Is there any rule of thumb to "this big" is "too big"
I'm collecting parts slowly slowly trying to grab all the bargains I can and I've found a nice set of injectors But I know little about the part in question.
My NA Injectors are 270cc..
Standard Twin Turbo 3000GT Injectors are 360cc
The injectors I've found at an insane price are almost double that of a Twin Turbo injector, Running the adjustable fuel pressure reg....Can I still use these higher CC injectors? Will it just give me more headroom for the future (being so big)

Dont wanna go too big if it's of no use. Can someone shed some light on this topic?

all i know is that if its too big you will get a terrible idle. cause they drip rather than spray,(somthing like that)

i wouldnt worry about th 360cc injectors. it would be more like the 1000cc injectors that caus the dramas on such short openings. (dribbling)

although they are getting better with multi point injectors. the big single orifice are not as good.

all i know is that if its too big you will get a terrible idle. cause they drip rather than spray,(somthing like that)

i wouldnt worry about th 360cc injectors. it would be more like the 1000cc injectors that cause the dramas on such short openings. (dribbling)

although they are getting better with multi point injectors. the big single orifice are not as good.
The one's I've found are something short of 700cc. Just getting some more information on them too But not sure if they are a single point tip or multi point.
Just not sure if I should get these as they are as cheap as most standard 360TT injectors. But I would rather get more for my money

i know most japansese injecotrs up to 770cc use a 4port pintle, so you can get as good as stock idle with the right tune. As you get bigger then this you will find a lot of trouble with idle quality

Can i ask how why you want to go so big, I understand that for the price you might as well get new in box items probably bigger then stock items and cheaper, but a 370cc injector in a 500cc pot, at 45psi can supply enough fuel with a safe tune for 14psi (extrapellated 2.0L 4pot @14psi at stable 12.2afr wide open throttle made 167wrkw obviously all other supported mods) so i assume you are looking to the future and possibley being FI

Anything bigger then stock and you will need after market management > i know you have that, but will also need to make sure it can handle any size injectors, some piggybacks can only run up to 50% larger then stock (greddy emanage for instance) and once you start getting over 800cc you may start to get into trouble with daily driveability. There are many many 500cc pot 4bangers that make over 300rwkw using 770cc injecotrs at 44psi base fuel pressure.

you enigne is 580cc per pot and i was reading on 3si.org that people use these bottom ends and dont even change their stock tune and done run into issues when running up to 12 pound on stock gto injectors, due to the rich factory tune.

i know most japansese injecotrs up to 770cc use a 4port pintle, so you can get as good as stock idle with the right tune. As you get bigger then this you will find a lot of trouble with idle quality

Can i ask how why you want to go so big, I understand that for the price you might as well get new in box items probably bigger then stock items and cheaper, but a 370cc injector in a 500cc pot, at 45psi can supply enough fuel with a safe tune for 14psi (extrapellated 2.0L 4pot @14psi at stable 12.2afr wide open throttle made 167wrkw obviously all other supported mods) so i assume you are looking to the future and possibley being FI

Anything bigger then stock and you will need after market management > i know you have that, but will also need to make sure it can handle any size injectors, some piggybacks can only run up to 50% larger then stock (greddy emanage for instance) and once you start getting over 800cc you may start to get into trouble with daily driveability. There are many many 500cc pot 4bangers that make over 300rwkw using 770cc injecotrs at 44psi base fuel pressure.

you enigne is 580cc per pot and i was reading on 3si.org that people use these bottom ends and dont even change their stock tune and done run into issues when running up to 12 pound on stock gto injectors, due to the rich factory tune.

ECU is fully standalone though not piggy.
And yes, reason being, I have found them cheap.
They dont change there stock tune but use a SAFC-II to control AFR's (I think that what it does..) So I dont really have a "stock tune" as of yet.

And yes this will be for FI Purposes.
I've seen smaller ones go cheaper. So If I can get these that would be pretty sweet, but wondering if the bigger size I will run into any more dramas.
ECu Has no limits to injector size AFAIK

']
ECu Has no limits to injector size AFAIK



i would find this out before forking out cashish!

i would find this out before forking out cashish!
Let me know if I missed something
http://www.adaptronic.com.au/products-e420c.php#Specs

']Let me know if I missed something
http://www.adaptronic.com.au/products-e420c.php#Specs


seems like there is alot of adjustability on the injectors.... seems fine. maybe one of the more tech savvy members can fill in.

what did you pay for it again? loooks like a decent unit.

You sure the 360 will give enough headroom though if you got TT?

There is a formula for it somewhere.

You sure the 360 will give enough headroom though if you got TT?

There is a formula for it somewhere.
Well, they are standard 3L DOHC TT Injectors...So probably not enough....But yeah....Just thinking weather or not to get them

there are a few 70rwkw/ cylinder engines out there running 770cc's but thats on 24-26psi, which is a lot more then your engine is going to take in stock form. I would say that 1 bar would even be pushing it so anything over 400cc will see you out.

I didnt realise your ecu was standalone, which is great but for the life of me couldnt remember which brand. I would have lookied it up otherwise.

the SAFC-II are used to add or remove fuel at key engine load points, but a SAFC-II will only bring 100% duty cycle on quicker with the same injectors. From what i read these guys just bolted in the bottom ends (keeping everything else stock) and had no trouble on the stock unadulterated tune, which doesnt suprise me, having run a turbo engine from a similar era, rich is the common word for tune. an extra 83cc capacity per cylinder wasnt causing lean enough AFR's to worry about.

Think I'm gonna get them, guy just wants them gone which is why they are cheap. Also came from a 10sec 3000GT :shock:
Getting these will be about 1/3rd as cheap as buying them from aus for a similar product

360cc injectors will flow enough fuel for 329Hp.

770cc injectors will flow enough fuel for 704Hp.

550cc injectors (Rx7) will flow enough for 502Hp.

http://www.rceng.com/technical.aspx

Depends how cheap, i've got my 360cc's for free...

Also ers we're talking 6cylinders here:P

And does anyone know what the standard fuel pressure is used to quote injector flow rates? Because this software is saying that mitsu undersized the injectors on the 3000gt unless its running about 50psi fuel rail pressure...

Im also talking about 6 cylinders.

All those HP figures are to flow with 6 injectors.

Standard fuel pressure in an EFI car is 40-50psi.

yurp but the first 329hp number according to those. I think i worked it out as 274 (and checked), not 329 im tired, its not for 8cyl either. Open to being wrong. EDit** just double check you calculated it at 100% dc... my bad.

Yeah 40-50psi is not what i'd consider a standard. I mean what the manufacturer quotes at.

40-50psi is standard for a fuel injected car, all depends on how much flow you need out of the injector. Go to the link I provided, there's calculators there to work out the flow rate vs fuel pressure.

40-50psi is standard for a fuel injected car, all depends on how much flow you need out of the injector. Go to the link I provided, there's calculators there to work out the flow rate vs fuel pressure.

Im well aware of what i run and what is acceptable. Im asking a different question.

"all rated at the industry standard of 3 BAR (43.5 psi)" to quote http://www.rbracing-rsr.com/fuelinjectors.htm was what i was looking for.

also have to remember how the car is tuned and what AFR works with the application, like said ive seen 300hp on 360cc but that was a turbocharged 4, which will be tuned richer then a NA, even with the same size pots

Injectors are costing me less then $200US posted.

']Injectors are costing me less then $200US posted.

As nice as that is,

700odd CC injectors on your car, turbo or not, will have a pretty bad spray pattern due to running them at less than 50% of the duty cycle.

Your car will make less power, chew more fuel, and be a pain in the ****...

These bastards have 6 spray nozzles PER injector!
Is that good or bad :P

700cc 4 pintle (ports) injectors from say SARD give stock standard idle and emmission acheivable smog results on 2 litre turbo 4bangers.

The smaller the pint, the bigger the blast, the 4-6pintle design was to eliminate the poor spray patterns associated with big injectors on street cars, and thus crappy running.

I know 1 person at least, who has spent a lot of time tuning his car (he owns and operates a performance shop) has an Apexi PFC (comparable to TUFFTR's ecu) gets over 550kms from a tank of 64L of PULP and on the same tune also makes 280rwkw when pushing on the dyno. Orange Silvia down the coast, some may know of him. He uses 770cc SARD 4pintle injectors. The car is completely engineered, including a better then factory exhaust gas component result.

Technology has come along way remember... they even have gas injectors now... sarcasm mostly. The above statements are true in that in the bad old days, big injectors meant big problems, and they do today as well, except now big injectors dont really start until you pushing over 1000cc per unit

Here they are
http://i9.photobucket.com/albums/a52/dodgeviper89/injector.jpg
cool eh

Horny!

']Is there any rule of thumb to "this big" is "too big"
I'm collecting parts slowly slowly trying to grab all the bargains I can and I've found a nice set of injectors But I know little about the part in question.
My NA Injectors are 270cc..
Standard Twin Turbo 3000GT Injectors are 360cc
The injectors I've found at an insane price are almost double that of a Twin Turbo injector, Running the adjustable fuel pressure reg....Can I still use these higher CC injectors? Will it just give me more headroom for the future (being so big)

Dont wanna go too big if it's of no use. Can someone shed some light on this topic?
I've heard rule of thumb is 25% so that would be 338 so 360 should be ok.

I've heard rule of thumb is 25% so that would be 338 so 360 should be ok.
Ah well....Too late now:bowrofl: got these 700cc units sitting next to me.
not bad for under $250AU SHIPPED!

']Ah well....Too late now:bowrofl: got these 700cc units sitting next to me.
not bad for under $250AU SHIPPED!
Oh well you better run about 60 PSI boost & then you might manage to use up all the fuel dribbling out the injectors :bowrofl:

like has been said TUFFY 700cc will allow you to run up to 22-26psi (although its unlikley you will ever put this much boost through it) Thats about the limit.

Just because they are that big doesnt mean they are always squirting all that fuel, not to mention the fact TUFFY has a standalone ECU.

like has been said TUFFY 700cc will allow you to run up to 22-26psi (although its unlikley you will ever put this much boost through it) Thats about the limit.
Phhhht I used to run 27 PSI through my 2 litre Nissan bluebird & totally reliable (except the diff) lol
If I kept it I was gonna go 30 PSI with Methanol secondarys on the carbys for another 100HP.

Phhhht I used to run 27 PSI through my 2 litre Nissan bluebird & totally reliable (except the diff) lol
If I kept it I was gonna go 30 PSI with Methanol secondarys on the carbys for another 100HP.

i meant as, its about the limit of the injectors, not the engine. WIth eough fuel to keep things cool enough there is plenty of boost to run even on 10:1CR engines.

Boost isnt the issue here anyways as boost is relative to engine displacement. Your 2 litre bluey at 2bar (~29psi) is an equivalant displacement of 6litres, where as tuffy's 3.5L @ 1 bar (14.7psi~) is already equivalant to 7litres of displacement.

i meant as, its about the limit of the injectors, not the engine. WIth eough fuel to keep things cool enough there is plenty of boost to run even on 10:1CR engines.

Boost isnt the issue here anyways as boost is relative to engine displacement. Your 2 litre bluey at 2bar (~29psi) is an equivalant displacement of 6litres, where as tuffy's 3.5L @ 1 bar (14.7psi~) is already equivalant to 7litres of displacement.
True & I was running 6.5:1 compression so it was a real dog off the mark but on boost it was a weapon. I had a modified xxxx beer keg in the boot full of water/methanol which was pressurised off the engine on boost via a one way valve. Primitive by todays standards but it used to produce the goods!

True & I was running 6.5:1 compression so it was a real dog off the mark but on boost it was a weapon. I had a modified xxxx beer keg in the boot full of water/methanol which was pressurised off the engine on boost via a one way valve. Primitive by todays standards but it used to produce the goods!

hahahaha beer keg, that is easily the best thing i've ever heard.lol

hahahaha beer keg, that is easily the best thing i've ever heard.lol
You don't wanna waste anything, once you finish the beer put in your boot full of water/methanol :bowrofl:

You don't wanna waste anything, once you finish the beer put in your boot full of water/methanol :bowrofl:
Thats awesome! hahahaa!
Reminds me on the 3000GT website, a member from russia joined up and was showing off his 3000GT at a drag day. They ran out of methanol so they started filling the tank up with vodka, weather or not it WAS vodka in the bottle is beyond me but looked pretty funny.
Good info there Lynel.