Jump to content
SAU Community

Tuning For Bigger Injectors

ossie_21

By ossie_21,
in Engines & Forced Induction

 Share

Recommended Posts

ossie_21 Grand Master

ossie_21

Posted
Posted

Hey all, just a quick question in regards to some tuning. I have an r33 with an engine being built as we speak, and it should be bedded in by the end of the month. In around a couple of months time I am then going to be looking at some bigger injectors to make over the 400rwhp mark, and then hope some shit don't break :)

So the question is this, with an already tuned ECU, what is the go for tuning for bigger injectors? Is it a "simple" tune & relatively cheap to do or does it still go a bit pricy? I've heard a couple of different things about it so I'm asking if anyone could tell me from first hand experience....Most people do the ecu & upgrade injectors at the same time but it's hard to tell the dyno time/cost for injectors only, searching provided nothing for me.

While I'm here, with a GT30R (500hp) with 45mm external gate, what size injectors would be the most ideal for me? Daily the car will be driven about 40kms, plus whatever on the weekends (or my days off because I will end up working them again soon). Does bigger injectors also mean more fuel consumption, or is that down to the boost level I run at? Looking at keeping it lower for the daily driving but then of course putting it up at the appropriate times.....

Cheers, any help appreciated!! :(

Link to comment
https://www.sau.com.au/forums/topic/137477-tuning-for-bigger-injectors/
Share on other sites
CEF11E Veteran

CEF11E

Posted
Posted

If you are after 400 rwhp I would be going for 600cc.

If you have a power FC you already have toyr fuel and timing maps done. put the injectors in and change the size /flowrate/latency and dyno it and you are done.

If you have a remapped stock ECU you change the

K value to suit the larger injectors

reference the void blast off time. then you need to recalc your boost table.

Can be a lot of fu$%ing around on a stock ECU if you do it properly.

I am assuming u have a power fc tho?

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Nismo 555cc injectors for the RB25DET.

Direct bolt in affair, not stuffing around. I wouldnt be using anything else.

Well the stock injectors are going to be maxed around 220-250rwkw. So you wont be able to do a full tune to begin with.

It wont be "as much" as a from scratch tune, but it wont be a 20min adjustment either.

Should be around 3/4 of the price... Most full tunes are around $500, i'd expect to pay around $400 give or take if i changed injectors and needed a reasonable update to the tune

As for fuel consumption, that is governed by one thing and only one thing.

Your right foot

ossie_21 Grand Master

ossie_21

Posted
  • Author
Posted
Nismo 555cc injectors for the RB25DET.

Direct bolt in affair, not stuffing around. I wouldnt be using anything else.

Well the stock injectors are going to be maxed around 220-250rwkw. So you wont be able to do a full tune to begin with.

It wont be "as much" as a from scratch tune, but it wont be a 20min adjustment either.

Should be around 3/4 of the price... Most full tunes are around $500, i'd expect to pay around $400 give or take if i changed injectors and needed a reasonable update to the tune

As for fuel consumption, that is governed by one thing and only one thing.

Your right foot

Yeah, my right foot seems to handle it quite well, the most I've driven my car was freeway to and from work, so cruising was easy. But with what it will be for now I'll have to wait & see :D

Sorry the thing I didn't mention was that my ecu is a wolf ecu, and the tuner I will be using prefers these over anything else. They seem to get more out of the stock injectors than a pfc can, because my power level was just over 260rwkw, and there are a few similar cars (standard rb25's) that were getting more power too!

But thanks to both of you, also got a helpful pm too so that will be something to look forward to! Cheers, Nathan

Cubes Grand Master

Cubes

Posted
Posted

Out of curiosity....

Why or more importantly how did the old motor pop?

You can make plenty of power on the std injectors.. ramp that fuel pressure up and thats it. Not too good for reliability though.

I've known 1 rb25 to push 258rwkw on std injectors and it popped a little while after. Did its ring lands. Suprise suprise on std injectors. :D

ossie_21 Grand Master

ossie_21

Posted
  • Author
Posted

It was just piston no. 1 that went, thats why when he took the engine apart he was suprised at how well everything looked except for that one which has a nice hole in it :)

Haven't seen it as yet but will see it & find out next week, who knows maybe injector failure was the reason!! Boost will be down until the injectors anyway because I will be bedding the engine in & by the end of that it will be ready. For my 21st the hint hint to my mum is for the injectors :O

Cubes Grand Master

Cubes

Posted
Posted

Hrmm a hole you say....

Ahh well live and learn. Buy injectors to suit the power level and you will be looking at and enjoying a reliable motor providing the engine builder and tuner know what they are doing. :)

As R31Nismoid said... 550cc injectors will suit your power level.

GeeTR Grand Master

GeeTR

Posted
Posted

Howdy,

Are we talking about the spreading of a cylinders fuel requirements over two injector openings? Instead of opening once on intake stroke, it opens twice in the 4 stroke period, two half openings, effectively squirting fuel on the back of the closed intake valves.

This was done with older OEM injected engines, plus is a method used by thems today with cheaper AM ECU's, as you only need half the mosfet's or "injector drivers"

I dont quiet understand its relation to the Wolf though, pause on the pop corn and give us a hint :whistling:

- Michael

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      One Headlight isn't working - Driver Side Fuse Keeps blowing

      By GTSBoy · Posted

      Yeah, but knowledge of one wire's insulation worn through to short on earth implies the possibility of other wires doing the same. I had my power steering die, because the wire that runs to the solenoid valve on the rack runs in the same loom as the power wire for the O2 sensor. And when the O2 sensor/wire did something stupid and burnt part of that loom to death, the only indication was the shit(ter) fuel economy and the heavy steering. It took deep excavation of the looms in the bay to find the problem. Not wear through in that case, but similar shit.
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      Ah, I thought he'd wired it to one of the spare ECU inputs! Too long ago since I read that post, ha ha. I've been arguing with radiators, harmonic balancers, alternators and rust since reading it.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      Correct. The ECU cannot read oil temp. (Well, I think it probably can in some situations. I did have the thought of potentially repinning the ECU when I was doing oil pressure). I am using this into the MPVI dongle, so that the MPVI dongle can read oil temperature. It is attached to a VDO gauge which is obviously calibrated to whatever curve the sender actually is using. This would be easy if I could setup a table of voltage to temperature like many sensors, but it appears I cannot do this and can only setup the transform rule which appears to be Input (voltage) x Multiplier, and add an offset. This to me means it MUST be linear. So it may be a complete waste of time wiring this into the ECU. The idea was that the MPVI3 has standalone logging. I wanted to use this instead of a laptop with serial cable (for wideband) for long datalogs. Given the wideband also has electric interference, I may never trust this either in a world where the serial wideband and the analog output wideband do not agree. Last time I did a trace I could see the two wideband traces follow each other, but one was a little leaner than the other. I plan on playing with voltage offsets and actually driving the thing to see how close they correlate. If they never correlate... then, well, maybe I'll never use either. Ideally I'd like to have the Analog wideband read ever so slightly leaner than the serial one, because the serial one is 'correct'. Tuning the car to be ever so slightly too-rich would be the aim. Not needing to have a laptop flying around in the footwell connected with cables is... an advantage. About the only one from the forced upgrade to MPVI3.
    • MBS206
      One Headlight isn't working - Driver Side Fuse Keeps blowing

      By MBS206 · Posted

      Hopefully not, since he knows the fuses work ha ha ha
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I don't think he's got it on a gauge and on the ECU. I think he's got it on the gauge and on the HPTuners DAq thingo. Remember, we're talking about oil temp here, not something that the ECU is actually interested in for its own sake.
×
×
  • Create New...