i want to up grade my fuel system so i can pump out more boost. around 23-25 lbs of boost out of a t3 t4. im getting a 255lph walbro fuel pump, bbk fuel regulator but im curious on what size fuel injectors i should get. thank you for your help
65#
You will not be able to just throw some 65# injectors in it and go. You'll need some way to tune the ECU for the new injector size.
42lb er's and a tune.
what tuner can i use? i heard about some piggy back tunner from turbocoupetgill. does anyone know where i can pick one up?
If you want to be able to tune "real time, on the fly", I've heard good things about the Moates Quarterhorse. This way you won't have to pull the chip and reflash it everytime you want/need to make a change. You'll still need software to tune with. Moates should be able to help you out with the whole package. The prices there seem reasonalble, and enough people use them, so support is good.
You can max out 42lbs injectors with least a stock T3. Need at least 65lbs injectors.
Get over to TF, check out the proven combos, and copy the one that best fits your goals and budget.
:iagree:Good advice. Would've never thought of that.
O ok 42lber's are good for 500+hp.
I run them in my 302 with 500+ with no problems and an 80% duty cycle.
You'll be fine with 42s.
65s are good for over 800hp,you don't need those.
Ummm, except he's got half the number of fuel injectors? Divide all your numbers by 2 and keep in mind that high boost needs more injector to run right at all (with tune).
Agreed.
So half of a 5.0L is 2.5L's right.
Therefore 42s should support in the neighbourhood of around 250-275hp on a turbo'd 4cyl.
That should be where he will be around upgrading the turbo and boost numbers.
Even if it was slightly higher that could easily be adjusted with an adjustable fuel pressure regulator,not to mention the factory regulator is boost sensitive and up's the pressure equal to boost,up'ing the injectors output quite a bit under boost.
55's would be the next bet but 65s are still just to big for the application.
If you can get away with the stock 36's on 18lbs of boost from the stock T3 42s should be sufficent.
IIRC, 42's with boost at those levels are also at pretty high duty cycles. You'd want at least 20% on top of whatever you need. I agree that 65 is a bit much but 42's may be too small.
I'm not sure what was up with the early SVO's but Ford gave these things 36lb injectors for 190hp. It doesn't take long to see that it's a good idea to use more than 42's.
A 302 and a 2.3L are total different beasts. Cut the amount of injectors in half, while keeping the same amount of power, and what happens? You double your duty cycle. So then you think, chop your power in half, 250+, 4 of those same injectors are then working at an 80% duty cycle. You can get away with adding pressure, but as you add pressure, your spray pattern suffers.
Not to mention, 42# injectors for your V8 are high impedance.
On a turbo 2.3L, 65# injectors are good for about 400-450.
Did not know about the impedance differance but there should be something smaller out there for the low impedance, from what i understand the low systems can use both.
He won't be pushing that kind of power by just upping the boost and not doing anything else so i figure he'll be just shy of 300hp.
The stock regulator ups the pressure under boost anyways 1psi-1lb of boost so running 25 pounds of boost should raise the pressure the same over base allowing for more fuel flow.
I agree on all that. Doing simple/very rough math and excluding MANY variables, he would be increasing fuel consumption 30% when going from 15psi to 25. 14.7 atmosphere, 15 boost, 10 on top of that to get to 25psi. 40/30*36 (rough pressure after 25psi, rough pressure currently, divided by stock fuel injectors) = 48lb fuel injectors.
I'm sure 55's would work fine but I wouldn't do 42's. 2.3's are not easy/cheap to make street friendly with 400hp+ so I don't think he really needs 65's.
Yes, the low impedance systems can use both high and low impedance injectors, but the high impedance injectors don't respond as quickly. They don't open and close as quickly.
Granted he won't be pushing the power by upping the boost, and basic bolt ons, by if you were to spend 220 on 42# injectors, why not spend the 220 dollars on the 65# injectors, and never worry about it again?
Yes, the factory regulator increases boost 1psi per 1psi of boost, but that isn't always enough at higher boost levels. Increasing the base pressure can get you a little bit more out of your injector, but like I said before, the spray pattern suffers.
Let's not forget about BSFC. It's generally higher on a forced induction application meaning you'll need more gasoline/diesel/whatever.
To add: as pressure increases the flow through the injector; it DECREASES pump output.
I would never want to see more than 60 PSI @ the rail.
yup yup. three words: high pressure pump.
not just 255lph, but 255
HP lph.
only takes 22psi boost at base fuel pressure(39psi) to be over 60psi FP under full boost. if youre cheating injectors by raising base pressures, you will be over 60psi under boost in no time.
Walbro gss340 i believe is what your after.
so people are saying 42# and 65# and SEEK said 55# which sounds the best because its inbetween what everyone else is saying. i like the idea of the 65's because what it sounds like is that they wouldnt have to work as hard but if its not working very hard wont that effect the spray pattern?
DOMINATOR: whats the difference between the 255HP lph and a gss340?
thank you for your help and advise, you guys are very knowledgeable.
The GSS will put out more gas in relation to the 255 HP when both are subjected to high rail pressures.
They sell two pumps,gss307 High volume,gss340 high volume high pressure.
The 340 will maintain pressure at higher rail pressures as where the 307 will fall off after 55psi if i remember correctly.