Fitting Slightly Larger Injectors On A Stock Ecu.

[sonicz]

My car is leaning out so instead of cleaning out the stock injectors I figure buy another set that is slightly bigger.

I believe the stock are 370cc. Can I fit bigger injectors that are around 450cc or 500cc? I'm not ready for a new ecu and tune yet.

I figure the computer should be able to adjust for the extra fuel slightly and If its running a big rich that's ok cos I have the boost higher and the car is running lean as it is anyway.

Anyone have any direct bolt in recomendations?

[vorse]

its going to go into rich and retard mode

[sonicz]

ok. Even with say 400cc injectors? How would it know? Especially if you unplug the o2 sensor? I've done it and car doesn't run and worse with 02 sensor unplugged.

[GTSBoy]

Rich and Retard is just the top corners of the fuel and ignition maps being very rich and very retarded (respectively). If you are running enough boost to go up to those parts of the maps you will be in R&R regardless of what your oxy sensor says (and the oxy sensor has nothing to say about it unless you're on cruise anyway - no effect at medium+ loads).

If you put in 400cc injectors it will be richer. At cruise the oxy sensor (assuming it's functional) will dial back the extra, but under load it will be rich. If you're already running up into the R&R part of the map this will not be a good idea.

If you actually are leaning out, then have you looked into the health of your fuel pump?

[sonicz]

if you put in 400cc injectors it will be richer. At cruise the oxy sensor (assuming it's functional) will dial back the extra, but under load it will be rich. If you're already running up into the R&R part of the map this will not be a good idea.

If you actually are leaning out, then have you looked into the health of your fuel pump?

Thats exactly what I want, richer. Its currently running lean and pinging.

Yes I have. That was the first thing I did. Ive tried 3 different new fuel pumps, now on walbro 255 voltage modded.

These plugs were only exposed to stock boost levels for a month or so. As low as my boost controller goes. about 6-7 psi. The car doesnt ping at this level, but does higher.

I cant really tell if the car is hitting R&r but i haven't noticed any retardation or richness or loss of power. i have turned the boost way up past 14-15 and I hit the AFM cut-off where the car suddenly jerks with a loss of power, but my problems are not anywhere near that level.

Edited May 23, 2013 by sonicz

[GTSBoy]

This is on an R33? Smart move is to not try to run more than stockish boost until you can actually take control of this shit, otherwise you are inviting trouble.

Problem with running 400cc injectors where you are running lean on 370s is......do you only need 385 to get you back into the right range and therefore will the extra several % fueling you get make it too rich? Or is 400 not enough? You simply don't know. It's best to do this stuff properly. Pick injectors with headroom and change the tune.

[sonicz]

Yes this is on a r33 gts-t

I would love to do new ECU +tune. The problem is that opens the door to another 3-4 k cost minimum, which I cant do. So its this or nothing.

So what if its running a tiny bit rich? I don't see the huge problem especially since I can turn the boost up to compensate. I have already checked my ecu+AFM doesn't go crazy until about 13-14 psi which I'm more than happy with.

Rich for a change may be good.

I remember seeing 200sx injectors were a drop in upgrade or something like that.

Edited May 23, 2013 by sonicz

[vorse]

Yes this is on a r33 gts-t

I would love to do new ECU +tune. The problem is that opens the door to another 3-4 k cost minimum, which I cant do. So its this or nothing.

So what if its running a tiny bit rich? I don't see the huge problem especially since I can turn the boost up to compensate. I have already checked my ecu+AFM doesn't go crazy until about 13-14 psi which I'm more than happy with.

Rich for a change may be good.

I remember seeing 200sx injectors were a drop in upgrade or something like that.

you don't have to do everything at once just tune at your current limits i would be more concerned if you want to make the car more fun in a manual conversion

the standard rb25 injectors are 370 side feed high impedance sr turbo injectors are the same

my experience is with an rb20 going from the standard 270s to 315cc as a replacement it didn't like it

[sonicz]

What do you mean by didn't like it? As in ran rough? too rich, loss of power etc?

Looks like I will just go with a clean of the stock injectors if that's the case.

[MBS206]

3 to 4K for an ECU and tune?

You're getting ripped off.

[hypergear]

just wire in an additional injector into cooler piping or some thing. Old school fuel tech.

[sonicz]

just wire in an additional injector into cooler piping or some thing. Old school fuel tech.

not really sure how that would work on a mostly stock rb25?

the standard rb25 injectors are 370 side feed high impedance sr turbo injectors are the same

Vorse. Looked into this . Yes most of SR turbo are 370cc, except for the manual S15s. Spec R are 480cc and the Spec S 440cc. They are a direct fit for the Rb25. This is what I was thinking of.

Edited May 23, 2013 by sonicz

[sonicz]

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Edited May 23, 2013 by sonicz

[STATUS]

buy and ecu and tune or buy a corrolla. you either want performance or you dont.

[ARTZ]

here a crazy idea, clean your injectors, cost less than 200$ and may just solve all your problems...

[Missileman]

buy a new fuel pump too

[ARTZ]

can never have too many fuel pumps

[Dose Pipe Sutututu]

not really sure how that would work on a mostly stock rb25?

Vorse. Looked into this . Yes most of SR turbo are 370cc, except for the manual S15s. Spec R are 480cc and the Spec S 440cc. They are a direct fit for the Rb25. This is what I was thinking of.

oh man you are so off... S15's run 448cc injectors 3 bar pressure, because Nissan revised the base fuel pressure in the S15 it increased the overall flow to 480cc.

Spec R and Spec S run the same motor, same injectors, same everything (ADM)

Spec R is Turbo, Spec S is N/A (JDM)

and don't be stupid, and how would the stock ECU know there are larger injectors OR how would it compensate for it? (according to your theory).. come on bro, this isn't streetcommodore backyard bogan tuning

if your car is leaning out and pinging off it's tits, there's someone else that is wrong with it, stock ECU will never run lean, go bang on a wideband on your exhaust and find out actually how it's running...

sighhhhhhhhhhhhhhh..

[Dose Pipe Sutututu]

here's a thought, why don't you use a timing gun and see if your timing is set correctly.. maybe some wannabe tuner advanced the crap out of the CAS

[sonicz]

buy and ecu and tune or buy a corrolla. you either want performance or you dont.

Very nice attitude. Hows the view from up there? I actually think I've seen you make similar comments a number of times in the past, but don't quote me on that.

Wanting the car to run right at 7-10 psi i.e mostly stock is not asking for anything special. I don't think its unreasonable to want the stock tune to handle that. I see it done all the time.

In addition, do you realize the kind of people that are now buying skylines, especially r33s gts's? They treat them like absolute crap and they are bought and sold for chips. They are treated as next to worthless. If you should be talking down to anyone, its them, not the people that actually want to take care of them. If I sell it and buy a corolla as you suggest the car will probably end up in a scrap yard.

here a crazy idea, clean your injectors, cost less than 200$ and may just solve all your problems...

Yup I've already been advised of this and thats definitively what I'll most likely do. I just wanted to know instead of blowing the money on a clean if I could get a small upgrade at the same time. Thus the reason for this thread.

buy a new fuel pump too

Already done and fitted.

here's a thought, why don't you use a timing gun and see if your timing is set correctly.. maybe some wannabe tuner advanced the crap out of the CAS

Its possible, but unlikely. I actually have managed to convince myself the timing is ok via Nissan consult. It mostly sits on 15 at idle, the reading sometimes flaps about from 0-15, but I tested another r34 and it was doing the same thing so I think its normal. Theres a thread about it I've made on SAU i think.

As for the ecu knowing about the injectors. Your right, it woudlnt. I was wondering that too because I have heard the ECU can adjust timing and duty cycle a certain amount But if the 02 sensor only works at idle, the ECU would have to be going purely of programmed stock maps with all stock parts.

Edited May 23, 2013 by sonicz