Gotcha! 'Gen V' Engine Details... DOHC!

[LSxcellent]

More info:

In the new issue of Motortrend there is an article on the new Corvette, and on the first page of this article, they reference something interesting:

"A mid-engine C7 would get a version of GM's upcoming "high-feature" V8, expected to be an efficient, direct-injection 5.0L+ gas engine with quad-cams and four valves per cylinder and due to launch in 2009 to replace the Northstar V-8"

This is VERY intersting, in that it moves the timeline for this "high-feature" V8 up quite a bit to the year when the Camaro is due to launch! IF this is true (and MT is usually full of **it) then it presents an interesting possibility...

If The General wanted to, he could easily bring this engine over to the Camaro Z28 as the high-feature engine.

For those that are unfamiliar with these technologies, the major advantage to a Quad-Cam engine is that the engine is capable of revving much higher than a pushrod V8 which allows it to make more power.

This is just one possibility... and pure speculation, but it fits in nicely with the image and product range.

~LSx

[LSxcellent]

Originally Posted by Mindz

Which has more potential for power LS3 or that? I know which is better for mpg, but are the power potentials similar?

Hmmm. There seems to be some confusion about this so I will clarify...

Engine Power is the (Torque x RPM)/5250

You can increase engine power by either increasing torque, OR increasing RPM, or both.

The limit to RPM is usually 'valve float' which is when the valve is opened so forcefully, that it actually floats away from the rocker arm, and then valve motion is not controlled accurately, and bad things happen.

On a pushrod engine, the weight of the pushrods themselves actually factor into this equation, and their additional weight lowers the RPM where the valves begin to float. In a DOHC engine, the valvetrain is effectively lighter, allowing higher RPM, and thus more power.

The premier example of this technology is the new BMW M3 which has a 4L V8 that can rev to 8450rpm!!! In doing so it makes ~425hp!

If GM creates this sort of engine, it has two options:
1) Maintain output around 400hp while decreasing engine size (and weight)
2) Maintain engine size and make the proverbial 'A$$Load' of power.

Either way, its a smart move for GM, they need this engine technology.

~LSx

[Mr. Wyndham]

Nice Find, LX...now that's the second mention of the Gen V being offered in 2009. Interesting, indeed.

I'll be a little sorry to see the Pushrod tech finally take a dirt nap if this works, but I'll get over it quickly.

On top of all that power, there is another equation to use, not literally , but Fuel Economy. SIDI (Spark Ignition, Direct Injection) will help, and "quad", or "dual cams" alike (OHC) will make VVT easier to do, and offer even better fuel economy gains. Then add AFM to that, and you're getting tremendous increases in fuel economy for the power it's creating...

So my point is, "LS3 vs 'this' "? 'This' gives better fuel economy - and as LSexcellent stated above - AND more power!

^= see why I'm so excited about this?

[TAG UR IT]

Originally Posted by LSxcellent

If GM creates this sort of engine, it has two options:
1) Maintain output around 400hp while decreasing engine size (and weight)
2) Maintain engine size and make the proverbial 'A$$Load' of power.

~LSx

I'll take option #2, please!!! VERY good find! Two mentions of the engine possibly being offered in 09??? Hmmmmm......

Originally Posted by Dragoneye

I'll be a little sorry to see the Pushrod tech finally take a dirt nap if this works, but I'll get over it quickly.
So my point is, "LS3 vs 'this' "? 'This' gives better fuel economy - and as LSexcellent stated above - AND more power!

^= see why I'm so excited about this?

I'm happy to say goodbye to the pushrod in favor of more power and less weight....fine by me. And fuel economy? We'll be saving lots of cash in the long run getting the great mpg's this engine could offer. This is great news!

[LSxcellent]

Originally Posted by Dragoneye

Nice Find, LX...now that's the second mention of the Gen V being offered in 2009. Interesting, indeed.

I'll be a little sorry to see the Pushrod tech finally take a dirt nap if this works, but I'll get over it quickly.

We'll I wouldn't worry too much about that... I am pretty sure GM isn't going to ditch pushrod V8's anytime soon. They offer way to much 'bang for the buck' and can be used all over the place with ease. I think they'll be around for a while longer...

Originally Posted by Dragoneye

On top of all that power, there is another equation to use, not literally , but Fuel Economy. SIDI (Spark Ignition, Direct Injection) will help, and "quad", or "dual cams" alike (OHC) will make VVT easier to do, and offer even better fuel economy gains. Then add AFM to that, and you're getting tremendous increases in fuel economy for the power it's creating...

So my point is, "LS3 vs 'this' "? 'This' gives better fuel economy - and as LSexcellent stated above - AND more power!

^= see why I'm so excited about this?

We'll, let's take a moment for reality here... all of the technologies you stated will certainly help fuel economy, but the reality is that you won't see 40mpg in this car. Its just not going to happen. The physics of internal combustion are at work, and all of these technologies are eeking out the last one or two percent... I would expect the Camaro (with a V8 containing 'the works') to max out around 27-30mpg (highway) if we are lucky. That's about it... not that its anything to sneeze at, but not 40mpg.

But yes Dragoneye, I DO see why you are excited!

~LSx

[Justcallme61]

that's all i have to say...

[JeepinMatt]

Originally Posted by TAG UR IT

I'll take option #2, please!!! VERY good find! Two mentions of the engine possibly being offered in 09??? Hmmmmm......


I'm happy to say goodbye to the pushrod in favor of more power and less weight....fine by me. And fuel economy? We'll be saving lots of cash in the long run getting the great mpg's this engine could offer. This is great news!

Pushrods weigh less than OHC and DOHC engines and are more compact

[Mr. Wyndham]

LSX, I know that - I'd be foolish to expect 40mpg...not that it isn't possible. Just not now.

I'm betting a little higher, though - around 30-32 hwy

[LSxcellent]

Originally Posted by JeepinMatt

Pushrods weigh less than OHC and DOHC engines and are more compact

This is true... the LS7 in the Corvette weighs almost 200lbs less than the 500hp engine in the M5. Keep It Simple Stupid!

Pushrods have less parts, and are simpler overall.

The problem is that I think they are reaching their performance limit... I don't think they are capable of keeping up with other modern engine designs. At least not in an economical way... The major issue is emissions and engine RPM.

Here's the logic train...

Engine Power = engine speed * engine torque

If Engine Speed is fixed (by design, since pushrods are limited) then engine torque must increase to compensate.

The problem is greater engine torque = greater engine emmisions (torque can be achieved either by greater stroke (which limits RPM = bad) or greater bore (which hurts idle emmisions=bad). Either way, increasing torque hurts emmisions, and so cannot be used as a solution.

In the end, GM really doesn't have a choice. It can't change physics, and thus has to find a way around this problem... The LS7 is one of the highest revving production pushrod V8's EVER, and it has titanium connecting rods, sodium valves, forged pistons, etc. It's VERY expensive. I don't think they could use these technologies for an 'average' engine.


~LSx

[LSxcellent]

Originally Posted by Dragoneye

LSX, I know that - I'd be foolish to expect 40mpg...not that it isn't possible. Just not now.

I'm betting a little higher, though - around 30-32 hwy

True. Who knows what technology may be available... the problem for GM is that you won't get to 40mpg in a car like this without (A) Hybrid Drivetrain or (B) Diesel Engine.

Most folks don't realize that your gasoline engine has a HARD limit on its efficiency that depends on compression ratio.

At a compression ratio of about 10:1 the theoretical limit is ~60%... but this assumes perfect compression and expansion with no heat gain/loss. In reality the limit is somewhere closer to 30% or less.

This is one of the big reasons why diesels are so popular, their theoretical efficiency limit is higher, providing designers more room to improve.


Personally, I'd love to see how a diesel-Camaro would drive... I think it would actually be pretty awesome. LOTS of torque, with plenty of power for the road... Oh, and THEN I could see it reaching 40mpg... but only JUST.

~LSx

[Mr. Wyndham]

Bob Lutz did an interview, for the GM blogs saying something along the lines of Diesels and gas-engines becoming more and more alike, (in terms of emmisions.) Which is why GM hasn't undertaken a widespread use of diesel powertrains. It'd be cheaper(maybe not), and simpler just to continue advancing gasoline engines.

Now, he's not God, and I know that, but he's close

I guess what I'm saying is that pushrods have had their day...they'll be around for some time to come, but very generally speaking, the age of the pushrod is over. and I'm confident (knowing what GM could do with pushrods) that we're in for a wild ride with these Overhead Cammers!

[Power Junkie]

Originally Posted by Dragoneye

Now, he's not God, and I know that, but he's close

. and I'm confident (knowing what GM could do with pushrods) that we're in for a wild ride with these Overhead Cammers!

Amen to that brother...

[LSxcellent]

Amen!

~LSx

[Mr. Wyndham]

(really deep, loud voice)

Can I get a haleluiah? I said, Can I get an Halleluiah?



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