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Yeah, larger droplets have a smaller surface for the flame front to attack. Look at a diesel. The soot which comes out of the exhaust ist mainly unburned fuel due to too bigger droplets.
The Boxer 4 in the GT86/BRZ has the mentioned direct injection as well as standard port injection and has a good power to consumption ratio.
Port injection is more eco friendly, as it produces a more homogenous mixture rather than a punctual one. Less NOx, next to no soot, ...
@Warren
Using those X Type injectors, are you mit worried that the jet might not spray narrow enough to get past the drop into the runners? I mean, hard to explain, if you look at the standard injectors, they have a long injector nose with a pintle cap on top. That seems to reach deeper into the runner. The X Type ones (basically Ford) seem to be quite short around the nozzle...
Using those X Type injectors, are you mit worried that the jet might not spray narrow enough to get past the drop into the runners? I mean, hard to explain, if you look at the standard injectors, they have a long injector nose with a pintle cap on top. That seems to reach deeper into the runner. The X Type ones (basically Ford) seem to be quite short around the nozzle...
The nozzle on the OEM V12 injectors is not deeper into the runner by more than a few mm's. It's a little deceiving the insertion depth is almost identical at both ends. the body on the Denso is shorter.
I have removed most of the injector bump inside the runner, which shrouded the V12 injector nozzle. The Denso injectors are flush with the inside of the runner and the V12 is a little proud
something that has me thinking, when engine is cold it does run fairly well! but some thing i always notice is after driving and good and hot 185/190F (digital) it runs really great much more responsive,
There is a lot less internal friction in the engine, gearbox and final drive too, Ron. That must account for some of the change.
About 2/3rds down the article there are dyno charts for the SAME engine running hot manifold/low boost cold manifold/high boost, high boost gives a much finer atomisation and 42ft/lb's.
that is true, but cold hi boost air is much more dense, so friction of the injected fuel breaks up into smaller spheres.
which is good , but we are not having any boosted air!
a little known fact is fuel when injected at a certain pressure, for each full bar pressure increase the size of droplets reduces around 50% .
imagine the size droplet for a DI engine with 2000+ psi FP!!
pic of my injector test bench , Amazing what you can learn ,when you have time and patience, to PLAY with things.
Intake manifolds with injector bump almost removed. I have test fitted the manifolds and checked the transition into the port which is far smoother with a very small step up into the port.
First pic is stock injector second is Denso injector.
The reasons I went with the Denso injectors are
1 The V12 injectors needed rebuilding and the Denso were cheaper than having mine rebuilt and all 12 are flow matched.
2 I am going to run a Megasquirt so I can configure the fuel map, they are also high resistance so no need for resistors or PWM for current limiting.
These injectors will not work on a stock V12 with Lucas ECU.
Shame. There is a company here which can make modern I jectors fit into classic injector 'shells'. Mainly for the classic car scene where original parts are hard to get now... I think a modern spray pattern might actually help the V12 a little...
Shame. There is a company here which can make modern I jectors fit into classic injector 'shells'. Mainly for the classic car scene where original parts are hard to get now... I think a modern spray pattern might actually help the V12 a little...
What do you think?
Not to be a wet blanket, Daim, but I think it would make naff-all difference to an otherwise stock engine. In Warren's case, of course, where he needed new ones anyway and the entire engine and management is being redesigned and upgraded, it has got to be a good plan.
I guess you're right, Greg. Especially since the V12 is an olddesign. What good would some modern jets do in combination with some primitive injection system on it's own...
Greg is right just upgrading injectors will do nothing. There are many other things that need addressing first. If you want to play then port the heads and match the intake to the ports.
The stock ports have a very crude 45Deg cut on the entry, smooth this down into the port without opening the port at the valve guide more than a 1mm and cut most of the guide boss away and profile it. Then match the exit if the intake keeping the exit a smidge smaller than the port entry. All this can be done with the heads on.
Valves lapped in and cam carriers torqued down, now for hard part (relatively) setting valve clearances, Norm was a gem and gave me his little draw of a 1000 shims. But as the intake valves are slightly longer I will see if his shims will set clearance without having to shorten the stem.
Right, when I ever should buy some more heards, I'll be Sendung them to 'Stralia (mate) and Warren can do some work for me
I just fell off my chair laughing, doing everything by hand I have over 100hrs in these heads, no wonder a good head job is expensive.
As soon as I get the valve clearance done I can take these to Norman and get cracking on completing the engine.
I still have a fair bit to do when I get the engine back. I will be using the 6.0L ribbed belt and either Ford or Toyota AC compressor, I was lucky I got the 6.0L AC compressor mount on the engine and idler pulleys.
I need to make a new engine wiring harness because the injector loom and plugs are different and I will be using 2 of the injector wires going to the resistor box to run the ignition.
