Boost levels?
- Thread starter appletonn
- Start date
rcsalmons
New member
ORIGINAL: 944 man
Brilliant, thank you. I dont mean to worry anyone but 370cc injectors are only good for just under 300bhp! Anyone running them in an application equalling or exceeding that needs a KnockLink or a wideband lambda which they keep one eye on all the time, think:
[]
Simon
Well that adds up on my car. 294bhp at 18 psi with standard injectors. Wideband shows fueling OK.
Dont know duty cycle of injectors though - are the chip mappers/programmers likely to adhere to the 80% limit?
Rich
sawood12
New member
In don't think the chippers will be. They will gladly run your injectors upto 100% duty. At 1.2 bar boost on stock injectors you are bound to be pretty much up there. Really if you are increasing boost you really should consider larger injectors. I wish I had and will do as soon as I get my backside in gear.
sawood12
New member
If your injectors are too large then you're duty cycle can be too low and the injectors wont atomise the fuel properly as the flow through the injector never really gets established properly. However not sure if modern injectors have improved in this area because as Ed says the Vitesse kit runs 72 lb and even 83 lb injectors just fine on 2.5ltr 944 turbo's with perfect idling and no lumps in the power delivery - or so i've read from others' experience at least!
sawood12
New member
I'm sure you're right Paul, I have no idea why John at Vitesse chooses to use 72lb injectors with his kit. However wont the type of injector sequencing also affect your size of injector? The 944 turbo ECU fires all the injectors at every rev, so they are firing on all cylinders where three of the four cylinders will have their inlet valves are closed (I think i'm right with this) at any point in time. However that fuel is not wasted and still adds to the fuel injected on the subsequent induction stroke. However the Vitesse kit provides you with batched injector firing. I'm not quite sure how this works, but I think it pairs up the injectors and only fires two at a time (maybe only one injector is firing against a closed inlet valve?) so maybe it stands to reason that if you don't have that extra fuel fired on the backs of the closed inlet valve then you need to pass more fuel during your induction stroke therefore will need larger injectors. If you were to go fully sequential then maybe you'd need even larger injectors. I'm just guessing, but John at Vitesse know's his stuff and i'm sure has good technical reasos for injector sizing, so i'm not sure where the line is before you get into the realms of overkill, but I for one don't mind a bit of over-engineering.
Fat Albert
New member
I guessed that was the case by the way the needle behaves, it jumps straight to 1 Bar as you touch the pedal, it then progresses from there.
At the mileage of mine I am happy to leave it the way it is in the interests of mechanical sympathy.
ORIGINAL: Frenchy
Looks like the Tial wastegate and Greddy EBC is the way to go cheers Paul/ UK Porker, what chips are fitted to that car what is the tuning spec ? is it running standard injectors ?
319 bhp and 1 bar @ 6k would do for me ..............................for now [
Frenchy
Its got a 3 bar FPR and 55lb injectors - I am not sure what chip its got in it - it will be whatever Jon Mitchell would have supplied in 2005. ( I think they may be GURU chips - perhaps someone who knows the car can confirm?)
Richard
They were Guru'd at the time of the rr session, then they were replaced with better Jon Mitchell chips from his German source.The dyno gurus had some fuelling issues and caused some cutting out at certain revs in 5th gear.
The rear tyres were not the gripiest last time I drove it, what brand are they now?
Tony
The rear tyres were not the gripiest last time I drove it, what brand are they now?
Tony
sawood12
New member
ORIGINAL: pauly
Think I need to do some homework [
The only instances of where two injectors per cylinder that i've heard about is for staged injectors where smaller injectors are used at low RPM's and low boost levels and at higher RPM's and higher boost levels the larger injectors kick in which gets around the disadvantages of running huge injectors when you start running higher and higher HP's.
ORIGINAL: sawood12
ORIGINAL: pauly
Think I need to do some homework [
The only instances of where two injectors per cylinder that i've heard about is for staged injectors where smaller injectors are used at low RPM's and low boost levels and at higher RPM's and higher boost levels the larger injectors kick in which gets around the disadvantages of running huge injectors when you start running higher and higher HP's.
RS 500 ?. A few bikes use 2 injectors per cylinder and a quick google threw up the Ford GT as well.
Thanks for the info Paul/Tony a phone call looks as though it is in order,the Ford Cosworth RS 500 Came with a second set of injectors as standard though not plumbed in, this was for homologation purposes aswell as producing the 500+ vehicles,seem to remember ths rear suspension arms were adjustable also.
appletonn
New member
I've just been in touch with Lindsey Racing to see if the chips they originally supplied for my car could be set to work with 55lb injectors - the reply is that I would have to buy a new DME chip that would be programmed especially for the higher flow injectors @ $299 for the chip!
They would do the Siemens 'flow matched' injectors for $350 per set or $290 for a set of Siemens non-flow matched ones.
So around £232 plus carriage and duties.
Hmm, might be better spending that $299 towards a session with Wayne Schofield and get a dedicated chip setup?
They would do the Siemens 'flow matched' injectors for $350 per set or $290 for a set of Siemens non-flow matched ones.
So around £232 plus carriage and duties.
Hmm, might be better spending that $299 towards a session with Wayne Schofield and get a dedicated chip setup?
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
