Sniper EFI for boat.

[FreeBird236]

You guys are light years ahead of me, but the last 50 or so posts have been a very enjoyable read, ole E/N even did a political drive by.

 

[4Waters]

Friend...you are talking about a primitive, 1987 automotive implementation of Speed/Density, four decades old technology and apparently (as you say) was well known to be a crappy implementation from day one. No, I've never owned a 1987 Mustang but what does that have to do with putting EFI on a boat engine here in 2024?

But it's even worse. Some quick research tells us that the '87 Mustang 'Speed Density' system wasn't even a true Speed Density system in the first place because it didn't use a MAP sensor!!

"on first glance it seems that its true speed density however ford uses MAF in order to find actual MAF and uses speed density calculations to find the corresponding MAP...upper limit for mass air flow defined by finding the roots of the quadratic equation." ​

https://forum.hptuners.com/showthread.php?67357-Ford-Mustang-Speed-Density

Ford's 1987 implementation here was clearly a cost-saving mathmatical 'kludge' and a dumb one at that, given that they had to redesign it two years later. I thought I'd seen every stupid thing ever done by an auto manufacturer...LoL! Kind of like Ford's 'Nucleate Boiling' cooling system in the ill-fated 6.0L PowerStroke diesel.

I'm new here but I am absolutely certain you know as much about automotive Speed-Density vs MAF EFI systems as it is possible to learn without actually comparing automotive and marine implementations. These are the risks and pitfalls of bring an automotive background to modern marine applications.

Bottom line, you can't do Speed-Density by calculating MAP from a MAF sensor, SD requires an ACTUAL MAP sensor.

If you'd like (send me a DM), I'd be happy to share my GM-MEFI marine certification training manual. It's from 2005 but it covers modern marine Speed-Density systems in great detail.

Speed density is speed density, the reason why they don't use MAF sensors in the marine industry is in testing they found that little wire in the sensor was breaking as a result of the constant bouncing and jarring the boat goes through.

 

[Racey]

Speed density is speed density, the reason why they don't use MAF sensors in the marine industry is in testing they found that little wire in the sensor was breaking as a result of the constant bouncing and jarring the boat goes through.

And because you can't go up a steeper hill or down one, MAF is irrelevant to close the load error that you can have a hard time sensing from MAP alone.

 

[HST4ME]

I see we got another argumentative fucktard expert from google search

 

[rivrrts429]

Good job @DaveH and @Racey running off our EFI bot

 

[Blackmagic94]

So anyways


Sniper efi on my jeep. 1000x better then the carb. One o2 failure. 60 dollar fix


Sniper 2x4 efi on jet boat. 1000x better. Zero issues

 

[4Waters]

So anyways


Sniper efi on my jeep. 1000x better then the carb. One o2 failure. 60 dollar fix


Sniper 2x4 efi on jet boat. 1000x better. Zero issues

Did you turn up the fuel pressure?



This will be used with the phrase "have you tried a different prop"

 

[Bigbore500r]

So anyways


Sniper efi on my jeep. 1000x better then the carb. One o2 failure. 60 dollar fix


Sniper 2x4 efi on jet boat. 1000x better. Zero issues

Just keep another complete sniper unit with fresh 02 sensor under the seat so you don't get stranded! Lol

 

[Bigbore500r]

Did you turn up the fuel pressure?



This will be used with the phrase "have you tried a different prop"

Have no fear.......just call the dockside fuel pressure adjuster!

 

[DaveH]

Speed density is speed density, the reason why they don't use MAF sensors in the marine industry is in testing they found that little wire in the sensor was breaking as a result of the constant bouncing and jarring the boat goes through.

this may very well be true, but the ultimate proving ground is off road. every 6100 truck with a stock MAF LS3 engine gets the living shit pounded out of it and there hasnt been a single MAF failure that i am aware of. sure this isnt millions of trucks but its real world data none the less.

my guess the reason the marine world doesn't use MAF is because what racey already eluded to....marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world.

 

[4Waters]

this may very well be true, but the ultimate proving ground is off road. every 6100 truck with a stock MAF LS3 engine gets the living shit pounded out of it and there hasnt been a single MAF failure that i am aware of. sure this isnt millions of trucks but its real world data none the less.

my guess the reason the marine world doesn't use MAF is because what racey already eluded to....marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world.

That was my thought as well, maybe they used it as an excuse. Could you imagine people doing a little head work to their vortec heads, port matching and putting a bigger cam in it. They would be breaking drives and water reversion, the poor alpha drives wouldn't stand a chance

 

[ElectroNautical]

Lol you don't understand how EFI works buddy.

The injector pulse widths are determined by the lookup table in an MEFI system. When you up the fuel pressure you absolutely ARE applying a global % trim of additional fuel.

This absolutely does nothing to address the fact that the volumetric efficiency at many given points changes dramatically when cams are swapped and you have a 10-15kpa different idle vacuum.

If the system is VE based your pulse widths are still determined by a lookup map, there are just multiple maps starting with VE, then Target Lambda, Then air temp, then fuel pressure, then fuel injector flow characteristic.

100% wrong. We are not talking about EFI (automotive), we're talking about MARINE EFI (MEFI).

this may very well be true, but the ultimate proving ground is off road. every 6100 truck with a stock MAF LS3 engine gets the living shit pounded out of it and there hasnt been a single MAF failure that i am aware of. sure this isnt millions of trucks but its real world data none the less.

my guess the reason the marine world doesn't use MAF is because what racey already eluded to....marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world.

MAF sensors do not work reliably in Marine environments because the air-intake filtration is typically non-existant on marine engines (we call them 'flame arrestors' for precisely this reason). Cars and trucks use intake air filters to prevent road dust and dirt from getting crammed into an engine moving through space at 70+ mph (and fouling the MAF in the process). No road dust out on the water, right? And, marine engine compartments are MUCH cleaner environments to begin with. @Racey, DaveH is right -- this has nothing to do with vibration. Also, because of flexible rubber engine mount isolators used in cars/trucks, vibration of the MAF is actually MUCH higher in a car engine than it would be in a boat engine bolted solidly to the stringers of a massive hull. Remember F=MA?

Re: "marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world". Exactly right. This is also why 95% of all Marine Electronic Fuel Injected engines ever produced do not use (and do not need) oxygen sensors.

Here's why. Consider that a car/truck engine spends ~90% of running hours producing less than ~20% of it's maximum horsepower, while a boat engine spends ~90% of running hours producing more than 70% of maximum horsepower (for a planing hull). Then remember that automotive EFI uses "closed loop" (oxygen sensor inputs) to reduce emissions at off-throttle or low-throttle and that "closed loop" does almost nothing once the engine is working at more than about 30% of maximum HP.

Again, the VAST majority of Marine EFI engines ever produced were designed from the ground-up to NOT use O2 sensors! To say that these systems are "Open Loop" is silly because without O2 sensors there simply IS NO LOOP to be 'open' or 'closed'. Talking about "Open Loop" in this context is like talking about spark advance in a diesel engine, or like talking about Teats on a Boar Hog. Not only silly but useless and only serves to confuse people.

 

[MonkeyButt70]

100% wrong. We are not talking about EFI (automotive), we're talking about MARINE EFI (MEFI).

View attachment 1371796

MAF sensors do not work reliably in Marine environments because the air-intake filtration is typically non-existant on marine engines (we call them 'flame arrestors' for precisely this reason). Cars and trucks use intake air filters to prevent road dust and dirt from getting crammed into an engine moving through space at 70+ mph (and fouling the MAF in the process). No road dust out on the water, right? And, marine engine compartments are MUCH cleaner environments to begin with. @Racey, DaveH is right -- this has nothing to do with vibration. Also, because of flexible rubber engine mount isolators used in cars/trucks, vibration of the MAF is actually MUCH higher in a car engine than it would be in a boat engine bolted solidly to the stringers of a massive hull. Remember F=MA?

Re: "marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world". Exactly right. This is also why 95% of all Marine Electronic Fuel Injected engines ever produced do not use (and do not need) oxygen sensors.

Here's why. Consider that a car/truck engine spends ~90% of running hours producing less than ~20% of it's maximum horsepower, while a boat engine spends ~90% of running hours producing more than 70% of maximum horsepower (for a planing hull). Then remember that automotive EFI uses "closed loop" (oxygen sensor inputs) to reduce emissions at off-throttle or low-throttle and that "closed loop" does almost nothing once the engine is working at more than about 30% of maximum HP.

Again, the VAST majority of Marine EFI engines ever produced were designed from the ground-up to NOT use O2 sensors! To say that these systems are "Open Loop" is silly because without O2 sensors there simply IS NO LOOP to be 'open' or 'closed'. Talking about "Open Loop" in this context is like talking about spark advance in a diesel engine, or like talking about Teats on a Boar Hog. Not only silly but useless and only serves to confuse people.

You came back for another beat down?

 

[DarkHorseRacing]

You came back for another beat down?

The force is strong with this bot…

 

[ElectroNautical]

Have no fear.......just call the dockside fuel pressure adjuster!

All GM based SFI marine engines ever produced used a 60PSI pressure on the fuel rail except for one, the Vortec 8100 (even though the systems were otherwise identical). GM's engineers reduced the fuel pressure to 42PSI for ONLY that engine. So...on the day you (or @MonkeyButt70 or anyone else here) can say WHY they did that, then you will also understand why Raylar Engineering moved the pressure back up to 60PSI for their performance modified Vortec 8100s. Until you actually understand that and can prove it, your laughter is a clownish display of your ignorance.

I get the sense that @DaveH is maybe beginning to grok this. Dave, care to comment?

 

[ElectroNautical]

Bullshit there isn't a lookup table, I've worked on them many times.

That first box you in your diagram is referencing the lookup table itself, it's RPM X MAP

Here's the screenshot of one of the software suites that allows you to tune the table. Good lord.

See that pink table, RPM Rows, and MAP columns.

Spark is the same as fuel, RPM x MAP. View attachment 1371786

Maybe you should start by understanding what is meant by the term "Look Up Table", because it is clear that you are clueless. Google it and then come back when you have a clue. Maybe start here?

 

[ElectroNautical]

Speed density is speed density, the reason why they don't use MAF sensors in the marine industry is in testing they found that little wire in the sensor was breaking as a result of the constant bouncing and jarring the boat goes through.

No, Speed Density in a system that uses O2 sensors is only a fallback when Closed Loop is not available, it's only there as a backup. This is how it works in the automotive world.

Speed-Density in a system that does NOT have O2 sensors (~95% of all marine EFI systems ever built) is far more sophisticated, reliable and accurate because it is the primary and ONLY way that air-fuel mixtures are controlled.

Also, you'll see I (and @DaveH) have corrected the MAF sensor wire breakage myth elsewhere in this thread.

 

[ElectroNautical]

Embarrassed?

Nah, i'm just concerned that you'll sell your services and ruin somebodies boating season . . .

One more question, based on your reply above:

Your saying that the ECM will command additional pulse width (more fuel) to compensate for a drop in fuel rail pressure?
Theres no fuel pressure sensor on these motors . . .that absolutely does not happen.
But please - school me, i'm always open to learing!

Service Manual #33 - Mercuiser 8.1L

Well, if you actually READ your Service Manual #33 (instead of just looking at the pictures) you'll learn that fuel pressure is established by the fuel pressure REGULATOR on the FUEL RAIL. When the pressure from the rail pump exceeds the maximum rating of the REGULATOR, excess fuel is sent back to the tank (or to the Fuel Cell in Volvo Penta) such that the pressure in the rail is maintained.

You'd know this if you'd ever actually worked on one...

 

[ElectroNautical]

Maybe you should start by understanding what is meant by the term "Look Up Table", because it is clear that you are clueless. Google it and then come back when you have a clue. Maybe start here?

Well??? The section on 'Look up Table' in older fuel injection systems is about half way down the article, if you need help finding it...

 

[rivrrts429]

I don’t know about you all but this guy is really starting to grow on me, I kinda like him

He’s the LOF of EFI. I’m thinking we invite him to the cookout

 

[Flatsix66]

It's like ChatGPT, LOF and Grads had a threesome.

 

[4Waters]

No, Speed Density in a system that uses O2 sensors is only a fallback when Closed Loop is not available, it's only there as a backup. This is how it works in the automotive world.

Speed-Density in a system that does NOT have O2 sensors (~95% of all marine EFI systems ever built) is far more sophisticated, reliable and accurate because it is the primary and ONLY way that air-fuel mixtures are controlled.

Also, you'll see I (and @DaveH) have corrected the MAF sensor wire breakage myth elsewhere in this thread.

You're fucking hilarious . Put a bigger cam in a stock marine efi engine, bump the fuel pressure and nothing else and let me know how that idle surge is

 

[4Waters]

100% wrong. We are not talking about EFI (automotive), we're talking about MARINE EFI (MEFI).

View attachment 1371796

MAF sensors do not work reliably in Marine environments because the air-intake filtration is typically non-existant on marine engines (we call them 'flame arrestors' for precisely this reason). Cars and trucks use intake air filters to prevent road dust and dirt from getting crammed into an engine moving through space at 70+ mph (and fouling the MAF in the process). No road dust out on the water, right? And, marine engine compartments are MUCH cleaner environments to begin with. @Racey, DaveH is right -- this has nothing to do with vibration. Also, because of flexible rubber engine mount isolators used in cars/trucks, vibration of the MAF is actually MUCH higher in a car engine than it would be in a boat engine bolted solidly to the stringers of a massive hull. Remember F=MA?

Re: "marine engines work in a very narrow power range compared to automotive engines and the need simply isnt there, not to mention emissions being anywhere near as strict as the auto world". Exactly right. This is also why 95% of all Marine Electronic Fuel Injected engines ever produced do not use (and do not need) oxygen sensors.

Here's why. Consider that a car/truck engine spends ~90% of running hours producing less than ~20% of it's maximum horsepower, while a boat engine spends ~90% of running hours producing more than 70% of maximum horsepower (for a planing hull). Then remember that automotive EFI uses "closed loop" (oxygen sensor inputs) to reduce emissions at off-throttle or low-throttle and that "closed loop" does almost nothing once the engine is working at more than about 30% of maximum HP.

Again, the VAST majority of Marine EFI engines ever produced were designed from the ground-up to NOT use O2 sensors! To say that these systems are "Open Loop" is silly because without O2 sensors there simply IS NO LOOP to be 'open' or 'closed'. Talking about "Open Loop" in this context is like talking about spark advance in a diesel engine, or like talking about Teats on a Boar Hog. Not only silly but useless and only serves to confuse people.

Maybe you should go take a ride in a boat

 

[mattyc]

All GM based SFI marine engines ever produced used a 60PSI pressure on the fuel rail except for one, the Vortec 8100 (even though the systems were otherwise identical). GM's engineers reduced the fuel pressure to 42PSI for ONLY that engine. So...on the day you (or @MonkeyButt70 or anyone else here) can say WHY they did that, then you will also understand why Raylar Engineering moved the pressure back up to 60PSI for their performance modified Vortec 8100s. Until you actually understand that and can prove it, your laughter is a clownish display of your ignorance.

I get the sense that @DaveH is maybe beginning to grok this. Dave, care to comment?

Earlier you said changing fuel pressure has no effect because ecm will adjust injector pulse width

 

[77charger]

All this tech talk I still use a carb

 

[ElectroNautical]

Earlier you said changing fuel pressure has no effect because ecm will adjust injector pulse width

Yes...not exactly what I said, but close. @DaveH said increasing fuel rail pressure (from 42psi to 60psi) would increase fuel FLOW rates. I said no, this is wrong. Increasing the fuel rail pressure from 42psi to 60psi (as Raylar Engineering does) would not cause the expected increase in fuel FLOW, because MEFI Speed-Density computer will adjust (shorten) the injector pulse width (in real-time) to keep fuel flow constant. Later, I said that the reverse would be true, a reduction in fuel rail pressure would likewise result in an increased injector pulse width and again fuel flow rates would remain constant. Now obviously if the fuel rail pressure falls TOO low you'd wind up with injector pulse widths max'd out (running 100% duty cycle) but the engine would be fuel starved -- MEFI can only do so much.

So, the riddle is "why did GM reduce the pressure on the Vortec 8100 to 42psi from the 60PSI standard used on all other engines?"
@DaveH and (especially) @Racey; Still waiting for your comments.

 

[ElectroNautical]

All this tech talk I still use a carb

Nothing wrong with that!! There are very few reasons to upgrade from the good old "Venturi Principle" to an electronic system, and of those there even fewer good reasons. If you know how to maintain, troubleshoot and repair a carbuerator then stick with it!

 

[ElectroNautical]

I don’t know about you all but this guy is really starting to grow on me, I kinda like him

He’s the LOF of EFI. I’m thinking we invite him to the cookout

Ohhh Noooooo! You're a Data Scientist? I'm assuming LOF is "Local Outlying Factor" in which case I will say adamantly "I RESEMBLE THAT REMARK!!!" (and take it as a compliment). If "LOF" means something else, I'm not sure I want to know... ;-)

 

[Racey]

Yes...not exactly what I said, but close. @DaveH said increasing fuel rail pressure (from 42psi to 60psi) would increase fuel FLOW rates. I said no, this is wrong. Increasing the fuel rail pressure from 42psi to 60psi (as Raylar Engineering does) would not cause the expected increase in fuel FLOW, because MEFI Speed-Density computer will adjust (shorten) the injector pulse width (in real-time) to keep fuel flow constant. Later, I said that the reverse would be true, a reduction in fuel rail pressure would likewise result in an increased injector pulse width and again fuel flow rates would remain constant. Now obviously if the fuel rail pressure falls TOO low you'd wind up with injector pulse widths max'd out (running 100% duty cycle) but the engine would be fuel starved -- MEFI can only do so much.

So, the riddle is "why did GM reduce the pressure on the Vortec 8100 to 42psi from the 60PSI standard used on all other engines?"
@DaveH and (especially) @Racey; Still waiting for your comments.

If you are talking Mefi 4 and earlier (the most common MEFI boxes), those systems do not have a fuel pressure sensor, so no, they will not shorten or lengthen the pulse based on fuel pressure, as they have no ability to know what the fuel pressure is.

One reason to drop the fuel pressure is it means less strain on the pump, less electrical load. This means greater longevity for a warrantied vehicle with a long expected lifespan, and it also helps to gain those fractions of a percent in mileage by reducing the overall electrical load.

Also as the manufacturing technology for the injector nozzles got better and better, they could get proper atomization with lower and lower base fuel pressures. Running higher fuel pressure used to be a way to overcome mediocre atomization from old school injectors. There was also a time when high impedence injectors emerged, and due to their lower power consumption they could have a problem overcoming fuel pressure to open consistently, so lower pressure was beneficial.

All of this is totally irrelevant to your comments on how the MEFI system works though.

And there isn't a single modern fuel injection system that doesn't rely heavily on dozens and dozens of look up tables, all of them do.

 

[DaveH]

Yes...not exactly what I said, but close. @DaveH said increasing fuel rail pressure (from 42psi to 60psi) would increase fuel FLOW rates. I said no, this is wrong. Increasing the fuel rail pressure from 42psi to 60psi (as Raylar Engineering does) would not cause the expected increase in fuel FLOW, because MEFI Speed-Density computer will adjust (shorten) the injector pulse width (in real-time) to keep fuel flow constant. Later, I said that the reverse would be true, a reduction in fuel rail pressure would likewise result in an increased injector pulse width and again fuel flow rates would remain constant. Now obviously if the fuel rail pressure falls TOO low you'd wind up with injector pulse widths max'd out (running 100% duty cycle) but the engine would be fuel starved -- MEFI can only do so much.

So, the riddle is "why did GM reduce the pressure on the Vortec 8100 to 42psi from the 60PSI standard used on all other engines?"
@DaveH and (especially) @Racey; Still waiting for your comments.

well the answer is they could have done it for a number of reasons.

1 maybe the 8.1 makes less power then other eninges but uses the same injector.

2 they could have gone to a bigger injector than other engines

3 maybe they are just a screwed up OEM and change stuff because they can, which generally translates to they found a way to make something cheaper.

 

[ElectroNautical]

If you are talking Mefi 4 and earlier (the most common MEFI boxes), those systems do not have a fuel pressure sensor, so no, they will not shorten or lengthen the pulse based on fuel pressure, as they have no ability to know what the fuel pressure is.

One reason to drop the fuel pressure is it means less strain on the pump, less electrical load. This means greater longevity for a warrantied vehicle with a long expected lifespan, and it also helps to gain those fractions of a percent in mileage by reducing the overall electrical load.

Also as the manufacturing technology for the injector nozzles got better and better, they could get proper atomization with lower and lower base fuel pressures. Running higher fuel pressure used to be a way to overcome mediocre atomization from old school injectors. There was also a time when high impedence injectors emerged, and due to their lower power consumption they could have a problem overcoming fuel pressure to open consistently, so lower pressure was beneficial.

All of this is totally irrelevant to your comments on how the MEFI system works though.

And there isn't a single modern fuel injection system that doesn't rely heavily on dozens and dozens of look up tables, all of them do.

Nope, wrong, wrong, wrong and wrong. But since you are not reading any of the references I've provided and you can't seem to grasp the basic concepts, there won't be any convincing you.

But for other readers' benefit...you need to understand what a Look-up-Table is and why real-time computing has replaced them (in MEFI-1), and you need to know how a pressure regulator regulates pressure mechanically (without a pressure sensor), everything you've written above is mindless drivel.

Now, are you ready to put your money where your mouth is? Name the amount (friendly bet) and then each of us will send a paypal to a third party member of riverdavesplace.com. If you can present evidence that GM's MEFI system uses look-up tables, you win and the pot goes to you. If not, the pot goes to me.

Enough of your BS. Time to put up or STFU. Here are two pages from GM's 533 page MEFI technical manual, published by GM. I will upload this manual to a cloud share for everyone reading this.Any evidence you provide must also be published by GM or Delphi. Are you game? Or just all mouth and no money?

 

[Bigbore500r]

Well, if you actually READ your Service Manual #33 (instead of just looking at the pictures) you'll learn that fuel pressure is established by the fuel pressure REGULATOR on the FUEL RAIL. When the pressure from the rail pump exceeds the maximum rating of the REGULATOR, excess fuel is sent back to the tank (or to the Fuel Cell in Volvo Penta) such that the pressure in the rail is maintained.

You'd know this if you'd ever actually worked on one...

I thought you’d never reply, that was a long absence!

Tough day on the docks crankin up fuel pressure?

I’m convinced your some sort of AI created chat bot abortion at this point that masturbates to old Raylar content.

If your a real person - god help your customers…

 

[ElectroNautical]

well the answer is they could have done it for a number of reasons.

1 maybe the 8.1 makes less power then other eninges but uses the same injector.

2 they could have gone to a bigger injector than other engines

3 maybe they are just a screwed up OEM and change stuff because they can, which generally translates to they found a way to make something cheaper.

Nope...three strikes. Here is the answer. Like in a diesel engine, fuel is used to feed the engine but also to cool the injectors. Reducing the pressure causes a longer injector pulse width and allows cool fuel more time to absorb heat from the injectors. The injectors run cooler as a result. That is also why Volvo-Penta added a raw-water cooled 'fuel cell' to remove heat from the fuel coming back via the return line (and also why it must be winterized along with the engine in freezing climates). This is primarily a benefit in reliability terms but was only needed for the Biggest of the Big Blocks, the Vortec 8100. Now you know...

 

[ElectroNautical]

I thought you’d never reply, that was a long absence!

Tough day on the docks crankin up fuel pressure?

I’m convinced your some sort of AI created chat bot abortion at this point that masturbates to old Raylar content.

If your a real person - god help your customers…

Yet another low-effort response...and utterly ignorant of the facts. Pearls before swine...

 

[rivrrts429]

It’s a chat bot and I’m not sure why the mods haven’t killed it off yet.

 

[Bigbore500r]

Yet another low-effort response...and utterly ignorant of the facts. Pearls before swine...

The weather is lovely today, what did you have for lunch?

I enjoy a nice walk on the beach when the tide is low

The Dinar never quite caught on, but why?
Have you met Frank Holbert?

I find the 2020 election results to be accurate and representative of the populace

 

[Racey]

Nope, wrong, wrong, wrong and wrong. But since you are not reading any of the references I've provided and you can't seem to grasp the basic concepts, there won't be any convincing you.

But for other readers' benefit...you need to understand what a Look-up-Table is and why real-time computing has replaced them (in MEFI-1), and you need to know how a pressure regulator regulates pressure mechanically (without a pressure sensor), everything you've written above is mindless drivel.

Now, are you ready to put your money where your mouth is? Name the amount (friendly bet) and then each of us will send a paypal to a third party member of riverdavesplace.com. If you can present evidence that GM's MEFI system uses look-up tables, you win and the pot goes to you. If not, the pot goes to me.

Enough of your BS. Time to put up or STFU. Here are two pages from GM's 533 page MEFI technical manual, published by GM. I will upload this manual to a cloud share for everyone reading this.Any evidence you provide must also be published by GM or Delphi. Are you game? Or just all mouth and no money?

View attachment 1372290

10 grand, Let's have RiverDave take the money. MEFI 1, 2, 3, 4 all have look up tables. These are tables that have either 2 or 3 dimensions, where a user can adjust the values inside them. Fuel delivery, spark timing, based on axis of engine speed vs manifold pressure, other trim tables that apply value multipliers based on coolant or inlet temps, etc....

As a matter of fact, about 8 years ago someone asked me specifically about MEFI 1 and i posted screenshots from my own laptop of some of the lookup tables:

Mefi 1 rev limiter.

Is mefiburn the only way to raise the rev limit on a mefi 1 ecu? Are there any other options? (Without sending it to someone.) Thanks!

www.riverdavesplace.com

You obviously have never actually tuned a MEFI box, sounds like all you know is the diagnostic side. You would be stupid to take this bet, but go ahead and send RiverDave your money if you really want to.

Real time computing just means the tasks are processed immediately, not on a thread or schedule that can be delayed missing a critical event. It simply means the tasks are processed as quickly as possible, this is in contrast to say your phone or pc where tasks are processed on a thread priority and schedule, they do not happen 'real time' even though it may seem to a human that they do.

The booklet you published is referring to how the MEFI processes data in a block diagram. It doesn't talk about the tables because a tech has no business messing with them. In fact Delphi doesn't even provide the tech/consumer with any ability to manipulate these values. Some guys have gotten ahold of Delphi software that was snuck out of the company, but almost everyone relies on a break in like MEFI Burn, and Tuner Pro, to read, adjust, and write these table values back to the ECU. This is what an engine tuner does.

If you want to bet just for pride, let's call it $1 and you can learn something.

Edit: BTW if this clown actually makes this bet Dave can take all the money for an RDP inmate super extravaganza bartab at Fox's If you are voting for Biden you can't come

 

[DaveH]

Nope...three strikes. Here is the answer. Like in a diesel engine, fuel is used to feed the engine but also to cool the injectors. Reducing the pressure causes a longer injector pulse width and allows cool fuel more time to absorb heat from the injectors. The injectors run cooler as a result. That is also why Volvo-Penta added a raw-water cooled 'fuel cell' to remove heat from the fuel coming back via the return line (and also why it must be winterized along with the engine in freezing climates). This is primarily a benefit in reliability terms but was only needed for the Biggest of the Big Blocks, the Vortec 8100. Now you know...

View attachment 1372293

sorry but a longer pulse means a higher duty cycle which is what creates heat in the injectors.

they arent cooling the fuel to cool the injectors, its to combat vapor lock.

marine engines run wayyyyyy cooler then their automotive counterparts, yet those pesky "automotive" injectors seem to do just fine well north of 200' and no fuel cooling.

 

[ElectroNautical]

And because you can't go up a steeper hill or down one, MAF is irrelevant to close the load error that you can have a hard time sensing from MAP alone.

Seriously? Maybe you don't understand that "Manifold Absolute Pressure Sensor" is the engineering term for "intake manifold vacuum sensor", and that intake manifold vacuum (combined with TPS) is the one and only TRULY definitive way to measure engine load? Try thinking back to your carburetor days (if you had any). Remember when pumping the vacuum-assisted power brakes would flood the intake manifold with extra air and stall the engine? Smaller engines were particularly susceptible, remember? Remember what happened when you had a vacuum leak with a Rochester Quadra-Jet and the low vacuum would fool the carburetor into opening up the 'Big Barrels' prematurely and fuel economy would drop by half? Remember that coil of bi-metal spring on every carbuerator ever put into a car, the one that sensed the ambient temperature and compensated for low air-density at higher temperatures? Today we call that an IAT sensor. Now look again at the MEFI model for determining injector pulse widths (I've shown you three times) and tell me again...

Re: "And because you can't go up a steeper hill or down one..." How about you try running a 50' pilothouse motor yacht into a 20 knot wind and tell me again how "you can't go up a steeper hill".

Your ignorance is only matched by your bravado...

 

[Racey]

Seriously? Maybe you don't understand that "Manifold Absolute Pressure Sensor" is the engineering term for "intake manifold vacuum sensor", and that intake manifold vacuum (combined with TPS) is the one and only TRULY definitive way to measure engine load? Try thinking back to your carburetor days (if you had any). Remember when pumping the vacuum-assisted power brakes would flood the intake manifold with extra air and stall the engine? Smaller engines were particularly susceptible, remember? Remember what happened when you had a vacuum leak with a Rochester Quadra-Jet and the low vacuum would fool the carburetor into opening up the 'Big Barrels' prematurely and fuel economy would drop by half? Remember that coil of bi-metal spring on every carbuerator ever put into a car, the one that sensed the ambient temperature and compensated for low air-density at higher temperatures? Today we call that an IAT sensor. Now look again at the MEFI model for determining injector pulse widths (I've shown you three times) and tell me again...

Re: "And because you can't go up a steeper hill or down one..." How about you try running a 50' pilothouse motor yacht into a 20 knot wind and tell me again how "you can't go up a steeper hill".

Your ignorance is only matched by your bravado...

a 50' pilot house running gasoline big blocks on MEFI computers eh? I bet there are a lot of those out there

You are reaching buddy.

Wanna take that bet? RDP is rooting for you

You keep referencing that material you posted, but what you don't realize is that every one of those parameters you keep talking about it tied to a look up table.

 

[Bigbore500r]

Seriously? Maybe you don't understand that "Manifold Absolute Pressure Sensor" is the engineering term for "intake manifold vacuum sensor", and that intake manifold vacuum (combined with TPS) is the one and only TRULY definitive way to measure engine load? Try thinking back to your carburetor days (if you had any). Remember when pumping the vacuum-assisted power brakes would flood the intake manifold with extra air and stall the engine? Smaller engines were particularly susceptible, remember? Remember what happened when you had a vacuum leak with a Rochester Quadra-Jet and the low vacuum would fool the carburetor into opening up the 'Big Barrels' prematurely and fuel economy would drop by half? Remember that coil of bi-metal spring on every carbuerator ever put into a car, the one that sensed the ambient temperature and compensated for low air-density at higher temperatures? Today we call that an IAT sensor. Now look again at the MEFI model for determining injector pulse widths (I've shown you three times) and tell me again...

Re: "And because you can't go up a steeper hill or down one..." How about you try running a 50' pilothouse motor yacht into a 20 knot wind and tell me again how "you can't go up a steeper hill".

Your ignorance is only matched by your bravado...

Vacuum Venturi throttle body intake sensor gasket port plenum volume velocity ratio equal length resonance tune Raylar injectior psi tune runner cross section manifold pump gas MEFI

 

[ElectroNautical]

10 grand, Let's have RiverDave take the money. MEFI 1, 2, 3, 4 all have look up tables. These are tables that have either 2 or 3 dimensions, where a user can adjust the values inside them. Fuel delivery, spark timing, based on axis of engine speed vs manifold pressure, other trim tables that apply value multipliers based on coolant or inlet temps, etc....

As a matter of fact, about 8 years ago someone asked me specifically about MEFI 1 and i posted screenshots from my own laptop of some of the lookup tables:

Mefi 1 rev limiter.

Is mefiburn the only way to raise the rev limit on a mefi 1 ecu? Are there any other options? (Without sending it to someone.) Thanks!

www.riverdavesplace.com

You obviously have never actually tuned a MEFI box, sounds like all you know is the diagnostic side. You would be stupid to take this bet, but go ahead and send RiverDave your money if you really want to.

Real time computing just means the tasks are processed immediately, not on a thread or schedule that can be delayed missing a critical event. It simply means the tasks are processed as quickly as possible, this is in contrast to say your phone or pc where tasks are processed on a thread priority and schedule, they do not happen 'real time' even though it may seem to a human that they do. No. 100% wrong.

The booklet you published is referring to how the MEFI processes data in a block diagram. No. I published a SCREEN SHOT. The entire 500+ page document is now uploaded. See below.

If you want to bet just for pride, let's call it $1 and you can learn something. Chicken-$hit. See below

Edit: BTW if this clown actually makes this bet Dave can take all the money for an RDP inmate super extravaganza bartab at Fox's If you are voting for Biden you can't come

I'm down for your $10K number (minus your weasle-words) but since $10K way above the IRS reporting threshold for PayPal transactions I doubt anyone who doesn't have a vested interest will agree to escrow the bet. I'll also bet you knew that before proposing the number, and then suggesting a $1 bet. Sounds like chicken-$hit to me.

Racey's Weasle-words:

Weasle #1: RiverDave holds the bet? Nice try. He's the OWNER of this site, not a MEMBER. Moreover, you (Shane) and your dad (Steven) have had a business relationship/affiliation with riverdavesplace.com since long before your dad (Racey Industries) bought the molds from Spectra, so RiverDave would quite naturally have a vested interest in preserving your reputation. Then, you offer to GIVE THE MONEY to him (100% vested interest). I was born at night, but it wasn't last night. And you're calling ME stupid? LoL...

Resolution: The rules say (1) a member (not the owner) will hold the bet. Consistent with the rules, I nominate the OP @Rajobigguy, and will accept any amount he's comfortable with, as long as he (or any other non-affiliated MEMBER on this site) can demonstrate an understanding of what a "Look-Up-Table" is. The criteria for demonstrating understanding will be the identification of the five-letter humorous acronym used to describe the function of a look-up table by the inventor circa 1960.

Weasle #2: Talking your way down to a $1 bet? LoL...hardly worth my time. Nice try. I would think your reputation here is worth more than that.

Resolution: Let's use your $10K number as a start, but as you knew before suggesting it, nobody without a vested interest is going to bite on escrowing that much.

Weasle #3 You already know that GM/Delphi has published (in dealer-confidential documents) the details needed to modify MEFI parameters, and I am putting 566 pages into evidence, right here, right now. I guarantee that document will provide all the details proving that there are no "Look-up-Tables" in any GM MEFI system.

Last comment...nothing you posted above (screenshots, etc.) has anything to do with a "Look-Up-Table". You are confusing MEFI PARAMETERS presented in a TABULAR FORMAT with "LOOK UP TABLE VALUES".

This explains your problems comprehending. You simply don't know the meaning or function of a "LOOK UP TABLE".

So, my evidence is uploaded to the cloud HERE. Bring it on Racey, let's get on with the bet.

 

[Racey]

Last comment...nothing you posted above (screenshots, etc.) has anything to do with a "Look-Up-Table". You are confusing MEFI PARAMETERS presented in a TABULAR FORMAT with "LOOK UP TABLE VALUES".

Hahahahahahahah there is your weasel out right there. Look up tables are exactly that, parameter values held in tabular format. You just admitted it yourself.

Nice try buddy. Send cash!!!

"It depends on what the definition of 'Is' is"

I think you need a lesson in the english language, as your Large Language Model appears to be failing.

Lookup table - Wikipedia

en.wikipedia.org

 

[ElectroNautical]

a 50' pilot house running gasoline big blocks on MEFI computers eh? I bet there are a lot of those out there

You are reaching buddy.

Wanna take that bet? RDP is rooting for you

You keep referencing that material you posted, but what you don't realize is that every one of those parameters you keep talking about it tied to a look up table.

No, twin Cummins 6BTA diesel engines, but gasoline or diesel makes no difference here. Running into a headwind is no different than running uphill. And you still don't know the difference between a "Look-Up-Table" and a set of parameters you once saw presented in tabular format.

 

[Racey]

No, twin Cummins 6BTA diesel engines, but gasoline or diesel makes no difference here. Running into a headwind is no different than running uphill. And you still don't know the difference between a "Look-Up-Table" and a set of parameters you once saw presented in tabular format.

Literally the same thing turd brain.

In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation, in a process termed as direct addressing. The savings in processing time can be significant, because retrieving a value from memory is often faster than carrying out an "expensive" computation or input/output operation.[1] The tables may be precalculated and stored in static program storage, calculated (or "pre-fetched") as part of a program's initialization phase (memoization), or even stored in hardware in application-specific platforms.



Send cash troll

 

[ElectroNautical]

Hahahahahahahah there is your weasel out right there. Look up tables are exactly that, parameter values held in tabular format. You just admitted it yourself.

Nice try buddy. Send cash!!!

"It depends on what the definition of 'Is' is"

I think you need a lesson in the english language, as your Large Language Model appears to be failing.

Lookup table - Wikipedia

en.wikipedia.org

No...and you should know better than to rely on Wikipedia for anything. I already gave you the info you need, but I'm not surprised you didn't read it. Reading comprehension doesn't seem to be in your wheelhouse. That said, if you re-read what you failed to comprehend from Wikipedia (especially the part about "replaces run-time calculation", you might take a short step toward comprehending.

 

[Racey]

No...and you should know better than to rely on Wikipedia for anything.

Ok fine we'll use the source you posted:

https://www.allaboutcircuits.com/textbook/digital/chpt-16/look-up-tables/

A very common application for look-up table ROMs is in control systems where a custom mathematical function needs to be represented. Such an application is found in computer-controlled fuel injection systems for automobile engines, where the proper air/fuel mixture ratio for efficient and clean operation changes with several environmental and operational variables.

Tests performed on engines in research laboratories determine what these ideal ratios are for varying conditions of engine load, ambient air temperature, and barometric air pressure. The variables are measured with sensor transducers, their analog outputs converted to digital signals with A/D circuitry, and those parallel digital signals used as address inputs to a high-capacity ROM chip programmed to output the optimum digital value for air/fuel ratio for any of these given conditions.

Sometimes, ROMs are used to provide one-dimensional look-up table functions, for “correcting” digitized signal values so that they more accurately represent their real-world significance. An example of such a device is a thermocouple transmitter, which measures the millivoltage signal generated by a junction of dissimilar metals and outputs a signal which is supposed to directly correspond to that junction temperature.

 

[Racey]

How do you adjust the air fuel ratio on a diesel smarty pants?

 

[ElectroNautical]

Literally the same thing turd brain.

In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation, in a process termed as direct addressing. The savings in processing time can be significant, because retrieving a value from memory is often faster than carrying out an "expensive" computation or input/output operation.[1] The tables may be precalculated and stored in static program storage, calculated (or "pre-fetched") as part of a program's initialization phase (memoization), or even stored in hardware in application-specific platforms.



Send cash troll

I've underscored the words you failed (again) to comprehend.

 

[Racey]

I've underscored the words you failed (again) to comprehend.

Lol ok buddy bot. You aren't even splitting hairs here, you are so far into left field you might as well be in the parking lot.