What size injectors?

boxy · Post by **boxy** » Sun Nov 19, 2006 9:44 pm

[quote="dynamix"][quote="LR6GSR"]This was a thread on the MLR the info is a good source Andy RSX

As a rule, if you base the sizing on bsfc of 0.55 and the injectors running std pressure at 100% duty then you get the following figures

560cc = 0.00224 m

LR6GSR · Post by **LR6GSR** » Sun Nov 19, 2006 9:52 pm

Cant say what the fit on a Scoob is like on E6 the walborow is an in tank fitment!
This requires dropping the tank to do the swap i did mine at home so can be done lol
The Fuel Pressure reg will replace the factory one on the fuel rail. The thing to note is you need one with a gauge or the ability to plug one in to set the base pressure.

Duncan i think you are right to not go OTT on the injector size and as you say the current duty cycle is at the top end.
Best swapped before any issues arise.

Liam

PS i see a how to thread comming soon

LR6GSR · Post by **LR6GSR** » Sun Nov 19, 2006 9:58 pm

Boxy have you done a Scooby one?
You can lift the top off on an Evo one but it is hard piped so you can not lift the tank pump access lid more than 2-3cm
So you have to drop the tank of the pump if that makes sence.
Hence it is a bit more involved LOL

Liam

boxy · Post by **boxy** » Sun Nov 19, 2006 10:04 pm

No never done it on a scooby one, just the skyline, but can`t imagine there is much difference and if you buy a walbro one they are usually designed for the specific model, not universal.

duncan · Post by **duncan** » Sun Nov 19, 2006 10:09 pm

Liam - cheers. I see a "why to" before the "how to"

From logging I have seen a huge hike in power and torque from the decat/ram air mod and mapping. I am getting top end injector cycles and right towards the max of the MAF current scaling. This top out at 300 grams/sec (see sep thread on AIR = POWER). AFR is spot on so without the benefit of a RR printout I have to say that power estimates are about 370-380 bhp

Once I get the pump sorted I will get it on clive's RR for a full comparison to previous figures.

I am sure the pump will be a slot in change but I am confused as to whether the pump on its own will increase pressure or whether I will need a FPR to sort it to get the increase in flow - any ideas guys?

LR6GSR · Post by **LR6GSR** » Sun Nov 19, 2006 10:15 pm

So Duncan needs a Scoob owner to confirm if it is a lift out the top job or a tank down job?
The pump comes with an aplication kit perhaps diferent for each model? mine had filter clips and the electric plug was the same as the OE one :-D
So good fit no wire chopping
Lucky the Skyline is a doddle nice when it is like that.

Liam

Edited to add the fuel pump should not increase the base pressure on a std fuel set up it only gaurentees a lager volume delivery, the Std regulator will retun the exess back to tank.
This could ofcourse prevent lean top end when Std pumps hit the limit and fail to deliver.
If you require base pressure adjustment i am sure you will need a Regulator.

TonyB · Post by **TonyB** » Sun Nov 19, 2006 10:15 pm

My GT4 fuel pump was a pita, as I had to drop the tank - but it has been undisturbed for 17years

:lol:

<Teach Sucking eggs?> You will also need to alter your map if you fit new injectors and/or increase base pressure. If you fit a rising rate FPR then it is likely to 'rise' at a different rate to your stock one, so it will not be a case of take a set % out of the map! </Teach Sucking eggs?>

TonyB · Post by **TonyB** » Sun Nov 19, 2006 10:19 pm

dynamix wrote:
I am sure the pump will be a slot in change but I am confused as to whether the pump on its own will increase pressure or whether I will need a FPR to sort it to get the increase in flow - any ideas guys?

The pump will flow an amount of fuel, at a max pressure. The FPR will control a set pressure across the fuel rail.

duncan · Post by **duncan** » Sun Nov 19, 2006 10:25 pm

rising rate FPR ???? - dont confuse me

not sucking eggs at all - open to all advice.... please - my mind is like a sponge at the moment. Seriously considering enrolling for the EFI101 courses to get more hands on knowledge and theory.

TonyB · Post by **TonyB** » Sun Nov 19, 2006 10:36 pm

Not very difficult. A rising rate FPR will increase the pressure with boost, you will find they have a vac line going to them. You set the base fuel pressure by removing, and blocking, the vac pipe. So, at idle you may have 1.5bar pressure and at full chat it increases to say 3bar.

The important thing is that it will have a big, and probably non-linear, effect on your actual fueling.

It is a shame there are no planned EFI101 courses planned in the UK. I would also quite like to attend, as that is the environment that I learn best. But saying that I am taking in more and more, and the course will not be justified at some point.