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[LS3] Is the Euro 5 VFII affected by detuning... is it 304?

monstar

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If your going to note putting higher ratio rockers on one, you cant leave out the other.. apple's to apple's.

Ls3 daily driving charectoristics aren't going to change leaving the stock cam as is. Having more up top is just a bonus..

This is one example of how close they can be stock. Theres plenty of vf1 only just cracking the 200rwkw mark. Whilst majority of vf2 cracking the 230-245kw mark.

Maybe you need more stock vf1 dyno graphs to analyze. Do you really think the vf1 would have 299fwkw and have holden market it as 260fwkw? No chance in hell. But it suits your agenda so we'll roll with it..
There you go again, don’t quote figures without evidence, that’s for the general forum not here. Stop putting generalised 2¢ worth without backing it up with qualified evidence. Not welcome OK? Third fricken time nobody is interested in vague comment here in the tech section.
Are you just trolling to get a reaction?
Piss off with your maxims else put up some qualified data.
In any case, higher ratio rockers won’t help the cam in the LS3.
 

PeteSS

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Hmm. a stock VF1 pulling 236rwkw ?

Mine might even crack 500rwkw on that dyno....

One thing that needs considering too is the majority of tuners, be it Harrop, Walkinshaw, or your smaller operations (Russo, OZtrack, CHE, Sam's, etc) all quote higher power figures for the same mods when comparing a VF1 to VF2.

For example the basic Harrop mods on a VF1 is quoted at 325fwkw, whilst the same mods on VF2 is quoted at 375fwkw.

they can't all be wrong ??
 
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monstar

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Hmm. a stock VF1 pulling 236rwkw ?

Mine might even crack 500rwkw on that dyno....

One thing that needs considering too is the majority of tuners, be it Harrop, Walkinshaw, or your smaller operations (Russo, OZtrack, CHE, Sam's, etc) all quote higher power figures for the same mods when comparing a VF1 to VF2.
For example the basic Harrop mods on a VF1 is quoted at 325fwkw, whilst the same mods on VF2 is quoted at 375fwkw.
they can't all be wrong ??
Yes @PeteSS there is a lot of unqualified misinformation floating around and of course it is in the shop's interest to portray the starting point as low as possible and the end point as being incredibly high.
The disparity in specific reports is the purpose of this thread, so lets get some qualified dyno reports and analyse them. There is a lot to learn from about the engines (specifically cam) and what is / isn't possible by analysing and understanding both fact and fiction.
The one credible real-world source has the stock VFI at 236.4 rwkw, and VFII at 242.2 rwkw. I have had conversations with the operator, know his background enough that he was a contributor the 821 development through L92 prototypes before the our L76 and intake were finalised (several years before the LS3), the nature of the tools and software hence high confidence in the figures backed by actual strip times.
Do I believe any properly calibrated and corrected dyno log? Absolutely as long as all the crosschecks and checksums like typical BMEP add up, sure.
Problem is most dyno logs are accepted as being accurate at face value, and are not much more than normalised line art to depict a marketing goal.
For the time being the stock delta VFI->VFII, verified by runs down the 1/4, is 5.8 rwkw.
I've yet to come across any technical source inside GM or aftermarket who can fully explain the cam events of the L76 vs L98 vs L77, and why. Yet in the aftermarket there is always a tried and trusted cam from yesteryear that will improve peak HP. Just need to change a few thing$...
Am I skeptical about the snake oil tactics and overinflated figures and the performance equation dumbed down to one number? Sure.
Anyway Pete if you have some stock VFI or VFII dyno logs to post would be appreciated.
 

monstar

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Another way of asking the same question: When did the LS3 tune (camshaft?) change to make peak at 5400 PM?
Since the first dyno released by GM Powertrain in 2008 through HSV / GXP in 2009 through Camaro in 2010 and Chevy SS in 2015, the LS3 made 317 at 5900. The HSV's GTS 325 made 325 at 6000 and the SV340 made peak at 6100.
View media item 496
Indeed we believe the output of our LS3 is the same as the US car. So...

Many of the VFII dyno charts clearly depict LS3 stock peak power (and some even when modified o_O) occurs at 5400 RPM, depicted as ~183 kph in 3rd gear pulls.

With it's marine variant, with a different camshaft, GM shows it is possible for the LS3 to make peak power at 5400. This suggests VFII may have a different camshaft to the Chevy SS and HSV models.
View media item 495
This correlates to the anomaly evidenced in recent video trial of the VFII vs the KIA Stinger GT where the first shift from 1st-> 2nd was at a surprisingly low speed, around 45 kph, or 5300 RPM.
That is not the 6300 WOT RPM shift point setting in the tune, rather it's the Part Throttle Shift (vehicle speed all part throttle normal shifts will occur based on throttle position) triggering at 43 kph. So yeah, that's different! Why has it been calibrated to do that for this engine and ignore the WOT RPM Shift setting?
 
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lmoengnr

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This coincidentally is also the WOT shift point 1st-> 2nd gear with the VFII stock tune, which came as a surprise when evidenced in the recent video time trials of VFII vs the KIA Stinger GT here.

MY17 transmission tune, WOT shift point 1st to 2nd is 6200RPM with transmission in normal mode.
 

monstar

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Here is a good example, a screenshot from a video testimony posted in another recent thread. Although there is no data basis shown for determining the level of output (data panel removed / not calibrated nor corrected), it does indicate the VFII stock power peak occurring at 5400.
The purpose of the diagram is to show that with a tuning target near typical LS3 peak (6150 @ 208 kph) the engine is shown to make 385 kW and presumably driveline 304 rwkW.
Screen Shot 2018-03-15 at 12.43.59 pm (2).jpg


Also Post #6 above shows stock VFII tuning target at 5400 again, also claims with CAI and tune makes 285 rwkWw (362 kW) at same RPM.
 
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3rspecB

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I will load the Chevy SS tune and perform a detailed comparison to the VFII tune calibration in detail and post results here.

Yes please. From my powertrain colleages who worked on both variants, they have advised that the engine cals are slightly different (more agressive for the Chev SS). Also the Chev SS stock exhaust is different to the stock Aussie VF2 LS3 exhaust. Chev SS sedan utilises H pipe in the mid section.

Resized_20180315_145535.jpeg
 
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monstar

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Yes please. From my powertrain colleages who worked on both variants, they have advised that the engine cals are slightly different (more agressive for the Chev SS). Also the Chev SS stock exhaust is different to the stock Aussie VF2 LS3 exhaust. Chev SS sedan utilises H pipe in the mid section.
I was hoping to find a J1349 chart for the VFII, not published nor ever listed on GM Powertrain, so that 5400 stock peak remains a practical mystery for the time being :confused:.
 

3rspecB

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I was hoping to find a J1349 chart for the VFII, not published nor ever listed on GM Powertrain, so that 5400 stock peak remains a practical mystery for the time being :confused:.

I'll ask the question. All the engine/trans work for VF2 LS3 and Chev SS LS3 was done internally by GMH Powertrain so unlikely a J1349 will ever be publicly released. Engine dyne, chassis dynes and ecu/trans cals all done here..
 
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