In reply to jamscal :
Ford has traditionally done cylinder deactivation by frying an ignition coil or blowing a spark plug out of the head.
In reply to jamscal :
Ford has traditionally done cylinder deactivation by frying an ignition coil or blowing a spark plug out of the head.
In reply to Pete. (l33t FS) :
You made me spit my coffee across the office.
ProDarwin said:Out of curiosity, is there an easy way to disable cylinder deactivation on the trucks? I know on Hondas, VCM-Muzzlers have been a thing for a while due to the negative effects of it.
There were tuners that can turn it off in previous trucks, not sure about current models. There are other tricks too depending on manufacturer. Manual shift mode, tow mode, unplug the right thing, etc.
Whats a good way to measure an engines "effort" under load? Throttle position comes to mind, but seems too simple.
Engine #1 required 80% throttle to maintain peak torque under X load.
Engine #2 required 65% throttle to maintain peak torque under same load.
I know this gets into a lot factors and physics but from the drivers seat its about 'feel'
In reply to Gearheadotaku (Forum Supporter) :
A good way, really the only way, is "Load percent", which is actually a PID you can get in generic OBD-II. It is essentially measured (or calculated, when the MAF is ignored or not present) air mass per cylinder cycle vs. what the air mass would be at 100% volumetric efficiency.
Throttle position has absolutely nothing to do with engine load given the number of engines out there that have direct injection, variable valve timing, turbocharging, or some combination of the three. And then there are the BMWs and other highly variable applications where the throttle is always at WOT and is basically only there in case there is a problem with the cam actuation.
Just an example that is fresh in mind. Some of the wiring under the hood of my Volvo got crispy and the dumbass who put the transmission in didn't secure the wiring well, and after a few years the PCV heater power supply wire was shorting to the trans, popping the fuse. This fuse also supplied power to, amongst other things, the camshaft actuator solenoids. The engine is very old school as far as 2022 is concerned, it has port injection and the cams can only advance and retard, no lobe switching or variable lift or variable duration (Hyundai's been doing that one for a few years).
With the cams stuck in full retard, the engine basically did nothing below 4000rpm and it needed 1-2psi boost just to maintain 60mph in top gear.
With the fuse in place, and the cams able to advance, it could easily pull 6th gear at a few inches of vacuum.
Now, does that mean the engine was under more load when it was under boost? The amount of power needed to go 60mph did not change. What changed was the cam timing, the engine was much less volumetrically efficient at 2000rpm when the cams were stuck fully retarded, so it needed more manifold pressure to make the same mass flow through the engine.
This is also why all of these great technologies did not really surface until drive by wire was ready for prime time. With drive by wire, the accelerator pedal is a torque request, because the engine torque has almost, or entirely, nothing to do with throttle position.
Gearheadotaku (Forum Supporter) said:
Whats a good way to measure an engines "effort" under load? Throttle position comes to mind, but seems too simple.
Engine #1 required 80% throttle to maintain peak torque under X load.
Engine #2 required 65% throttle to maintain peak torque under same load.
I know this gets into a lot factors and physics but from the drivers seat its about 'feel'
Pedal or throttle? And the translation from the pedal demand to the engine can be very different between the two engines. "Feel" can be so easily tuned by calibrators.
Let alone, with 8 and 10 speed transmissions, the actual amount of relative power that is needed to do what you say is a very quick shift to a totally different speed and engine load. And the trans response can be very tuned like the pedal response.
Besides, with turbos, there's generally more available torque at lower speeds than normally aspirated engines. Not always, though.
Gearheadotaku (Forum Supporter) said:ProDarwin said:Out of curiosity, is there an easy way to disable cylinder deactivation on the trucks? I know on Hondas, VCM-Muzzlers have been a thing for a while due to the negative effects of it.
There were tuners that can turn it off in previous trucks, not sure about current models. There are other tricks too depending on manufacturer. Manual shift mode, tow mode, unplug the right thing, etc.
I don't know if the Pontiac G8 had a different version of DOD, but when I was seriously considering one of those, I looked into it. The kits are $500-plus and installation involves pulling the heads, new lifters, etc. Not trivial.
Tom_Spangler (Forum Supporter) said:Gearheadotaku (Forum Supporter) said:ProDarwin said:Out of curiosity, is there an easy way to disable cylinder deactivation on the trucks? I know on Hondas, VCM-Muzzlers have been a thing for a while due to the negative effects of it.
There were tuners that can turn it off in previous trucks, not sure about current models. There are other tricks too depending on manufacturer. Manual shift mode, tow mode, unplug the right thing, etc.
I don't know if the Pontiac G8 had a different version of DOD, but when I was seriously considering one of those, I looked into it. The kits are $500-plus and installation involves pulling the heads, new lifters, etc. Not trivial.
I can't imagine they were totally legal.....
QuasiMofo (John Brown) said:2021 Silverado 2.7T Custom Crew Cab 2wd owner here.
Simple facts:
39k miles
22.9 mpg average over those miles including no less than 4000 miles towing a 22ft open hauler with at least 4k lbs aboard.
1 issue with PCM at 300 miles.
I have not replaced anything beside oil, filters and wiper blades on it.
I added a pair of 10" subwoofers in an under seat pre fab box as well as a 1000 watt amp. It sounds amazing.
It's big. It's actually fast. It's really comfortable. It's quiet. It's been cheap. It's a simply amazing traveling companion. I give it a 9 out if 10 for my experience.
Thanks for sharing some insight from the owner's perspective on one of these trucks. I have Frontier I'd like to upgrade some day since towing with the 'small' truck and 4.0L is pretty taxing at times, usually pulling 5k lbs with other associated gear for a fun car event. I just want some extra capacity and breathing room. A new 2.7L that makes more power and torque than yesterday's V8s is fine by me. I don't want to daily drive a truck, I just need a tool for the job, I have a comfortable efficient car for the everyday.
alfadriver said:In reply to Gearheadotaku (Forum Supporter) :
A lot of those features are on iron V8's too. Especially GM's with the variable displacement tech in it.
Also, I4's have half as many cylinders as V8's.
But "simplicity" isn't why the 7.3 came back- that was all about certification rules. If it were about simplicity and reliability, the 5.0l would have been dead many years ago.
Alfa's last comment here about certification rules rings true in the HD industry where I work too. As time goes on, most projects only seem focused on meeting the next set of regulations coming our way. And we don't have much of a choice if developing, building, and selling engines is part of the company or industry you work for. Eventually the alternative technologies will make more sense to spend development dollars on over ICE.
As a car guy, I do hope some niche areas get to keep their special engines, sports car and the like. Or at least that older gas and diesel platforms are supported for years to come as recreational things like horses are today.
But I digress, lets get back to the turbo vs V8 truck talk. 
alfadriver said:Tom_Spangler (Forum Supporter) said:Gearheadotaku (Forum Supporter) said:ProDarwin said:Out of curiosity, is there an easy way to disable cylinder deactivation on the trucks? I know on Hondas, VCM-Muzzlers have been a thing for a while due to the negative effects of it.
There were tuners that can turn it off in previous trucks, not sure about current models. There are other tricks too depending on manufacturer. Manual shift mode, tow mode, unplug the right thing, etc.
I don't know if the Pontiac G8 had a different version of DOD, but when I was seriously considering one of those, I looked into it. The kits are $500-plus and installation involves pulling the heads, new lifters, etc. Not trivial.
I can't imagine they were totally legal.....
None of these kits are legal.
I'm not one to run a car without a cat or anything, but I did consider the VCM muzzle for the Odyssey.
It can cause a weird shudder, oil burning, failed engine mounts, etc. Not the type of crap many people want to deal with, even if the VCM version is rated for a whopping 2mpg better on the highway (the same van is available without VCM, but only in the lower trim packages). Thankfully as a by product of getting divorced, that van was removed from my life I didn't have to deal with that stuff anymore.
Tom_Spangler (Forum Supporter) said:Gearheadotaku (Forum Supporter) said:ProDarwin said:Out of curiosity, is there an easy way to disable cylinder deactivation on the trucks? I know on Hondas, VCM-Muzzlers have been a thing for a while due to the negative effects of it.
There were tuners that can turn it off in previous trucks, not sure about current models. There are other tricks too depending on manufacturer. Manual shift mode, tow mode, unplug the right thing, etc.
I don't know if the Pontiac G8 had a different version of DOD, but when I was seriously considering one of those, I looked into it. The kits are $500-plus and installation involves pulling the heads, new lifters, etc. Not trivial.
What you are describing is removing the system vs just turning it off.
ProDarwin said:It can cause a weird shudder, oil burning, failed engine mounts, etc.
They are blaming the awful V6 engine mount failures on VCM now? People must be happy that they have a new boogeyman besides ethanol in fuel 
Honda has used the same weak mounting design since the beginning of the J engines and they have broken depressingly often since the beginning. The entire weight of the engine and some of the trans rest on the two fore and aft mounts, which are simple rubber bushings with no internal interlock, like an old Taurus but worse. Load reversal on them from engine torque just rips 'em apart. The VCM engines have a little vacuum controlled dealy that basically does nothing after the mount breaks, which happens no sooner than in the non VCM applications.
I remember when it was a 60k service on Pilots to replace the broken motor mounts while the trans was out for rebuild. Save labor costs AND frustration in the shop by waiting until the trans dies before replacing the mounts.
In reply to ProDarwin :
BTW, I'm not in favor of the variable displacement systems- having done work on one, they suck pretty bad. But taking them off, well...
Thankfully, the Ford version isn't the worst version that is available out there. It's just bad.
In reply to Pete. (l33t FS) :
Off topic, but a buddy of mine's Pilot just crapped it's transmission at 52k miles. It was a 2017 Pilot, he bought brand new, and had never towed anything with except for a small motorcycle trailer once, about 400 miles. Of course the trans died 6 hours from home, and Honda's dealership network apparently employs a number of hammer mechanics. He's sworn off Honda products for the rest of his life- he told the customer service lady from them he wouldn't buy a *expletive deleted* lawnmower if it said Honda on it.
Pete. (l33t FS) said:ProDarwin said:It can cause a weird shudder, oil burning, failed engine mounts, etc.
They are blaming the awful V6 engine mount failures on VCM now? People must be happy that they have a new boogeyman besides ethanol in fuel
Honda has used the same weak mounting design since the beginning of the J engines and they have broken depressingly often since the beginning. The entire weight of the engine and some of the trans rest on the two fore and aft mounts, which are simple rubber bushings with no internal interlock, like an old Taurus but worse. Load reversal on them from engine torque just rips 'em apart. The VCM engines have a little vacuum controlled dealy that basically does nothing after the mount breaks, which happens no sooner than in the non VCM applications.
I remember when it was a 60k service on Pilots to replace the broken motor mounts while the trans was out for rebuild. Save labor costs AND frustration in the shop by waiting until the trans dies before replacing the mounts.
Are you saying they have no internal bumpstop/restrictor? That would surprise me. I used to be involved in design of this type of mount back in early/mid 2000 and I remember buying all of them available at the time and cutting them in half (sectioned vertically). All of them had a bumpstop & restrictor to my knowledge.
It may not be a case of VCM destroying them as it becoming so much more apparent they are destroyed on VCM models. When its running on 3 cyl it shakes like crazy.
Also, the cost of replacement if you have VCM is eyewatering:
If you wanted a GM truck without Active Fuel Management, find a 2022. GM built them without AFM due to the chip shortage. A lot of the guys at work specifically went and bought 2022s, because it's extremely common on the '19+ trucks for them to break lifters and bend pushrods before the first oil change. In fact, GM's procedure was that if the vehicle was under 8000 miles, you replaced the lifters on both banks, but with over 8000 miles, you were only allowed to replace the bank with the failure under warranty. We had several customers with 8500ish miles where we replaced just the bank that failed, and then 1000 or so miles later they came back with misfires and valvetrain noise on the other bank.
In reply to NickD :
OT.. And this is why I refuse to buy a new truck. Back on topic, the 2.7 is intriguing, simply because you bypass all that AFM nonsense. I wonder how much headroom it has if you crack the ECM and turn up the boost?
ProDarwin said:It may not be a case of VCM destroying them as it becoming so much more apparent they are destroyed on VCM models. When its running on 3 cyl it shakes like crazy.
They have the restrictors inside but I think the visco fluid inside degrades over time and even when in "hard" mode are too soft and beat themselves to death. I did two replacement sets, then went to vcm muzzler and the mechanical mounts and never looked back. The whole thing is stupid for 2mpg but at least it's relatively easy to get around ... unlike the work needed on the ls based engines.
I dont think the fluid degrades, its just glycol. And that's basically just to keep it from freezing.
IMO, most mounts are too soft & poorly designed, especially on FWD vehicles, but that's a whole different discussion.
jamscal said:They're pushing the 2.7 in commercials as dxman says above.
I talked to a guy who went to get a new Chevy and he had to tell the salesman..."If you say 2.7 one more time I'm leaving." ...he wanted a V8 and got it.
I know the world is changing and small displacement turbo motors are at least the immediate future, but the clientele for trucks is probably older and still values the V8 and is a bit leary of a turbo engine.
I just bought a F-150 and got the 5.0 probably for the same old-man reasons lol. I like the look of the GMCs better but definitely didn't want a 2.7 and don't like the dod or whatever it is on the 5.3.
4 cyl in a full size truck seems unnatural.
I'm not brand loyal but like the aluminum body and 5.0 of the Ford, plus the interior. I was coming out of a 2004 GMC so anything was an upgrade.
When I drove mine on a test drive I chose Sundance Chevrolet in Grand Ledge for two reasons, they are a huge used car dealer and they had identical 2.7 and 5.3 Trucks on the lot.
When the salesman heard I wanted the 2.7 he swore I said "I DON'T want the 2.7" I had to convince him I did.
NickD said:If you wanted a GM truck without Active Fuel Management, find a 2022. GM built them without AFM due to the chip shortage. A lot of the guys at work specifically went and bought 2022s, because it's extremely common on the '19+ trucks for them to break lifters and bend pushrods before the first oil change. In fact, GM's procedure was that if the vehicle was under 8000 miles, you replaced the lifters on both banks, but with over 8000 miles, you were only allowed to replace the bank with the failure under warranty. We had several customers with 8500ish miles where we replaced just the bank that failed, and then 1000 or so miles later they came back with misfires and valvetrain noise on the other bank.
No chip but same terrible parts and a ridiculously high failure rate even on the 22s
The interesting thing is that cylinder shutoff and turbocharging a smaller engine are two sides of the same coin: an engine is more efficient when it is under heavier load. So you either cut back the number of cylinders in use when you are under low load, or you have a smaller engine with a turbo or two to add power for the 1% of the time you need it.
But with either one you are still dragging the parasitic loss of a large oil pump and heavy duty water pump. Thus, the electric water pumps and variable displacement oil pumps, when the engineers are allowed to do it right.
06HHR (Forum Supporter) said:In reply to NickD :
Back on topic, the 2.7 is intriguing, simply because you bypass all that AFM nonsense.
Errr, no you don't. The 2.7T also has active fuel management.
In reply to NickD :
Cue the sad trombone... You mean that thing runs on two cylinders at certain times?
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