I decided that given all the questions on this board, I'd write a little section with some answers about the L76 and LS2 engines.

Firstly, the LS2 is being phased out because it is old. Its been out since 2005, and it was out all through 2005 and a little bit in 04 (as the 05 models arrived then). So by the time the G8 launches in 2008, the LS2 will be a four year old engine. This is detrimental to General Motors, as its then just like the other two of the big three in that it keeps its engines around forever. And as Ford and Chrysler are not in the cush, they wouldn't want to be who you took your ideas from huh?

But look at BMW, who seems to have a new engine with every new model. Mercedes is probably designing a new V8 this week, and Audi released a new engine in the time it's took me to write this! But look at struggling car companies: the 4.2 Liter supercharged V8 that Jaguar is using for the XF is over 10 years old! Is Jaguar doing well? No, and its no wonder. In tens years so many advances have come about that have made it possible for other car companies to make the same power on naturally aspirated engines, checkout Maserati. And you know it could be doing better in the MPG department, given they just updated their software.

In other words, successful car companies update and revise their engines and release new ones quite often. GM does not want to just retain their fanbase: its already kinda small. They need to take market share from other car companies, and if other car company's customers want new engines often, then GM needs to do so as well.

Now onto the G8: its been rumored that these are not the L92 heads, but rather an all new engine-heads code called L76 as well. They would basically be cheaper-to-make L92 heads. But until a special someone from Australia gets the guff to take his/her Commodore to a place and ask them to remove the heads so we can figure out what they are (Immortal, pretty please? we will :hail:you as a god if you do!).

As to the engine internals, GM High Tech Performance Magazine is reporting that this engine is just an LS2 with the new intake and heads (although they do not specifically say its the L92 heads, they do mention them), and a different cam. The compression ratio was reduced by changing the settings in the on-board computer to detune for 87 octane. Apparently all you will need to do is retune the spark timing and fueling to get back the original compression ratio and wring maybe 40hp out of the car. A new cam will remake the L76 into an LS2 with L92 heads and L76 intake, and SLP Performance was able to use a new cam with L92 heads on an LS2 to make 500hp at the flywheel!

So what we already knew was that the L76 was a blessing in disguise to us enthusiast tuners, since it was cheap. But why buy a GXP for $35,000 without options when $3000 in aftermarket parts will get you more performance out of the GT level? Let the sleeper-car-battles commence this coming 2008.

As to future GM engines, GM is rumored to be already in the works for a new Generation V small-block for the turn of the decade. The Gen IV will last as the LS3 (the new 6.2 Liter engine for the 2008 Corvette) and LS9 engine (in the 2008 STS-V, unless the STS being canceled takes effect 2008), in addition to the L76.

So, new cam, engine tuning and exhaust (that five hundred horsepower from SLP was with free-flow exhaust) should land us in the mid to upper 400s with the L76.

Nice.

Very nice first post!

Old? GM made that 3.8 L for years(like 30)! 4 Years doesn't seem old.

Awesome post

Appletonrc: yes GM made the 3.8 V6 decades ago. Doesn't it seem none to odd that all cars with that engine have not been selling as well as their import-counterparts for oh 25 years? The dominance of GM was challenged back in the 70s all through the 80s, with the 90s only being a good spot thanks to truck and SUV sales.

Some argue that cars with that engine also sold reasonably well at the time, but I for one never like to count fleet sales as part of total sales, but rather a separate unit. Reason being that fleet models tend to be sold at so low of margin that the manufacturer barely makes a profit. It DOES, don't get me wrong, but a small one by comparison to whats needed to run a company.

Also, the last incarnation of that engine I am familiar with got 240 hp: todays 3.5 liter of Ford makes 250, and Lexus, Infiniti and the latest Cadillac engine (in the CTS) make 300 hp. And get better gas mileage (some argue the figures are the same, but it depends on how you drive: people in the Infiniti G35 Sedan are getting 4 mpg better than their pre-2008 EPA estimates with conservative driving).

And in other news, I recently found out that the two interior options on the G8 are possibly not all thats going to be offered. Someone at cardomain said they spotted a test mule in Sydney with a yellow leather for the seat inserts. This is the same guy who told me that the Nissan GT-R would debut in hot pink, so I don't trust it entirely. Still, I guess its something to hope for.

A hot pink Nissan! What to do, what to do. Ha ha. BTW GM has nevr actually stopped making the small block V8, just various upgrades but each and every V8 in current production can trace its roots back to a 265 which became a 283-305-350-etc and for the record, the L76 in the G8 is Mexican-built, but the V6 is Australian sourced.

Appletonrc: yes GM made the 3.8 V6 decades ago. Doesn't it seem none to odd that all cars with that engine have not been selling as well as their import-counterparts for oh 25 years? The dominance of GM was challenged back in the 70s all through the 80s, with the 90s only being a good spot thanks to truck and SUV sales.

Some argue that cars with that engine also sold reasonably well at the time, but I for one never like to count fleet sales as part of total sales, but rather a separate unit. Reason being that fleet models tend to be sold at so low of margin that the manufacturer barely makes a profit. It DOES, don't get me wrong, but a small one by comparison to whats needed to run a company.

Also, the last incarnation of that engine I am familiar with got 240 hp: todays 3.5 liter of Ford makes 250, and Lexus, Infiniti and the latest Cadillac engine (in the CTS) make 300 hp. And get better gas mileage (some argue the figures are the same, but it depends on how you drive: people in the Infiniti G35 Sedan are getting 4 mpg better than their pre-2008 EPA estimates with conservative driving).



That 3.8 was a die hard engine. The thing went for ever. I had 150K miles on mine before selling it (grand Prix) to get the GTO. The 3.8 was very long in the tooth, but was a proven performer.

My point was that 4 years doesn't seem like that long.

The LS1 had a run of 8 years, and wasn't an LS2 the same basic block with different heads? (maybe a cam too? - taken from an ls6?). So really, the LS1/2 had a run of 12 years.

Seems to me the DoD (or what ever they call it now) put the LS2 to bed, but that is just my speculation.

Scryer_360,

About the heads, well they are L92's, it's been confirmed from several Aussie based shops :)

As to the engine internals, GM High Tech Performance Magazine is reporting that this engine is just an LS2 with the new intake and heads (although they do not specifically say its the L92 heads, they do mention them), and a different cam. The compression ratio was reduced by changing the settings in the on-board computer to detune for 87 octane. Apparently all you will need to do is retune the spark timing and fueling to get back the original compression ratio and wring maybe 40hp out of the car. A new cam will remake the L76 into an LS2 with L92 heads and L76 intake, and SLP Performance was able to use a new cam with L92 heads on an LS2 to make 500hp at the flywheel!
The intake manifold is the L76 while the heads, as previously stated, are L92's.
The compression of an engine cannot be changed through tuning as:

http://img227.imageshack.us/img227/9205/formulafo1.jpg

Now being that both the LS2 and the L76 have the same bore and stroke (4" or 10.16cm bore & 3.62" or 9.1948cm stroke) they would produce the same Cylinder Vol (Pi/4 * bore^2 * stroke).
So evidently the only variable is the Chamber Vol. which is exactly what the main difference between the LS2 and the L76/98, being that the L76/98 heads are larger (69.8cc).

The LS1 had a run of 8 years, and wasn't an LS2 the same basic block with different heads? (maybe a cam too? - taken from an ls6?). So really, the LS1/2 had a run of 12 years.



The LS2 is a "revision" off of the LS1 motor. It is designated as the next generation motor but small changes were made to the block, knock sensors, cam sensor, cam (07+ = single bolt), timing set, front cover, valley cover, crank reluctor ring (E38 PCM), and water pump. Then you have different variations with VVT, AFM, different intake, heads, and camshaft depending on the vehicle.

To increase the compression ration you need to do one (or more) of the following:

Pull the heads and mill them (best bet on the L76)
Replace the heads.
Replace the pistons and/or rods with taller ones.
Replace the crank with a longer stroke unit if there is room (also adds displacement).
Tear down the block and mill the deck height down.

None of these are cheap or easy, and you will need to triple check that the pistons and valves won’t meet.

On the bright side a low-compression motor will make more power with a blower or turbos than a comparable high-compression motor can on the same gas.:gears:

But I plan to buy one as a daily driver and keep it pretty stock.:embarrassed:

A motor with less compression would make less power then one with high compression. The reason why FI applications prefer lower compression is because it lowers knock due to the reduction of heat from the combustion cycle.

So we can say now that these are definitely the L92 heads.... hmmm....

When GM High Tech Performance had SLP tear down the LS2 and use L92 heads and L76 intake, it maintained the stock compression ratio.... oh, crap. Re-reading the article, it says they decked the heads to maintain stock 11:1 compression. Huh, decked? New term Tuesday anyone?

Hmmm, funny, I thought (and here is where my inexperience in engines comes in) that retuning for higher octane fuel also had something to do with compression ratio, as thats the main reason you need higher octane in the first place: to keep the engine from hitting early detonation. So... why would just adding higher octane with different spark timings have any affect at all? The physics behind that please?

Oh well, it still means we have plenty of room to move with forced induction. The highest octane you can buy here in the US is 91 octane, except in some places where 93 octane is available. There is a formula to figure out how much boost you can run at a certain compression ratio, and of course a certain ratio corresponds to a certain optimal octane rating. Anyone happen to have that on hand?

OH and Appletronc: you had good luck with one, but I've known plenty of people who hated that engine with a passion. And there are many more old imports on the road than domestics on the road with over 200,000 miles. Forbes and Autotrader confirmed that.

I agree that for its time it was not a bad engine, but there were just so many better engines for the consumer who buys a car new and keeps it for five years during the 3.8s lifetime.

So we can say now that these are definitely the L92 heads.... hmmm....

When GM High Tech Performance had SLP tear down the LS2 and use L92 heads and L76 intake, it maintained the stock compression ratio.... oh, crap. Re-reading the article, it says they decked the heads to maintain stock 11:1 compression. Huh, decked? New term Tuesday anyone?

Hmmm, funny, I thought (and here is where my inexperience in engines comes in) that retuning for higher octane fuel also had something to do with compression ratio, as thats the main reason you need higher octane in the first place: to keep the engine from hitting early detonation. So... why would just adding higher octane with different spark timings have any affect at all? The physics behind that please?

Oh well, it still means we have plenty of room to move with forced induction. The highest octane you can buy here in the US is 91 octane, except in some places where 93 octane is available. There is a formula to figure out how much boost you can run at a certain compression ratio, and of course a certain ratio corresponds to a certain optimal octane rating. Anyone happen to have that on hand?

decking = milling
you can "trick" an engine with poor gas (read 87 or way less during WWII) by using a water vapor injector , they used such a device on airplanes and I had one on my 1979 3014 bbl, and yes, it does actually work, or did with carbs, don't know about f.i. but it densifies the air, basically by cooling the air charge with moisture. Newer cars with knock sensors are not as affected but a 30 year old car will pep up when you drive in a cool rain as opposed to desert heat of high noon. With a fixed (but variable by distributor advance) timing you have to manually set it for gas with higher anti-knock properties. This and most new engines do this dynamically while you are running, in the background and you don't even know it's happening. There is a limit built into the ecm as to how much advance can be dialed in by upping the octane. Break the code and rewrite the map first, and then you can see some aditional power from 93 octane (here in the east) or 91 out west as opposed to 87. But as this engine is dialed in for 87 you won't see much happen without a ecm tune for premium.

OH and Appletronc: you had good luck with one, but I've known plenty of people who hated that engine with a passion. And there are many more old imports on the road than domestics on the road with over 200,000 miles. Forbes and Autotrader confirmed that.

I agree that for its time it was not a bad engine, but there were just so many better engines for the consumer who buys a car new and keeps it for five years during the 3.8s lifetime.

I've read some of the stuff per this engine (3800) and coolant leaks, warped manifolds, etc, but having had 3 of our own with acombined 400,000 miles and 2 others in the family with 80,000 each we (knock on wood) have never had an engine problem. Never had a tranny issue in the 6000STE either but apparently tons of Luminas and regular 6000 did.

OH and Appletronc: you had good luck with one, but I've known plenty of people who hated that engine with a passion. And there are many more old imports on the road than domestics on the road with over 200,000 miles. Forbes and Autotrader confirmed that.


I read that import owners typically take better car of the car, general maintenance, than domestic. There are many factors at play when comparing the two. The 80's were a sad time for domestic automakers, so it doesn't surprise me if many of those have "passed on" ;) No need to make this a Domestic/import discussion. Heck, I have an import- GTO, and will get another - G8:gears:

http://en.wikipedia.org/wiki/Compression_ratio

A motor with less compression would make less power then one with high compression. The reason why FI applications prefer lower compression is because it lowers knock due to the reduction of heat from the combustion cycle.

FI motors like low compression because it moves some of the compression from the compression stroke to the supercharger/turbo and lets the intercooler remove some of the heat generated by the compression. This means that for the same absolute pressure at TDC of the compression stroke the charge is cooler and less likely to pre-ignite, so you can run safely more boost that you could in a high compression motor. So much so that you can achieve a high absolute pressure in the combustion chamber at TDC and get back more power than you lost by dropping the compression ratio.

But the real advantage of a low compression motor is the bigger combustion chambers.

Even if the absolute pressure and temperature at TDC (at full throttle & full boost) on the two motors the low compression motor still has more power because of the bigger combustion chamber. A greater volume filled with air & fuel at the same pressure and temp obviously contains a greater mass of air and fuel. The low compression motor moves more air & fuel per revolution, it is the function equivalent of a stroker version of the high compression motor.

Believe me or not but Gale Banks (http://www.bankspower.com/twin-turbo-engine.cfm) seems to agree. He builds custom twin turbo small blocks the make 800+ HP on pump gas and runs 8.5:1 compression. And HPA (http://www.motortrend.com/features/performance/112_0610_2008_hpa_volkswagen_r32) is building twin turbo 525 hp VW R32s (3.2 liter V6) and actually pull the heads and install a spacer to lower the compression ratio.

I heard about that on the R32s. The great thing about those are how small they are though. I owned a Ford Festiva once (it did come with that funeral wreath by the way), and you'd be amazed at the spaces I could park that thing in. Once in Chicago the only space I could find during a Jazz festival was between two dumpsters in an alley, and as close together as they were I could wedged the car in there. It had craploads of trash on it when the weekend was up, but the car looked crappy anyway.

Anyway, I kind of started this thread as a "latest news" thread for us.... but I have not had any time to update it. Anyone want to take the torch?

Mexican built engine = poor build quality that ='s very unreliable.

since costs are being held down due to parts of the car being built in Mex, the cost of the car should be under 29k for a well equipted G8 GT

Base GT's start at 29,995

FYI guys (Scryer), an engine’s “age” as here with the LSx motor, has nothing to do with it going away! If it works, is efficient, easily serviceable, and delivers reliable HP/TQ, then why fix what ISN’T broken. FYI, the L76 may be a different RPO code, but it is still an LSx architecture motor. Just the next evolution of it!

The LS2 traces it’s lineage back to the introduction in 1997 of the C5 Corvette then 1998 in the F-Body. However, it was on GM’s drawing board back in the early 90’s. It’s overall design, albeit updated over the years and improved upon, is now a nearly 60 year old design. Why fix what isn’t broke! In it’s latest incarnation, it’s efficient both for MPG and emissions, is easily serviceable, is reliable, is simple, usable across many platforms (which is particularly important with the V8’s as their cast iron versions are used in the trucks in order to keep costs down), but best of all…DELIVERS WORLD CLASS POWER! I fail to see why you think it needs to be changed frequently to “keep up” with the rest of the “Jones’s” in the automotive world the rely on more overly complicated multi-cam designs which aren’t overly more efficient or more powerful, but in the process add more complexity to repair, are more labor intensive when something does go wrong, and add higher warranty costs as such (which GM hates… they want warranty costs to a minimum)!

I see the 3.8L V6 mentioned here. It too, like the SBC V8, traces it’s lineage back nearly 60 years as a farm tractor engine. FYI, the cars GM puts it in now DO SELL. Look around you. You can’t swing a stick without hitting an Impala/Lumina, Monte Carlo, Grand Prix, LeSabre/Park Avenue, Bonneville, or any other GM mid-size to full size front driver I may have forgotten. It doesn’t matter how it was sold, private party or fleet, they still sold and are still on the road. They are extremely reliable, durable, and efficient. Which is why GM used them for sooo long! Parts are easily interchangeable and because of this, much like the SBC V8, parts are cheap! Last time I was at the drag strip with my GTP (with it’s ancient 3.8), I annihilated a Maxima. When I got back to the pits I didn’t wish I had his more sophisticated multi-cam wizard motor under the hood, honestly, I didn’t really care because mine got the job done and is as efficient netting me 27 mpg on the highway, was quiet (unless listening to the S/C under full tilt), and was rock solid at 107k even running twice the stock levels of boost through the motor. Once again, if it ain’t broke, don’t try to fix it! It works for a reason!

What the reason behind GM moving to new engines, is the ever more stringent C.A.F.E. and ever more stringent EPA requirements for higher mileage and to reduce emissions. This is forcing automakers to be more proactive in updating their powertrain designs on tighter intervals. It has nothing to do with an engine’s “age”.