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Old 01-31-2006, 03:36 PM
importvic importvic is offline
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aftermarket cylinder deactivation kit???

I'm in the market to buy a vehicle with a V8 but I'm really turned off to buy due to all the high gas prices. I've noticed some manufactures offering electronic cylinder deactivation/cutoff devices in thier new gas guzzling models. What I'd like to know if the aftermarket has addressed the need for a device to perform this function for older cars with electronic injection & ignition? Thanks alot.

Regards, Vic
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Old 01-31-2006, 03:51 PM
dougbfresh dougbfresh is offline
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Highly unlikely you'll find anything like this since it's just coming online with the manufacturers. This is interesting reading: http://www.gm.com/company/gmability/...er_052101.html looks like they even have special lifters to to mention all the electronics. Don;t think I'd be in any hurry till they work out the kinks anyway, last time they tried this, it was a disaster.
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Old 01-31-2006, 06:20 PM
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I haven't worked on one yet, but I think the v8 your talking about and the one that comes equipped with it are two different v8's These v8's are designed and balanced to run on 4 cylinders. Unlike your old style v8's. But you never know they maybe able to make something down the road. Some of these new v8's can do stuff like shut off valves and also cut off fuel supply to the cylinders it doesn't need. So it would be hard to make that happen with some old style Tbi. I know in a year or two gm will offer this deviation system for their trucks and suv's equipped with the v8
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Old 01-31-2006, 07:45 PM
Saltmine Saltmine is offline
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It takes some pretty sophisticated computer software and components to make cylinder de-activation work properly. GM is probably one of the leaders in this field today. Most people probably won't remember in the early '80's Cadillac actually sold cars with de-activation on their cylinders, the "4-6-8" Unfortunately, the hardware andthe computer software weren't up to the task and many were converted back to plain 'ol V-8 engines. I did a lot of the disabling of the cylinder de-activation hardware.
Cadillac almost lost their butts on that one. Between their attempts to offer cylinder de-activation (4-6-8), the 350 diesel, and the Cadillac Cimmaron, Cadillac almost went bankrupt. Several manufacturers have attempted it, without any credable success.
Ford tried it on an inline six-cylinder. Honda tried it on a couple of motorcycles and the Honda Civic, Chrysler is trying to use it on their "Hemi". (the jury is still out on this one)
Chevrolet has been using it on several of their car and trucks, with some measure of success. They even have a "Hybrid" half-ton pickup truck that de-activates it's cylinders when switched to "power supply mode", working as a job-site generator.
VW has attempted a type of cylinder de-activation on one of their turbo-diesels, but, they are finding that shutting the engine off at stoplights saves more fuel.

I seriously doubt if anybody will be offering a kit to install cylinder de-activation for cars (or trucks) anytime soon.
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Old 02-01-2006, 01:50 AM
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I was going to bring up the old caddys, but saltmine already did so. I may be young, but I know way too much.

When a cylinder is cut from the system you need to stop the cylinder from firing. You stop the coil from igniting the plug beacuse the plug lighting off will cause ignition or lean missfires. You need to cut the fuel if you cut the ignition because the unburnt fuel is verry bad for emissions and will also cause fouled plugs and other drivability problems. So not only do we need a way to cut the fuel and spark for a specific cylinder, we also need to eliminate the compression so the other cylinders arent fighting against a dead hole. If I remember right the old caddys had a solinoid that would release compression in the cylinder, while the new engines have a solinoid that keeps the intake valve from opening. Way too much stuff to do/change to make a variable displacement system work on an existing vehicle. The only way to cut the fuel/ign to a specific cylinder is with individual coils/injectors anyways.

As for the VW (this is my area ), yes the experamental TDI saves more fuel when its shut off at stops, but the constant injection at startup makes it an almost wash with the cylinder deactivation. I know there was a lot of problems with the experamental TDI engines which eventually led to the development of FSI. By putting the injector directly in the coumbustion chamber (you loose one of the 5 valves to the injector) you see a 20% gain in fuel economy as you dont need as long of an injector on time since the injector is only firing at the same time the plug is being lit. YOu also save fuel because its not evaporating in the intake plenum before it gets a chance to get to the cylinder. Its claimed that the older non FSI engines were detuned, the FSI equipment was added, and then the power ratings and fuel economy were slightly higher than the previous stock engines. The cool thing about FSI is the ability to someday eliminate the starter.
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Old 02-01-2006, 08:18 AM
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Quote:
Originally Posted by Saltmine
It takes some pretty sophisticated computer software and components to make cylinder de-activation work properly. GM is probably one of the leaders in this field today.
Chevrolet has been using it on several of their car and trucks, with some measure of success. They even have a "Hybrid" half-ton pickup truck that de-activates it's cylinders when switched to "power supply mode", working as a job-site generator.
Are you talking about the new 2006 V-8 Chevrolet Impala SS.... it's a "4-6-8", but, I'm pretty sure it uses some technology other than what the Caddy used..
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Old 02-01-2006, 08:33 AM
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The new Tahoe (2007) is equipped with the 5.3 L cylinder deactivation engine. It shifts to 4 cylinders under light load, and where it does its fuel savings is generally on the highway at steady speeds on more or less level roads (and not towing). The shift from 8 to 4 is claimed to be seemless (or at least hardly noticable) and in return yields 16/22 for two wheel drive and 15/21 in four wheel configuration. That may not sound too good but consider the size vehicle and it's best in class. Getting back to the original question, if you want this technology, you'll have to buy new. Even if someone comes out with a deactivation kit, I feel, you'll never recoupe your investment from the conversion (and it probably won't work as well as a factory installed unit).
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Old 02-01-2006, 07:52 PM
Saltmine Saltmine is offline
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Carsandcycles is right. Getting that kind of fuel economy out of a vehicle that big is quite an acomplishment.... Out Sheriffs Department is using Ford Expeditions and they barely get 10 mpg. The cylinder de-activation they use on a new Impala SS is completely different than the system they used on the Cadillac "4-6-8". And yes, the shift between 8 and 4 is seamless, both ways (I've driven one.)

Bear in mind, though, the 5.3 Chevy V-8 is a VERY efficient engine without cylinder de-activation.
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