Rb30det Fuel Consumption

[KamikazeR33]

lower cr = more fuel and air needed to burn?

[sky30]

paulr33:- You can't adjust the microtech injector increments, thats why im forced to run richer than needed.

Seems like 10 to 11 litres per 100kms is posible with 400-550cc injectors, sounds much better than the 13-14per100km i was getting.

Im serriously looking at going power FC with my next engine set-up in my GTS4, plus im going to use GTR head with multi-throttles so a AFM ecu is almost necessary.

Anyone else got some fuel economy figures to share?

[lukits01]

I have 450cc high flows with a wolf3d

running in the engine atm

and I get about 13-14L/100Km

[paulr33]

paulr33:- You can't adjust the microtech injector increments, thats why im forced to run richer than needed.

Seems like 10 to 11 litres per 100kms is posible with 400-550cc injectors, sounds much better than the 13-14per100km i was getting.

Im serriously looking at going power FC with my next engine set-up in my GTS4, plus im going to use GTR head with multi-throttles so a AFM ecu is almost necessary.

Anyone else got some fuel economy figures to share?

Hi Sky30,

So do other ECU's allow finer increment adjustments?

Does the PowerFC let you accomplish this task?

Sure having larger injectors is different but it sounds to me like the ECU is the limitation and not the injectors. An aftermarket stand alone ECU should support any variant of injectors and allow fine corrections to them to support them correctly. To me it sounds like the microtech injector control is very limited

[r33_racer]

I know alot of drag racers use microtech and also alot of rotaries use them...rotary performance place down the road here at brendale, the bloke specialises in microtech + rotaries...Everyone knows that rotaries and fuel consumption never ever go hand in hand! Obviously the pick for people who arent worried about light load tuning for good road use fuel consumption. I dont know this spec for microtech is for sure....i just put 2 and 2 together from whats being stated in this thread and what ive heard from down the road.

[Guilt-Toy]

I been working on my RB30DET & fuel economy for a while now.

This is what ive found if i do the below then my car gets around 10.5ish litres per hundred k's 60% of that is highway driving

1: Keep the air filter clean.

2: Keep the revs below 2600rpm (around 100ks an hour)

3: Dont hit boost.

4: Dont load the engine up too hard - try not to go below 10mmhg - this can be hard to do but when you get used to it then it can be OK.

5: Keep the AFM as far away from the turbo as possible.

I do 120ks a day to work and back and have been experimenting with this for ages. I find that the cheapest option for me is to use that crappy 91 octane fuel which then forbids me to hit boost and use light throttle (keeping an eye out on knock in pfc sometimes for 2 big hills on the freeway i quickly go into ing/inj and take out 6 deg timing till i get to the top of the hill )

My setup is

Apexi PFC

Nismo 740CC injectors (has 4 holes)

Plazmaman Plenum

Top mounted GT3540 / 35mm gate

Big front mount

Q45 AFM

260rwkw on light tune for the moment.

Running it very lean on crooze and advanced timing.

I am pretty happy with the economy. But if i drive to work at 120 or 130ks an hour I could use an extra 5 or more litres per work trip (120ks)

[Cubes]

Another thing to note is that bl4ck32 and my own head have been ported by the same ppls. Not so much porting but cleaned up in order to achieve better flow around the bowl and valve stem area's, they received the usual 3 angle valve job and another type on the opposite valve as to suit the airflow direction. I forget which valve job was done on the which in/exh.

The inlet port was roughened up like hell to improve fuel atomization. Valves deshrouded to improve low lift airflow and the combustion chambers were removed of all sharp edges.

Maybe the little bit of head work helps fuel economy?

Guilt-toy, When doodling around I keep rev's under 2600rpm and use more throttle to get the car moving rather than less throttle and higher rpm.

I actually find I change up just over 2000rpm, sure I am in 5th by the time I'm at 40-50km/h but meh.. the torque lugs it fine and i'm still up with traffic if not in front.

[someonestolecc]

You guys get better economy than my SR20. ... You also have MUCH more self restraint.

[Guilt-Toy]

You guys get better economy than my SR20. ... You also have MUCH more self restraint.

Im willing to bet that my car would use nearly double yours would on full song.

[lukits01]

Slightly related question, what gear and RPM is 100KM/h on your RB30?

[WetGTR]

lower cr = more fuel and air needed to burn?

I have a tricky question......

If only the compression was raised on an engine say 8.2:1 raised to 9:1, what would be the real world results?

Has anyone just raised the compression and found that they have gone from using 16L/100km to 11L/100km?

Keeping in mind that squish plays a part if compression was raised by just using a head gasket.

Edited May 17, 2006 by WetGTR

[Craved]

Slightly related question, what gear and RPM is 100KM/h on your RB30?

that would depend on the G/box and diff you have.

[Sydneykid]

Some things I have found along the way;

1. Power FC's run big injectors better than any of the mid range ECU's. You have to get to the Motec or Autronic level to get anywhere near the injector control of a Power FC.

2. I tune the cruise and idle fuel economy with the standard lambda sensor (closed loop running) turned off.

3. I tune for 15 to 1 A/F ratios for cruise and idling. Much over that and the idle gets fragile and there is some hunting at constant cruise. I guess this is why Nissan chose around 15 to 1 for the closed loop A/F ratio aim on RB’s.

4. The closed loop running doesn’t cut in very quickly and is easily opened by a tiny touch of the accelerator. So by having the open loop A/F ratios close to the closed loop aim target, I can get as good a fuel economy as possible.

5. I have tried many different injector styles on the engine dyno, and I have NEVER EVER seen even a handful of horsepower increase from using different spray pattern injectors on a turbo engine. Personally I think injector spray patterns on turbo engines are an urban myth.

6. I run as much ignition advance as the engine will take, it makes a larger difference to engine efficiency than almost anything else you can do.

cheers

[mr_rbman]

the microtech also doesn't run closed loop does it? Which surely would cause bad/worse fuel economy?

[Bl4cK32]

the microtech also doesn't run closed loop does it? Which surely would cause bad/worse fuel economy?

the man above u answered it

The closed loop running doesn’t cut in very quickly and is easily opened by a tiny touch of the accelerator. So by having the open loop A/F ratios close to the closed loop aim target, I can get as good a fuel economy as possible.

[sky30]

I know alot of drag racers use microtech and also alot of rotaries use them...rotary performance place down the road here at brendale, the bloke specialises in microtech + rotaries...Everyone knows that rotaries and fuel consumption never ever go hand in hand! Obviously the pick for people who arent worried about light load tuning for good road use fuel consumption. I dont know this spec for microtech is for sure....i just put 2 and 2 together from whats being stated in this thread and what ive heard from down the road.

Microtech has alot of features designed especially for rotaires, thats why they are used alot.

[paulr33]

even without closed loop functionality, you should be able to get fairly good economy. ive tuned my powerfc with closed loop off and have left closed loop off and im getting better economy than i was with closed loop on.

you can certainly get good or better results if you take the time and tune the INJ map (a lot of work) and get the load AFR's spot on.

[sky30]

even without closed loop functionality, you should be able to get fairly good economy. ive tuned my powerfc with closed loop off and have left closed loop off and im getting better economy than i was with closed loop on.

you can certainly get good or better results if you take the time and tune the INJ map (a lot of work) and get the load AFR's spot on.

As i said earlier, the injector increaments on the microtech arent fine enough to run the 550cc injectors at good AFR at low rpm, its either too rich or too lean. I have spent alot of time tunning cruise maps.

[paulr33]

hi ash,

have you considered ECU change then? it sounds like you are at the mercy of the ECU, which i think should never be the case with any car/setup

[warpz0r]

any updates on fuel economy?

thanks