4th gen 4.7 engine v8 can disconnect 2cyl for fuel economy ? myth?
- Thread starter cesarel
- Start date
Register to hide this ad
BlackWorksInc
New member
Well the 4.6L V8 is more fuel efficient than the older 4.7L unit. But there was never any cylinder deactivation on the older engines, actually I don't even thing Toyota decided to go that route. I believe that's more of a GM/ChryCorp deal.
Not a joke real question... Like chevrolette have tht type of engines.
Are 2004 4.7 vvti? Or vvti came at 2005?
RCs4Runner
New member
2005.
Hooo ok so i guess 2004 is not as efficient as 05. Hoe big is the difference? Im thinking about getting a 04 but gas makes me wonder...
NJshadow93
New member
It's less of the gas mileage, more of the power. There's about 30 more horsepower and 10 ft/lb torque more with the VVTi.
Copy that so the best option is a vvti 2005 or +
Im used to the mileage of a gen3 v6 auto ...any idea if its a big difference?
Thanks for the help btw.
Atlanta_man
New member
same numbers here w/ my 2005 v8
except I can get close to 20 on the interstate with cruise control set to 74
sometimes with heavy city driving I'll get in the 15's on that tank full
trailer is a killer for mpg even when you slow down to 60
In 81 Cadillac invented the 4-6-8 motor that shut of 2 and 4 cylinders for fuel efficiency. So GM was the first to do it, and in recent years it was revisited by Chrysler Corp in the Hemis.
GM re-adopted the tech in more recent years also, but it has never really taken off in any other markets because the US is the only country so reliant on Gas and not diesel.
I personally feel it's a gimmick, because the couple cylinders less fuel, does not seem to be enough to make up the load under parasitic drag. IMO
GM re-adopted the tech in more recent years also, but it has never really taken off in any other markets because the US is the only country so reliant on Gas and not diesel.
I personally feel it's a gimmick, because the couple cylinders less fuel, does not seem to be enough to make up the load under parasitic drag. IMO
WillK
New member
GM, Dodge, Honda to name a few. Believe it or not, Cadillac was one of the first (if not the first, I don't know) to try cylinder deactivation to save on fuel.
They actually used the term 8-6-4 as a selling point. But it was a huge failure.
We had family friends who had them and they had nothing but problems with them.
From wiki...
For 1981 Cadillac introduced a new engine that would become notorious for its reliability problems (with the electronics, not the robust mechanical design), the V8-6-4 (L62). The L61 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system called Modulated Displacement that would shut off two or four cylinders in low-load conditions such as highway cruising, then reactivate them when more power was needed. When deactivated, solenoids mounted to those cylinders' rocker-arm studs would disengage the fulcrums, allowing the rockers to "float" and leave the valves closed despite the continued action of the pushrods. These engines are easily identified by their rocker covers, which each have elevated sections over 2 cylinders with electrical connectors on top. With the valves closed the cylinders acted as air-springs, which both eliminated the feel of "missing" and kept the cylinders warm for instant combustion upon reactivation. Simultaneously, the engine control module would reduce the amount of fuel metered through the TBI unit. On the dashboard, an "MPG Sentinel" digital display could show the number of cylinders in operation, average or current fuel consumption (in miles per gallon), or estimated range based on the amount of fuel remaining in the tank and the average mileage since the last reset.[5]
Another rare and advanced feature introduced with DFI was Cadillac's truly "on-board" diagnostics. For mechanics who had to deal with the 368's, the cars contained diagnostics that did not require the use of special external computer scan-tools. The new Electronic Climate Control display, along with the MPG Sentinel, provided on-board readout of any stored trouble codes, instantaneous readings from all the various engine sensors, forced cycling of the underhood solenoids and motors, and on the V8-6-4 motors, manual cylinder-pair control. The L62 produced 140 hp (104 kW) at 3800 rpm and 265 lbf·ft (359 N·m) at 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across the whole Cadillac line.
While cylinder deactivation would make a comeback some 20 years later with modern computing power (and using oil pressure to deactivate the valves by collapsing the lifters) Cadillac's 1981 V8-6-4 proved to have insurmountable engineering problems. The main issue was that the Engine Control Module simply lacked the robustness, programming and processing speed to efficiently manage the cylinder-deactivation under all load conditions. In the era before electronically operated EGR valves, the engineers also made an error in using a "back-pressure-type" EGR valve... While this early effort to match the vacuum-controlled EGR volume more accurately to the engine's load made sense in a 'normal' engine, it had the effect of causing pinging (detonation) problems in the V8-6-4 engine, because 4 cylinders operating under higher load needed more EGR, while they were actually producing less exhaust flow and therefore less back-pressure to operate the valve...
Off topic a little...
They actually used the term 8-6-4 as a selling point. But it was a huge failure.
We had family friends who had them and they had nothing but problems with them.
From wiki...
For 1981 Cadillac introduced a new engine that would become notorious for its reliability problems (with the electronics, not the robust mechanical design), the V8-6-4 (L62). The L61 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system called Modulated Displacement that would shut off two or four cylinders in low-load conditions such as highway cruising, then reactivate them when more power was needed. When deactivated, solenoids mounted to those cylinders' rocker-arm studs would disengage the fulcrums, allowing the rockers to "float" and leave the valves closed despite the continued action of the pushrods. These engines are easily identified by their rocker covers, which each have elevated sections over 2 cylinders with electrical connectors on top. With the valves closed the cylinders acted as air-springs, which both eliminated the feel of "missing" and kept the cylinders warm for instant combustion upon reactivation. Simultaneously, the engine control module would reduce the amount of fuel metered through the TBI unit. On the dashboard, an "MPG Sentinel" digital display could show the number of cylinders in operation, average or current fuel consumption (in miles per gallon), or estimated range based on the amount of fuel remaining in the tank and the average mileage since the last reset.[5]
Another rare and advanced feature introduced with DFI was Cadillac's truly "on-board" diagnostics. For mechanics who had to deal with the 368's, the cars contained diagnostics that did not require the use of special external computer scan-tools. The new Electronic Climate Control display, along with the MPG Sentinel, provided on-board readout of any stored trouble codes, instantaneous readings from all the various engine sensors, forced cycling of the underhood solenoids and motors, and on the V8-6-4 motors, manual cylinder-pair control. The L62 produced 140 hp (104 kW) at 3800 rpm and 265 lbf·ft (359 N·m) at 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across the whole Cadillac line.
While cylinder deactivation would make a comeback some 20 years later with modern computing power (and using oil pressure to deactivate the valves by collapsing the lifters) Cadillac's 1981 V8-6-4 proved to have insurmountable engineering problems. The main issue was that the Engine Control Module simply lacked the robustness, programming and processing speed to efficiently manage the cylinder-deactivation under all load conditions. In the era before electronically operated EGR valves, the engineers also made an error in using a "back-pressure-type" EGR valve... While this early effort to match the vacuum-controlled EGR volume more accurately to the engine's load made sense in a 'normal' engine, it had the effect of causing pinging (detonation) problems in the V8-6-4 engine, because 4 cylinders operating under higher load needed more EGR, while they were actually producing less exhaust flow and therefore less back-pressure to operate the valve...
Off topic a little...
Thanks everyone for your comments i was reading that the 2004 makes 15 in the city that is good i guess for a v8
Gas Mileage of 2004 Toyota 4Runner
Ill try to convince myself to buy it...
Which version would be more expensive? Limited or sport?
Sport or sr5?
Thanks again for the help!
Historically the limited is more expensive.
BlackWorksInc
New member
Yeah GM was the first to do it and they were HUGE problematic monsters back then. The technology has gotten much better now, but they are still complicated systems and I genuinely do not think the gain is much, but the guys at GM and ChryCorp believe it is because the new Corvette has Cylinder Deactivation and the Hemis all have it too.
Atlanta_man
New member
Some cars deactivate (kill) the entire engine at every stop. Hit the gas and the starter gets busy restarting the engine.
Not for me, no thanks.
Not for me, no thanks.
Those systems all come with an off switch. If you don't like it, turn it off. In stop and go traffic, start-stop systems can save a lot of gas. They come with larger batteries and stronger starter motors. And they actually start the engine when you take your foot off the brake, not when you hit the gas.
Last edited:
