Need advice on what to do

[Rusty_S85]

I remember it well, David. I used the term "optimum AFR" on purpose. That isn't exactly 14:1. It varies by what you are wanting to do. If you are wanting power it needs to be closer to 12:1. If you want economy it needs to be more like your 17:1. And along with the varying AFR comes varying ignition timing.

Carbs and "dumb" ignition systems just cannot be "right" at all points like today's multi-port EFI systems that control not only the AFR but also the ignition timing and transmission gear and, therefore, RPM.

But wouldn't that be an advantage to having a carburetor?

These "dumb" systems cannot prevent you from tuning *your* vehicle the way *you* want to. If your goal is maximum power, your carburetor and ignition timing can be tuned to achieve a 12:1 AFR. Likewise, if your goal is maximum fuel economy, your carburetor and ignition timing can be tuned to achieve a 17:1 AFR.

Wouldn't that also mean that - with all other things being equal - a carburetor can be adjusted to have more power than an EFI system, OR it can be adjusted to get better fuel economy than an EFI system?

An advantage to EFI is the ability to self-tune - but isn't is programmed to always revert to the "optimum" AFR of 14:1?

I wouldnt say its an advantage to have a carb cause it can be tuned. the Sniper for example can be tuned a lot more than a carb ever could be tuned.

You can set up a fuel map where AFR can vary from 12.3:1 rich for power down to 16.5:1 to 17.5:1 for cruise economy.

A carb you can tune it with in reason but you cant tune it to vary down to every 100 rpm like you can with fuel injection like a sniper for example.

Below is a fuel map that I did not even attempt to mess with but you can fine tune it so much better than a carb. This is where something like the sniper shines is you can get it so precise that you will see a improvement in economy. With a carb you may have to make concessions since you cant tune a carb down to such a small point.

Now if we are talking about OEM OBDI EFI then yeah a carb would be better as those systems dont have the adjustability and the tech is no longer there due to how old the system is at this point now.

[Rusty_S85]

I have a quick change spring kit on my Holley 750, and two pit boxes full of floats, jets, boosters, etc...

I do not however have an AFR installed, sooooo ?

I have a quick change kit for my Summit carb but never ordered the jets and the accelerator pump as that was lower on my purchase list. But the more I thought about trial and error for making changes to fine tune it and how many times id have to take the carb apart to make changes, I started thinking about EFI. The bright side with EFI is I can have it dyno tuned as well if I wanted to since a laptop can be used with it, dyno shops around here wont touch a carb unless you just want to see how much power your engine makes as far as tuning goes they wont touch a carb. They really wont even touch OBD I systems either since it is obsolete and the tech to make the changes in the computer just isnt out there anymore.

[ArdWrknTrk]

I have a quick change kit for my Summit carb but never ordered the jets and the accelerator pump as that was lower on my purchase list. But the more I thought about trial and error for making changes to fine tune it and how many times id have to take the carb apart to make changes, I started thinking about EFI. The bright side with EFI is I can have it dyno tuned as well if I wanted to since a laptop can be used with it, dyno shops around here wont touch a carb unless you just want to see how much power your engine makes as far as tuning goes they wont touch a carb. They really wont even touch OBD I systems either since it is obsolete and the tech to make the changes in the computer just isnt out there anymore.

Rusty, SD was all bank fired.

It wasn't until EECV and MAF that it went sequential port fuel injection.

[LARIAT 85]

Thing is how many people are actually going to the trouble some of us have to tuning a carb to its limits.

Majority of people out there are either running a bone stock OE carb or they are running a aftermarket carb out of the box.

I do know that when it comes to the sniper itself in typical holley fashion they have it set to run on the rich side for safety. This results in lower fuel economy than if you were to have it tuned to what your engine actually needs.

Same with my 2150 OE 2V, that carb is getting me around 12 mpg city during summer months and 11mpg city during winter months. Highway is around 14 to 15 mpg. In my case over my OE carb, I will see a good increase in economy as there is no reason for me not to see 14 to 15 mpg city. With tuning I dont believe there is a reason why I couldnt see 16 to 17 or possibly even 18 mpg city.

In the end those that actually change the AF ratio by playing with jets, and secondaries and accelerator pumps are actually in the minority when it comes to people that are building vehicles. Majority that I see come through where I work just bolt parts on and dont really touch them. Those are the same people that are making the switch to EFI as they say carbs are junk. I dont believe carbs are junk, I just dont care to invest the time to mess with a carb to get it where it needs to be when I can just spend a little more money and go EFI.

It sounds like you are completely sold on the Holley Sniper EFI system, and that is fine. But it also sounds like the main reason for replacing your carburetor with it is because you simply don't want to take the time to tune it. That is also fine.

The fact is, a carburetor is an analog device and it simply cannot self-tune or self-diagnose. The main advantage to an EFI system is that it can. In exchange, you pay a much higher price for it and get a whole mess of wiring, numerous sensors, and a computer to make that happen.

To be fair, manufacturers originally calibrated their carburetors (and ignition timing) for each specific application when they were new. So they were set up pretty well when they left the factory. As the years went by, vital carburetor parts often went missing (such as the choke, solepot, and air cleaner, for example) and they were often maladjusted to compensate for these missing pieces or to cover up a completely different problem. Even worse, carburetors were unknowingly exchanged for a rebuilt unit with a different calibration than what it was originally designed for. Or - in your case - the fuel blend changed, but your carburetor was calibrated to run on a much different mix.

I hope your aftermarket Holley EFI system works well for you. *PLEASE* don't be one of those people who replaces a very old, worn out, and out-of-tune carburetor they have simply lost interest in with a brand new EFI system, takes the time to install on their engine and goes through the programs required to properly set it up, and then claim it is so much better than a carburetor ever could be. It takes TIME to properly set up a carburetor - just like it takes time to install and set up a complete EFI system. All other things being equal, there isn't much difference between a well tuned and matched carbureted system and a properly functioning EFI system.

[ArdWrknTrk]

It sounds like you are completely sold on the Holley Sniper EFI system, and that is fine. But it also sounds like the main reason for replacing your carburetor with it is because you simply don't want to take the time to tune it. That is also fine.

The fact is, a carburetor is an analog device and it simply cannot self-tune or self-diagnose. The main advantage to an EFI system is that it can. In exchange, you pay a much higher price for it and get a whole mess of wiring, numerous sensors, and a computer to make that happen.

To be fair, manufacturers originally calibrated their carburetors (and ignition timing) for each specific application when they were new. So they were set up pretty well when they left the factory. As the years went by, vital carburetor parts often went missing (such as the choke, solepot, and air cleaner, for example) and they were often maladjusted to compensate for these missing pieces or to cover up a completely different problem. Even worse, carburetors were unknowingly exchanged for a rebuilt unit with a different calibration than what it was originally designed for. Or - in your case - the fuel blend changed, but your carburetor was calibrated to run on a much different mix.

I hope your aftermarket Holley EFI system works well for you. *PLEASE* don't be one of those people who replaces a very old, worn out, and out-of-tune carburetor they have simply lost interest in with a brand new EFI system, takes the time to install on their engine and goes through the programs required to properly set it up, and then claim it is so much better than a carburetor ever could be. It takes TIME to properly set up a carburetor - just like it takes time to install and set up a complete EFI system. All other things being equal, there isn't much difference between a well tuned and matched carbureted system and a properly functioning EFI system.

You really can't seem to accept that technology has left you in the dust.

But whether you choose to accept it or not, time moves on.

99% of things get better, not worse.

And titanic industries like semiconductors, automobiles and petroleum have been investing billions and billions of dollars to make these improvements while you've had your head buried in the sand.

No matter how many times you repeat your mantra, the past is not coming back, nor was it superior.

Are you down with the whole "Clean, beautiful coal!" garbage too?

Perhaps we should put electricity aside and go back to steam power and belching smokestacks spewing sulphur, mercury and arsenic.

So thick that it obscures the sun at midday, like Pittsburgh a century ago?

Because, you know, things just worked better then...

Or like the '60's & '70's when the air was yellow with automobile exhaust and your eyes burned in that acrid soup.

Modern EFI engines can actually have cleaner exhaust than the air they take in, in cities like Delhi or Bejing.

[LARIAT 85]

You really can't seem to accept that technology has left you in the dust.

But whether you choose to accept it or not, time moves on.

99% of things get better, not worse.

And titanic industries like semiconductors, automobiles and petroleum have been investing billions and billions of dollars to make these improvements while you've had your head buried in the sand.

No matter how many times you repeat your mantra, the past is not coming back, nor was it superior.

Are you down with the whole "Clean, beautiful coal!" garbage too?

Perhaps we should put electricity aside and go back to steam power and belching smokestacks spewing sulphur, mercury and arsenic.

So thick that it obscures the sun at midday, like Pittsburgh a century ago?

Because, you know, things just worked better then...

Or like the '60's & '70's when the air was yellow with automobile exhaust and your eyes burned in that acrid soup.

Modern EFI engines can actually have cleaner exhaust than the air they take in, in cities like Delhi or Bejing.

That seems a bit uncalled for.

I am only comparing the power and fuel economy numbers of a properly tuned and matched carburetor with a properly functioning EFI system. All other things being equal, there simply isn't that much difference.

I agree with you in that modern engines do tend to burn a bit cleaner. But that has less to do with EFI and more to do with better heads, camshafts, catalytic converters, etc. Even so, EFI is still going to be a bit cleaner for our environment because it can constantly self-tune. That not only helps modern engines to last longer, but it also helps to keep our air cleaner if (and when) a problem arises, and every little bit helps.

That being said, no one ever says they want a fuel injection system for "better emissions." Instead, I often hear things like "better cold starts" and "better performance" or "better economy" as reasons why from the companies who market them as well as the people who purchase them. Those are simply not valid reasons to replace a carburetor with a fuel injection system. The truth is, if you replace your carburetor with an EFI system and you get "better cold starts" and "better performance" or a big increase in fuel economy, then something was not right with your carburetor.

Perhaps I misrepresented myself in this discussion. I do understand why carburetors were replaced with EFI. I do not think a carburetor is "superior" over EFI. I have two other newer vehicles with EFI, and I would absolutely not replace either of them with a carburetor.

 

[FuzzFace2]

You really can't seem to accept that technology has left you in the dust.

But whether you choose to accept it or not, time moves on.

99% of things get better, not worse.

And titanic industries like semiconductors, automobiles and petroleum have been investing billions and billions of dollars to make these improvements while you've had your head buried in the sand.

No matter how many times you repeat your mantra, the past is not coming back, nor was it superior.

Are you down with the whole "Clean, beautiful coal!" garbage too?

Perhaps we should put electricity aside and go back to steam power and belching smokestacks spewing sulphur, mercury and arsenic.

So thick that it obscures the sun at midday, like Pittsburgh a century ago?

Because, you know, things just worked better then...

Or like the '60's & '70's when the air was yellow with automobile exhaust and your eyes burned in that acrid soup.

Modern EFI engines can actually have cleaner exhaust than the air they take in, in cities like Delhi or Bejing.

That seems a bit uncalled for.

I am only comparing the power and fuel economy numbers of a properly tuned and matched carburetor with a properly functioning EFI system. All other things being equal, there simply isn't that much difference.

I agree with you in that modern engines do tend to burn a bit cleaner. But that has less to do with EFI and more to do with better heads, camshafts, catalytic converters, etc. Even so, EFI is still going to be a bit cleaner for our environment because it can constantly self-tune. That not only helps modern engines to last longer, but it also helps to keep our air cleaner if (and when) a problem arises, and every little bit helps.

That being said, no one ever says they want a fuel injection system for "better emissions." Instead, I often hear things like "better cold starts" and "better performance" or "better economy" as reasons why from the companies who market them as well as the people who purchase them. Those are simply not valid reasons to replace a carburetor with a fuel injection system. The truth is, if you replace your carburetor with an EFI system and you get "better cold starts" and "better performance" or a big increase in fuel economy, then something was not right with your carburetor.

Perhaps I misrepresented myself in this discussion. I do understand why carburetors were replaced with EFI. I do not think a carburetor is "superior" over EFI. I have two other newer vehicles with EFI, and I would absolutely not replace either of them with a carburetor.

EFI takes all the fun of driving a car / truck with a carb from starting it when cold and needing to find what it takes to start. Do you pump 1, 1.5 or 2 times? Hold it a little bit or half way down after the pump?

Also going from carb to EFI for a few more MPG how long would it take for pay back?

Don't get me wrong I like EFI on the car & truck I have but they came with EFI.

Dave ----

[Rusty_S85]

Rusty, SD was all bank fired.

It wasn't until EECV and MAF that it went sequential port fuel injection.

I thought it might have been but I am not real up to date on EECIV based fuel injection that was a bit before my time as I didnt get training on computer systems on cars till after the 1995 OBD II switch over.

But I do know that group fired MPI EFI wasnt really much better than plain on TBI since they all fire at the same time just like on a TBI system.

[Rusty_S85]

It sounds like you are completely sold on the Holley Sniper EFI system, and that is fine. But it also sounds like the main reason for replacing your carburetor with it is because you simply don't want to take the time to tune it. That is also fine.

The fact is, a carburetor is an analog device and it simply cannot self-tune or self-diagnose. The main advantage to an EFI system is that it can. In exchange, you pay a much higher price for it and get a whole mess of wiring, numerous sensors, and a computer to make that happen.

To be fair, manufacturers originally calibrated their carburetors (and ignition timing) for each specific application when they were new. So they were set up pretty well when they left the factory. As the years went by, vital carburetor parts often went missing (such as the choke, solepot, and air cleaner, for example) and they were often maladjusted to compensate for these missing pieces or to cover up a completely different problem. Even worse, carburetors were unknowingly exchanged for a rebuilt unit with a different calibration than what it was originally designed for. Or - in your case - the fuel blend changed, but your carburetor was calibrated to run on a much different mix.

I hope your aftermarket Holley EFI system works well for you. *PLEASE* don't be one of those people who replaces a very old, worn out, and out-of-tune carburetor they have simply lost interest in with a brand new EFI system, takes the time to install on their engine and goes through the programs required to properly set it up, and then claim it is so much better than a carburetor ever could be. It takes TIME to properly set up a carburetor - just like it takes time to install and set up a complete EFI system. All other things being equal, there isn't much difference between a well tuned and matched carbureted system and a properly functioning EFI system.

Well the main reason is because my 306 build is going to be 4V regardless. I have a Summit 600cfm 4V carb which is built by holley for Summit which is an upgraded variant of the holley carb based off the ford 4100 carb.

I was fully content with investing the time and doing carb, but with each installation of EFI and seeing how much better the sniper runs out of the box than a carb out of the box I started thinking to myself, for a truck I want to drive do I want to have to worry about making adjustments all the time like a lot of aftermarket carburetors tend to need which there is no guarentee that the Summit carb would be as bullet proof as the ford 2150 carb I would be replacing. That is the thing that had me seriously weigh between the EFI and carb. Can I be confident that once I invest the time to properly set up the carb would the carb run the same regardless just like my old 2150 that is being replaced or is it going to be like the holley 4150 I have on my 63 that needs the air/fuel mixture played with at least once a month.

For a truck that I plan to drive every day I dont want to spend more time under the hood making adjustments I rather be able to get in the truck and basically go.

That is what ultimately sold me on the sniper.

As far as the wiring, youd be suprised how little wiring there is with the sniper. If you are doing it bare bones and not adding all the bells and whistles that you dont need for it to operate you only need to hook up five wires. A battery hot, a battery ground, a rpm signal, a key hot, and run the blue fuel pump power wire. In my case I would be actually hooking up seven total wires, a AC signal wire to provide idle up function with AC on and a AC trigger wire that on wot will trigger the relay it is attached to which will break the AC compressor circuit for an AC cut out.

This isnt like an EECIV or EECV type fuel injection system with 200 wires, the sniper has all the wires self contained with only a few hook ups needed for basic operation and then optional wires you can hook up for more features.

As far as my setup goes, the engine will be built, the system will be installed the basic tune will be setup then I am going to Crosby to a well known tuner and give him $200 for a dyno tune on the sniper. Everyone I talk with he is the worlds best and has his custom tuning in cars in every country around the world.

Only reason I am losing the 2150 carb is a 2V carb is not going to be enough for a 306 build with a aftermarket roller truck cam with over .500" lift and AFR Renegade heads. I need to switch to a 4V and that is where my concern with the carb comes in.

[Rusty_S85]

EFI takes all the fun of driving a car / truck with a carb from starting it when cold and needing to find what it takes to start. Do you pump 1, 1.5 or 2 times? Hold it a little bit or half way down after the pump?

Also going from carb to EFI for a few more MPG how long would it take for pay back?

Don't get me wrong I like EFI on the car & truck I have but they came with EFI.

Dave ----

I dont find it fun when you hop in your car ready to go and your aftermarket carb is running bad and you have to play with the idle mixtures. That is how my holley 4150 is on my 63. That is what I started fearing with my Summit 600 cfm vac secondary which is built by Holley for summit. I want to drive my truck not get it in to go some where and the thing starts running horrible and instead of getting in cranking the truck up and leaving I have to pop the hood and lean over the fender and make adjustments.

If I had 100% undeniable proof my summit carb wouldnt do that I would gladly stick with it. But for me its not just the extra mpg, its the over all package ontop of me not having to go under the hood like on my Holley 4150 that needs the idle mixture played with at least once a month.

Now if your only reason for EFI is for fuel economy then yea I say dont do it cause its not worth it if you just want to improve fuel economy. But if you want something that will adjust itself and doesnt require you to pop the hood every month or so to play with the idle mixtures like is common with aftermarket carbs like Holleys then I would suggest looking into it.

Me I have numerous reasons to go for it, the fuel economy improvement is just the cherry on top for me especially with a 16 gallon saddle tank.