VF Series 2 V8 Fuel Consumption

[BLOWN-WH]

The idea of "idling to warm up" is a hangover from carburettor days.

I know you are correct here as i have heard this before also.
Gotta break the habit thats all

In truth i reckon 2-3 mins should still be ok before you drive off. I can't see that doing much harm to the engine (at least i hope!).

 

[panhead]

The idea of "idling to warm up" is a hangover from carburettor days.


See this link: http://www.roadandtrack.com/car-culture/videos/a30249/why-you-shouldnt-warm-up-your-car/

As is pumping the accelerator half a dozen times before turning the key.

Sir Les is right, start and drive.

The Commodores are designed to make allowances for the lowest common denominator so not much damage will occur but nothing is gained either while fuel is being wasted.

If it was a highly strung Euro performance car then the owner's manual would tell you not to warm idle it.


.

 

[redvxr8clubby]

Sorry I know this thread is primarily for the LS3 6.2 L engines but I was wondering to find out if the figures I'm getting on mine which is a L77 6.0 L is considered ok?

Originally when I picked up the car it had a full tank a fuel and was showing 390km distance to empty. Today I got the fuel level close to empty and filled up with BP Ultimate 98 and managed to get it showing 480km distance to empty now. Avg fuel consumption is showing @ 15.4 L.

With AFM and a 6 speed trans I would have thought I'd be getting better fuel economy figures compared to my last Gen V8 I owned (WH) LOL

I've previously had a LS1 VXII Calais and still have my VX R8 Clubby (manual), I also have a VE AFM SS - I'd say AFM fuel saving as about 10% over my Calais. AFM only activates on very light throttle, even with pretty light throttle openings, AFM deactivates.

 

[monstar]

the calculation for the fuel usage can be changed in the tune file, but it is usually pretty spot on so as long as the injector data is correct then actual fuel used will be correct, with "actual fuel usage" being correct the error is in the L/100 calc which has all the variables that are constantly changing

Nah, not for e38? how do you change that?

 

[07GTS]

Nah, not for e38? how do you change that?

yep E38 E67 and the flex fuel 08 E38 and newer have a sliding scale for ethanol percentage, even some gen3 can, its the "fuel density" in HPT, its the only way i can keep my calculations correct for a scaled tune to suit my injectors

 

[monstar]

yep E38 E67 and the flex fuel 08 E38 and newer have a sliding scale for ethanol percentage, even some gen3 can, its the "fuel density" in HPT, its the only way i can keep my calculations correct for a scaled tune to suit my injectors

Ah ok, but fuel composition / density is not the reason Instant Fuel Economy on my DIC shows like +50% more than actual at times. Can't compensate GenIV on EFIlive like you could GenIII on HPT.

 

[07GTS]

the density gets it correct for the injectors so when it says u used 1 litre that u actually used 1 litre, then all other fuel economy is based on that but as i said all the other info is a constantly moving target like the "instant liters/100" is only accurate if u stay in the exact situation for a full tank worth of fuel which is impossible, also the fuel tank level is used so it knows how much fuel is in the tank as a calc and thats not perfect either so the tank might say its gone down 5 liters and usage say u used 3 liters so then it has to change it calc to suit less fuel left in tank also, if anyone wants a good average fuel just dont reset it for 6 months then u will have a more average use that wont be affected by the little things

 

[monstar]

Using CALC.FUEL_FLOW based on a MAF value is still correct, so I can use l/hr divided by km/hr to get l/100 using logging software on phone. That is near dash most of the time so no biggie. However the CALC.FC.IFC (Instant Fuel Consumption) used to display on the DIC must be based on stock fuel rate lookup, not actual MAF values so becomes out of whack with mods. Also my tune is blended open loop with modified fuel pressure, hence IFR.
With e38 or e67 the work around by adjusting a density offset as you suggest the LS2 has in the e40, is not possible, at least not in EFIlive.

 

[monstar]

Ok well let me ask something bold, given I have an SSV Redline as a daily driver.

What if anything can be done to increase the fuel economy?

Hypermiling to save a quid on fuel in a two tonne V8 does makes sense if you intend to clock several hundred thousands of kms, for work (definitely not worth it for most garage queens). Tuning is the most expensive part, so the way to net savings is with a small investment in a wideband sensor and scantool. This ultimately pays dividend with spend less at the pump and with your tuner.
TL;DR - Tuning and mechanical tweaks are required for serious consumption drop, tuning for alternative, cheaper fuel is key.
Stage -1 Drive like you are 10 mins from the servo on the last five litres of fuel.
Stage 0 - Swap 2.92 gears, retain standard plugs and thermostat. Keep lubrication fresh, air filter and sensors clean (MAF, O2). Use Unleaded e10 fuel that's 95 RON (eg United). Do full wheel alignment with 245s and consider nitrogen to easily set optimum tyre pressure.
Stage 1 - Minimise pressure drop through induction and exhaust with off-the-shelf bolt-ons eg. Air Dam, CAI, catback or axleback.
Stage 2 - Maximise velocity and air speed efficiency with devices tuned to (RPM of MBT and peak HP) of near stock motor eg. ported throttle, extractors, secondaries and HFCs, proper x-pipe.
This necessitates a tune - Swap [electronic throttle position and DFCO] per US Camaro. Calibrate fuel injectors for idle / cruise (no extra pulse, SOIT etc) smooth out part throttle transient fuel compensation.
Stage 3 - Increase the volumetric efficiency by introducing tumble in the runners via manifold Rod Mod, install high ratio rockers and beehives to increase time / area duration of stock cam for more torque with better fuel atomisation. If auto then consider retrofitting revised AFM per L99. Tune again.
Stage 4 - Raise the overall thermal efficiency through increased compresssion and expansion ratio by shaving heads, decking block (or both) and installing a cam optimised for max torque in the operating range. Consider VVT cam and phaser per L99. Swap stock flimsy balancer for a larger Fluidampr to smooth and store torque. Tune again.
Stage 5 - Patch the fuel composition sensor and tune again to enable flex fuel calibrations in the tune and fill up with ~$1/litre fuel where available + similar consumption = better $/km.
Bottom line: Stock BSFC is 0.47 on PULP, with some minor modification you can achieve much better than that. Better still you can get similar (0.50) on e85, which comes at 1/2 to 2/3 the price. Most NA mods are all about HP and can blow BSFC out to 0.60 while screwing cruise torque and quality of transitions.

 

[WHYtheFACE]

Currently averaging around 15.5L /100km in my vf2 redline.

Cruising at any sort of speed limit/70+ will see it sitting between say 7L/ and 16L/ sitting on 110 in 6th will be around 10-12L/100km at the lowest, so pretty average on fuel compared to the claimed figures, but surprisingly better on fuel than any of the old pos commodores I've owned before this. (VT ecojet on gas/L67 VT, VU SS LS1) all of which were pushing 20L/100km all the time.