Well i think its time to start planning my fuel system upgrade as im keen to finally finalise the performance modifications to my car (yeah right).
What im after? well basically enough fuel to support a minimum of 300hp @ the flywheel.
So first things first, what is the current fuel system capable of supporting? As far as the Injectors are concerned they are capable of 360cc @ 15 ohm's which equates to a support figure of around about 288hp ([360/5] * 4) @ 100% duty cycle. Now that sounds pretty good to me so with a Fuel Pressure regulator we should be able to see an increase of 20% which bumps up that figure to about 346hp @ 100% duty cycle.
Of course no-one wants to run 100% duty cycle so if we bring that down to a more reliable 85% your looking at around 295hp with the FPR and without approx 245hp with the stock injectors.
So it looks like i may be able to get away with the stock injectors after all, there is also the possiblitiy of high-flowing the stockers which should see a substantial gain as well.
ok so what about after market options? heres a few that i have came across which according to some will fit in our cars without any modifications to the fuel rail.
440cc Toyota Supra, 7MGTE (88-91 or something)
460cc 13b series 4/5 RX7
550cc 13b Turbo series 4/5 RX7
ok just doing some quick calculations we can get the hp support figures...
Ok looks like for my application the 440cc or 460cc will be ideal as it will get me to the 300hp mark without a FPR which leaves me with a little more room to extract a few more hp further down the track. One thing worth noting though is that it seems the Supra 440cc injectors are low impedance?, according to the next century performance book by julian edgar and the article here from autospeed. So it seems as though they are out of the question without a resistor pack, so it looks like 460cc's are probably my best option?
However it also seems that the stock injectors aren't really that small after all, so for those of you who are just looking for up to 250 to 280hp it looks like you guys just need a fuel pump and RRFPR and ecu modifications.
Let me know what you guys think about this, any input would be great, im also thinking of getting a bosch 984 600hp fuel pump so i can run those high pressures with a FPR sometime down the track without compromising reliability.
I would like to hear from any1 who has upgrade injectors as well, what cc and how its effect low end response and normal driving conditions.
what does everyone think about this? if you guys are running lean with 10psi then i better invest in them now before the big re-tune. I would like to run around 17psi with the vf22 when everythings sorted...
i dont think the stockie injectors will like that much, i've heard of them sticking shut (1 person) when you get up high in the duty cycle, maybe those 550cc are worth the investment but a what cost to drivability and additional expense in terms of tuning
let me know your thoughts guys, im sort of in two minds here.... oh peterd maybe when we sort this out we can throw it in the faq, might help some?
I'm 90% sure I will be getting the RX7 injectors when I get a bigger turbo, especially since the FE requires 'minor' mods to get them to fit aswell. Double bonus.
My current injectors are running close to 90% duty cycle and I'm at 17psi on the stock turbo. Which would probably suggest that they won't be up to scratch with 17psi on the VF22's. Cam22t might be able to tell you what the duty cycle is for his injectors (which are the slightly smaller ones).
hmmmm i can get 460cc / flow test for $35 / $55, seems like a decent price, there apparently are the exact same shape as the 550cc so the install shouldnt be a hassle, question is will they be big enough.. hmmmm...
I have seen 12A turbo injectors or 700cc/min used on a high revs F/I 3L RB twin cam and they were thinking they woudl be just enough eg at 60% duty cycle on 14psi = WRONG find at estimate 78%. Always go bigger but not too big. 550CC is basicly the biggest you go on say a 1.8L Twin cam, so on a 2.2L should be right on.
im not sure on what power its pulling out yet...waiting to gather enough money so i can tune the car and get it dyno...but ill let you know when i get it done
but for now the car is running abit to rich...so i carry extra spark plugs with me just incase it floods the ones in the engines...
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