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Ranger50
Ranger50 UltraDork
10/24/12 2:06 p.m.
GameboyRMH wrote: Could that thing that looks like a huge idler wheel not be a PS pump? I think I see two hose fittings on the back. The presentation says e-throttle will be standard on this engine, hopefully they won't take the opportunity to muck it up. Looks good but the big appeal of the LSx is cheapness, and this won't be cheap for a while.

The big pulley with holes in it under the alternator? If it is,that is the water pump pulley. It is very reminisent of the LS4 in the FWD W bodies.

PHeller
PHeller UltraDork
10/24/12 2:17 p.m.

I wonder if GM's claims are referring to naturally aspirated production engines available in a new road going vehicle.

HiTempguy
HiTempguy SuperDork
10/24/12 2:18 p.m.
Javelin wrote: and don't provide any real benefit with the advent of variable valve lift/duration technology (the "cam in cam").

Camception?

Sry, just had to

yamaha
yamaha Dork
10/24/12 2:20 p.m.

In reply to PHeller:

Even then they'd be wrong......

bravenrace
bravenrace PowerDork
10/24/12 2:24 p.m.
yamaha wrote: In reply to PHeller: Even then they'd be wrong......

Yup.

GameboyRMH
GameboyRMH PowerDork
10/24/12 2:25 p.m.
Ranger50 wrote: The big pulley with holes in it under the alternator? If it is,that is the water pump pulley. It is very reminisent of the LS4 in the FWD W bodies.

Ah that's probably it. The two little fittings and unusually large pulley threw me off.

yamaha
yamaha Dork
10/24/12 2:29 p.m.
bravenrace wrote:
yamaha wrote: In reply to PHeller: Even then they'd be wrong......

Yup.

Also, what do the 6.1L and 6.4L chryslers make hp/L that would decide if GM can even claim highest hp/L of n/a pushrod engines.....

DoctorBlade
DoctorBlade SuperDork
10/24/12 2:30 p.m.

They are claiming big TQ gains, which would be nice.

codrus
codrus Reader
10/24/12 4:20 p.m.
PHeller wrote: I wonder if GM's claims are referring to naturally aspirated production engines available in a new road going vehicle.

To match an S2000's 120hp/L, an LS1 would need to make 684hp, an LS2 720, an LS3 756, and an LS7 840. They don't. (yes, I know they don't make the S2000 any more, but the original question was more about inherent attributes of technology, rather than what's currently being sold).

DOHC engines rule the specific output (hp/L) world, the thing is that specific output is really only an interesting number if you have rules limiting your displacement (race class regulations, for example, or govt taxes based based on engine displacement). Or, well, if you're a ricer who needs to come up with a reason why a B18C is better than an LS1. :)

Pushrod engines win in the power/engine weight, or power/underhood volume categories, which are much more important from a practical standpoint in street car. The US doesn't have vehicle taxes based on displacement, so US manufacturers are more inclined to use pushrod motors than Japanese or European manufacturers who do have such taxes in their home markets.

kreb
kreb SuperDork
10/24/12 6:00 p.m.

It's not just a rush to highest specific output. The LT1 has a broader powerband than most if not all comparable OHC engines. The S2000 is irrelevant, because the list of people willing to tollerate that sort of powerband in a V8 is very short. Apples and Oranges, or do you want to add motorcycle engines into the mix? The pushrod motors cary their weight lower, have a smaller footprint to make packaging easier, and are simpler. While no fanboi, I think that it's remarkable how far they've developed those motors. That they're even in the discussion with 4-valve designs is a testament to the skill of GMs designers. I'm just sorry that Ford gave up on their smallblock pushrod. Would love to have seen them build a compact all-aluminum 5 liter pushrod motor that breathes and is as reliable as a LSx.

vwcorvette
vwcorvette Dork
10/24/12 6:49 p.m.

Don't forget too that this is just the first application of this motor. I'm sure GM has upgrades coming as the years go by.

DirtyBird222
DirtyBird222 SuperDork
10/24/12 8:13 p.m.

I always love when someone states "OHC designs are so much more modern and efficient." I wish people knew their history before making such statements. While wikipedia isn't exactly the most credible source for information, you can reference the information anywhere http://en.wikipedia.org/wiki/Overhead_camshaft go to history.

Yes some cars make better hp/l than others, but some of those like the F20 from the S2000 don't hit that powerband until they are up past 6000 revolutions per minute and create significantly less torque than engines like this new LTJuan.

I don't understand why they are using the same engine designation from their red headed step child of the GenII LT1. It'll be cool to see what a few mods will do to this engine. I do like the option for wet or dry sump on it as well. Not like I'll be owning one of these anytime soon anyways, maybe like 10 years from now.

novaderrik
novaderrik UltraDork
10/24/12 9:04 p.m.
kreb wrote: It's not just a rush to highest specific output. The LT1 has a broader powerband than most if not all comparable OHC engines. The S2000 is irrelevant, because the list of people willing to tollerate that sort of powerband in a V8 is very short. Apples and Oranges, or do you want to add motorcycle engines into the mix? The pushrod motors cary their weight lower, have a smaller footprint to make packaging easier, and are simpler. While no fanboi, I think that it's remarkable how far they've developed those motors. That they're even in the discussion with 4-valve designs is a testament to the skill of GMs designers. I'm just sorry that Ford gave up on their smallblock pushrod. Would love to have seen them build a compact all-aluminum 5 liter pushrod motor that breathes and is as reliable as a LSx.

it's kind of funny that the year after Ford put the last Windsor in a truck on an assembly line, GM came out with an engine that looks an awful lot like a Windsor when you strip it down to a long block- the port layout on the heads is damn near identical and you can use 5.0 headers with a different flange welded to it if you swap an LS into your Fox Mustang, and the head gaskets look like they are almost interchangeable.. they even use a Ford 5.0 distributor if you buy the front mount distributor kit from GM..

it's almost like GM went with that design just to show Ford the error in ther ways for going OHC instead of OHV..

WilberM3
WilberM3 Dork
10/24/12 9:36 p.m.

the specific output i am really interested in is HP/lb. i wouldnt be surprised to find GM's gen3+ aluminum variants to be some of the highest of current production engines.

and i dont think you can include the LS9 or the shelby as once it's force fed it's a different ballgame.

novaderrik
novaderrik UltraDork
10/25/12 5:27 a.m.
WilberM3 wrote: the specific output i am really interested in is HP/lb. i wouldnt be surprised to find GM's gen3+ aluminum variants to be some of the highest of current production engines. and i dont think you can include the LS9 or the shelby as once it's force fed it's a different ballgame.

power is power- the tires know not or care not what is providing the power, they only know and care that there is power.

bravenrace
bravenrace PowerDork
10/25/12 5:44 a.m.

In reply to novaderrik:

Plus most of the comments on HP/Liter were in response to earlier comments regarding HP/Liter of the LT1.
And I don't agree that the F20 is irrelevant. It may be to the guy who posted that, and that's fine. But it was a huge achievement, one that IIRC hasn't been eclipsed even now, 13 years later. That's not irrelevant in any way.

racerfink
racerfink SuperDork
10/25/12 6:24 a.m.

It's not a V8 though, which was the point of this thread.

sobe_death
sobe_death Reader
10/25/12 6:33 a.m.

Doesn't matter, the Ferrari 458 makes 562 hp from a 4.5L engine. That's 124 hp/L, naturally aspirated.

Anyways, here is a graph showing the old LS2 below, with the LT1 and LS7 engines on the top.

bravenrace
bravenrace PowerDork
10/25/12 6:37 a.m.

In reply to racerfink:

HP/liter is independent of the number of cylinders.

DoctorBlade
DoctorBlade SuperDork
10/25/12 6:46 a.m.

I think the new LT1 has a better chance of hitting even 25k miles than any Ferrari engine. So I assume they're designed for the long term.

tuna55
tuna55 UberDork
10/25/12 6:50 a.m.
bravenrace wrote: In reply to racerfink: HP/liter is independent of the number of cylinders.

But it is NOT independent of cylinder size. A smaller cylinder will always produce more power per displacement than a larger one. Obviously, once the pistons starting getting the size of thimbles, this stops being true, but for all normal sized applications it's right. Comparisons per displacement are pretty irrelevant anyway, since other than specific racing classes, nobody could possible even notice. If tomorrow you found out that there had been a huge mistake and that the BMW V8 was actually 6.2L and the LS3 was actually 4.4L, would it matter to anyone?

No.

Knurled
Knurled SuperDork
10/25/12 7:13 a.m.
yamaha wrote: With modern technology, you would figure that this has been solved, but I still suspect that the longer stroke engines can't rev as high reliably.

The bottom end isn't really the limitation, now that the manufacturers are bothering to spend money for stiff blocks and stiff cranks and rods that aren't made of cast cheese.

Figure that a B18 has a longer stroke than the 429 that was in my first car.

Now, if one were to argue that short stroke engines are just more fun to drive, then I'm with you. They're not as thermally efficient as an undersquare engine, though.

Knurled
Knurled SuperDork
10/25/12 7:16 a.m.
GameboyRMH wrote:
Ranger50 wrote: Looks like EPAS is coming too, note no PS pump and belt. But it does look like the balancer is fitted for a 8 or 10 rib belt. Hello supercharger?

Could that thing that looks like a huge idler wheel not be a PS pump? I think I see two hose fittings on the back.

That's a water pump. Water pumps on pushrod engines are not buried under the timing cover like in OHC engines.

The presentation says e-throttle will be standard on this engine, hopefully they won't take the opportunity to muck it up.

I can't think of anything that is throttle by cable. Even the super cheap Korean cars are drive by wire. They have a throttle cable that goes to a remote mounted APS unit and not the throttle body. (Yes, weird)

Given that GM was one of the first companies to use throttle by wire, and incorporate it across the board, not using it would make little sense. (next up: points ignition)

Bobzilla
Bobzilla UltraDork
10/25/12 7:17 a.m.

is that graph showing 390ft-lbs of torque at 2000rpms and carrying that through 6000rpms after peaking out at 450ftlbs? That's one hell of a power band.

Knurled
Knurled SuperDork
10/25/12 7:19 a.m.
WilberM3 wrote: the specific output i am really interested in is HP/lb.

I pay attention to ft-lb/l. HP/l is just how high you rev the engine, ft-lb/l is how efficient the engine is.

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