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Tuning For Bigger Injectors

ossie_21

By ossie_21,
in Engines & Forced Induction

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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!! :(

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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

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