Variable displacement engine for the C6

[extremespeed]

In the latest issue of Motortrend magazine they suggested that a variable dissplacement engine could be the next engine in the Corvette. It would have a fuel economy of 25/30. What do all of you think about a variable displacement engine in the new Corvette?

 

[vette-dude]

:cry :cry :cry :cry :cry :cry :cry :cry

Nuff said!

Randy

 

[GreyGhost]

Variable displacement engine

You won't see me with one.

 

[extremespeed]

I don't think there is anything wrong with variable displacement engines in Corvettes. You drive around using only 4 cylinders and save a ton of gas, and when you wanna GO you push the button and get kicked back into your seat. So where is the problem with variable displacement?

 

[vette-dude]

First, you would be rotating 4 pistons and rods that produce no power. Second, ask someone who owned a 4-6-8 Cadillac. Third if you are worried about mileage maybe a Vette is not for you. Fourth, pushing a button to add the other four cylinders would get real old real quick. ( I imagine the other 4 cyclinders would be devised to kick in on demand anyways.) Fifth, and I repeat

Randy

PS: but each to their own I guess!!

 

[LongTimer]

GM has a firm policy that it will not produce cars that have gas gusler tax assessed. Therfore, the only way to keep increasing the HP - I assume we all want that!! - is to make improvements that keep the gas miliage up above the tax mark (20-21? mpg).

The Cadillac 4-6-8 was an experiment with VERY, VERY limited electronics "muscle" supporting the concept and should never have made it to the street (remember the gass crissis?).

Today's engineers understand much better how the computer can control the engine. The Northstar has had a DOD limp home capability since introduction (1994?). One of the car mags tested the capability (drained the radiator in the desert) and strongly blessed it.

The vette now has throttle by wire, so IF the engineers can make DOD invisible to the driver, and give us more HP - I'm all for it.

Show me the POWER!

 

[vette-dude]

Longtimer:

Good points. Still don't think I want it though. I guess I subscribe to the "Gee I could have had a V-8!" way of thinking. I realize it is a 4 to 8 that through computers and electronics becomes a full V-8 but I would still not spend the money for it.

Randy

 

[extremespeed]

Vette Dude,

The Caddy your talking about was developed in the late 70's or early 80's. They didn't have the technology we have today, and GM claims that the variable displacement engine was very easy to develop with today's technology. They also claim that the 4 cylinder shut off isn't even noticeable. In other words the car doesn't jurk all over the road when you hit the button etc. What I'm trying to say is if they have the technology to make more horsepower and create a better fuel economy at the same time, then they should do so. Besides, they are not going to make their Corvette into a clunky disaster.

 

[SlowRide]

Right now a 2003 Z06 will get 27-28 miles per gallon on the highway cruising at about 70-80 in 6th gear (I experienced this personally on a road trip to Florida last week). To me that is great. Better than my current 4-banger that I drive to work in. I worry about the electrical "gremlins" that could show their ugly little heads with the varible displacement engine.


Nick

 

[LongTimer]

Right now a Viper can dust it and the lowly Mustang is sneaking up from behind.

 

[Daryllawman]

I'm with Vett-Dude>>>>>>>>>>>> :cry They need their>>>>>>>>>

 

[ELTGuy]

I am sure that if GM does implement this, there will be an ECU "piggy back" or some such thing in the aftermarket to, errr.. override the DOD system.

...the lowly Mustang

ad


:t

 

[2000FRC]

Longtimer is right. However, I think that they will wait untill the 42 volt electrical system is developed and operational before they go to Variable Engine Displacement.

With electrically operated valves, not only can the engineers get Varialble Displacement, but also variable valve timing to achieve higher HP and torque, as well as sustained higher HP and torque over a wider RPM range.

I'm told that the 2005 "Z06" engine will have conventional variable valve timing, 6 liter + , displacement, dry sump, electric pump engine cooling, and produce 500 HP and 500 Lb-ft of torque. The car will weigh in at less than 3000 lbs.

Any camparison of these new systems with the old Variable Displacement Engines is ludicrous. I don't know about the rest of you but I'm for better technology that leads to better and more powerful engines.

 

[Eric Von Zipster]

I'm with you 2000FRC. I like technology and would like to see lots of new technology in the next generation Corvette.

However, DoD (Displacement on Demand) is going to be introduced first into GMs truck line. I was told this by a Detroit engineer who is working on the technology at the SAE show a few weeks ago.

So, if it gets introduced first in a truck, and it's not introduced yet, I doubt it will make it into the first C6s.

Also, the technology is rather interesting. They put tiny hydraulically actuated shocks on the bottom of the push-rod. When the cylinder is in use a pin locks the shock and the push-rod moves with the cam. When the cylinder is not in use, the shock moves with the cam and the push-rod stays put.

This keeps both intake and exhaust values closed, and the piston acts like an air spring with nearly 0% energy loss.

 

[LongTimer]

I also read something about GM trucks getting DOD first. This could mean that the 2004 trucks due in the fall could get them, then the C6 next summer. Or, maybe we really are a few more years away from DOD. Either way, I think it is inevitable, and I welcome MORE POWER.

I look back to days of yore when working on engines was simple and more driveway friendly (now only this way in hot rods and pre-70's). However, DOD is just another step in development, just like that 405Hp LS6 compared to a '67 427. Try running that LS6 without an ECM - technology. The 427 didn't need no stinkin' ECM, but the Z06 is faster. Seriously, thanks to Hypertech and others, most of us have found the ECM as a power resourse, not a handicap.

At some point in the future, there will be a place on this forum where we share our successes in wringing out DOD for hidden HP.

 

[DRTH VTR]

My question is 'what will the exhaust sound like?'

 

[Black Ice]

OOOh Please God Nooooo Nooooo No DOD! Chevrolet dealers cant fix 1/2 of the problems with C5 can you imagine DOD? Ohhh Nooo God Noooo I cant stand the thought of bringing my new C6 in to a dealer with a DOD problem. OOooohh Noooo Oh I gotta go take a Zanax now bye. :cry :cry :cry :cry

 

[Saving 4 C6]

OOOh Please God Nooooo Nooooo No DOD! Chevrolet dealers cant fix 1/2 of the problems with C5 can you imagine DOD? Ohhh Nooo God Noooo I cant stand the thought of bringing my new C6 in to a dealer with a DOD problem. OOooohh Noooo Oh I gotta go take a Zanax now bye. :cry :cry :cry :cry

Calm down man. Everything's going to be alright, I hope.