Rpm!
 

Hey, its been awhile since my last post which was more about idling then anything (Worst MPG possible), I've since become a truck driver and I lease my truck which means fuel economy means everything to me as its my biggest expense (22 Cents per mile for last weeks settlement), and I was taught in school and have since learned this for myself, that RPM's are *everything* when it comes to fuel economy (at least with a diesel), if I shift progressively I.E. Low Gear to 1000rpm's 1st to just over a thousand, 2nd to 1100 3rd at 1100 or so, pretty much shifting at as low an RPM as possible without lugging the engine and keeping your oil pressure up, fuel economy goes up during the most fuel intensive part of driving (2 gallons when@80,000lbs) to get up to freeway speeds, as well as keeping your RPM's low when you drive, I avoid going above 1300 rpms while driving on a regular basis, if you pull a hill at 1800 rpms you might get up it faster, but if you keep it lower, you save *tons* of fuel.

Also its something alot of people might not consider is wind resistance, I average 5.8-6.1 or so at 65mph and 7.3-7.8 at 58 mph, may not seem like a huge difference in the world of hypermiling, but at driving 600+ miles a day, it is an insane difference in fuel cost.

Re: Rpm!
 

Now we're talking. We have a member hypermiling an 18 wheeler! Just remember to keep it safe, and don't travel significantly slower than the flow of traffic, of you may end up in the middle of an accident.

Re: Rpm!
 

That's about 30-40% difference. That IS huge. It would sound more significant in the form of gallons per 100 miles (or similar measure). I'd go from 40 MPG to 65 MPG with the same improvement.

As for RPM, I've found the same to be true for gasoline engines in my vehicles. If you learn how engines work, how vehicles work, and where the energy goes, it makes sense. Because it's called a "gas pedal", people think that using more of it (which is necessary to produce the same power at lower RPM) means more fuel used; it does not. All it does is remove an air restriction, and at low RPM that just means the same amount of air comes in more easily rather than more air coming in. Then people go and spend loads of money on intakes that flow better so they will think they can close their throttle more...it makes no sense! They could just open the throttle for free and get better results.

Now, with diesels, I understand there is no throttle and the go-pedal is connected to the fuel pump. I'm glad to hear that the result is the same.

You mentioned lugging...is it even possible to lug a diesel? Lugging is severe pre-detonation caused (if I understant correctly) by high cylinder pressure.

Re: Rpm!
 

Heck, I don't think he needs to worry about that. Half the states out there still are double nickel on the interstates. (At least for trucks)

Re: Rpm!
 

it makes sense that aerodynamics would play a huge part in semis..... only 13x8 front surface area and with few exceptions, not exactly smooth in front. far more than even a pickup truck which will only have a few planes much less a car which are usually somewhat aerodynamically shaped to start with (certainly relatively speaking)

Re: Rpm!
 

My scangauge backs up your rpm observations.

Re: Rpm!
 

Thanks for the tips. It's good to see how it works in other vehicles. I haven't heard of progressively higher shift points, I'll have to try it.

Re: Rpm!
 

I guess its not lugging, but this is what I understand what is happening, when you are at lets say 1000rpms in 8th gear, and trying to pull a hill, your engine starts spitting, and the trucks computer is dumping more fuel then can be burned and with my trucks Regeneration system (My truck doesn't throw out black smoke I have a particulate filter that catches it and then burns it at an absurdly high temp once every 600 miles) gets all plugged up, and yes you can lug a semi, lets say you are trapped in slow traffic, and 2nd gear at idle is 5mp 3rd is like 7sh 4th is 10sh and its a really lazy way to roll but when you start up a hill your rpms will drop below 600rpm (idle) and it makes a hellacious noise.

Re: Rpm!
 

rpm IS everything in a diesel.
Not so much for a gasser, here's why;
(I just deleted a long technical explanation...here's something simpler)
A diesel doesn't require vacuum to properly atomize the fuel droplets like a gasser. If you use 1/4 throttle and lope along, worste case scenario you lose speed/rpm on a hill.
With a gasser, (for milage) keeping the engine in it's peak torque band with the highest vacuum will give the best milage. What this means is, a gasser can get better milage at 1/8 throttle @ 2500rpm than it will at 1/4 throttle @ 1400rpm.

Actual example;
81 f-100 300 6 cyl,3 spd,2.75 rear gear. 19mpg and 1/2 throttle if a hill is on the horizon.
Pull engine out and put in another truck. (and the following day)
81 f-350 4spd (np435) 4.56 rear gear. 25mpg at 1/8 throttle @ 2500rpm or so.

So, what happened? Same engine put in heavier truck with lower gears?
The engine was so low in the torque band and was constantly using so much throttle it killed the vacuum. Around 9" of vacuum most of the time which was letting the power valve open and dump excess fuel in. If there were no hills then in theory it would get better than 19mpg but I never saw it.
The one ton was like driving in first gear, no throttle at all. 17" vacuum all the time and could bump to 20 if I let off the throttle at all. Even loaded down hauling a cord of wood it got 22mpg @ 60 mph.

My present truck (93 f-350 4 door,7.3IDI) gets 25mpg at 100kmh and about 21 at 120-130kmh. If I'm idling down a back road at 80kmh or less it seems even better but I've never done it long enough to actually check milage.
Oh, and furnace oil is about 22mpg@100 and 19mpg@130kmh.

Re: Rpm!
 

dieselmech, what you said about vacuum is true in carbureted gasoline engines, but not so with MAF-equipped fuel injection. In fact, if you've got a lot of vacuum then you're wasting energy making that vacuum. Additionally, with each revolution comes the same reciprocating and frictional loss (or, if what I've read is true, friction goes up as a square of RPM); extra revolutions are extra waste.

Unfortunately I'm having some difficulty getting used to my carbureted car. With my previous fuel injected car, equipped with MAF and wideband O2, the best results came from flooring the accelerator and keeping the RPM between idle and 1500RPM. Now that I'm using a carburetor I'm feathering the accelerator and experimenting with different RPM, but this car seems to respond to ultra-low RPM too. If I let it get up to a little bit higher RPM it runs smoother but fuel economy suffers. However, perhaps this belongs in another discussion since this discussion is about diesels.

Re: Rpm!
 

WOW I had no idea that the engines could pull that hard at such a low RPM as that. Yeah watch out for the really low heavy throttle use as I typically see around here in the city the trucks without the filters in the exhaust are pumping out tons of black soot that gets all over my car parked behind my building from the traffic heavy street in front. I would think at lower speeds in lower gears loosing a little fuel but burning clean with slightly higher RPM would be acceptable since you have to consider engine cooling and tranny load losses too. Too bad there isn't a way of monitoring the exhaust emmissions to see what is the best burn rate for highest combustion burn efficiency. I also imagine that keeping the revs low makes it easier to shift between gears too. You might want to check into using Synlube in the motor and gear boxes since it is a BIG Friction reducer and can cost a lot less to use than conventional oil with their much more frequent oil changes.

Re: Rpm!
 

Holycow, yes I was thinking carb. Not that vacuum plays no role in a FI engine, but comparitively speaking, yeah.

As far as making vacuum though, think about it. High vacuum is a product of a tight cyl seal and a restriction to fill that cyl, whether cam timing,valve/port/intake/carb or throttle body. The very thing that "makes" higher vacuum is what makes the engine efficient in the first place. To reduce the vacuum, you would have to have too much port volume or too much overlap etc. This would certainly outweigh any benefits of the less vacuum produced.
If everything was kept equal, the ring seal going away would lower vacuum but that would also equate to less cyl pressure on compression which again would be bad, not good.
Ideal engine has low rotation losses but good seal.

crap...I keep forgetting we're not talking about a drag engine but a big diesel. LOL!

Re: Rpm!
 

Well, in a throttled engine, vacuum is made by those things but only exists because the throttle is closed. Keeping a vacuum uses energy that could go to the wheels instead.

In a diesel...uhh, can there even be vacuum? I thought that was one of the reasons diesels are more efficient.

Re: Rpm!
 

Diesels need a vacuum pump to operate vacuum operated accessories on the engine.

Re: Rpm!
 

Actually you can have vacuum at wide open throttle. Cfm of a 4bbl is rated at...ah crap, I forget..3 inches I think and 2bbl's are rated at 1.5.
If you put too small of a carb on(because of class rules) you can actually have several inches of vacuum at wot.
Example, 396 2bbl stock elim drag engine. Carb flows 320cfm stock but when installed on an engine spinning 7200rpm it shows almost 4 in vacuum on the dyno. At 4 inches on the flow bench, the carb is actually flowing 414cfm! Just by sticking on a 500cfm holley 2bbl hp jumped 23 and torque by 34 or something like that. Vacuum with the 500 went to just under 1".

Buddy of mine Bruce Fulper (rock and roll engineering) wrote an article in car craft about the new(at the time) pontiac pro stock heads. What he was saying is that the difference between a full out stock head and these new heads was worth 100hp. This was on a 500 cube 9500rpm pro stock engine.
The way they wrote the article though said "gain 100hp with these heads".
Bruce was livid! In essence they were letting people believe if you bolted these heads onto a street 455 you would gain 100hp!

What it actually showed, if you look at it from another angle. Take a pro stock engine making 1100hp and bolt on stock restrictive heads and you will lose 100hp. Same as if you pulled the 2 dominators and stuck on a single 600, you'd probably have so much vacuum the powervalve would never open!

Oh, something else, with the bad heads and tight ring seal, the vacuum in the intake is not as high (before the port) as it is in the cyl. When this gets extreme it can cause ring flutter because of the extreme difference on top and below the piston. This is helped with a vacuum pump to scavenge the block but I've seen it destroy rings and walls after only a couple passes.

Oh, and diesels are more efficient because of the higher compression and higher cyl pressure. Gas has higher btu per pound if memory serves me which means if you could run a gasser like a diesel you would have the best of both worlds..oh wait, ford is doing just that with their new ecoboost engines. High compression,turbo's,direct injection....

Even on a gas engine you gain X amount of power/efficiency from Y amount of compression increase all other things being equal.
(man my memory is getting worse..I used to be able to know that stuff off the top of my head) LOL!

Re: Rpm!
 

Thellra...what you are experiencing ...noticing...
is the thermo-dynamics of the
sweetspot...
of the water pump and oil/flow pressure at the optimal heat exchanges.
This keeps the head temperatures at a more constant value...
compression ignition...

which has the MOST to do with diesel efficiencies...
gasoline efficiencies...
This is the rpm range that allows maximim torque...with minimal fuel
Back in the late 1960's early 1970's...
an individual using the cummings motor...
total load maxed for the time...65,000 pounds GVW
using mechanical injection...
modified the water pump... entire cooling system...
to be able to
use a special military grade oil...still secret today.
And driving in the east coast areas....
averaged 20 mpg...for over 10 years...daily driving...loaded.
with a smaller engine...than you have...
This is the real reasons the higher rpm's...
create the imbalance...
the reasons when low rpm "lugging will break the heads"...
It is also why a diesel engine is so noiesy/loud when idling...
another example...
An engineer designed the water pump...
using conventional coolant system...
not to have a thermostat based design...
to be driven off the power steering unit...
to control/manage the head temps more accurately..
and got average of 20% improved mpg...
at lower rpm's and higher rpm's.
That concept has been shelved...by the major company he works for.
Since they own the intellectual property rights...
we probably will never see that in mainstream manufacturing.

the famous Tucker engine...
had many of the same features of the coolant system...designed into it...
that got better torque and mpg than diesel engines in the 1950's...
The engines lasted over 100,000 miles...no major re-builds...

As much as aero-dynamics are a factor...
That man in the 1970's proved...
they are not the most important issues to address.

I am from a long line of long haul truck drivers...3 generations...
My Father was...and always will be the "Master of the OLD GRAPEVINE"...
in California...
I am also the true historical inventor of a new technology...
new field of study... declared by US Patent Office...
of improving the thermo-dynamics of the internal combustion engine...
so radically...
it is somewhere in the range of 400 to 500 % improved...
my test engines...gasoline...carbed..
will out perform current diesel engines...2004 duramax...
in identical 1000 mile test runs...on open roads...no test track.
pound for pound...mile for mile...
It is based on keeping the head temps constant....
I achive maximum torque...at 600-900 rpm's...
low compression engines...
Robert W Hull

Re: Rpm!
 

Robert, take the tinfoil hat off. "special military oil? I am in the military as a diesel mechanic for over 27 years....we buy the cheapest that fits the spec. mostly esso 15/40.

Cyl head temps are important, it's why iron headed engines make more power than alum all else being equal (ask any race engine builder) but they will certainly NOT effect anything to the extent you are saying. CC ing a head and making all chambers exact (including plugs) will make a minimal difference same as balancing ect. In performance or efficiency you can't add 100hp, but you can add 1hp in a hundred places.

Also, the tucker engine was an air cooled engine if I recall correctly. And of the few that were built, NONE have over 100,000 miles on them!

You want to know the "secret" to power in an engine as far as temps go? Keep the block hot so the oil is thin and the rings seal good without to much drag and keep the heads ice cold so you can pack in as dense a fuel as possible. check out Stock/SuperStock dragracing where guys are using block heaters to heat the block but putting ice on the intake and heads because they have a heads up run coming.

I don't know, maybe you wrote that with your tongue firmly planted in your cheek and I missed it, if so, you got me. If you were serious...well...stop reading so many conspiracy theory books and take the tinfoil hat off.

Re: Rpm!
 

LOL
I think you nailed it when you said 'take the tinfoil hat off' !
If you have an hour and many excessive brain cells to kill, try reading his first thread 'The Hull Effect', but I warn you, it's equally painful and much longer.

Re: Rpm!
 

dieselmechanic...DRW...
tin foil hat...how amusing...
guess what...it don't bother me..
Google TASA...Tucker collector car group...
Pics show coolant system...
historically...
first of its kind...
converted air-cooled helicopter engine.
People on my forum brought it to my attentions...
compare me to his efforts that were thwarted...
Live and learn...

The certified John Deere diesel mechanic...15 years standing...stopped laffing
after the dyno testing.
It sure can...that is why they call it a...
historical new field of study...invention...
I dissipate 1000 F of heat...off the exhaust manifolds...
in 1/2 inch...of air space...
hold your hand 1 1/2 inch away from 1400 F exhaust headers...
and not even scald you...

The heads are "cooled off" externally at the same time.

Come April...2011...the International Patents will be in place...
Then it goes to research and developement...

Yupper....have your fun.
Read about me in the future publications...

Re: Rpm!
 

DRW...you slammed on me in the past...
people are testing this in 16 countries...
privately...out of their own pockets.
The ex-vice president of research and developement of Cummins Diesel engines...the ones on the road today...
just listened to the engine idling...in the street.
and immediately...called the men in charge at Cummins presently...
We impressed him...in 5 minutes.
I am not regretful that you considered it wasting brain cells.

Re: Rpm!
 

Ok, let me get this straight. As opposed to Smokey Yunick building an engine that controls/keeps heat to make it more thermally efficient (most of the energy of gas in a regular engine is wasted/converted to heat/exhaust waste) your saying your removing heat to make it more efficient?

The fact that heat travels to cold, therefore more heat being removed from the cyl, is going to increase efficiency? Even though engines that lose more heat through the cyl walls are less efficient? Back to back testing on equal cyl heads with the sole differentiation being the casting material (iron vs alum) shows a marked loss in hp and torque with the alum?

If you told me you invented a new way to process cheese than I might believe you because I know nothing about cheese...processed or not. But making drastic changes due to keeping a cyl head or an engine at a more consistent temp? Buddy, I can't count the amount of race engines I've built that were class and national winners. That includes drag/stock and mudbogging. I'm not a shlep that bolts on a set of headers and then brags about "blueprinting the engine".

Find out who David vizard and Joe Mondello are along with Alan & John Armstrong.

When you patent this device and it proves to be the end-all and be-all then I will personally come on here and publicly say you were right and I was wrong. Until then, as I tell my boys, talk is cheap, don't TELL me what your going to do, SHOW me.


Unless you want to get in on MY invention? It's a shrader valve for tires that keep them at EXACTLY 35.137732 psi which jumps the milage of every car I tested by 300%. My 4 door one ton now gets 80mpg!! Everybody laughed but I showed the guy from Goodyear and he stopped laughing after one drive!

You just wait, maybe we'll see each other in the patent office?

Re: Rpm!
 

get this straight...it is more than a devise...it is the most accurate/precise fuel management system...that means the coolant and oil...all thermo-dynamically balanced...

Smokey Yunick limited himself to the thermo-dynamics of the existing standards... coolant and oils....maxed them out...for what he knew.
Pay attention...rate of exchange of BTU's...(that means how fast is the heat removed from the areas it is generated)
that is the "KEY" to torque...
I was a round AAA fuelers.... before they were strectched out rails like they are now...too spendy for me.
As far as rolling resistance...coasting to a stop..average of 25% farther...after installation...with a manual transmission...engine idling....in neutral
farther compared... coasting distances.... with higher speeds....ergo wind and rolling resistance is affected...
just the opposite of what would be expected....
So it really does matter your past experiences...have proven great.
This is new technology...not something dug up from the past...
As far as your tire pressure devise....KUDDO's...
very smart...expansion/contraction... of inner gases...
(did you use nitrogen?)...like a bladder in a well pump....as temps of friction alter the frictional footprint...
causing side walls to heat up....more flexing...more fuel to move down the road.
As a high pressure steam fitter...I have designed/fabricated/ installed such
gasous expansion/contraction devises...
over the distances of 5 miles of piping...
never something that tiny...
Damned good idea...RFID signals better be resettable/floating parameters...

As soon as the patents get approval....the shows will begin...
80 mpg...is very impressive...for EFI...
How much do you have to spend...to get that mpg?

Re: Rpm!
 

Yupper...not into racing anymore...
As I stated before....don't intend to debate it here..
posted it onn this forum to give a heads up...of the future.

Re: Rpm!
 

Smokey Yunick limited himself to the thermo-dynamics of the existing standards... coolant and oils....maxed them out...for what he knew.
(he knew a fair amount)
Pay attention...rate of exchange of BTU's...(that means how fast is the heat removed from the areas it is generated)
that is the "KEY" to torque...
I was a round AAA fuelers.... before they were strectched out rails like they are now...too spendy for me.(AAA fueler? WTF?? A Altered? AAA baseball?)As far as rolling resistance...coasting to a stop..average of 25% farther...after installation...with a manual transmission...engine idling....in neutral
farther compared... coasting distances.... with higher speeds....ergo wind and rolling resistance is affected...
just the opposite of what would be expected....(opposite? Why, coasting in neutral or even shutting the key off gets GREAT milage, nothing new there)So it really does matter your past experiences...have proven great.
This is new technology...not something dug up from the past...
As far as your tire pressure devise....KUDDO's...(it was SARCASM!)very smart...expansion/contraction... of inner gases...
(did you use nitrogen?)...like a bladder in a well pump....as temps of friction alter the frictional footprint...(temps of friction...do you listen to yourself?)causing side walls to heat up....more flexing...more fuel to move down the road.(uh, no actually, if your tires are low the sidewalls flex more each rotation which causes more heat not the other way around!)As a high pressure steam fitter...I have designed/fabricated/ installed such
gasous expansion/contraction devises...(you should stick to steam fitting)over the distances of 5 miles of piping...
never something that tiny...
Damned good idea...RFID signals better be resettable/floating parameters...

As soon as the patents get approval....the shows will begin...
80 mpg...is very impressive...for EFI...
How much do you have to spend...to get that mpg? (nothing, just bull****ted like you did. Great thing about the internet, you can make up crap all day long and somebody will believe you)

I gotta go now, I converted my truck into a flying device (nuclear powered of course) and have to get more photon crystal's from the nebulous galaxy. when I get back we can discuss how I made a CB radio transmit 4500 miles by polishing the entennae with 1200 grit wet sandpaper. I tried various grit until i found the grit that acts as a perfect resonance on the frequency I'm using. The only problem is, I can only transmit 4500 miles on one channel, as soon as I change the frequency the resonance is off at the molecular level and sparks fly from the tip. Quite exciting to have sparks flying off the antennae at 70mph while passing a copcar! Luckily I had my cloaking device i made from a blender/electric razor and a tennis shoe, so the cop didn't see me.

Later

Re: Rpm!
 

OK...now a small test for your expertise...
set up a 351 Ford V-8 to idle in the truck....everything hooked up...
No internal modifications...carburated only.
at 600 rpm's for 8 hours ...using 128 ounces...(one gallon) of regular 87 octane fuel...or E85 ethanol...
That should be rather easy for you to do...with all those accomplishments
I want to thank you for this exchange of information...
your time is most valuable...as is mine...
and as is everyone who reads these posts.

As with every "race engine motor head" I have encountered....
it is not possible....unless you learn how to do it.
It is "the ego" that is in all of them...
that must admit... they do not understand...thermo-dynamics...
as well as they could/should....
and then "lead" other people down the same road.

Re: Rpm!
 

You get the same energy out of regular 87 octane gas as you do e85? wow, you are talented. Just how do you bend the laws of thermo dynamic's and change btu per pound anyway? Golly gee mister, you sure are one smart cookie.

You got a website or business or anything anybody can check or your just going to show us "real soon". I'm guessing you'll be the American hero on the news talking about how you single-handidly solved the oil crisis and all cars will now run on rainbows/sunshine and butterfly farts.

Again, don't TELL me what your going to do, SHOW me.
You see, if there is a "magic spot" that everything is perfect and all the planets will line up, in all the history of internal combustion engines, no engine has EVER hit this point? Seriously?
Like, eng temp at 190, oil at 220, abiant temp blowing on engine 70, left blinker on, radio on, front left tire low, tranny in 1st, wipers off, dog in back seat...I mean seriously, of all the engines ever built nobody has hit the specific temps or combo of temps to magically do everything but walk the dog?
Puh-lease!
If you did something to reduce friction, or better seal the cyl pressure, or better atomize/produce a more uniform mixture, or...then I could be intreaged. But ensuring stable eng temps by tight control on fluid flow magically does all this? Nope, not buying it. (literally)

Oh, as far as the "race engine motor head" comment, that I could agree with as I've proven many things which people said shouldn't/can't work. One example is running a 13.5:1 engine on the street on reg gas. I closed the intake REAL late and bled all the cyl pressure off. It had 160psi cranking pressure. The main problem was the reversion in the intake was making a black mess and it wouldn't pull above 4500rpm if I remember correctly. And that started because I ran 351C in a stock car and being one of only two fords, I got away with running a closed chamber head on one side and an open on the other. Top three places were checked for cyl psi, min ground clearance and rim width mostly. I always had the right cover off and a plug out by the time they got there. then a chevy whinner said to check the other side...hehe I had 145psi on the right and 225 on the left LOL! My next trick was to run a long duration cam with a lot of overlap. Kept the cyl pressure down in the rules but didn't run strong until I was above 7000. went through 5 cranks in 8 races..then learned how to block the cam feed and run an outside line from the oil press sending unit up into the valley and feed the cam from there. I could go on, but these were all logical 1+1=2. I even did some 2+2=4 stuff, but your saying 2+6=47! AND, your not showing any prove beside talking on the internet!


(And I'm the idiot still talking to you...duh)

Re: Rpm!
 

And I'm STILL laughing over this line;

"use a special military grade oil...still secret today.

If you have any doubts about whether I'm in the military and have been for 27 years, call me at work, I'll pm you my number if you want.

Re: Rpm!
 

I don't think that would turn out well for anybody.

I'm not sure if anybody is still paying attention. I am quite sure that neither of you will convince the other.

Re: Rpm!
 

the fact that you mentioned the "magical mix of coolant flows" and all that is achievable...intrigues you enough...
I remind you...this was an accidental discovery....outside the labs...by a backyard scientist...who is not a racing motor head...
racing is now a sport...entertainment value only...
it is very addictive...such skills should now be used to prove efficienices...
I will not give out my private number...
on my forum...which most of all I state most of my work..
before getting going through the patent processes...
I have "friends" that have spent thosands of dollars...out of pocket
just to duplicate my work...and that was done voluntarily...
so if anything 'happened to me"... my work will continue...
I do give my home address...in Missouri, USA...
but don't think about trying to come without my specific invitation...
The board members...investors...don't have that privledge...anymore.

Re: Rpm!
 

BWAHAHAHAHAHAHA!!

You....are....hilarious....
to put it in your style of writing, trying to make cryptic messages or appear "all knowing" are we?

I agree with Holycow, we've derailed this thread too much for too long.
If you want to continue "enlightening" us all with your mythical brilliance, please start another thread.
Just name it something along the lines of "how to get 400mpg by attaching a papercup to your tailpipe" or something just as believable! LOL!

Re: Rpm!
 

Yeah, Dieselmech has a point. Either this thread will be brought back onto topic, or it will be closed. If discussion of this device is relevant, a new thread may be created for its discussion in the proper forum.

Re: Rpm!
 

I would like to see this thread go back to the original topic.

I would also like to see another thread started to discuss this type of new technology. I personally don't understand how it works but will remain
open-minded.

Re: Rpm!
 

pqfpro...very good of you to be open-minded...
as for complete and detailed scientific explainations...
That does not exist...
this system was originally designed for stationary gensets...
water cooled....the most simple of carb designs...non- EFI
the unexplained phenominas...
rolling resistance and aero-dynamics issues...
have been reported by other experiementers....
with a varity of vehicles...worldwide...different fuels used...
when they applied the devise...to engines in vehicles...
These many reports...given freely on my forum...

Re: Rpm!
 

Start....a new thread.....
in another forum....this is off topic....
this was about......
rpm and it's effect......
on milage.......
pertaining to vehicles.......
in this universe.........



I've stated my findings on rpm vs milage. I've been talking to others at the shop with different engines/vehicles/gearing etc.
Kepp in mind I'm talking about how a mechanical inj diesel (6.9/7.3 ford 5.7/6.2/6.5 gm) works. The throttle pedal is only connected to a spring inside the governor box(in effect). When you step on the throttle you are only pulling a spring and allowing the governor to move to a new limit. The injectors spit the same volume of fuel at a throttle setting and the only difference is rpm.
In other words, lets say it's 50cc of fuel at low rpm governor setting, it is also 50cc at high rpm governor setting, only it fills the vial faster.(when setting the inj pump up on the bench) It only gives more fuel to accelerate the engine as once the no load rpm is reached the throttle is back to idle position. (low or high idle it's called even though I called it low/high rpm setting)
Not sure if I'm explaining it clear enough, I'll try to use % to clarify.
Idle no load 750 rpm = 10% throttle
high idle no load 3500 rpm = 10% throttle
Accelerating = 11% - 100% throttle until desired rpm is reached then 10%
Decellerating from high idle = 0% until low idle then it goes to 10%

This is in a perfect world etc.
Reality is 10% low idle and probably 13-14% at high idle because of the extra resistence from the higher rpm.
Also, driving (with a load) it would be different too.
100% to accelerate then 20% to maintain 50mph (example)
100% to accelerate then 25% to maintain 60mph.
This is why not only rpm uses more fuel, but the increase in resistance causes the throttle to return to a higher % setting which also uses more fuel.

The question then is, what is more important or causes more effect, rpm or throttle setting?
From my experience, I say rpm, because whether empty or loaded (the truck, not me) the milage doesn't vary. But empty or loaded the milage varies it's greatest amount by changing the rpm.

Empty 100kmh 25mpg
empty 140 19
loaded 100 23
loaded 140 17

So, rpm makes 6mpg difference and load makes 2mpg difference.

Also, 6.2gm 3/4ton reg cab/6ft box with 3.73 gear turbo 400 tranny (no OD) 19mpg at 100km's.
He's turning almost 3000rpm. My 7.3/e4od/3.55 gear one ton/4 door/8ft box gets 25 but I'm turning around 2100rpm.

Anyone else have any results from driving at different rpm's and want to share?

Re: Rpm!
 

Oh, Thelra, I forgot to mention, do you suck the trailer in while on the highway? (or can you on the type of truck your driving?)
Brother and a few friends drive semi's and most slide the 5th wheel forward so the front of the trailer is tucked up tight to the cab for wind resistance. They just have to remember to slide it back before hitting a town or doing any tight turning as they will crunch the cab and the trailer together on tight turns.
Oh, this is done with a air cyl to slide the 5th wheel.

Re: Rpm!
 

I understand the warning...as well as the last post of dieselmechanic...