Photo of stock injector

[FTOLTD]

Funny... now we're posting same links... (Dave, look above! )

Contacted RPW, they might know what we have...

...and here is another link:
"Takakaira.com" List of injectors upgrades available to other cars...

"CD5A [evo 1-3 shape] lancer GSR injectors 390cc top feed low impedence
CM5A [95 onwards (evo 4 shape)] lancer GSR injectors ???cc top feed high impedence. "
above info came from here:

If information, that 1996 EVO GSR 1.8(4G93T/CM5A) injector is the same as in 8G VR-4, then we have an answer - high imp!

So this should fit our cars prefectly (from the link to Takakaira.com above):
550cc Injector; Skyline HCR32 RB20DET; Connector type - Angle; # of Nozzels - 1; High imp; Price - ¥12000 US$111

Most Turbo Toyota injectors would also fit the bill, with some modifications to connector...

sorry buddy but they are not the same as 6A13TT engine, the 6a13TT has a top feed high impedence injector with a oval connector with 4 nozzles

how ever you have come very close to the mark with the toyota comment, you would need to get injectors from or for the late model 2.5 ltr 1JZ VVTi motors. these are very similar to the 6A13TT injectors and are about 10mm longer.

[enigma]

The biggest problem is that the 6A13 TT injectors are only about 56mm long and are very short compared to normal injectors, i did find some short ones at 550cc but are still too small for my needs.

550s will do me nicely...............where did you find them?

[enigma]

grrrr bump as it doesn't show my post ^^^^^

[valmes]

FTOLTD thanks for clearing up some of the confusion...
and yeah... where did you find 550cc? It'll work better then stock!

Here is a rough guide to injectors maximum efficiency (6a13 VE 85%, TE 74%, I/CE 80%, A/F 12.5:1, FP 300KPa, 100% Dcycle):

390cc* at 14 PSI Boost (540 CFM) ~ 360 BHP
440cc** at 18 PSI Boost (620 CFM) ~ 410 BHP
540cc at 26 PSI Boost (770 CFM) ~500 BHP (for VE 100% at 19.5 PSI)
660cc at 36 PSI Boost (960 CFM) ~ 610BPH (for VE 100% at 27.5 PSI)
720cc at 41 PSI Boost (1050 CFM) ~ 660BHP (for VE 100% at 32 PSI)

*stock 6a13 injectors
**stock JDM 1JZ-GTE VVTi injectors

Keep in mind that as volumetric efficiency increases... so does the Air Flow... hence even more fuel is needed at the same boost levels... same if you want to get A/F ratio down... so to be on the safe side, when calculating for injectors sizes, consider VE to be 100% and A/F of at least 12.5:1 !!!

Rising Fuel Pressure helps to flow a bit more...

Convert PSI to BAR or KPA

[Kieran]

Am I reading your calculations correctly, and you're basing the injector size on a 100% Injector duty cycle?

If so, I thought you should always calculate based on a 80-85% duty cycle - to safeguard the injectors when you're at wide open throttle?

[valmes]

Above calculations just suggest a maximum flow of differently sized injectors on our cars... not a "safe" limit!

So at stock fuel pressure (300KPA or 44 PSI or 3 Bar), with stock turbos (rated at 275 CFM per turbo... 550 CFM for both) working hard producing almost 1 bar of boost (14 PSI... 1 bar is actually 14,7 PSI), but still in their efficiency range ...

... you can get out 360 BHP or a even more, but at risk of eventually leaning out (you won't be able to keep A/F ratio 12.5:1 if you go above 360 BHP) due to your injectors failing to provide the needed amount of fuel...
If you want to keep it safe - keep it stock! But we do like to push our cars to their limits!

In fact injectors are rated at fixed Fuel Pressure(mostly at 44PSI)... so if we want to flow more (i didn’t say it was safe! ) we can rise this a little. FPRegulator (stock one keeps things even = for every 1 bar of boost it ups the pressure in fuel rail by 1 bar) does just that, it allows you to "play" with fuel pressure, but you'll be pushing stock fuel pump to its limits (our pump is of better performance than EVO6, but not by much).

So with everything stock you can "safely" get 300-310 BHP.
Wouldn't have much trouble going into 330-340 BHP range! :-D
Can occasionally push it all the way up to 360 (some people do it on a daily basis and can still get away with it! :rolleyes5 )!
And can "theoretically" achieve even higher figures... like 370-390 BHP, but at risk of looking for a spare engine!

Here... if you want to calculate a "safe" sized injectors use this formula below:

Sizing Injectors
While there are many different types and styles of injectors on the market today, it's important to note that all manufacturers use the same basic method of sizing, regardless of country of origin. Domestic injectors usually measure fuel flow in terms of pounds per hour (lbs/hr) while international applications measure in cubic centimeter (cc's).

A simple way to figure what size injector you need is to divide an engine's peak horsepower at the flywheel by the number of injectors. That number should then be multiplied by the Brake Specific Fuel Consumption (BSFC). For a naturally aspirated engine, this number is typically. 50 After you've finished multiplying, divide that by a Duty Cycle of .80. The formula looks like this:

HP / Number of Injectors x BSFC / Duty Cycle

Here's an example for an eight cylinder engine that we found would need a 24 lb/hr injector:

300 HP / 8 = 37.5 --> 37.5 X .50 BSFC = 18.75 --> 18.75 / .80 Duty Cycle = 23.43

To convert lbs/hr to cc's, multiply by 10.2. To convert cc's to lbs/hr, divide by 10.2.

Readers should note, however, what Brake Specific Fuel Consumption factor is in order to use the above formula correctly. A BSFC of .50 means an engine will use .50lbs of fuel per hour for each horsepower it produces. Competition engines with high volumetric efficiency should use a BSFC of .45 while forced induction engines should use a figure of .65.

PS: For our cars it would look like this:
Stock:
280/6= 46,67
46,67*0,65= 30,34
30,34/0,80= 37,93 lbs/h
37,93*10,2=386,89 (Well... our stock injectors are 390cc)

And in order to get "safe" 360BHP we would have to run 497cc injectors!

[enigma]

... you can get out 360 BHP or a even more, but at risk of eventually leaning out (you won't be able to keep A/F ratio 12.5:1 if you go above 360 BHP) due to your injectors failing to provide the needed amount of fuel...
If you want to keep it safe - keep it stock! But we do like to push our cars to their limits!

......................

So with everything stock you can "safely" get 300-310 BHP.
Wouldn't have much trouble going into 330-340 BHP range! :-D
Can occasionally push it all the way up to 360 (some people do it on a daily basis and can still get away with it! :rolleyes5 )!
And can "theoretically" achieve even higher figures... like 370-390 BHP, but at risk of looking for a spare engine!

New engine is being fitted next week :$
I am looking for new injectors
I have the EManage ready to go in

[valmes]

Well, same here!

Full e-manage package+e01BC, GreddyWideBand+EGT sensor, Walbro 255L/H HP Fuel Pump, NGK PowerCable and some other stuff waiting to be fitted.

I am also trying to source the injectors... hopefully I can find 550-720 cc (before I fit new turbos)... .

[Kieran]

PS: For our cars it would look like this:
Stock:
280/6= 46,67
46,67*0,65= 30,34
30,34/0,80= 37,93 lbs/h
37,93*10,2=386,89 (Well... our stock injectors are 390cc)

And in order to get "safe" 360BHP we would have to run 497cc injectors!

Very interesting and useful information!! Thanks!

For my stock V6 - I've used a BSFC of 0.50 (which I've read is the figure for a standard n/a engine):

161/6= 26.83
26.83*0,50= 13.415
13.415/0,80= 16.76 lbs/h
16.76*10,2=170.95

The V6-24 is fitted with 210cc injectors I think - According to Dave, these injectors have a maximum 'Safe' rating of 192bhp before you need to increase fuelling - And the above formula bears this out! Excellent!

Look out for the all-new Galant 180-S evil5:

[borgan]

I may be the one that's wrong but I've always assumed that you divide injector cc by 5 & multiply by number of injectors for hp amount at 100% flow. Browsed the net & found the info below.


So, how much power is this injector good for? That depends on the air/fuel ratio that is used, but a good rule of thumb is to divide this flow figure by 5 to get a hp capability. So, 185cc divided by 5 = 37hp maximum fuel flow with this injector. If you want to be pedantic, it's the mass of the fuel (not the volume) which is the critical factor. Assuming a "normal" fuel density, the mass of the fuel in pounds per hour can be worked out by multiplying the cc per minute figure by 10.2. For this Bosch injector, that gives a mass flow of 18.1 pounds/hour. To convert from pounds/hour to horsepower capability, multiply the figure by 2.04. So 18 pounds/hour multiplied by 2.04 gives a horsepower capability of 37hp - the same as we got from the cc/minute figure.


Taking into account BSFC 0.5/0.65 is aprox 0.77 so you'd expect to have multiply 0.77 by total hp for new figure if you were using a turbo. However, running 10 psi of boost would mean increasing fuel pressure by 10 psi. If base fuel pressure was 43.5 then at 10 psi of boost your fuel pressure would be 53.5 psi. 53.5 / 43.5 = aprox 23% more fuel pressure. So you'd have 23% more flow through your injectors but would require 23% more fuel for each hp produced. Therefore the above calculation would apply for n/a & turbo engines.

I could be so wrong here (maths/physics were never my forte) so please enlighten me. Am I right or wrong. I thought that that (390/5) * 6 * .85 would mean that std injectors good for aprox 400 hp at 85% duty cycle. My car was mapped by Owen Developments at 378 hp & 383 lb/ft before front turbo seized. No fuelling issues on std pump, regulator & injectors. Never had any issues with excessive egt's.

Also curious that 3000 gt only run with 360 cc injectors.

[FTOLTD]

grrrr bump as it doesn't show my post ^^^^^

http://www.power-enterprise.co.jp/

[valmes]

Stock FPR is set to 1:1 ratio... so for every 1 bar of boost at manifold it rises pressure in fuel line by 1 bar. That means that "relative" pressure of an injector(tip) against a mass of compressed air pushed into the cylinder chamber stays the same all the time(at about 44 psi). So the flow is unchanged... well here:

The differential fuel line pressure (psi) is the difference between the actual line pressure and the boost pressure in the manifold. Our cars are designed to maintain a 43 psi differential pressure.

Look at the bottom of the page for fuel flow and inj sizing calculation

More links:

Fuel Injector Flow calculator (if "relative" pressure is changed)

Precisionturbo.net - about injectors

One more link with inj sizing calculator

MSD injector sizing calculations

Increasing fuel pressure

PS: MSD offers two higher flow injectors that are designed primarily for quick response time with a 12 volt saturated circuit driver. The PN 2018 Injector is rated at 38 lb/hr with 12 ohms and the PN 2013 is a 50 lb/hr, 12 ohm injector. Look here

[valmes]

David T. from RPW replied:

"WE have access to some 450cc injectors for your car but these are special
low impedance unit to my knowledge on the vehice.
There are some 650cc units I beleive i can get which will be a direct bolt
in for your vehicle same design as the stock injectors."

Still waiting for the price quote...

[enigma]

low impedence?????

[valmes]

I think we can use low imp+resistor pack (might be what was meant by "special") as long as they are "direct bolt in" in all other ways(size, top feed, etc).

... or may be they have no clue...