25turbo/gtr injectors boost issue.

[geng]

Just a few questions.

I just finnished installing my gtr injectors and resistor pack and rb25 turbo onto my 20. i understand it would be running rich obviously. but when i try to boost it pops and blows out some black smoke so my questions are.

1. would it running rich cause it pop and fart and basicly cause it not to boost properly*it still revs high just theres no power in it boosting*

2. what sparkplug gap should i be running still the .25? i was running stock?

3. i have the waste gate actuator on the turbo ran to the bottom right*orange* circled nipple on the intake and the other one is to my stock recirc


and finally i modded my 20 turbo elbow to fit and im wondering if also this is causing the probelm? but im not sure how to test if this would be the issue? so im hoping if you guys can eliminate some of these it will point me to where my error is. thanks in advance.

[love_boost]

running rich can be a problem and cuasing it to missfire.
depending on the boost your running the gap can be a problem, i would reduce it down to a .8mm
if your running rich and have colder plugs it can also cause a missfire like that.
also if your modded elbow leaks on boost that can explain all your problems, do you have any pictures of your elbow?

[geng]

i will take picture of it tomorrow and post. 2 of the 3 holes are now slots with spacers on the topit seems on there tight. but thanks for the plug comments

[Snow]

With a resistor pack and GTR injectors, it would probably be safe to say it would be very beneficial to get a tune done...

What psi are you running? Or you can't build any boost because of the misfire so you're not sure?

[nelsonmxmarc]

Maxxed afm?
Definitely requires a tune. 25 turbo is doable with sufficient room
to play in terms of afr, twice the size of oem injectors is a much different story.. Power fc or nistune should clear that up as well as help smooth and gain a few ponies.
Plugs at .75 ish are definitely a good idea with a larger setup. I've even heard of .60 being okay as well..

[Snow]

I'm running an RB25 turbo... but I'm still on stock injectors

So you could always do that if you're pushing off your tune. Then again if you took apart your bi-fold to do the injectors, I know it can be a bit of a PITA to go do it all over again lol.

And I can't imagine you've maxed out your AFM, since mine is still stock... Definitely something that should be upgraded however I will agree.

[nelsonmxmarc]

Considering the ECU doesn't understand why there's so much fuel, it will try to compensate with greater air flow, thus my reasoning for maxing the stock AFM. People tend to believe that the AFM deals solely with HP readings, when in reality its a mix of air and fuel that tunes both in harmony. If one is low or too high, the other will compensate and vice versa..

25 turbo can easily be run without a tune and with stock injectors. Its max power output at around 14.7 lbs is only going to be around 240 whp (Considering temp and altitude avg). That's based on zero tune, no fuel controller - nistune or any time of daughter board. AFR's will be a little lean but still driveable without sufficient knock. This will also be near 100% duty per injector and nearly 100% readings from the AFM, however this is doable and has been done on SAU a number of times, even with a stock gts fuel pump i believe too!

Anyways, another thing to take into account is temperature. Boost levels will fluctuate dramatically during the winter months as air is much denser @ colder temps, thus boost increases and spikes will occur much more frequently. Perhaps you're detonating or your knock sensor is kicking in and ECU is going into limp mode? I've had this happen before, only real answer to the prob is to set the car up the way you like and then bring it in for a tune. No more hassles!

[love_boost]

it also could be spikingand your hitting factory boost cut?
nelson: thats interesting but i dont understand how that would work? the MAF only measures the air coming in, and cant compensate for anything? i thought the only way it can be max'd out is higher hp since the engine takes in more air? i can be wrong though.

bottom line though you do need a tune. and like snow said, your not making enough on the 25 turbo to max the stock injectors.

[Snow]

Considering the ECU doesn't understand why there's so much fuel, it will try to compensate with greater air flow, thus my reasoning for maxing the stock AFM. People tend to believe that the AFM deals solely with HP readings, when in reality its a mix of air and fuel that tunes both in harmony. If one is low or too high, the other will compensate and vice versa..

25 turbo can easily be run without a tune and with stock injectors. Its max power output at around 14.7 lbs is only going to be around 240 whp (Considering temp and altitude avg). That's based on zero tune, no fuel controller - nistune or any time of daughter board. AFR's will be a little lean but still driveable without sufficient knock. This will also be near 100% duty per injector and nearly 100% readings from the AFM, however this is doable and has been done on SAU a number of times, even with a stock gts fuel pump i believe too!

Anyways, another thing to take into account is temperature. Boost levels will fluctuate dramatically during the winter months as air is much denser @ colder temps, thus boost increases and spikes will occur much more frequently. Perhaps you're detonating or your knock sensor is kicking in and ECU is going into limp mode? I've had this happen before, only real answer to the prob is to set the car up the way you like and then bring it in for a tune. No more hassles!

Ah I understand. I was comparing his car to mine and ignoring the fact that he's upgraded the injectors. I see your logic however, which reaffirms that a tune would be ideal in this situation...

it also could be spikingand your hitting factory boost cut?
nelson: thats interesting but i dont understand how that would work? the MAF only measures the air coming in, and cant compensate for anything? i thought the only way it can be max'd out is higher hp since the engine takes in more air? i can be wrong though.

bottom line though you do need a tune. and like snow said, your not making enough on the 25 turbo to max the stock injectors.

I'm sure instantly after install, running 1 bar, you likely would not be making enough. After a good tune with some 440's I'm sure you could break those numbers and make use of them for sure.

That's the plan anyways...

[klys]

OK let's get clear on some issues here:
RB20 injectors are 270cc/min
RB26 are 440cc/min

the ECU cannot know what injectors you are running.

fuel is injected based on a pulse witdh modulation meaning. it will send an electrical signal for x amount of time (in milliseconds)

your 270cc/min injector will inject x amount of fuel as a 440cc/min wil inject 1.6x for the exact same pulse width.

you must also know that the length of the pulse is based on a fuel map in the ecu AND wether it's using the O2 sensor in your downpipe(while in closed loop).

the fuel map is based on RPM and load(a value return by the MAF)

you ABSOLUTELY need an ecu retune to run different injectors.

and the theory that the AFM is maxed out doesn't hold, because load is based on the amount of air that passes through the MAF, if will be maxed out when your car will make alot of HP, and the way it's running now, it just can consume enough air to justify maxing out the MAF.

if you want a simple solution for your problem please PM me and we could work something out.

[klys]

Also, running the WG actuator from behind the TB is can be troublesome as the boost signal is not what's actually after the compressor wheel. ie. when the throttle is closed the pressure seen by the WG is negative where as it might not be just after the compressor wheel.

in other words, it's not as precise as on the turbo elbow or right after the compressor wheel

[Skym]

R32 RB20DET injectors are actually 259cc (same as R31 RB20DET). Bigger stock 135lph fuelpump on R32 GTS-T (135lph fuelpump works with 370cc injectors, as found on stock R33, R34 RB25DET engines) makes the 259cc injectors look like 270cc injectors.

I agree, stock ECU needs a retune to adjust settings (scaling) for bigger injectors. Also I would recommend fitting a Z32 AFM, especially when you upgrade injectors, fuelpump.

Think of it this way (simple way to understand what's happening), at 2000 rpm (in neutral), when injector is opened say 5%.

5% of 259cc injectors = 12.95cc
5% of 440cc injectors = 22cc

As you can see, GTR injectors inject more fuel while using same setting on ECU. You have to rescale injection tables on ECU, so ECU opens injector 2.9431% of 440cc to get 12.95cc or inject the same amount of fuel as factory injectors did at 2000rpm.

[geng]

got it tuned. fixed the issues besides the fact the resistor pack is fried. my maf is dead and we could put in an o2 wideband sensor becuase my o2 sensor was impossible to get out becuase wrenchs and sockets were hitting my brake boost and i didnt have an exhaust on to put on a test pipe with a bung with this said and done the issue is a dead resistor pack and it was running to rich. my spark plug gap is .25 my turbo elbow was fine we did a ROM tune and just put on a basicly map for a stock 20 with 440 injectors to get it back home. once i get a new resistor pack put in and my maf put in and my downpipe on we will be tunning it properly it was only making 10 psi due to the issues. although once tuned i plan to hit 1 bar to 1.3bar with things as they are it it was driving decent on the way home in high rpm due to the amount of fuel in it and it was hauling ass if thats only a taste of whats to come from it im extremely excited that said if anyone has a spare resistor pack that doesnt want me to sell and arm and or a leg for it lmk. i need one ASAP