Anyone else have 550cc injectors?

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jammin1911's picture
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Oakville, Ontario

Nov 8, 2008
Anyone else have 550cc injectors?

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nick's picture
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Nicholas Chu
Vancouver

Jan 24, 2008

I'm in boost at over 120km/hr and I'm almost never in vacuum when cruising. I've only got a mines ecu tuned for 1.1bar ( altho i only run 1.0), arc top mount, downpipe, test pipe, catback, filter, oem injectors and oem maf. I don't know what my injector duty cycle is, but i bet its maxed out as well as the maf. I find the car is quick to about 150km/hr from stand still then its more of a struggle as 1. its shaped like my fridge 2. drivetrain losses. Is it detonating? maybe its pulling timing?
base timing is 20 degrees. Which is the farthest marking to the right I believe.

no_boost's picture
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Jan 21, 2008

i got 550s and im at about 80 to 90 percent dutycycle at 1.2 to 1.5 bar.
adn im at around 1 psi at 120 km

ZED_not_zee's picture
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Really Noneyourbuis
Canada

May 11, 2008

excelent questionbigger injectors... do none of you have a wide band? or EGT?

I got a MAF from an SVT lightning and some bigger injectors to install soon I post pics and wiring how toos

Mine isn't bigger than yours.. I just like to drive

jammin1911's picture
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Oakville, Ontario

Nov 8, 2008

would be interested to see the MAFS wiring for sure.. what kind of power is the SVT lightning MAFS good for?

On our 240sx's with SR20DET we just use Z32 MAFS

Thanks a lot for the tips guys...

To answer the question above, I do have wideband.

Glad to know I'm not the only one cruising around in boost... I can cruise at just about any speed in my 240 without making boost even on a smaller turbo.. I assume drag coefficient and drivetrain loss/load come in to play here.

no_boost, if you're at 90% duty cycle at 1.2 bar I've definitely got something wrong with my setup.. I don't know whats going on.

AFR is fine, boost is 0.9bar.. injectors are getting up as high as 95%. What might cause this?!

nick's picture
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Nicholas Chu
Vancouver

Jan 24, 2008

whats your fuel pressure set at? most people use z32 mafs as well.

French_connection's picture
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Vancouver

Mar 30, 2008

keep in mind that a higher boost does not mean more power and might not do the same to the injectors. Boost pressure will be much higher on a more restrictive engine and will not make more power. The one thing to keep in mind which would apply to both is that fuel pressure is increased directly with boost pressure. So a restrictive engine will need more boost and more fuel pressure to do the same power then a less restrictive one.

just food for thoughts.

ZED_not_zee's picture
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Really Noneyourbuis
Canada

May 11, 2008

are you running a stock ic? a front mount may drop more pressure than the TMIC.. this might make the stock turbo work harder and factor into the above equation... oh is your BOV vented or RE-circed?

the SVT lightning maf is good for 500 hp... and has a larger diameter to flow more cfm... also around the same price as a Z32... that's what made me decide to go with the ford maf.. some creative wiring and a lil tune.. should work well.

I'll try a few set ups.. stock injectors with bigger maf... 720 CC inj with stock maf... and both bigger injectors and bigger maf. without a tune for each set up It will be hard to really compare but i guess we will see.

Mine isn't bigger than yours.. I just like to drive

French_connection's picture
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Vancouver

Mar 30, 2008

ZED_not_zee : I would have went for the mustang gt maf since its a bit narrower and better for idle tuning. the lightning maf is very wide and sometime give a pulsating idle that is harder to tune. Do you plan on upgrading the intake track to match the oversize of the maf? if not there is not much point on upgrading unless your maf is pegged out already. Also I dont see the point of running untuned mafs and injectors?

jammin1911's picture
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Oakville, Ontario

Nov 8, 2008

thanks for the tips guys..

the car has an hks fmic.

not sure about fuel pressure - I already suspenct that the regulator might be faulty.. something in the fuel system is making a funny squeeking noise when the car is off and fuel pump is on and I'm pretty sure its the FPR.

I've got a couple sr's sitting around that I can try an FPR from, I'm sure its the same as a RWD sr20det... just haven't got around to it yet... I guess low fuel pressure would explain why the injectors are working so hard to keep the AFR where it should be.

jammin1911's picture
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Oakville, Ontario

Nov 8, 2008

ok so i checked fuel pressure yesterday and it is approximately where its supposed to be (~45psi i think it was)

im still hitting 100% duty cycle at about 7000rpm on a pretty good tune.. not running rich at all.. 550cc evo 8 injectors...

what are the possibilities here?? Fuel pressure at high boost is too low? what might cause that? bad vacuum source perhaps? bad fpr?

could the fuel filter have something to do with this? i have no idea what it was last changed.....

this is frustrating :D

s3by's picture
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GATINEAU , near Ottawa

Mar 16, 2008

you most be running way too rich..

do you have a wideband to tune your car ?
on what do you base your self to say you're not running rich .

jammin1911's picture
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Oakville, Ontario

Nov 8, 2008

i have a wideband ;)