i am in the process of making my inlet manifold for a 2.0l zetec. i have got some R6 throttle bodies which i have split and respaced to suite the zetec ports. i have the option of using the original zetec fuel rail and injectors which would feed from the top and the injectors would be mounted in the manifold. or using the R6 throttle body injectors which fit in the bottom of the throttle body and would feed fuel in from the bottom. which would work best? any opinions welcome. what do most of you do when using the more common gsxr throttle bodies on a zetec

if it were me, I owuld use the injector in the TB.

so the manifold is simpy just bits of tube and TB are not adulterated.

I used the the GSXR600 injectors and holes.........After reading up a little on injector position, the only conclusion I could come up with was that injectors far away from the valve was good for top end, and close to the valve for low end......Thus, somewhere in the middle would appear to be a good compromise.....Also, there are theories about the shearing effect of the air just after the butterfly (which is a good thing, as it breaks the fuel down further)....Etc, etc...

However, be warned, the fuel rail can be a pain - you will need a blank and get it drilled specifically for the injectors....This cost me 60 quid in total!!!!.......

That said, it is neat....

PJ.

Use both! It depends on what ECU you have though.

Were using both with a Megasquirt...

Well were actually using the set in the manifold at prescent and there copeing just fine! Jeeeeeeeess is it quick!.

On the Pinto the set in the manifold spray directly onto the back of the valves and is a completely different spray pattern to those in the TB's (designed to atomise on the back of the vlaves as apposed to fogging in the air). As said spraying onto the valves is suppoed to be better for lower rev's and economy.. and further out for higher revs.

An idea of injector sizes..
The manifold injectors are 165 cc/min
Our R1 injectors are (aparently) 200 cc/min

I've been using the TB injectors on my XE but found I was getting lean spikes on acceleration which I could not tune out. On my rebuilt engine I've put injectors in the manifold although not running on them yet. May have a play with running both sets of injectors at some point in the future.

slightly off topic, but yes there can be good gains by using both injectors, just need a computer that can handle it all. On a set up I have seen the motec computer used the close injectors upto 5000rpm then injectors further away injectors from 5000rpm all the way to 9000rpm! (Engine was a toyota beams 3sge)

Use both fuel rails on my Zetec SE (R1 TBs and stock Ford Focus fuel rail). The only mod needed was to replace the R1 rails fuel reg with an L-shaped bit of tube. The stock Ford Focus fuel reg pressurises both rails (tested the R1 reg, but the Ford one is set to a higher pressure - runs at 4 bar).

All controlled by Emerald ECU and works fine - Ford injectors are used until high revs and then it brings in the R1 injectors. The beauty is that it saves you having to buy uprated injectors (and allows plenty of scope for future tuning).

If your using the staged injection on the MS be VERY careful which calculation you use when setting it up.

The MS help files suggest:
Primary Injector Flow/Total Inj Flow

So for us this was 165/365=0.452 and MS only accepts 1 and above!.

But looking through MegaTunix tonight I Found that suggested doing something more along the lines of
(Primary injector flow/total injector flow) *560

Which gave a massively different value of 235 or the like so I make no wonder it was going lean... it switches over perfectly now and goes like stink

doing the same thing with R1 ITB's on a 2.0l Zetec, just got the manifold done



after this shot was taken, I decided to flip them over to make it look a little cleaner.
still need to extend the fuel rail and linkage,