I bought 10 of These

gumpy · 05-31-2010, 02:18 AM

There is some sense to that thing...

Nissan were hoping to find a solution to the complexities of direct injection by some how creating a swirl in the cylinder when the fuel is added...

this might add swirl... i'm skeptical but there is some logic behind it...

1slow370 · 05-31-2010, 02:59 AM

nope no swirl. honda had swirl figured out years ago and the only real effective way to do it without to much turbulence is to have either one intake valve open farther than the other or to have one valve bigger than the other. all the intake swirl in the world isn't going to help the air get shoved down the runner. you need swirl inside the cylinder. there are various head designs in the 2 valve world that work to pull it off as well. so far as the direct injection goes that has all been figured out long ago as well it's called a diesel engine and it's been around forever. the shape of the piston head on a diesel engine (which is very similar to the shape of the head on a DI gas engine) allows a lean center flame due to the quench areas on the piston allowing as high as over 40:1 fuel ratios without burning up the pistons. Diesels actually make that black smoke and generate super high egt's (performance tuned ones watch a tractor pulling video or something) when operating at what they call near stoichiometric conditions which is a fancy way of saying 15/16:1. deisels always run lean or else there isn't enough air to cool the charge down and the super high cylinder temps melt/blow the engine apart. DI in a gas engine works the same way. it injects very little gas right before the spark to prevent detonation and relies on the shape of the piston to allow it to be able to burn such a small quantity of gasoline.

XwChriswX · 05-31-2010, 03:13 AM

Quote:

Originally Posted by 1slow370

honda had swirl figured out years ago

Modshack · 06-02-2010, 12:29 PM

Quote:

Originally Posted by gumpy

There is some sense to that thing...

Nissan were hoping to find a solution to the complexities of direct injection by some how creating a swirl in the cylinder when the fuel is added...

this might add swirl... i'm skeptical but there is some logic behind it...

well....errr.....This might have been the case back in the days of carburetors. Swirling would help atomize the fuel. Hardly the case with fuel injection though where a highly atomized mix is injected just upstream of the valves. Also, a modern MAF controlled Fuel system needs a clean flow of air over the MAF to accurately calculate injector duration...

There is no point at all to these on a modern car..

370Zsteve · 06-02-2010, 12:39 PM

Quote:

Originally Posted by Modshack

There is no point at all to these on a modern car..

It helps the VVEL kick in, y0!

05-31-2010, 02:59 AM	#2 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	nope no swirl. honda had swirl figured out years ago and the only real effective way to do it without to much turbulence is to have either one intake valve open farther than the other or to have one valve bigger than the other. all the intake swirl in the world isn't going to help the air get shoved down the runner. you need swirl inside the cylinder. there are various head designs in the 2 valve world that work to pull it off as well. so far as the direct injection goes that has all been figured out long ago as well it's called a diesel engine and it's been around forever. the shape of the piston head on a diesel engine (which is very similar to the shape of the head on a DI gas engine) allows a lean center flame due to the quench areas on the piston allowing as high as over 40:1 fuel ratios without burning up the pistons. Diesels actually make that black smoke and generate super high egt's (performance tuned ones watch a tractor pulling video or something) when operating at what they call near stoichiometric conditions which is a fancy way of saying 15/16:1. deisels always run lean or else there isn't enough air to cool the charge down and the super high cylinder temps melt/blow the engine apart. DI in a gas engine works the same way. it injects very little gas right before the spark to prevent detonation and relies on the shape of the piston to allow it to be able to burn such a small quantity of gasoline. __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50

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05-31-2010, 02:18 AM	#1 (permalink)
gumpy Enthusiast Member Join Date: Oct 2009 Location: Sydney Posts: 449 Drives: 09 370z white manual Rep Power: 16	There is some sense to that thing... Nissan were hoping to find a solution to the complexities of direct injection by some how creating a swirl in the cylinder when the fuel is added... this might add swirl... i'm skeptical but there is some logic behind it...