"Capacity on demand"
- Thread starter simonjrwinter
- Start date
There are also engines that can switch from four stroke to two stroke, ( Ricardo ) not sure of the benefit of that myself though
Hmmm... I have never heard of this engine! Please do tell more!
Ask Ricardo Engineering UK , I dont know either, I only know it exists ! Frank
Doesn't the current Chrysler offering have a similar feature?
Hmmmm..... may not be relevant but I remember reading some years ago how in the fuel strapped times of WW2 there was a conversion available in NZ to convert the ubiquitous Ford SV V8 to four cylinders to conserve fuel.
From memory I think it involved removing 4 pistons and rods from the rotating assembly. Not sure what this would have done to the balance though.... I guess if you suddenly found you needed more power it'd just be a matter of booking it back into the garage to refit the deleted parts! Not quite power/economy on demand! You would have had to book it in, in advance!!
I also guess this solution may have been dreamed up by some poor misguided souls not long emmigrated from the 'mother country'. That was the country responsible for the 8hp 'economy' versions of the neck snapping Austin 10 etc!
Ron Earp
Admin
GM pioneered this feature in the early 80s with the 8-6-4 V8. It would selectively cut cylinders depending on demand. In short, I understand the engine was a disaster.
Enter the modern age and GM, Chrysler, and Honda have selective cylinder deactivation to conserve fuel. From what I've read the transition is seamless and happens in 10s of milliseconds. Chrysler offers it on their "Hemi" line of engines but not on the performance SRT-8 versions. I'm not sure on which lines GM and Honda offers it but someone on the forum will know.
Cool stuff in my opinion.
Enter the modern age and GM, Chrysler, and Honda have selective cylinder deactivation to conserve fuel. From what I've read the transition is seamless and happens in 10s of milliseconds. Chrysler offers it on their "Hemi" line of engines but not on the performance SRT-8 versions. I'm not sure on which lines GM and Honda offers it but someone on the forum will know.
Cool stuff in my opinion.
I have a LWB stretched Chrysler 300 with a Hemi in it. With my wife driving it it gets 23-25 miles per gallon. When I took it to Road America last year with Me driving it it only got 18-20 miles per gallon. I'm not sure what was up with that. Maybe it was all the long twisty roads on the way there.
Regards Brian
Regards Brian
Howard Jones
Supporter
Brian.....I think your foot might be bigger than hers...................Not a bad thing..........but more than likely true........right?
Howard !!
That is a possibility. I was very eager to get to Road America each day. My other thought was -- sometime ago, I lost most of my left foot in a accident, and I count on my right foot for balance. Perhaps I was just unstable. Either way, you can not tell when it cycles down, and the throttle response is right there when you need it.
Regards Brian
That is a possibility. I was very eager to get to Road America each day. My other thought was -- sometime ago, I lost most of my left foot in a accident, and I count on my right foot for balance. Perhaps I was just unstable. Either way, you can not tell when it cycles down, and the throttle response is right there when you need it.
Regards Brian
Capacity on demand = turbocharger or supercharger.
More air plus more fuel = more capacity.
More air plus more fuel = more capacity.
Actually the 8-6-4 was a great engine, but only lasted a year ('81). You could easily bypass
the system, or even wire up a switch. There are 8-6-4s that have turned over 500K miles.
Contrary to popular misbelief, the engine was discontinued after one year not because of
mechanical issues, but because it still did not meet EPA MPG marks.
The follow up engine, the HT4100 ('82-'85), was a complete disaster, and many people
associate the 8-6-4 with the HT4100.
Ian
Charlie Farley
Supporter
God, that's one ugly car.
I cant tell from the overhang at each end, where the engine was.
Or did it have one at each end ?
lol/
I cant tell from the overhang at each end, where the engine was.
Or did it have one at each end ?
lol/
I believe the Cadillac V8 Northstar engine shut down one bank (in some models) and ran on four cylinders during light load. Was supposed to get a couple more miles to the gallon and be pretty seamless in the getting back on the power. I never drove one so I don't have any first hand knowledge but the Northstar engine had a pretty good reputation.
Dave Wood
Lifetime Supporter
I recall that there were issues with the Caddie 8-6-4. That is not to say there aren't some that have tons of miles, but there were issues with the system. I have had several high mileage Fiats, but wouldn't suggest those as any stellar auto...but I like them, maybe the fact that I have been a tech since 1969 makes them easier to deal with than someone that relies on service persons. My understanding of the systems issues had to do with the "canceling" procedure. I believe that it was set up so that it didn't cancel the same cylinders so as to keep wear among them fairly equal. It may have been cut because it didn't help meet CAFE standards, but in this area they were notorious for malfunctioning.
Those were designed to cancel injector pulse if I recall correctly, I think the newer systems deactivate the valve train on different cylinders.
In the gas crunch of the 70s I remember Crower( of cam fame) offering a kit not unlike the one described that was used during WW2. It basically removed the piston/rods on 2 inner and 2 outer cylinders on opposite banks and effectively made it a V4. The problem I saw with it was that they were only made for large barges...Caddies,Toronados,Lincolns,etc... So the decrease in power was quite dramatic because of the cars' mass. JC Whitney even offered them for awhile...but that was probably after they tanked in early marketing and needed to unload some of them. They were fairly elaborate kits, including items to retain the lifters in their passages with springs when the pushrods were removed. The kit was expensive and the labor was more. Then, if you wanted to sell it or convert back when the gas flowed again...more expense. Interesting concept but fell a little short in application.
Those were designed to cancel injector pulse if I recall correctly, I think the newer systems deactivate the valve train on different cylinders.
In the gas crunch of the 70s I remember Crower( of cam fame) offering a kit not unlike the one described that was used during WW2. It basically removed the piston/rods on 2 inner and 2 outer cylinders on opposite banks and effectively made it a V4. The problem I saw with it was that they were only made for large barges...Caddies,Toronados,Lincolns,etc... So the decrease in power was quite dramatic because of the cars' mass. JC Whitney even offered them for awhile...but that was probably after they tanked in early marketing and needed to unload some of them. They were fairly elaborate kits, including items to retain the lifters in their passages with springs when the pushrods were removed. The kit was expensive and the labor was more. Then, if you wanted to sell it or convert back when the gas flowed again...more expense. Interesting concept but fell a little short in application.
My wife had one as well. We sold it. For a Honda, it got lousy fuel economy - we never could get much more than 24 mpg on the highway and around-town mpg was terrible (not surprising considering it weighed something like 4.600 lb). It was a very complex system - because of the engine vibrations when running on less-than 6 cylinders, it had active motor mounts and active noise cancelation through the audio system.Too much to go wrong, IMO, even for a Honda. Bought her a CRV and never looked back.
