injector questian

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25-01-11, 21:12
darren C

injector questian

rite lads im just after buying a set of nismo 740cc injectors for my 180.

setup at moment..
sr20 black top
tomie pon cams
tomie rocker arm stoppers
denzo platinum plugs
trust front mount
s15 bb turbo
stainless manifold
full stainless turbo back
greddy boost controller
upgraded fuel pump
tomie intake hard pipe kit
hks mushroom filter
performance wise think dats it

now my questian is im after gettin a set off 740cc injectors and want to run these wit z32 afm and mapped on nistune.. are these injectors gonna work or are they too big??
25-01-11, 21:14
drift student

they'll work fine once mapped. im sure.
25-01-11, 21:18
darren C

im gettin very mixed answers on these from friends.. any1 else on here wit experiance wit um??
25-01-11, 21:22
Newsome

Who ever is doing the map can set the fueling up for them. Granted they are over kill for an s15 turbo but there wont be a problem.
25-01-11, 21:23
darren C

ya they are a bit much but got um at a very gud price so hoping to use if i can
25-01-11, 21:45
will_c

740s are too big, better off with 550s the theory is that you use an injector that's closer to max duty cycle rather than too far away, because it affects injector spray pattern and therefore fuel atomisation. And if your fuel ain't been atomised properly, it can't burn properly and effeciently!! And s15 turbo basically can't flow enough cfms to support that fueling..
25-01-11, 21:53
darren C

Quote:

Originally Posted by will_c

740s are too big, better off with 550s the theory is that you use an injector that's closer to max duty cycle rather than too far away, because it affects injector spray pattern and therefore fuel atomisation. And if your fuel ain't been atomised properly, it can't burn properly and effeciently!! And s15 turbo basically can't flow enough cfms to support that fueling..

dats they kinda answer i was lookin for in a way bt dunmno wat to do now..

any1 hav any other views on this???
25-01-11, 21:58
will_c

My other view is get the injectors and a bigger turbo ;)

You've potential for big power with that setup
25-01-11, 22:02
darren C

i bought the injectors while ago :D so wat to do ???????????
its my road car so i want usable power.. 300 to 350 ish
25-01-11, 22:15
will_c

S15 turbo will kinda struggle past 320ish tbh..

Sell/swap the 740s for 550s, get a gt2871r and the pick your power figure up to 400bhp!!
25-01-11, 22:18
darren C

wat are these turbos goin for?? id be happy anough wit 320 if i got it :D
25-01-11, 22:58
CillianS14a

You'd be looking at in around 8-900euro for a 2871r new, and prob around 5-600 second hand, they're a great turbo on sr20's. If your interested in sellin the 740's darren drop me a pm
25-01-11, 23:04
darren C

Quote:

Originally Posted by CillianS14a

You'd be looking at in around 8-900euro for a 2871r new, and prob around 5-600 second hand, they're a great turbo on sr20's. If your interested in sellin the 740's darren drop me a pm

pm'd there lad
26-01-11, 07:55
tweek

You don't need smaller injectors 740cc will be grand if they are a good make this problem was with older injectors not the more modern ones speak to the mapper he will set you straight unless he is trying to sell something everyone else is probably guessing or googleing it.I'll be running 740 sards on a sr20det with a set up around 320bhp I rang them on a 350 bhp setup before with no problems.but all of this depends on the quality of the injectors.
And in relation to poor atomisation that is purely up to the quality of the injectors and if the atomisation was poor a car wouldn't even idle correctly.

As said already best not ask on a forum but talk to your mapper he will have more experience than most
26-01-11, 17:17
Doofer

Quote:

Originally Posted by tweek

You don't need smaller injectors 740cc will be grand if they are a good make this problem was with older injectors not the more modern ones speak to the mapper he will set you straight unless he is trying to sell something everyone else is probably guessing or googleing it.I'll be running 740 sards on a sr20det with a set up around 320bhp I rang them on a 350 bhp setup before with no problems.but all of this depends on the quality of the injectors.
And in relation to poor atomisation that is purely up to the quality of the injectors and if the atomisation was poor a car wouldn't even idle correctly.

As said already best not ask on a forum but talk to your mapper he will have more experience than most

Well said!!!!.. I feed on the Knowledege of the experienced..
26-01-11, 18:42
darren C

Quote:

Originally Posted by tweek

You don't need smaller injectors 740cc will be grand if they are a good make this problem was with older injectors not the more modern ones speak to the mapper he will set you straight unless he is trying to sell something everyone else is probably guessing or googleing it.I'll be running 740 sards on a sr20det with a set up around 320bhp I rang them on a 350 bhp setup before with no problems.but all of this depends on the quality of the injectors.
And in relation to poor atomisation that is purely up to the quality of the injectors and if the atomisation was poor a car wouldn't even idle correctly.

As said already best not ask on a forum but talk to your mapper he will have more experience than most

i recomended against so cillians14 is buying them and i am just going to buy 550s
cheers for the info tweek :D
26-01-11, 18:48
tweek

Just wondering who recommended against it and for what reason?it will clear things up for people in the future
26-01-11, 18:53
darren C

Quote:

Originally Posted by tweek

Just wondering who recommended against it and for what reason?it will clear things up for people in the future

robbie in tdp
hes exact words:
The smaller the injector the greater the accuracy of the fuel delivery. You should ideally use the closest injector to what you need.
26-01-11, 21:57
will_c

Aye I was told the same by another mapper, sorry I didn't mean to sound like a forum know-it-all but I am a mechanic interested in tuning management systems so that's what I'm learning about at the moment
26-01-11, 22:02
darren C

no problem lad.. im just going to sell them now and get 550s insted..
26-01-11, 22:15
tweek

I guess I'll have fun mapping my trackcar on 1000cc injectors.I'll keep Ye updated
26-01-11, 22:37
ian g sr20

have to agree with tweek on this 1...

lots of threads on here turn into a guessing game half the time lots of googleing on i thinks :rolleyes:
26-01-11, 22:46
will_c

I suppose with so many different opinions floating around online and from different mappers it's hard to know until ya go at it yourself..

Tweek were you running e85 or have I mixed ya up with someone else?
26-01-11, 23:02
tweek

Quote:

Originally Posted by will_c

I suppose with so many different opinions floating around online and from different mappers it's hard to know until ya go at it yourself..

Tweek were you running e85 or have I mixed ya up with someone else?

Not anymore back to petrol mow e85 is gone.had my car running on e85 with 1000cc injectors with no idle control valve and had no problems idling so I can't see any issues arising from doing the same with petrol.
Bottom end bearing gave up on that engine for a finish so she is getting a bit of a refresh at the moment
26-01-11, 23:04
will_c

That's what I was gonna say, with the e85 gone.. Hoping for same power?
26-01-11, 23:09
tweek

Quote:

Originally Posted by will_c

That's what I was gonna say, with the e85 gone.. Hoping for same power?

More power with this set up I reckon just a smaller power band (bigger turbo and my vtec controller trick) if I had known they were getting rid of e85 I would have went a different route and saved a fair lump of cash
26-01-11, 23:46
colm

Quote:

Originally Posted by tweek

More power with this set up I reckon just a smaller power band (bigger turbo and my vtec controller trick) if I had known they were getting rid of e85 I would have went a different route and saved a fair lump of cash

vtec controller trick? whats that now? :eek: :p

im running 1200cc injectors and idles grand. i heard the same thing about injectors being too big and fucking up your idle and spray pattern etc but havent experienced it
31-01-11, 01:16
paulr5

Quote:

Originally Posted by tweek

my vtec controller trick

:confused: fill us in/????
31-01-11, 09:22
Bradley_Motorworks

740s are perfect...Ive used pretty much every size and never had problems runiung a smooth lean idle...I have used 1100cc without problems

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