Flash99

I was just at TPE yesterday and I asked Jeff a few weeks ago about the Grand Sport, and I'm not sure if its dawned on anyone, but the GS now has the dry sump oil system. I was almost positive you would gain between 10-30hp with that system alone. So the real question would be does the car make upwards of 450hp now? Why would they not re-rate them, because it is bringing the LS3/6.2 closer to the LS7 Z06? Or could it just be a CARB or emissions issue that they don't want to send the vehicle through the tests again... Dont know, that's why I'm asking. bring on the educated, and uneducated guess's!


*EDIT* Hmm I'm late, but apparently they have a forged crank and are hand built with the MN6... sweet.

yanniz

not sure how you would gain from the dry sump...less windage?

Flash99

This is what I'm thinking:


The main advantage of a dry sump system is the ability for the engine to generate more horsepower. Since there is very little oil in the pan the oil is not getting sloshed around when the car is moving. On a wet sump system the crankshaft and the oil essentially share the same space and the oil oftentimes gets splashed onto the crankshaft. The excess oil on the crankshaft requires horsepower to turn and in doing so you lose horsepower. As we mentioned, on a dry setup the oil is stored in an external tank so there is no oil to splash onto the crankshaft.

Besides getting better oil control with a dry sump system there is another key benefit of having this type of system; the ability to pull a partial vacuum from the crankcase.

dumpster

My uneducated guess is that the dry sump is for lubrication improvement rather than HP.

Mykill Myers

You were expecting possibly 466hp with just adding dry sump?

If only...

MLCZ51

2006c6keller

dumpster: "My uneducated guess is that the dry sump is for lubrication improvement rather than HP."
In addition, just because you eliminate the wet sump oil pump, you are still adding TWO electricial sump pumps which also take energy to operate.

If you have too much oil in the pan and hitting the crankshaft you could get foaming (bubbles) which will cause improper lubrication, just ask the Z06 guys about bubbles in the oil at over 1G left long sweep for over 4 seconds or longer, lose an engine (thread by dreamin).

By the way, they still have trouble with oil sloshing around (from braking, high accelaration, and turning) in the dry sump so they modify it by adding a "windage tray" to reduce it.

In addition, the crankcase has a partial vacumn on it for federal emission requirements.

Hopefully, this will help clarify the systems.

Flash99

NO I was expecting 900, but I suppose 466 wouldnt be bad either.

I guess we will have to wait and see for the dynos to come through, cant wait to get mine. So what I'm seeing here is there will be absolutely NO GAIN IN HORSEPOWER? No one has yet to chime in and say that it should give it a potential jump in power?

Knightsport

My educated guess is that it adds as much horsepower as the side gills do.

Or those little terminator skulls everyone seems to affix.

LTC Z06

One of the ways a dry sump can give HP is by reducing back pressure under the pistons, but that was already fixed with the LS6.
http://www.ecsracing.com/ecsracing/showthread.php?t=485
So what are the advantages of the dry sump over the wet sump setup?

The major reason a wet sump setup is not generally used in a racing application is because of the high probability of oil starvation to the pump. Because of the lateral forces caused by road racing the oil can have the tendency to run up the sides of the oil pan or away from the pickup. If the pickup runs dry on oil, even if only for a split second, the oil pressure in the engine can drop causing internal part failures. The dry sump greatly aides in the prevention of oil starvation because of the oil being stored in a larger separate tank, almost always containing enough oil for the pump to use. Other benefits of a dry sump is a good working system will pull a vacuum on the crankcase from the scavenge stages pulling oil out of the engine. That vacuum created can help piston ring seal and cut down on engine blow by. Also being that the oil is stored in a separate tank it has a better ability of staying cooler since it is stored away from the hot moving parts of the engine. The dry sump greatly eliminates aeration of the oil as compared to the wet sump setup. When the oil is stored in the wet sump pan it is prone to splash or being whipped from hitting the internal moving parts of the engine. “Whipping” of the oil creates higher temperature, along with aeration and loss in horsepower. Also a greater amount of oil can be ran in a dry sump, the stock corvette can hold 7 quarts race ready. The dry sump tank that will be utilized for bob will hold 12 quarts of oil. So why can’t you put 12 quarts in your wet sump? Following correct oil level amount in a wet sump is extremely important. An overfill situation will cause the oil level to be too high causing the oil to be whipped by the crankshaft. An under fill situation will make it easier for the oil pump to run away or run dry of the oil in the pan.

So IF whipping occurs you can lose horsepower, but it doesn't mean a dry sump will ADD horsepower.

Bat Man

I thought the corvettes wet system was different then most. It has shields to prevent splash? IF that's the case I don't see the benefit besides on a track(errr and not making 1g sustaind left turns )

C6~Missle

What you save from less to no windage.. you pick up in alternator drag from running the electric pumps.. A good tradeoff especially if you seriously track the car

Dudeurgettnavette

I also heard it increased HP.

haljensen

Electric pumps? I thought they were still mechanical. The reason for the extended crank snout on the forged crank was for the additional oil pump.

wolfdogs

throw some twin turbo's on it when you buy it along with a good tune and dont' think twice about sumpPower.......

redzone

No idea why anyone would think otherwise.......

CMY SIX

because thats all the HP it has? did I win?

dvilin

Ding Ding A Winner!!!!!

Tyson1

"Terminator skulls" LOL!!

Blue Angel

Any small increases in power offered by the dry sump system will more than be offset by the increase in vehicle weight over the standard coupe. The GS will be a slower car - all the flare (weight) of the Z06 cosmetics with no extra power to offset the weight gain, and exactly none of the weight saving pieces from the Z.

The car looks fantastic, for sure, but that's because the Z looks fantastic and this is basically a factory Z replica. I can definitely see where people will find it desirable, either because they like the look of the Z but couldn't afford it, or because the Z was just a little too hardcore for the automatic convertible crowd.

The biggest problem I have with the GS is that it REPLACES the Z51, which until 2010 was THE performance car bargain. An '09 Z51 would surely be quicker overall, on paper at least, but now to get (almost) that level of performance the buyer is forced to spend more on the GS... bad move, GM. Get ready to see the Corvette losing (instead of winning) magazine comparisson tests, since the Z51 was the car of choice for such things.

Let's wait to see what the reviews bring.

On another level, though, the modder has an attractive package to throw a TVS blower onto that would definitely overcome the lack of power compared to the Z. It will have that tight new LS3/9 block and a forged crank... That will keep the forums happy, but won't do a damn think for the public perception of the 'Vette as their opinions are based on magazine info.

Sad to see the Z51 go. It will be sorely missed.