If you give me a way to provide proof I will gladyly provide, but if I do what I normally do, fillup, drive from the gas station to an area I know the mileage away, loop back and fillup then divide, I can give you exact numbers from a fillup, but you probably still wouldnt believe it. If you can think of a way to provide concrete evidence I will gladly do it!!
Gas Mileage
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I actually quite like side posts, not a whole lot of corrosion and less room for guys that like to hammer on the wrong side top post terminal or even worse put a wood screw in it (seen that far too many times) It is a pain if they round but nothing a set of good vice grips cant handle, Im yet to have the threads strip knock on wood but I imagine that would entail lots of cursing and regret...
I was gonna put in some regular copper Champion or Delco plugs but I was able to get the e3s extremely discounted, less than the copper Delcos which is why I got them, whether or not they actually do anything, I know a lot of guys love them in lawn mowers lol. I dont think they did much but they were new replacements, so definitely better than the old. The set of 8 costed me around 38 bucks so I'll probably run them till they give me issues, but they havent yet!!
He's right though.. and I don't know any engineers that would be insulted by his statement. The school I went to had a 22% graduation rate for engineering tracks. You usually lost most of them in the second or third year where the real math and application courses started. "C's get degrees" is real. By definition, that means they are an average student... in an engineering course that is not easy.
The vast majority of students going into engineering have zero practical application experience or real world mechanical knowledge. I was one of only a few exceptions in my school as a veteran and as one that had spent his entire adult life previous to school working as a mechanic. I started out at 14 years old working in performance shops in Southern California in the 90's and early 2000's. Then went in to the Army as a M1 Tank Mechanic, then went to work as a heavy diesel Field Service Rep supporting and training military mechanics in Afghanistan.
The school I went to is specific to aviation and my entire senior year was spent doing a design and application project with a team of other engineers. My entire job on the team was to make sure we designed something that could actually get built and then to design and build the infrastructure required to actually test our product. It was eye opening the kinds of things these kids would come up with, that were absolutely not practical or even possible to make sometimes. They looked cool in the CAD software though!
We were sponsored by an outside company and designed a 1 metric ton thrust, second stage to orbit, liquid rocket engine. We then had the the injector face and manifolds manufactured and flow tested them on a test stand to show they functioned as designed and flowed the designed amount of fluid. We also manufactured and fired the ignitor for the engine and then presented the whole thing to a panel at the end of our project. Apparently the Air Force purchased the design and the company that sponsored us is building it for them. Our team captain went on to get her Doctorate in Propulsion Engineering from Purdue and I think she is now working at Blue Origin.
All of that to say, lots of the veterans that I went to school with graduated with a 2.5-3.0 GPA and went on to work as Engineers in places like SpaceX, Blue Origin, Garmin, Scaled Composites, NASA, the Air Force Research Lab, etc..
I have actually seen numerous employers pass on someone with a 4.0 GPA because those guys generally burn out fast or are so socially awkward that they can't work in a team or take criticism. The 3.0 range is usually the comfort zone, but if you have any other redeeming skills, the big boys will absolutely take a lower GPA. The reality is that it is a profession that has far more demand than there are available bodies to fill it. It is difficult and expensive to go through an engineering program and you have to have enough intelligence and grit to do it... it isn't underwater basket weaving or English that you just have to be breathing and show up to class to pass.
I just spent 2 weeks interviewing candidates for a mid level programming position. Half these people got an undergraduate degree in India or other foreign country and came over and got a Masters in the US. They all had "A" averages for grad school. Most couldn't answer basic questions.
I'd rather hire a guy that flunked out but could answer questions.
I'd rather hire a guy that flunked out but could answer questions.
Are you a C student?
Nope, but I work with quite a few(no idea how many, because no one cares about GPA once you graduate and get your first job). I also don't work for an automotive OEM.
Seems like you missed the whole point of what everyone is saying here... GPA doesn't mean much. Engineers aren't superhuman and you shouldn't expect that they spent decades designing where that bolt goes in an application where it isn't necessary to do so. Assume that an average guy did the best he could with what he was given, because most of the team that did the design is going to be just that. They reuse as much as they can of the vetted and tried and trued designs, then they put it all together and try to troubleshoot and fix all the issues they find, then they get them on a test track and keep testing, troubleshooting, and iterating. The more time they have to do that and the less changes they have throughout a product line, the more refined the design will become and the better "engineered" it will be. But there are always cost/benefit considerations and the testing/refinement can't go on forever.
The implication is that everything is done by people who are just barely competent. I don't think it's correct, except perhaps in government.
* TLDR alert *
This is *exactly* the kind of discussion I was hoping would break out in this thread. From my perspective, in this forum the sum total
of brain cycles that have been spent on all things GMT400 (and/or vehicles in general) is vast, and I was hoping to see what others have
figured out that I haven't even thought about. (Trying to fix the 'I didn't even know that I didn't know' syndrome. :0)
I'm especially interested in where people have invested their own time & effort, made changes, and documented the success or failure of their
experimentation. (ie: The Edison approach with inventing the light bulb - he created something new via trial & error, guided by data
from thousands of iterations of incremental 'failures'.)
I think that the MPG discussion can be broken into 3 broad categories, in order of decreasing ease of implementation / bang for the buck:
1) Getting the most out of what you got to work with. (stock)
2) Realistic mods you make near term for short money. (aka parts bin engineering - 0411 upgrade with optimized tunes, fast-burn heads, camming to meet specific needs, etc)
3) Adopting more radical changes pioneered in the Aviation community or elsewhere since the General built the GMT400 product line.
1) Getting the most out of what you got to work with. (stock)
My thought process behind writing reply #26 was to try to illustrate that a given MPG number is based upon how
much work was required of the engine for the miles traversed. And the largest single efficiency variable in the powertrain is
the human behind the wheel, and the power they demand given the total gross weight, where they drive, how they
drive, etc. Reading between the lines of my earlier reply, I was simply minimizing how much work (power over time)
that I asked my stock truck to deliver per mile driven.
EDIT: One thing I should point out is that I think the some members on the forum do have an unfair advantage in the
MPG derby because they are not fighting the elevation changes, while others have no choice but to throttle up to climb
the grades where they live. For example, it turns out that Florida is even flatter than Kansas: (List of elevation changes by state)
2) Realistic mods you can make / parts bin engineering for the efficiency win
Pretty much everything @L31MaxExpress has been sharing in this forum is a good example of this.
If I had the good fortune to be in a position to dial in my L29 his way, I would:
A) Take careful baseline data of the current, unmodified stone stock chore truck and make enough backup copies
that I can't lose them all.
B) Refresh the motor. Do all the tricks that add up incrementally like optimum ring seal (fresh cylinder walls
finished with torque plates in place) ...modern ring package, careful valve job, zero-decking the block/optimizing
the quench, etc.
The goal? During the tuning process I want all 8 cylinders to start pinging/knocking together at the same time,
instead of having 1 cylinder where all the variables stack up wrong, knocks early & often, and causing the
KS to signal the computer to pull out timing prematurely for the other 7 cylinders. Minimize the 'octane appetite'
for a given cylinder pressure wherever possible. For that matter, do anything & everything to lower the noise
floor during engine operation. (ie: Optimize the environment that the KS is working in.)
C) Overthink/over-research the cam. :0) Seriously, OEM quality cam in terms of longevity & overall valvetrain
quietness, but at the same time try to take advantage of whatever has been learned in the nearly 30 years since
the original L29 cam was designed. Failing this, try to figure out how much to advance the phasing of the stock cam
in order to find the sweet spot in terms of DCR vs interaction with the stock L29 intake, etc. And of course
degree in the cam to that spec.
D) After the engine is back in, broken in, & verified good, repeat the baseline test in order to see what improvement,
if any, is realized just from the refreshed/ideal tolerance engine under stock Black Box control. (Baseline B)
E) Remove the Black Box & replace with 0411. Start the tuning process. For example, fine tune so that the engine
is just quiet across the range on 89 octane, but as a cross-check *just* pings on 87. Use knock counts as a
cross-check of how close you are to dialing in the tune to what the motor wants. At the end, decide to either leave
the tune where it is (& allow the KS to do it's job while feeding it 87 for light duty stuff) ...and being smart enough to
proactively fill up with 89+ in advance of any HD usage. (If this doesn't pan out, then back everything off a couple of
degrees and just run 87 octane all the time.)
F) Now rerun the baseline test. (Baseline C) Now I expect to see a demonstrable improvement in both efficiency and MPG.
Because Baseline A would represent a 25 year young 230K mile L29 tuned to work pretty much anywhere in the world
and be driven by just about any member of the motoring public who would drive a GMT400 with little or no focus on what's
going on in the engine bay. While at the same time without kicking the SES light or causing excessive warranty work
at the dealership. (Because that was the problem that the original engineers were given to solve, including meeting
emissions, etc.)
And Baseline C would be optimized for me driving around in my area, doing my thing, on a fresh motor that's tuned
to extract as much mechanical push as possible from today's ethanol-added 87 octane fuel...which was signed into law ~6
years after the truck was calibrated for straight gasoline, thanks to the Energy Policy Act of 2005.
(Ethanol - a byproduct in search of a problem to solve.)
And in the perfect world I would rerun the proposed Highway 36 economy run, and afterwards being able to report that
on this second run that the chore truck was able to drive some distance closer towards St. Joe, MO before having to
refill the same 24 gallon tank.
****
So the benefit of my optimization exercise would be higher efficiency for me. But other drivers picked at random may or may
not have issues with operating my truck, bringing with them the expectation that it will function as a self-protecting appliance.
Some may even react that after all my refinement the truck is for them worse than original. But please note that I have not
proposed disabling the EGR or deleting the cats.
As a matter of fact, I found reply #3 in the following thread to be a very interesting read:
(Using EGR to virtually lower engine (oxygen) displacement/pumping losses during cruise conditions)
****
At this point it's obvious that I fall into the camp described by ETA's take on L31MaxExpress's hands-on experiments in this area.
That is, with enough time, thought, and tinkering I can take an engineer's profit-oriented nationwide compromise solution and refine
it to meet my specific needs. Of course, it might take me weeks or months in the 2020s to eke out an improvement upon something
he was paid to figure out in a few days under tight time constraints in the mid-'90s, but it *is* possible to make a measurable difference
in efficiency. And it's fun to think about.
****
I was going to cover some of the more radical efficiency changes that have promise, but this is already longer than I wanted.
So instead I'll close this out with a quick description of similar efforts to improve on the original design but in a different hobby.
In the land of audio once upon a time there was an engineer who (IMHO) was the Ed Cole of loudspeaker design. His name was
Arnie Nudell, and after careful listening to some of his best efforts I wanted to know more about what made this guy tick.
In the context of his time, his products really stood out. For a given sound pressure level, you not only experienced the dynamics
musicals peaks, but at the same time you could also still hear the spaces between the individual notes. As I later learned, his focus
on power/weight ratios when it came to where the motor was placed vis-a-vis the driven diaphragm translated into drivers that
didn't slur what was going on, preserving transient response, imaging, immediacy, the elusive 'you are there' sensation, etc.
...But what was amazing & stood out from the crowded loudspeaker market in the '70s became an also-ran by the turn of the century,
thanks to the general technological improvements in the realm since then. One choice would be to retire the old behemoths, and purchase
new loudspeakers from today's marketplace.
Or, you could choose to use more modern technology to help better characterize the strengths & weaknesses of the original
design, and fix those old speakers so that instead of having a particular, recognizable 'sound' superimposed upon any music played
through them, they instead are more neutral, adding no sonic imprint of their own to the music, to the point where they sound
completely different during eachtune song, the sonic signature fully dependent only upon the music being played through them. (!)
Even though this test setup is no longer cutting edge in terms of test equipment, it's a couple of decades newer instrumentation than what
Arnie had to work with. (MLSSA) As it turns out, you gotta make sure that the cabinet isn't talking louder than the drivers
when stimulated at very specific frequencies.
****
So is it possible for newer, more powerful engine mgmt technology to up the efficiency and MPG of our old GMT400s? I *think* so.
Just gotta figure out how to instrument/document the journey in such a way that even Glock20 will find it persuasive. :0)
More to follow.
This is *exactly* the kind of discussion I was hoping would break out in this thread. From my perspective, in this forum the sum total
of brain cycles that have been spent on all things GMT400 (and/or vehicles in general) is vast, and I was hoping to see what others have
figured out that I haven't even thought about. (Trying to fix the 'I didn't even know that I didn't know' syndrome. :0)
I'm especially interested in where people have invested their own time & effort, made changes, and documented the success or failure of their
experimentation. (ie: The Edison approach with inventing the light bulb - he created something new via trial & error, guided by data
from thousands of iterations of incremental 'failures'.)
I think that the MPG discussion can be broken into 3 broad categories, in order of decreasing ease of implementation / bang for the buck:
1) Getting the most out of what you got to work with. (stock)
2) Realistic mods you make near term for short money. (aka parts bin engineering - 0411 upgrade with optimized tunes, fast-burn heads, camming to meet specific needs, etc)
3) Adopting more radical changes pioneered in the Aviation community or elsewhere since the General built the GMT400 product line.
1) Getting the most out of what you got to work with. (stock)
My thought process behind writing reply #26 was to try to illustrate that a given MPG number is based upon how
much work was required of the engine for the miles traversed. And the largest single efficiency variable in the powertrain is
the human behind the wheel, and the power they demand given the total gross weight, where they drive, how they
drive, etc. Reading between the lines of my earlier reply, I was simply minimizing how much work (power over time)
that I asked my stock truck to deliver per mile driven.
EDIT: One thing I should point out is that I think the some members on the forum do have an unfair advantage in the
MPG derby because they are not fighting the elevation changes, while others have no choice but to throttle up to climb
the grades where they live. For example, it turns out that Florida is even flatter than Kansas: (List of elevation changes by state)
2) Realistic mods you can make / parts bin engineering for the efficiency win
Pretty much everything @L31MaxExpress has been sharing in this forum is a good example of this.
If I had the good fortune to be in a position to dial in my L29 his way, I would:
A) Take careful baseline data of the current, unmodified stone stock chore truck and make enough backup copies
that I can't lose them all.
B) Refresh the motor. Do all the tricks that add up incrementally like optimum ring seal (fresh cylinder walls
finished with torque plates in place) ...modern ring package, careful valve job, zero-decking the block/optimizing
the quench, etc.
The goal? During the tuning process I want all 8 cylinders to start pinging/knocking together at the same time,
instead of having 1 cylinder where all the variables stack up wrong, knocks early & often, and causing the
KS to signal the computer to pull out timing prematurely for the other 7 cylinders. Minimize the 'octane appetite'
for a given cylinder pressure wherever possible. For that matter, do anything & everything to lower the noise
floor during engine operation. (ie: Optimize the environment that the KS is working in.)
C) Overthink/over-research the cam. :0) Seriously, OEM quality cam in terms of longevity & overall valvetrain
quietness, but at the same time try to take advantage of whatever has been learned in the nearly 30 years since
the original L29 cam was designed. Failing this, try to figure out how much to advance the phasing of the stock cam
in order to find the sweet spot in terms of DCR vs interaction with the stock L29 intake, etc. And of course
degree in the cam to that spec.
D) After the engine is back in, broken in, & verified good, repeat the baseline test in order to see what improvement,
if any, is realized just from the refreshed/ideal tolerance engine under stock Black Box control. (Baseline B)
E) Remove the Black Box & replace with 0411. Start the tuning process. For example, fine tune so that the engine
is just quiet across the range on 89 octane, but as a cross-check *just* pings on 87. Use knock counts as a
cross-check of how close you are to dialing in the tune to what the motor wants. At the end, decide to either leave
the tune where it is (& allow the KS to do it's job while feeding it 87 for light duty stuff) ...and being smart enough to
proactively fill up with 89+ in advance of any HD usage. (If this doesn't pan out, then back everything off a couple of
degrees and just run 87 octane all the time.)
F) Now rerun the baseline test. (Baseline C) Now I expect to see a demonstrable improvement in both efficiency and MPG.
Because Baseline A would represent a 25 year young 230K mile L29 tuned to work pretty much anywhere in the world
and be driven by just about any member of the motoring public who would drive a GMT400 with little or no focus on what's
going on in the engine bay. While at the same time without kicking the SES light or causing excessive warranty work
at the dealership. (Because that was the problem that the original engineers were given to solve, including meeting
emissions, etc.)
And Baseline C would be optimized for me driving around in my area, doing my thing, on a fresh motor that's tuned
to extract as much mechanical push as possible from today's ethanol-added 87 octane fuel...which was signed into law ~6
years after the truck was calibrated for straight gasoline, thanks to the Energy Policy Act of 2005.
(Ethanol - a byproduct in search of a problem to solve.)
And in the perfect world I would rerun the proposed Highway 36 economy run, and afterwards being able to report that
on this second run that the chore truck was able to drive some distance closer towards St. Joe, MO before having to
refill the same 24 gallon tank.
****
So the benefit of my optimization exercise would be higher efficiency for me. But other drivers picked at random may or may
not have issues with operating my truck, bringing with them the expectation that it will function as a self-protecting appliance.
Some may even react that after all my refinement the truck is for them worse than original. But please note that I have not
proposed disabling the EGR or deleting the cats.
As a matter of fact, I found reply #3 in the following thread to be a very interesting read:
(Using EGR to virtually lower engine (oxygen) displacement/pumping losses during cruise conditions)
****
At this point it's obvious that I fall into the camp described by ETA's take on L31MaxExpress's hands-on experiments in this area.
That is, with enough time, thought, and tinkering I can take an engineer's profit-oriented nationwide compromise solution and refine
it to meet my specific needs. Of course, it might take me weeks or months in the 2020s to eke out an improvement upon something
he was paid to figure out in a few days under tight time constraints in the mid-'90s, but it *is* possible to make a measurable difference
in efficiency. And it's fun to think about.
****
I was going to cover some of the more radical efficiency changes that have promise, but this is already longer than I wanted.
So instead I'll close this out with a quick description of similar efforts to improve on the original design but in a different hobby.
In the land of audio once upon a time there was an engineer who (IMHO) was the Ed Cole of loudspeaker design. His name was
Arnie Nudell, and after careful listening to some of his best efforts I wanted to know more about what made this guy tick.
In the context of his time, his products really stood out. For a given sound pressure level, you not only experienced the dynamics
musicals peaks, but at the same time you could also still hear the spaces between the individual notes. As I later learned, his focus
on power/weight ratios when it came to where the motor was placed vis-a-vis the driven diaphragm translated into drivers that
didn't slur what was going on, preserving transient response, imaging, immediacy, the elusive 'you are there' sensation, etc.
...But what was amazing & stood out from the crowded loudspeaker market in the '70s became an also-ran by the turn of the century,
thanks to the general technological improvements in the realm since then. One choice would be to retire the old behemoths, and purchase
new loudspeakers from today's marketplace.
Or, you could choose to use more modern technology to help better characterize the strengths & weaknesses of the original
design, and fix those old speakers so that instead of having a particular, recognizable 'sound' superimposed upon any music played
through them, they instead are more neutral, adding no sonic imprint of their own to the music, to the point where they sound
completely different during each
Even though this test setup is no longer cutting edge in terms of test equipment, it's a couple of decades newer instrumentation than what
Arnie had to work with. (MLSSA) As it turns out, you gotta make sure that the cabinet isn't talking louder than the drivers
when stimulated at very specific frequencies.
****
So is it possible for newer, more powerful engine mgmt technology to up the efficiency and MPG of our old GMT400s? I *think* so.
Just gotta figure out how to instrument/document the journey in such a way that even Glock20 will find it persuasive. :0)
More to follow.
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glock20
Newbie
This isn't hard to figure out, surely you've kept a log or something of your fillups if you're actually getting in the 20s because that is unheard of...hence my skepticism
and driving a 40 mile round trip while being intentionally easy on the gas pedal and returning to fill up isn't exactly an accurate representation of your fuel mileage
got a log you've kept from the last 5-6 fillups where you've used the majority of the fuel in the tank each time?
as said earlier, this mileage claim is a steaming pile of horse s h i t e. if you're going to exaggerate at least make it believable. i'd believe you and even be jealous if you had claimed 17
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