Jump to content
SAU Community

Recommended Posts

I have 660cc denso injectors im pushing out 220rwkw

but on normal driving im only getting just under 300km per tank

i know i went over kill on my injectors but do you think if i went the gtr injectors

it would be worth it Would i save more fuel or will it be the same still?

Im running a wolf ver 5

Link to comment
https://www.sau.com.au/forums/topic/157793-injectors-and-fuel-consumption/
Share on other sites

The injectors are way overkill for the power you are developing. What is your power target?

Obviously it would be easier to achieve fine control at light load with smaller injectors, but I'd suggest two main culprits:

Your light load AFR

Your driving style. Use lots of throttle and a bit of rpm, and you will use fuel; it's that simple.

Injector sizing may be a small part of the issue, but I'd look at the other two as the main cause of fuel use.

I have similar max power to you, but consistently deliver 400-440km per tank (50-52 litres to fill).

cheers.

660cc injectors are overkill for that power requirement. Most guys on SAU have had good results with 550cc which will more than feed what you want. However, run what you have, and aim on good consistent tuning.

Here's a development log I made in the past week:

post-19642-1172280065.jpg

Pretty self explanatory, with the numbers being average AFR:1 logged during a run, with O2 feedback turned off. My target from P3 - P9 load is 14.7 but I tolerate a variance of between 14.6 - 14.8. Extensive data logging has shown that you do get variance from run to run, but multiple variance analysis shows that over the long run it is fairly tightly controlled. There is a bit (lot) of mucking around to achieve the consistency though.

I'll pull up a shot of injector duty cycle too, just to demonstrate how much increase you get with load.

Check out how fast the flow requirements ramp once you load the engine in any rpm range, and if you keep sticking the revs into it. And if you've got more power, then you're going to use more fuel.

If you want economy then you need to keep it in that light load zone.

post-19642-1172280968.jpg

So the answer remains the same:

mechanical spec (this includes injector flow rating) will play a part, but not as big as you might think

tightly controlled AFR is important (yep, tuning)

controlled use of the throttle is the major factor

Hope this helps. :(

cheers

Dale

I got 430rwhp with PFC & AFM with Nismo 740cc injectors and on my last RTA Emissions test it recorded 11.8 litres per hundred which is over 500ks to a tank (60 litres) it did fail the emissions test because i tuned it to run good on fuel.. now after i retuned it it uses more fuel then before (keen to pass this test)

So yeah you can have big injectors and get good fuel economy. maybe its the computer that cant handle the injectors properly i do keep hearing that apexi power fc's handle big injectors well so that may be why mine is the way it is.

im getting my tuner to have a look at my cam timing cause he thinks its reterded a fair bit

im not making good power for what i have in my car and its all possibly related i will let you all know how it goes

its going in next monday

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Stock ECU (or more accurately stock tune) absolutely refuses to go over 10psi and behaves like you have seen. The Nistune is the same if it is the stock tune. If the Nistune chip has been tuned, the resulting tune could be literally anything for any combination of parts. The Nistune just makes the stock ECU Tunable.
    • So stock ECU does not like anything above 10 psi?  That Nistune one is just for "try" if it will be any different, I know it need to be tune for that. I know but YOU may know about these problem but i/we dont. They few little Skylines here let alone people who know anything about tham so that is why iam asking here  
    • So now we have a radiator with no attachments whatsoever. It lifts up with a particularly tight spot between the drivers side air box mount and the lower radiator outlet, but if you've got this far you will sort that too. This is the lower mounts with the rad out so you can see where the rubber bushes go, it is a straight shot upwards Done! Assembly is the reverse of disassembly, with blood less likely to be shed.
    • Right, onto the second last trick. The Air Con condenser is mounted to the front of the radiator and stays in the car when the radiator is removed. There are 2x 10mm headed self tappers holding the top of the condenser to the radiator, remove those The bottom of the condenser is attached to the radiator with clips. You need to lift the condenser out of those clips and clear (up, then forward). f**ked if  could work out how to do that last bit with the front bumper on. I hope you can, and you share the trick.  Bumper removal probably deserves its own thread one day once I've recovered the will to live, but basically you need to remove the wheels, front inner guard liners (clips and 10mm headed bolts), the self tapper between the guard and the bumper at the rearmost point of the bumper (same as an R32 that bit), any remaining clips at the top/front of the grill, an absolute bastard design with a plate that holds the top of the bumper above the headlight each side (only 1 bolt which is tricky to get to, but the plate catches 2 places on the bumper and must be removed....carefully!) and push clips between the bumper and guard under the headlight. If you've done all that you will be faced with wiring for the fog lights on both sides and in ADM Q50 RS at least, 4 nasty tight plugs on the driver's side for the ADAS stuff. So, the clips at the bottom look like this on drivers side (looking from the front) And on the passenger side (also from the front), you can see this one is already out Clearance on both of these are super tight; the condenser needs to move up but the upper rad support mount prevents that, and the radiator can't move down far because it is (rubber) mounted. Once you achieve the impossible and drop the condenser off those mounts so it does not stop the rad moving, you are good to go
    • OK, next the shroud needs to come off and there are a couple of tricks. Firstly, there is a loom from near the passenger side headlight to the fans, coolant temp sensor etc and there is no plug to undo.  In my case I was OK to leave the shroud on top of the engine so I just undid the passenger side fan plug and about 10 of the clips which gave enough free wire to put it aside. The fan plugs were super tight, the trick I used was a small falt screwdriver to push down on the release tab, then a larger flat screwdriver to lever the plug out of the fan unit....be careful with how much force you apply! If you need to remove the shroud altogether for some reason you will have to deal with all the plugs (tight) and clips (brittle)....good luck. I removed all of the clips and replaced them with cable ties that I will just cut next time. Also, in the Red Sport / 400R at least, the intake heat exchanger reservoir hose is bolted to the shroud in 2 places with 10mm headed bolts; so remove them (the hose stays in the car; no need to undo it at the t fittings down at the radiator lower mount. Once you've dealt with the HX hose and the wiring loom, there are 3x 10mm headed self tappers holding the top of the shroud to the radiator; remove those.   The shroud then lifts out of the bottom mounts where it sits on the radiator, up and onto the engine out of the way. Simples
×
×
  • Create New...