4 vs 8 injectors

I have too much too...I may source a set of 150 1.8T EV6 type for iners, after chatting to Eddie yesterday.
Smaller capacity, smaller droplets, better emissions for sub 4000 RPM running with a Cat / lamda.

I'll see what turns up...

Ideally, I'm fuelling for 240-260 BHP...with a very faint hope of ever getting close to the former! In many years time!

Plug connector level with the bellmouths on yours, is possible the same as mine with the connectors 20mm inside, in terms of spray head location?
Looks like we are both around the right starting point anyway.

Cheers!

I was trying to keep it as OEM looking as you can, and OEM means cheap too, and easy to source FPRs etc!
The looms are all cut 'n' shut OEM, it uses the OEM wire conduit etc...to keep it neat/factory.

I'll get a pic up soon.

They will?
I didn't know that.

I'm close to the inside of the dome filter on the outer rail (FPR) so going to a square filter will cure that, and adding extra height will allow the outer rail to come further out of the bellmouths...or the use of longer trumpets - currently 60mm + 15mm (6mm alloy plate, GRP backplate, 6mm alloy plate) + 20mm Jenvey spacers - so 95mm all in.

Glen

 

Some great stuff being discussed here.

Picked up an interesting item last night when reading about injectors - and that was about choosing injectors with different spray patterns for different applications.

Most oem injectors are sited close to the valve and have a very wide spray pattern. If these are used further away from the head, such as in an 8-injector setup, they spray onto the walls of the rampipe and fuel dropout results. For this app, injectors with a much tighter spray pattern are needed to make the most of the siting.

 

i will mention again, one more time, modern injector and fuel pressure will have a big effect on atomisation and thus air fuel mix - aka effeciency

good project tho.
regards
bill

 

rs500 motors ran 8 injectors.
but back in the day of them, the injectors were'nt as good imhop as modern high impedance ones, and low end opening/responce times made it tricky to control idle, low speed/throttle setups.

i used to run cossy blue injectors on my jetta way back when.., (1997) and 0.1ms change would swing fueling from off scale rich to off scale lean.. crude spurty injectors relative to whats available now

 

Agreed RobT.

8 valve digi 2 have pintle type EV1 units that atomise on inpact at the back of a hot intake valve.
The spray is narrow and the fuel drop lets are larger than later disc type units. I would expect this level of engine to not stand a chance with the emission stds from 92.
Feedgas would have a lot of unburned fuel (HC and CO). Either that or put a very expensive cat to aborb the crap.

EV6 units are disc type units that spray atomised in angles or 15-70 degrees.
EV12 being long reach units with the same character as the above.

I should have a list of injector part number vs spary angle somewhere.

For this type of set up you need to work out the estimated fuel flow CC for the projected power.
So for 250bhp you are looking at approx 450cc per cyl. From here you can split the injector sizes into a ratio that will give the best fuel droplet atomising depending on engine operating condition.

The point about having inboard and outboard injectors is to optimise on fuel droplet size and its interaction is the the incoming air to keep the fuel mixture homogenised to promote a faster burn and potentially allow the engine to achieve more torque/power for a fixed amount fuel.
This is even more important in this project where a catalyst must be retained to fulfil legality of road worthiness and emissions checks during MOT for both fast idle and idle.
In a 16v with ITBs and a 250bhp target the injectors can be EV6 210cc from primary units and 317cc secondary. This will be more than enough.
The small 210cc EV6 disc arrangement should provide a wide spray pattern and are actually a bit smaller than the 225cc side feed things that come STD on an ABF rail. So I would expect finer droplets to be emitted from the injector vs an ABF unit. This should quite able to supply fuel at full chat to more than 4000rpm on its own.
317cc EV6 units placed outboard again a disc type unit, will have slighty larger droplets , than the 210 units, which will be broken down further by the throttle plate and the heat from the inlet tract. Having a longer time to interact with the aircharge would improve mixture formation by the time the mixture column got to the valve. The optimum placement of the outbord will result in best inpact with the throttle plate as well as best time to mix with the air. This placement and tranisition conditions to turn on will have to be played with on dyno. Hopefully the baseline infomation that I pointed Glen to will get it close, then he can tailour to his liking.

Think the use of OE 1.8T rails was a very good idea. Maximum performance from simplicity

In this application you want to stay away from pintle type injectors or injectors sized too large else you would defeat the whole purpose and should have just stuck to a conventional 4 big injector setup.

 

Early Ibiza Bill, GTI 1.8 8v I think they were from...multi-point injection, long before the 1.8T.

I could do with a set of smaller 1.8T injectors from a 150 car, rather than 180 as I currently have.

 

Bill, you got any suggstions on injector type / fuel pressue?

In this case I'm limited to 3/3.5/4 bar FPRs and EV6 type injectors...and pointers to areas woth looking at?

 

Eddie, some good info in your post. Thanks.

Do you know if 1.8T 150 BHP engines use EV6 210cc injectors?

I could stick to 2 sets of 317s...but I suppose some 210s would be better.
Just not sure where to go looking for them...

 

if i were going to play with this i would be thinking 5bar fpr.. but thats on the high end of the injectors.. they flow test them to 5bar so ok but at their top end

 

Fuel pump rating implications also?

 

Do Bosch make a suitable 5 bar FPR, Bill?

Not sure the fuel pump will be up for it though..

 

Yeah...unlikely to cope, so will need replacing.
More cost.

I'd need to be sure there was a gain to be had before going 5 bar FPR - 2 x 5 bar FPRs and a new fuel pump = mucho cost.

 

Then you can argue that all injector sizes can even be smaller pending the std ABF/VR6 fuel pump being able to flow the fuel at that pressure.

 

if its not uo that pressure and delivery yes

if your going to build something build it right
not suggesting essthree is'nt, but there's milage to be had from improved atomisation which higher rail pressure will provide

there is no coincidence i run 3 fuel pumps in my ibiza - plenty of options to play with on fueling and pressure

 

i dont know.
i run aeromotive adustable fpr on my 8 injectors and twin 044 pumps delivering the lines. it can be whatever I wish it to be

 

At this one, (think ess three's does what im explaining but hard to tell in the photos)



One thing that bothers me so far is the way the injectors have been mounted, they are not clamped in they are atm held by the clip to the fuel rail, this clip does not give much clamping force, when pulling injectors and rails out in the past these clips slip off.

The 3 or 4 or 5 bar of fuel pressure putting force on these clips might not be enough to force them to fail, but add to that the movement of a high reving engine and a bumpy track and the injectors night just fly of the end and fuel will poor into the bay.

So i would fit something like this to clamp the injectors in place.

 

I used the Jenvey kit:



Jenvey supply the stand-offs the correct length for the injectors, tabs to weld to the fuel rail and the injector bottom stops.

You can see the 'tabs' TIG welded to the fuel rail here:



I had the alloy stand-off and bottom stop welded, so I could file and trim it away as I am tight on space. You can see they are tapered on the right hand edge as you look, to give clearance within the trumpets:



But, when the Jenvey set-up is used, they are rigidly mounted and clamped.

 

Good tip!!

My rail does not use the standard clips as it is just an extruded aluminum tube so have had to fabricate something to keep the injectors in. I used to run these at 5 bar in this rail without leaks or pop offs, and even for a time without the rail bolted down!! I do take your point tho which has got me thinking..........To be the safe side Id better get fabricating so we dont end up with:

 

Good thread guys. On conversation with Steve Grenald, he has some back to back dyno data for some ford duratec engines. I think he was looking at somewhere near a 10 bhp gain at the top end on a 300 ish bhp motor (3.3% ish). Yes you do get gains, and yes you do pay for it. If it were my engine I would develop the "engine" first and the "bolt-ons" after if you can't do everything at the same time, otherwise you will be looking at a strip-down and rebuild = more money in the long run. Build it once, build it right.

Regarding your comments and fuel pressure Bill, makes good sense, put your thumb over a hose at low pressure = dribble. Try the same at high pressure = mist. Common sense.