4 vs 8 injectors

I remember having a long conversation with the lat Bill blydenstein who always maintained efficiency was the key to making more torque/power...and he was certain that remote injectors would give a noticable gain in efficiency.

Cost, complexity, physical packaging etc all accepted...remote injectors *should* improve the efficiency of a, lets be honest, pretty inefficient device.

His argument was better air/fuel mixing = better and more complete cylinder filling = more power and torque.

We will see...

 

I also remember looking at a graph of temp plots along the intake tract, The temp of charge dropped(cant remember how much)as it approached head due to the energy required to evaporate the fuel mist as it went. It was small, but not to be ignored too.

 

For the sake of preventing this useful thread from degenerating into (yet another) depressing argument on CGTI, I am going to ignore the fact that you have said this.

I am not in the habit of making things up, and neither is the gentleman concerned.

I dont know the exact basis for his statement, but are merely relaying the information. Perhaps I'll just keep schtumn in future.

 

You've misread/mis interpreted what I've written entirely.

Take it as you read it - we're having a discussion over 4 vs 8 injectors, factually based to a point and the rest is discussion. Just because 'someone said' (that someone having a notable CV) doesn't mean we understand. That is where the cliff hanger is positioned.

Can we make further inroads?

 

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The BTCC Accord was the car I had a good look round at Mardigras Motorsport back in 2000ish...and I remember the remote injectors sticking in my mind ever since.

 

Nice - adds some proper animation to the thread.

It's amazing how much is going on - they're just the second set I assume?

 

Folks,
I'm more than happy to hear all the thoughts...there is no right and wrong..just different ways of trying to get more out of the 16v engine. Surely that's more interesting than debating the rights and wrongs of it?


If anyone is interested in the 'ins and outs' of the trial set-up I've built up, let me know...I have plenty (far too many) photos of the bits coming together I can post...

Of course, it may all be custom made, powder coated, scrap.
But I'm hopeful...

 

Certainly the 2nd set on the Accord...you can see the loom for the inners visible.

The inner fuel rail is visible just below the first bracing bar in this pic:


Another pic - shows the fuel rail:


I'm not sure how the inners/outers were phased on the BTCC cars. All on the outers once 'on cam' I'd imagine.

 

Unsure if the inners are completely dispensed with, but thinking about getting the charge in, logically one would disrupt the other?

 

I know this is for a N/A engine but i also remember reading an article about 15 years ago about high power escort cosworths wearing their engines out,not at high boost but at idle due to running such high flowing injectors being not that efficent at low flow (bore wash)
Think it was David Vizard but i may be wrong.
Again this is just food for thought,i do have a mate who has a BTCC team so i'll ask them next time i see them.

 

thats a familar airbox

on the btcc Audi the injectors were phased in various ways, they were controlled by super clever Bosch Motorsport ECU's

the inners are always on with the outers switching from 0 to 100% whenever required, I've been told they never fully switched to outers???

On my own build i'm switching to outers as soon as the engines happy to run them, were bound to get a hesitation or hick-up in between switching injectors.

here's my initial progress

running DTA, the injectors were set to switch @2000rpm to check function

http://www.vimeo.com/6741751

 

That seems to be an accepted issue with huge injectors on big power cars...poor atomisation can give bore wash, or poor emissions control - important on a road legal car that runs a Cat and needs an MOT.

 

I'm jealous...

I've heard various ways too...I plan on leaving the inners on to start with, and just adding the extra with the outers from 4000ish up.

I already have an obvious point where you can feel the power start to build - 4000 RPM, so I'll aim for that as a switchover point.

Sweet!

 

Most of this goes over my head but it's what I love about this forum, the 'man in the street' with his sleeves up trying new things, and pulling other people in with their knowledge and ideas can only help.

 

Glen finally break cover with his "what did i do with myself for 2 weeks at home" garage tinkering..

Had a quick speed read of the thread, looks like this will be interesting to see what results you get, what ECU are you planning to use?

 

Amazing work there ESS

I have been working on something similar on my valver:





Front injectors just some small Ford 150 CC jobbies

then at the moment some 440CC's directly down the velocity stacks.

In my experience with outboard injectors, as you bring them closer to the entry of the stack, on a dyno, power only dropped off as soon as the injector connector came in line with the entry to the velocity stack. Up until this point there seemed to be no effect to power so I can only assume minimal disruption to the airflow. I guess when you get yours running (space permitting) you can see if yours are slightly too far inboard.

 

Ahh...but less impressive when you consider I have 3 weeks off every 5 weeks...not 2!
But, yeah...this in one project.

There are others, of course!
At least 5..all ongoing.

Emerald K3, 3 selectable maps.

I've known Dave Walker & Karl for years (since the CCC day at Castle combe where I met Chris Eyre)...and Karl has been invaluable.

 

Cheers!
Yours isn't too shabby either!

Nice!
Your maximum individual cylinder flowrates are similar to mine @ around 600cc max.

< RS4 coilpack discussion split to here >

My injector connectors are just inside...not ideal, but space limitations don't currently allow much else.

Are the injectors you have experience of the long or short type?
Just wondering how the spray head locations compare.

I know mine are probably too far in.
I'd prefer to space them out another 25-50mm, which can be achieved with longer stand-offs:

The stand-offs are 3/8" SS Instrument Tubing (perk of the job...) which just happens to take a 6mm bolt just fine, so I can add any additional length I need - once I create the space for a bigger filter element.

 

Thanks mate,

RS4 coilpack discussion split to here

Audi V8 cam cover discussion split to here

At the moment that I have way more injector capacity than I need. This engine used to be turbo so I simply retained the 440s that I was using. In reality im sure i could get away with simply another set of the ford 150cc's for the outboard as I dont think this baby will ever make any more than 200!

I only ever tested longer std bosch type injectors in the outboard so can't comment on what difference their spray will be.


Really like your rail mods BTW. ITG can make you any size filter you want once you get your position finalised.