New VF commodore

[RevNev]

The 3.6 SIDI engine was so much better. Actually the 3.6 was better all the way through from VZ, VE and VF.

With the option of a V8 we tend to underestimate the 3.6 but they're in fact pretty good particularly the LFX variant. There not as torquey down low as the 4 litre Falcon but they rev nice with better top end. With an exhaust and tune, they're not slow and rather an impressive V6 I think.

 

[RevNev]

I'm talking about when you're accelerating normally away from the lights, when there's a slight uphill incline and you need to use the accelerator slightly more with the 91 than with the 95 so it just doesn't quite feel "right".

There's a long hill in a 100kmph zone I've noticed on 91 in this particular SV6 it kicks back to 4th half way up on cruise control. With 98, it'll go up in 5th gear. The V8 of course has the torque to stay in 6th (top gear). Throttle response is better on 98, not massively, but a noticeable improvement.

 

[YRUHATIN]

91 would be more than fine to run on a standard sv6 but the occasional tank of 95 or 98 would do it some good.

I always notice that I get more mileage out of 98 and 95 than I do with 91, i guess 91 burns quicker..

 

[Forg]

For the most, i'd say there is bugger all difference beyween 91 & 98, though in some high air temperatures cases the engine may be a little doughy on 91 as compared to 98. However, for many people even that is probably OK as it's safe (thanks to the knock sensor) and saves $15 odd a tank per week (or $750 per year).. Crawling along in traffic, many find the $750 more appealing than any perceived efficiency improvements with 98RON.

Our spending difference in the auto VS V6 wasn't near that much, but the fact that on 91 it felt like something was wrong all the time made it worth the extra expense for 95.

For the VF I just use 98, that's what it was designed to use & everything else involves electronomical gubbins to stop it from assploding itself. I couldn't be arsed with the months of experimentation for the sake of a few bucks.

 

[lmoengnr]

Our spending difference in the auto VS V6 wasn't near that much, but the fact that on 91 it felt like something was wrong all the time made it worth the extra expense for 95.

For the VF I just use 98, that's what it was designed to use & everything else involves electronomical gubbins to stop it from assploding itself. I couldn't be arsed with the months of experimentation for the sake of a few bucks.

Usually run mine on 95, when the 'discounts'(finally) kick in, I'll treat it to 98.

 

[Skylarking]

Our spending difference in the auto VS V6 wasn't near that much, but the fact that on 91 it felt like something was wrong all the time made it worth the extra expense for 95.

For the VF I just use 98, that's what it was designed to use & everything else involves electronomical gubbins to stop it from assploding itself. I couldn't be arsed with the months of experimentation for the sake of a few bucks.

Sorry, I should have been clearer, those $ numbers were a guestimate based on tank size adjustments as compared to another of my vehicles fuel usage on 91 & 98. So it may not be what others who have gone to the trouble of testing their LFX/LS3 would find

As for the LS3, GM itself states "premium fuel recommended, not required" which means it can run on midrange gasoline or their lowly regular

But in the USA they use the following three main grades fo gasoline:

Regular (the lowest octane fuel–generally 87)
Midgrade (the middle range octane fuel–generally 89–90)
Premium (the highest octane fuel–generally 91–94)

Of importance is the fact that in the USA, the gasoline number shown at the bowser is based on AKI = (MON + RON)/2.
AKI numbers are generally 4 - 6 points lower than that shown elsewhere in the world (where presumably RON is used).
That means 87AKI ~ 91RON... so that out RON fuels of 91, 95 & 98 lines up with their AKI fuels of 87, 90, 94

So, according to GM, their LS3's are OK on Regular and as such wont assplode if you use it (though it will produce some more herbs)..

However Holden simply stated "Premium fuel recommended" which is more vague, though the implication is one can still use something else as opposed to Holden having stated "Premium fuel required" where one can't use a lower grade of fuel for fear of their engine actually assploding itself.

But Holden were not so explicit, so 91 is OK, which is also why they couldn't blame fuel quality for their shite injector issues

Still, i'd like to see fuel differences quantified via various dyno runs with the various octaing rating fuels an engine is designed to run on, because my ass and grandpa driving style can't really tell the difference. So far I've onkly heard anecdotal evidence of how the car feels (which i don't outright dismiss).


Still, each to their own as it's their money to spend as they see fit and serving your donk a good drink of 98 isn't a bad thing

 

[Forg]

Are those comments WRT an LS3 in the USA relating to a VF?
It’s not that they’re not valid, but except for the cars we shipped over there, I wouldn’t expect the same engine tune; and it’s the tune which determines the fuel it can run on (to some degree ... I guess you can get such low octane that no engine management can help it ).

I‘d also be quite interested to see dyno-run comparos! Would be a little difficult, you’d have to do some tank-emptying between runs I reckon, as it wouldn’t be valid to use 3 different cars.

 

[Skylarking]

Yes but I also expect a tune would depend on chosen fuel octane an engine should run on, emission certification issues and marketing but least we know the engine is capable of 91 to 98 octane A
and that both GM and Holden specify premium recommended (so can use 91 - 98). We also know Holden states LS3 is Euro 5 compliant (but I don’t know what GM states for Chevy SS).

Regardless, knock sensors do (and must) take care of even an old batch of fuel, be it 91 or 98 (and who knows what octane rating an old batch of 91 will actually be).

Guess if one has interest and TIS2 access, one could always check the ECU calibration file for VF II against a Chevy SS and that would answer the question whether they are the same (but I do note that GM lists 310kw & 563nm for Chevy SS so it’s possibly there are some different or it’s just dyno differences, corvette has even more herbs).

Doing multiple dyno runs could have been easier if Holden kept the cabin access hatch (or even had a tank drain plug). With an access hatch one could make a jumper cable for electrical and fuel line and use a smaller 10ltr remote tank with pump. But no access hatch and no tank drain plug makes it more difficult. Its also something the tuners probably wouldn’t be interested in... since they want to sell tunes with bigger numbers after some mods (and 98 along with some mods will give them that).

 

[Forg]

Skylarking, that SS 310kW rating could be because the Australian method of quoting power needs to have ancillaries attached, whereas the US is still using the method from the 60's which is max power with nothing attached (eg. even the juice to run everything comes from an external source as there's no alternator).

 

[Skylarking]

Yeah I suspected that was the case, the old ECE/DIN verses the happy SAE standard which I poorly lumped under ”just dyno differences”