Nismo 555 Vs 740 Injectors? For Ecr33

[ausdrift]

I'm starting to put plans together to up the power in my R33 gtst. It has/will have a bunch or normal mods - bigger turbo, FMIC, boost controller, full exhaust, nismo fuel pump, Power FC etc.

The thing Im unsure about is that of fuel injectors. I had planned to go Nismo 555 as a step up from standard. I'm not planning to chase high power with my car, I'm just planning to make the most of my mods and get it tuned so its comfortable and reliable as my daily, but still has the power that these mods allow. That said, I'm wondering what life would be like getting the next size up injectors; 740s?

What's the difference in Nismo 555 vs 740?

For standard fitment, are they side or top feed?

and

Is a fuel pressure regulator something I would need in my modifications too, or is it unnecessary?

[discopotato03]

A tuner has told me that 740s tune up better than 555s , those aren't supposedly real good at idle .

If staying on petrol also consider the S15 injectors as they a bit bigger than R33 370s .

A .

[Dose Pipe Sutututu]

740cc man, 555cc you'll run out of injector very quickly.

I'm running 875cc stainless steel top feeds and at 343kW I'm already sitting at 87% duty.

Go top feed man, if you use half height injectors they will fit underneath the stock plenum easily without any silly spacers ot deleting hoses like other homo kits.

[KiwiRS4T]

The difference is 185cc.

555 would be fine for up to 350kw ...I bought 550 Deatschwerks but today I would buy something more modern like a set of ID750s from Scotty. Get in touch with him and he will give you a good steer.

Get a more modern ECU if you can afford it too - otherwise Power FC will be fine.

[boostn0199]

For the price of nismos you can get conplete kit with everything you need to fit top feeds into r33 its what i just did 1000cc xpurts 40mm length ,rail,aeroflow reg,fittings,hose all off Scott.

[ausdrift]

KO cool. Im leaning towards bigger ones now, and also away from Nismos just because of the cost

[Sub Boy32]

Not a big fan of the 740cc side feeds, we have tuned heaps of both the 555's and the 740's and the 740cc injectors never tune up anywhere near as nice, they don't idle as well, and the cruise isn't as nice.....WOT is no different but the rest is.

If it was me and needed anything bigger than the 555's I would be doing a top feed setup with Bosch 1000's

[R31Nismoid]

Can't say I had any idle issues with my Nismo 740s, was as good as factory. Cruise was also A-OK, economy was semi reasonable as well. Not as good as stock injectors, but that's always the way.

[Dose Pipe Sutututu]

I've tuned with the 740s before on a SR20 but not on a RB and didn't have real issues.. but taking note that per cylinder a SR uses more fuel than a RB hence idle/cruise might have been better as it required a higher duty cycle

[ausdrift]

Huh. Anyone else have similar issues?

[GTSBoy]

Huh. Anyone else have similar issues?

I don't think it matters if people have had issues or not. The simple fact is that there is no need to persist with ANY of those crappy old sidefeeds now that you can jam a set of ID14s in there for the same or less $$.

[ausdrift]

But Im pretty sure that top feeds are going to lose the sleeper feel to my engine bay, no?

[iruvyouskyrine]

No. Because you can jam them under standard plenum and nothing really looks any different apart from your fuel rail. Which if you get a black one no one is going to know.

[Dose Pipe Sutututu]

But Im pretty sure that top feeds are going to lose the sleeper feel to my engine bay, no?

no, mine looks stock as shit

[ausdrift]

Anyone using bosch top feeds? And what other brand, apart from IDs would you say are the best/smoothest etc ?

[GTSBoy]

Just ask Scotty.

[SargeRX8]

Take the majority advice dude, ditch the Power FC and go for something a little more modern(adaptronic, haltech), go with the bigger injector. I use 740cc Nismo injectors which are great. I've also used the 555cc nismo injectors. I had no issues with either car idling with my Power FC. My 740cc crack about 60% injector duty cycle so I have headroom for E85 but I will be cutting it OH SO CLOSE.

If you're gonna do it, plan it properly and do it right. I started modding my car years ago. Injectors have really come down in price and there are some more options for ECU's. The real pro's of a modern ECU are you can add inputs for mafless setups, flex fuel, other sensors etc. The pfc is a brilliant ecu but its outdated. A larger resolution can also give a tune far more detail and it can make the car feel just that much smoother.

If I was building my car today from scratch, none of the parts I have in there now would be used. They're good for their time and back then more affordable than what is available now. I also was lucky, I picked up my nismo injectors pretty damn cheap. Even cheap for todays prices. They've got up since I bought them.

With that said, I love my car

Edited September 7, 2015 by SargeRX8

[SilverECR33]

FYI;

Nismo 555's are Side feed, and drop in to your standard rail. yes you will need a reg, anytime you change your fuel system from stock, as you will need to re-calibrate the pressure. ID1000 or EV14 injectors are top feed and require custom rail/collars.

sounds to me your pretty much doing teh same thing i did, on my first round of mods, with a very similar parts list. in which i have my old pfc and tomei z32 for sale atm, which got me up and over 500rwhp.

as for the comment about the 1000's being cheaper, not true. sure the injector itself is but its all the other shit u gotta change that adds in the price, and will ultimately cost you more. the nismos drop into the stock rail/lines etc job done. the bosche 1000's need a rail, collars, custom sleeves machined, .. then lines, and fittings and a decent return.. and u still need a reg either way.

[Dose Pipe Sutututu]

No you don't, a regulator is there to regulate fuel pressure regardless of injector size.

[SargeRX8]

I use the stock regulator with my Nismo 740cc injectors. Pressure is fine.