How can I tell if I have a VF Series 2?

[monstar]

... but a bit irrelevant, because original question was answered within 15 minutes, and the thread was open to anything after that.

Brabham I have one of those amazing engines, if you pay for the conversion I'll do you the favour of taking that underwhelming LS3 off your hands.
Believe me, there's nothing more exciting than wondering if the AFM gear's gonna assplode with every drive; adds thrill to every trip!

In reality there have been about as many [Eaton deac] lifter explosions as LS7/LS3 lifter failures and hollow valve stem breakages. Delphi I & II in the L77 don't present a problem yet the "venerable" LS7 lifters still fail, like they all do.
Part of the thrill really innit!

 

[blackve76]

Yes people end up with this car for a whole range of reasons, mine is mega performance and efficiency over mega miles. No garage time, DIY tune, no dyno charts, hose down but no waxing / polishing, no dealer servicing, no branded bolt-ons.
I totally agree VFII is brilliant, an excellent evolution that should have happened five years ago.
In accord with that I'd like to believe the 0.2 l difference guarantees greater performance stock or even more potential when tuned. But after searching for a couple of years now can't find one iota of difference to the outgoing, all things being equal like tune, gears, bolt-ons.
I've seen real world dynos 220-240 rwkw calibrated and credible both engines out of the box. The practical difference is actually less than dyno error, there's quite a bit of placebo effect going on is all.

Pirates back......

 

[monstar]

Pirates back......

Granted, to suggest that the fuel-saving version of the GenIV engine developed and evolved in Australia for this particular car and our fuel is actually about as good as the plain vanilla crowd pleaser... is offensive as it sorta goes against the grain. Roger that and I beg pardon. Hardly treason enough to brand me pirate and have me dangling at the end of a long rope, savvy?
So in joyful strains let's sing in praise to GM almighty who watches over and lovingly delivers us... Glory be to the LS3 King... and a Happy and prosperous New Year to Ye.

 

[Forg]

But ... if you have to modify an L77 to make it nearly as good as an LS3, longevity issue aside, doesn't that mean the LS3 was better in the first place?

I mean you can modify just about anything to make it better.

 

[Geoff6666]

Thanks guys for a very entertaining thread! I have an L77and I'm pretty happy with it. Sure, an LS3 would be better, but it would cost me a lot to change it. (i.e. buy a new car) I thought 30+ Kw gain was incredible for 200cc increase in capacity. I believe they have improved ports and an improved exhaust system as well. Maybe someone with this knowledge can let me know?

 

[Forg]

I suspect monstar knows pretty-much what he's talking about (he's stretching the truth a tad when not comparing stock-for-stock, but knows what he's talking about WRT comparisons) ... it's all about the cam, by the sound of it, and the tune to match.

 

[Martyr]

But ... if you have to modify an L77 to make it nearly as good as an LS3, longevity issue aside, doesn't that mean the LS3 was better in the first place?

https://en.wikipedia.org/wiki/LS_based_GM_small-block_engine

The L76 is derived from the LS2.
The L77 differs from the L76 with its inclusion of Flex-fuel capability, allowing it to run on E85 ethanol.

The LS3 was introduced as the Corvette's new base engine for the 2008 model year. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6,162 cc (6.162 L; 376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551-inch (14.0 mm) lift, a 10.7:1 compression ratio, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.


TLDR;
LS2
L76 = LS2 + AFM
L77 = L76 + E85

LS3 = bigger bore LS2 + mods

 

[monstar]

https://en.wikipedia.org/wiki/LS_based_GM_small-block_engine

It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551-inch (14.0 mm) lift, a 10.7:1 compression ratio, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.

That really doesn't clarify L77 vs LS3?! Text refers to difference to previous designation LS2, presumably written for US audience.
L77 is by comparison identical to LS3 in all areas mentioned, except valvetrain and 0.058" larger bore. That's 3/4 mm either side, not a world apart but still notable as it extends capacity (more importantly CR) slightly.
Specifically the figures which do make a difference are the peak Intake valve lift being 1.0 mm less in order to extend longevity of cam / lifter at the face (larger base circle), and 4° Intake duration.
In other words L77 has street cam optimised for higher volumetric and thermal efficiency utilising AFM (cylinder deactivation) and ethanol - focus is part throttle, cruise and lower RPM - torque focus. PT torque favours L77 lift and events.
The LS3's bore creates a marginally better rod ratio and CR suited higher RPM - later IVC etc for HP focus. The latest LS3 cam spec is very similar to the LS2, swapping either cam into the L77 gets immeasurably similar performance.
Alternatively a cheaper yet effective mod mentioned above is to swap out the L77's rocker arms, springs and pushrods (simply by lifting the valve covers) to produce same intake lift and duration as LS3 with more exhaust duration. Original LSA remains same hence emissions under control, the main difference after VE tuning via steady state / load is the -0.1° diff in overlap (Bee's dick).
So without rockers same bolt-ons, there are near stock differences in the tune to suit cam and purpose. Full bolt-ons accentuates this to a degree, maybe 20rwkw top end difference. Not necessarily better overall is what I was saying earlier, difference valve events mainly. With the rocker mod the L77 has more tuning potential, especially with ZL1 fuel pump and other tweaks for e85.
Lastly the hollow intake valves are fantastic, but without $5k-$8k engine work they don't add performance near stock.

 

[monstar]

TL;DR
L76 was not without failings but revision in form of L77 played a significant role as tech development trunk of the LS tree, spawning the L99, which laid foundation for ecotec3 (GenV) including LT1 & LT4. Its importance and potential is undersold and misunderstood in relation to hype positioning the LS3:

https://en.wikipedia.org/wiki/LS_based_GM_small-block_engine

The L76 is derived from the LS2.

Yes, in one sense because LS2 has same distance between bore centres and internal design could say is derived from GenIII LS1. Most people call LS2 a GenIII because of outmoded gear like cathedral heads etc but is classified as a GenIV despite being more like the LS1. The L76 car engine was a breakthrough developed here (2005), first in the world with defining GenIV features like different ECU, Heads (first 5364 casting originated with Aussie L76 not L92 per 2007 Escalade), Intake, timing [basis], cylinder deactivation and VVT cam core.

The L77 differs from the L76 with its inclusion of Flex-fuel capability, allowing it to run on E85 ethanol.

Different cam, different fuel pump and controller, different lifters, different LOMA, different throttle, MAP and MAF sensors and intake, different water pump, different a/c and alternator. There's more...

The LS3 was introduced as the Corvette's new base engine for the 2008 model year. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6,162 cc (6.162 L; 376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551-inch (14.0 mm) lift, a 10.7:1 compression ratio, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.

That's riddled with errors from year of intro to bore size - coz Wikipedia.[/quote]

LS2
L76 = LS2 + AFM incorrect see above
L77 = L76 + E85 incorrect see above

LS3 = bigger bore LS2 + mods. No.

More correctly the LS3 evolved from L76, and the L77 update makes them nearly identical except to an expert eye. LS3 is not the evolutionary Grail in this context, L99 was. Current top branch of this development trunk is LT1.
If one were to simplify the performance difference between LS2->LS3 the key change is not displacement - rather the induction and combustion developments in our L76/L77. In general terms that is the venerable 5364 -> 821/823 heads and the tunability of the e38.

 

[Geoff6666]

My head hurts now. . . . .