ST215 3sgte injector info

[99gtt]

Just a question ,are the injectors actually 550 cc . reason for asking is not just me , but after putting in a fuel pump and fuel reg and turning the boost up to 17 or so psi you hit what many would think is boost cut. But with out the after market fuel pump and reg the car will pull 20 psi and no boost cut. I noticed twisted had the same problem. We now have an after market ecu installed and still factory injectors ,and can only tune to 14 psi as the injectors are running at 100% duty cycle, so therefore this earlier problem must be a fuel cut as the injectors are maxed out. Any thoughts would be appreciated.

[vvega]

so your running stock injectors at stock rail pressure ???

perhaps you have more flow now though the engine

just my thoughts


really needs all your enginw mods to give a more helpful answer

v

[99gtt]

3 inch exhaust pod filter boost tap at 20 psi , no problems. Same mods added a 500 hp fuel pump and rising rate regulator, fuel cut at 17 psi, this is all factory ecu and now tuned after market ecu the injectors are running 100 % duty cycle at 14 psi which makes me wonder if they are actually 550 cc injectors as compared to an evo or similar,you can tune to 18 psi with 510 cc injectors. unless the higher compression makes for a higher demand in fuel. Bigger injectors are needed any way but might be the answer to other peoples problems

[vvega]

did you connect the vacum boost line to the rising rate fpr and set it correctly ??

v

[99gtt]

Sure did tested out this on two cars and the same thing happens and had everything looked at by many brains . It is all hooked up correctly checked everything 3 times or more .The car runs perfectly now with the new ecu. Injectors just cant squirt any more

[vvega]

to me only 2 thinks will make what you have said happen
bad tuning
or you have massively decreased the restriction thought the engine meaning your flowing a lot more cfm

boost pressure measures restiction not flow so you cant take that as your datum for mesurement
hp is basically the mesurement you have to use

v

[flygt4]

i have a set of gen3 3sgte injectors ready to go into my car which i had flow tested when i got them..they came back at 500cc@44psi i think from memory. id be suprised if the caldina engine had different ones.

[CozmoNz]

its those damn 450hp ct26... keep sucking the fuel outta the fuel rail.

yeh.. thats it...

[matt dunn]

i have a set of gen3 3sgte injectors ready to go into my car which i had flow tested when i got them..they came back at 500cc@44psi i think from memory. id be suprised if the caldina engine had different ones.

Same story here.

I have a set of 6 supposedly 440cc injectors out of a 2JZGTE engine,
and I flowed them myself at work at 500cc at 3 bar which is about 45 psi.
It makes me wonder how much the 550's we put in it flowed?

As to your problem,
boost pressure is not always a good indication especially on cars with air flow meters. with the right mod's the same air can flow at less pressure.

Good example of this is a supercharged 4AGE.
Easiest way to up the boost is to crush the exhaust and watch the gauge rise.

Matt

[fivebob]

Factory rates them as 540cc, but you can see from http://users.actrix.co.nz/richardm/Page ... tors_j.xls that they actually flow 560cc @ a rail pressure of 3.05kg/cm2 (~43.5psi) and can be made to flow 610cc @ 3.55kg/cm2(~50.6psi).

At a standard rail pressure of 43psi there's no way that a properly tuned 3S-GTE (which has a known BSFC of around .52lb/hp/hr) should be running at 100% duty cycle, unless it making around 430HP at the crank. Not that you can run 100% duty cycle anyway, given the injector dead time of 0.89ms you can only run around 95% above 6000rpm, even then you'll run into problems with injector flutter if you do it for any length of time. Given that you can't even get that sort of performance out of a T-78, there's no way you'll get it out of a modified CT26. So there must be something wrong in the tune if the duty cycle is that high.

Assuming you've checked fuel pressure and tuned with a WBO2 sensor, then the possibilites are that you have a bad injector, bad injector wiring, or even incorrect placement of the WBO2 sensor. If you haven't been monitoring fuel pressure then it could also be due to incorrect fuel pressure setting,a clogged fuel filter, bad fuel pump, or bad fuel pump wiring.

It's also possible that because the ECU you're using cannot do sequential injection and run the 4 coils at the same time, that fuel economy has suffered, which it will do. However I doubt that it's to the extent that you run out of injector capacity.

If you haven't used a WBO2 sensor and tuned by "ear" then chances are that you've tuned too rich.

FYI @ 85% duty cycle the stock injectors should be good for around 310whp at stock rail pressures and up to 340whp @ 50psi.

[anthonym]

Did you flow test the fuel pump before you installed it? Depending on source they are often well below advertised spec.