GMRL

The SSR had an aluminum 5.3, as did the Trailblazer/Envoy.
Im not sure if the newer 5.3s are Iron or aluminum.


Either way, I hope/dont think theyll put a 5.3 in there.

Fbodfather

I think you'll be happy -- but I think you're wrong in your selection of drivetrains!!!!!

(sorry!)

Grape Ape

The LTT has a pretty flat (if lumpy) torque curve, but LNF's torque peaks at 2000 holds that "peak" to about 5300. I suspect that it is being limited by the ECM. The twin turbo DI V6 in the BMW 335 has a similar curve so it may be the nature of the beast.

http://media.gm.com/us/powertrain/en...F_Solstice.pdf

GM Media has a nice page full of engine data here: http://media.gm.com/us/powertrain/en...2008/08car.htm

Grape Ape

And as long as we a rooting around in the parts bin, I’ll take my Camaro with the LC3 from the XLR-V and CTS-V please. It uses 4.4 liters, DOHC, VVT and a roots blower to produce 443hp and 414 ft/lbs.

http://media.gm.com/us/powertrain/en...L_LC3_XLRV.pdf

AdioSS

Why not just add direct injection and VVT and AFM to the LS3? You'll make the same or more power and torque with less weight while getting better fuel economy.

Grape Ape

Why? Why money of course. Adding DI and/or VVT to the LS3 would require redesigning the (new) heads on an engine that only has a few years to live anyway. I'm sure that work is going on, but it is for the Gen V small blocks.

I think an LC3 would require far less development money and time since it is already in use.

The fact that the LC3 is only 4.4 liters means that everything should be smaller than it would be for the 6.2 liter LS3 and it could well weigh less than the LS3 even though it has 3 extra cams, 16 extra valves and a blower. Likewise the it should enjoy less friction which should allow it to be a little more efficeint.

FYI: I say that a VVT LS3 would need new heads because there are two kinds of VVT systems: the ones that suck and the ones that require twin cams.

Jason Dove

Can I get a 454 w/blower from the factory. I promise I won't complain about the body/interior.

AdioSS

The LC3 is a Northstar with an intercooled supercharger on top. Physically it is larger than a naturally aspirated LSx. It is comparable in size to the DOHC Ford Modular Motor. Do a search and you'll find all kinds of info and comparisons in size between the LSx stuff and the DOHC engines. The LC3 does NOT weigh less than the LS3. The smaller displacement is offset by much larger cylinder heads.

Any friction reduction from the smaller displacement would likely be offset by the drag of the supercharger and the additional valvetrain components.

Variable Valve Timing is already being used on production Gen 4 Small Block Chevy engines. Nothing new needed there.
Active Fuel Management is already being used on production Gen 4 Small Block Chevy. Nothing new needed there.
Gasoline Direct Injection is currently not in production, but prototypes have been reported. This needs to be introduced ASAP anyway.

The money spent on developing these would pay off in the long run since all future GM gasoline engines should use them to anyway.

Plus why would Cadillac want to give up their most premium engine that are going into very few vehicles? It is an expensive engine to produce. Each one is hand built using premium components. The LS3 is a mass produced engine in comparison.

I'm kinda wondering why you didn't include the LC3 that goes in the STS-V? In that car it makes even more power and torque (469hp/439tq)

teal98

Sorry, but it's kind of hard to take a name like Grape Ape seriously. I remember it from Saturday mornings many years ago.

The supercharged northstar is heavy, swallows a lot of fuel, and has only a little more power than an LS3. It's nearly obsolete. The ultra V8 would have brought the GM quad cam V8 up to date, but it's on the shelf, likely never to see the light of day.

The Gen IV smallblock does more with less than the Northstar.

If the STS-V had an LS3, it would probably be 200 pounds lighter, and very close in straight-line performance.

I see in the newspaper ads this weekend that 2008 STS-V's are available at $10000 off MSRP.

AdioSS

I don't know. I've found this to be a good website... http://www.grapeaperacing.com/

teal98

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

AdioSS

I remember the cartoon...

teal98

I had put it out of my mind until I saw a post from "Grape Ape"

Grape Ape

The heads are certainly taller, but they shouldn’t be as long or wide as an LS3 head. Likewise the block shouldn’t be as long as the LS3’s due to the narrower bores, which would shift some weight rearward.

If the LC3 really is bigger and heavier than the LS3 (I’m too lazy to look it up) then someone needs a pat on the back (at Chev) and/or a dope slap (at Cadi).

Hard to say.
VVT fall into two groups: VVT that requires two cams and VVT that sucks. The small block only has one cam.

Varying the timing of a single cam can widen you torque curve a little, but cannot add anything to the peak. Changing intake and exhaust timing independently allows high RPM overlap which can add power but would cause the engine to fail emissions & NVH standards at idle.

But as implemented in the G8 GT's L76 it limits valve lift and eats at least 38 HP (vs the LS2, even though the L76 has better heads). I'd say something is needed.

There is no long run for the LS3 or any of it's siblings unless the Gen V small block is farther off that we are being led to believe.

I suspect that the LC3s are hand built largely because of the low volume, after all the LNF comes off an assembly line but still gets even better HP & torque per liter. But I’m not seriously suggesting that the Camaro will get a Northstar V8, I’m just playing along with the “what might GM dig out of the parts bin” game.

I also think it would be a bad choice because a small displacement V8 wouldn’t have the deep rumble everyone seems to want.

AdioSS

well, if we're playing the "what if" game, what if they were to merge two Ecotecs with a common crankshaft? You could get a naturally aspirated 350hp 4.8L V8 or a twin turbo 520hp 4.0L V8. Is the Astra's 1.8L an Ecotec? If so, then there is a 275hp 3.6L V8