Injector Flow Rates
Discussion
My back-of-the-beermat scribbles seem to suggest around 300 bhp @ 100% duty cycle. I assume you'd want to run some way below 100% and also have a margin for enrichment. This sems to imply that the better 5L cars would be pushing the limits of the standard injectors. So no wonder the experts seem quite keen on bigger/better injectors.
GreenV8S said:
My back-of-the-beermat scribbles seem to suggest around 300 bhp @ 100% duty cycle. I assume you'd want to run some way below 100% and also have a margin for enrichment. This sems to imply that the better 5L cars would be pushing the limits of the standard injectors. So no wonder the experts seem quite keen on bigger/better injectors.
At 90% you're looking at 265 ish, however given the +/- 10% I'd like to think they are on the high side of the tolerence to get anywhere near the comfort zone of 80-85% max, pushing out a realistic 200cc/min or more.
Out of interest Peter what size are your injectors now, again doing the sums you must be in 300cc/min country to be safe
. Harry
GreenV8S said:worth mentioning that some experts also reccomend increasing the fuel pressure (to 45 psi i think) to run the std injectors up to about 320bhp as a viable alternative.seems to be working very well for me so far
So no wonder the experts seem quite keen on bigger/better injectors.
.catretriever said:No,not in all circumstances,but youd be crazy to leave it out permanently.Mines running the uprated fuel pressure to provide fuelling for the other mods ive had done.The ecu has never been re-mapped,but its at the limit of its capability in this sense.Its surprising how well it runs though,but all this was set up by pro's mind you.Ive never wanted this as a permanent solution,but it was a good option whilst i deliberated about which alternative ecu to choose,only once this has been done,can the full potential of the mods be exploited.
I assume all these upgrade options would also require ECU fettling?
mongoose said:
No,not in all circumstances,but youd be crazy to leave it out permanently.Mines running the uprated fuel pressure to provide fuelling for the other mods ive had done.The ecu has never been re-mapped,but its at the limit of its capability in this sense.Its surprising how well it runs though,but all this was set up by pro's mind you.Ive never wanted this as a permanent solution,but it was a good option whilst i deliberated about which alternative ecu to choose,only once this has been done,can the full potential of the mods be exploited.
what fuel pressure are you running now?, is the FPR the screw in type?
mongoose said:
I assume all these upgrade options would also require ECU fettling?
No,not in all circumstances,but youd be crazy to leave it out permanently.Mines running the uprated fuel pressure to provide fuelling for the other mods ive had done.The ecu has never been re-mapped,but its at the limit of its capability in this sense.Its surprising how well it runs though,but all this was set up by pro's mind you.Ive never wanted this as a permanent solution,but it was a good option whilst i deliberated about which alternative ecu to choose,only once this has been done,can the full potential of the mods be exploited.
The problem with doing this is that at low speed, when less than maximum fuel is required, your engine will run extremely rich. The ECU doesn't know the regulator has been squeezed, so thinks there is less fuel being squirted than there is.
The only way to do the job properly is to have the ECU remapped to compensate.
starmist said:
The only way to do the job properly is to have the ECU remapped to compensate.
That's how I see it too. After I've spent thousands on the engine getting extra power out of it, it seems a no brainer to me to get it checked and set up properly to ensure that I am getting the full potential from the mods.
Having said that, I've been running on the 14CUX for five months and STILL haven't got round to having it mapped properly or replacing it - but that's because I haven't finished straightening the car out yet
starmist said:
The problem with doing this is that at low speed, when less than maximum fuel is required, your engine will run extremely rich. The ECU doesn't know the regulator has been squeezed, so thinks there is less fuel being squirted than there is.
I see what your saying,but how it was put to me is that whilst the fuelling will not always be on target,there is some leeway in which you can still operate safely.I certainly have no problems caused from excessive enrichment,but other things were also adjusted as well as fuel pressure-airflow meter,tune resistor and timing are only the ones i know about.
starmist said:
The only way to do the job properly is to have the ECU remapped to compensate.
Totally agree,as i said,the way im running mine is only temporary.Its daft not to get the most out of your modifictions.
>> Edited by mongoose on Wednesday 11th May 13:28
GreenV8S said:
Out of interest Peter what size are your injectors now, again doing the sums you must be in 300cc/min country to be safe
Harry
They're just under 340 cc/min, so still some margin at the current boost levels.
Good for about 450 of any ones ponies then
. Harry
starmist said:
The problem with doing this is that at low speed, when less than maximum fuel is required, your engine will run extremely rich. The ECU doesn't know the regulator has been squeezed, so thinks there is less fuel being squirted than there is.
The only way to do the job properly is to have the ECU remapped to compensate.
Won't the lambda sensors sort this out at least to some extent?
Ian A.
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