What 550cc Injectors should I go for?

[Cubes]

Hi ppls,

I'm after a set of new ~550cc injectors.

I figure I could get a set of RX7 V 550cc injectors for a decent price but I would then have to have them flowed & tested which bumps the price up close to that of new injectors.

Another thing that concerns me with the RX7 injectors is the spray pattern.

'Apparently' they have more of a squirt than a fine atomistation.

The squirt is fine for performance as it works well to get the fuel in but for fuel economy it is not the best.

Has any one got these Injectors and have kept an eye on the fuel consumption before and after the install?

I am looking at possibly importing:

Sard 550cc's (~600-700)

Nismo 555cc's (~700-800)

or possible even go to the HKS 600cc (~800-900).

I have no idea on the spray pattern of the aftermarket injectors and if they are indeed setup to squirt or atomise the fuel for good emissions/fuel economy. For all out power the squirt type injectors are apparently the way to go.

I can find RX7 5 injectors for around $300 or so + $200 for flow & clean. Thats ~$500 which is pretty close to the price of bran spankin new injectors.

[Jolinator]

got my injectors flow tested, spray pattern checked, new pintle tips, o rings, filter buckets, the works, for 22 dollars each, so 132$

[funkymonkey]

get the RX7 injectors... they do the job, one of the guys on here got them, cleaned n flowed and a walbro pump to suit... seems to do the job.

[predator]

There is a guy up here who reckons he can highflow existing rb25 ones to 780cc.. Says not by simply enlarging the actual nozzle size which can cause spray issues, but replacing the whole pintle? Says they have been tested with excellent results at high HP with no issues (of course he would say that)

It sounded dubious to me.. What issues would there be with this? Is this guy talking out his butt?

[knore]

Whos that gordon?

The nismo 550cc are really good but cost an arm and leg

[Cubes]

I am willing to spend the $$.

Mid January is when the injectors will be needed so I've got a little time to do a little bit of research in to what is good.

I want some thing that not only does the job but does the job better.

My 32 is a daily driver so I prefer to have good fuel economy.

At the moment the 3ltr on the rb20det ecu nudges 500km's to a tank on occasions and never gets any lower than 430km's per tank, exactly the same as what the RB20DET used to get. I want to try and keep that fuel economy.

Providing the injectors are atomising the fuel correctly I don't see why a larger 550cc injector wouldn't provide the same fuel economy after the PowerFC is all tuned up to suit the 3ltr.

I would never think about highflowed injectors, they make me nervous.

I have a problem trusting peoples abilities.

Can any one throw around their fuel economy figures?

[Col-GTSX]

I had a set of RX7 injectors on my old rb20....

Works really well... but watch your fuel gadge drop as you floor it....

average 350km's from 62 litre tank...

[Bl4cK32]

larger injectors always mean bad fuel consumption....

More power = more fuel needed....as you know Joel

My RX-7 550's use about the same as std economy when off boost, but like said above, dont expect std fuel economy with some big guns installed

[Cubes]

I'm more concerned about the spray pattern and atomisation.

That is what affects fuel economy.

550cc's aren't that large and should still be able to atomise fuel well.

It appears there are also injectors that the spray pattern is designed around 2 inlet valves etc.

[carl h]

what bout some vr4 injectors or injectors from a 7mgte supra engine?

for the vr4 injectors you have to bore the rail a tad for them to slip in and i believe you have to do the same for the 7m ones.

you may have to run a dropping resistor pack for them, but its another alternative should you choose aftermarket injectors.

[Busky2k]

Are RB25DET injectors the same as the SR20DET? Ie side feeds?

[funkymonkey]

Rb25DET are side feed, but I dunno if they're the same volume as SR20DET ones

[INASNT]

I got the sard 550cc apparent side feed, but you need the collars. Had to use the stock o-rings plus the new o-rings supplied to get them to seal properly!!

Go for the nismo, hks or some denso injectors, as the sard one sux ass.

[mokompri]

yeah there both side feed, purple top sr20's injectors are 370cc injectors, s15 red top injectors are 480cc

a certain knowledgable person claims single pintle injectors are the only ones hes seen to have issues, ie sard.. and recommended to go for 4 pintle ones, ie nismo

logically thinking i would assume the 4 pintle ones would have better spray and atomisation over a larger single pintle injector

[RNS11Z]

I hi flowed my standard injectors to 660cc. No real difference in fuel consumption. Power from 380rwhp to 420rwhp with ease. Never had trouble with them. Now there making over 450rwhp. ONly difference noticed was at idle.

[Cubes]

Thanks Insant & Mokompri..

lol Your telling me what I want to hear.. hahahah

[GIGOLO]

I hi flowed my standard injectors to 660cc. No real difference in fuel consumption. Power from 380rwhp to 420rwhp with ease. Never had trouble with them. Now there making over 450rwhp.  ONly difference noticed was at idle.

What Idle differences did you notice?

I got the Nismo 555cc's and noticed that idle sounds a bit rough every now and again

[R31Nismoid]

joel, is this in the RB25 fuel rail?

[Cubes]

RB20DET fuel rail, at the moment tha RB30DET is running all the stock RB20DET sensors/injectors etc.

[DAN00H]

the twin nozzle injectors are from Power Enterprise, not sure how they stack up though. I'm going for around 550cc - 600cc injectors on my GTR.