The 2014 Corvette C7's new heart: LT1 6.2L DI VVT small block V8

[Hydrocket]

Originally Posted by aigel

Post 24 and 25 in this thread will answer these questions. Do you guys ever read threads or just post

G

It doesn't explain how it is done though. I tried to offer a very simple explanation of the way I've seen it done. Am not 100% sure until I see the Vette cam for how GM does it though.

[Flieger]

The pulley/sprocket that drives the cam has an outer housing that has the sprocket teeth and inside that is the cam shaft end with some vanes on it. The vanes seal to the inside of the housing and the housing is filled with oil. When oil pressure is increased on one side of the vanes, the cam rotates on the sprocket and so advances the timing. There may also be a return spring in there somewhere but it is oil-pressure activated.

That is the most common way to do cam-phasing, anyway.

[Hydrocket]

Originally Posted by Flieger

The pulley/sprocket that drives the cam has an outer housing that has the sprocket teeth and inside that is the cam shaft end with some vanes on it. The vanes seal to the inside of the housing and the housing is filled with oil. When oil pressure is increased on one side of the vanes, the cam rotates on the sprocket and so advances the timing. There may also be a return spring in there somewhere but it is oil-pressure activated.

That is the most common way to do cam-phasing, anyway.

IIRC, on their push rod engines, Dodge does the 2 piece cam-in-cam method.

[Scott R]

Originally Posted by Flieger

The pulley/sprocket that drives the cam has an outer housing that has the sprocket teeth and inside that is the cam shaft end with some vanes on it. The vanes seal to the inside of the housing and the housing is filled with oil. When oil pressure is increased on one side of the vanes, the cam rotates on the sprocket and so advances the timing. There may also be a return spring in there somewhere but it is oil-pressure activated.

That is the most common way to do cam-phasing, anyway.

This is how Volvo does this as well, they call it a "VVT" gear. Only I hope GM learned from Volvo and designed them better.



Oil pressure fed pistons acting against the outside ring. The problem with the Volvo unit is at some point starts leaking.

[Hydrocket]

Originally Posted by Scott R

This is how Volvo does this as well, they call it a "VVT" gear. Only I hope GM learned from Volvo and designed them better.

But that's a DOHC set-up. Quite a bit different on a push rod engine. Quite a bit trickier.

[Scott R]

Originally Posted by Hydrocket

But that's a DOHC set-up. Quite a bit different on a push rod engine. Quite a bit trickier.

Should be the same exact principle, not really any other way to do this unless you used an electric advance like the 968's.

[petrolhead611]

Peugeot and Mini use electric advance.

[onewhippedpuppy]

Originally Posted by Hydrocket

Wrong. The Coyote is lighter than the LSx engines. (444lbs vs 466 lbs) It's also shorter by 2.6 inches, and is the same height. It is however 4.3 inches wider...but that's because of the wider DOHC heads.

I said I wanted to put one in, not that it will actually happen.. There is a picture somewhere with the Coyote sitting next to a 302, it is substantially wider. Great motor though, I love it in my F150.

[kaisen]

Originally Posted by onewhippedpuppy

I said I wanted to put one in, not that it will actually happen.. There is a picture somewhere with the Coyote sitting next to a 302, it is substantially wider. Great motor though, I love it in my F150.

There is now a kit to put the Coyote 5.0 in the old Foxbody Mustangs

Originally Posted by Hydrocket

Wrong. The Coyote is lighter than the LSx engines. (444lbs vs 466 lbs) It's also shorter by 2.6 inches, and is the same height. It is however 4.3 inches wider...but that's because of the wider DOHC heads.

You're quoting crate-motor weight for the Coyote 5.0 (444lbs) and full dress weight for the LS3 or LT1 (465lbs)

You need to add the starter, alternator, air conditioning compressor, drive accessory brackets, computer, harness, coil covers, engine cover, and flexplate to the Coyote weight to be apples-to-apples

The crate-motor weight of the LS3 is 388 pounds, so you get an idea. The new Gen V LT1, stripped of it's accessories and brackets, should still be well under 400 pounds.

The Coyote is roughly 50 pounds heavier than the DI LT1

Originally Posted by Hydrocket

I guess perhaps I was expecting too much from this new engine. When I heard that the supposed "world leader" in V8 engines was investing $1 billion dollars for the next generation V8, I had very high hopes.

So we end up with:

6+ liters displacement, cylinder deactivation, DI, variable valve timing and 450+ HP. Not bad...except that the Hemi from Chrysler was doing this 3 years ago (no DI, however). And in 392 guise, it makes more power AND torque. This from Chrysler who was on their deathbed when the 392 was tweaked. And I'm rather certain no one will ever accuse Chrysler of being master of the V8. Nor did they need $1 billion to develop it.

Then we can look at the Ford 5.0 Coyote engine. It's one of the lightest V8 on the market, fairly compact and in Boss tune, makes nearly the same HP at 444. It will be DI next round, as the casting bosses are already in place. In terms of specific output, the 5.0 makes nearly 90 HP/L vs 73HP/L.

I dunno...maybe my expectation were unreal. Really...the new GM V8 isn't anything fantastic all things considered.

The 5.0L Coyote and 6.4L (392) SRT8 Hemi are really fantastic motors.

The Hemi weighs over 150 pounds more than the LT1 due in part to its iron block, and it's also significantly taller and wider. But 470hp and 470 lb-ft are fantastic peak numbers..... until you see that the LT1 makes MORE power over a broader range. The LT1 makes 50 lb-ft more torque at 2000 rpm, and gets to 400 lb-ft almost 700 rpm sooner. In a WOT drag run, you probably won't notice. But on a roadcourse, or just driving around on the street, it will be significant.

Remember, they're only willing to admit that it makes more than 450 hp and more than 450 lb ft. I'd mentioned that I've heard 475 hp.

The final cam specs for the 2014 LT1 is 0.551/0.524" intake/exhaust lift, 200/207-crank angle degrees intake/exhaust duration at 0.050-inch tappet lift and a 116.5-degree cam angle lobe separation........that's a VERY mild cam.
GM's current 480 LS3 crate motor ships with a 219/228 and 112.5 and makes 480 horsepower @ 5800 rpm and 475 lb-ft @ 4500 rpm (I expect the LT1's final SAE certification to be about the same).

You can buy a complete 480 LS3 crate motor from GM Performance Parts (PN 19258768) for about $6600 if you shop around.

GM said they have tested the LT1 with cams that made almost 600hp, but chose a cam profile that had the best overall power curve, with the lowest emissions, best fuel economy, and greatest durability.

The Coyote makes PEAK horsepower. 444 hp @ 7400 rpm (Boss Laguna Seca) from 5.0L is impressive for a cheap car. But it doesn't break 400 hp until 5700 rpm. The LT1 breaks 400 hp at 4200 rpm....1500 rpm sooner. The Boss peaks at 380 lb ft @ 4500 rpm. The LT1 makes 125-200 lb ft more torque from idle to 4000 rpm. That's significant. It's not just peak numbers, but area under the curve....power over a broad range. Useable power.

The 444hp Coyote crate motor (PN M-6007-M50B) is a little over $10,000 if you shop around.

Neither the Ford or the Chrysler have direct injection. Fuel efficiency, throttle response, and emissions are better with DI. None of those attributes show up when measuring an engine only by peak power stats at WOT. Agreed?

$1B development is fairly well justified when you consider that this engine will be used in about a million vehicles each year for several years. AND that these engines will carry a 100,000 mile warranty, even when used on the track.

Originally Posted by unclebilly

Any details on the vvt mechanism? I can't imagine this being all that variable given 1 cam and pushrods. Still pretty awesome.

Originally Posted by Hydrocket

The best description I can give is based on other cars with a similar design...think of a cam within another cam. That's the easiest way I can explain it.

Originally Posted by Hydrocket

IIRC, on their push rod engines, Dodge does the 2 piece cam-in-cam method.

It's nearly identical to Chrysler's 6.4L Hemi's VVT. Just a simple phaser at the cam sprocket. The only 2 piece "cam-in-cam" (concentric) is the new Viper.

Here's how it works:

[willtel]

Originally Posted by onewhippedpuppy

The new Ford Coyote 5.0 motors are about $5k, complete and ready to install. I want to put one in my Mustang.

Check these out...

2011 .0 Ford Engine & Transmission 5k mi pcm harness cluster
2011 Ford 5.0 Engine and Transmission less than 4k mi plus pcm etc

[kaisen]

Originally Posted by willtel

Check these out...

2011 .0 Ford Engine & Transmission 5k mi pcm harness cluster
2011 Ford 5.0 Engine and Transmission less than 4k mi plus pcm etc

Truck motors, but still the same basic thing. Still 120+ hp more than the old 5.0 Mustang motor, and lighter as it's all aluminum

Those are great deals

[onewhippedpuppy]

Originally Posted by willtel

Check these out...

2011 .0 Ford Engine & Transmission 5k mi pcm harness cluster
2011 Ford 5.0 Engine and Transmission less than 4k mi plus pcm etc

Damn, now you have me really thinking......

My plan with the 40k-ish original motor was to do the usual bolt-ons like headers, heads, intake, new carb, cams, etc. I'll pretty easily invest $2500 if I go this route. It's a bone stock 2 bbl 302 that has never been rebuilt, i.e. it requires a lead additive. Yanking and storing the original motor and doing a swap for similar money is actually an interesting proposition. There's the cost to integrate the EFI motor, but I plan to replace the fuel tank and lines anyway. Pelican sure is great at helping me spend money.

[clutch-monkey]

i dunno about the states but here the ford 5.0L motors are laughably underquoted by ford. the badges say 450hp, but drive the car off the dealer lot and onto a dyno (not an american one either mind) and they've been throwing out pretty much that hp at the wheels instead.. nuts

will be nice to get the LT1 into the holdens to even the score again!