[mrpike]

Hi all can anyone tell me what size in cc's are the standard fuel injectors on a 1.7 puma. I want to find some slightly larger ones may be from a focus 1.8 or 2.0 ltr to upgrade the power a bit with a larger throttle body as the cars really goes then flats out due to to much air and not enough fuel. I'm using a k&n cone filter with cold air feed and a full 4,2,1 miltex system with sports cat.

Any advice greatly received

Mrpike

[happy-kat]

The Puma 1.7 is already bored out so not sure what capacity there is to bore it any more.
Hopefully someone who knows about this stuff can answer your question.

[mrpike]

Hi happy Kat I didn't mean cc as in cubic capacity, but the fuel injector is measured in cc I think its something to do with the volume of fuel it delivers as a single shot.

Mrpike.

[Turby]

Don't know the injector size I'm afraid, but I do know that simply fitting larger ones wont give you any more power. In fact it will run rich, and the lambda sensor will lean off the injection timing such that it tries to run correctly. You will also have less MPG and will most likely emissions check at MOT time, along with polluting the lambda sensor.

To get more power you need to increase what the engine is trying to suck in. You can do this by having head work, changing cams or remapping the ECU (for slight gains). Remember the engine sucks air in through the filter and throttle body. Larger filter / throttle body will actually slow the air speed down and make the engine less efficient.

The reason the car goes flat is due to the cam shaft profile - they have been designed as a compromise between performance / economy / drive ability.

[mrpike]

Cheers turby that makes sense so back to the drawing board to find another way to gain a few more horses on the cheap.

[Brokenbrian]

Injector flow rates are usually peak flow rate so you could fit ones with a higher flow rate should you plan on getting more air into the engine at a later date should you go the turbo/supercharging route. You would not really need to up the peak flow rate on a std engine with mild cams or a ported head.

As Turby said getting more air in and out of the engine is the way to make power as more air means more fuel which means a bigger bang. So tubular manifold, uprated cams, ported haed and performance filter will all get good gains but sadly not cheap. Fitting a larger throttle body will give more air and power but only really at the top end of the revs on wide open throttle when the air is moving fast anyway, on part throttle the air speed should still be the same it would only slow down if you went wide open throttle at low revs. It may lose a bit of midrange torque but only if you fitted too big a TB. If you can find one a throttle body from a MK1 silver top 2.0 mondeo fits, the inlet manifold flange where it bolts on needs opened up to match the diameter of the TB though or you dont get any gains due to the lip restricting the airflow.