there isn't.