The only disadvantage to doing your Gen 1 SBC like the above post, is cost. It wouldn't be cheap to do all of that, although it would be the best Gen 1 performing EFI that still looked like a Gen 1 SBC.

 

I completely agree. I would advise moving away from the dual plane manifolds with throttle body EFI setups, and run them slightly richer as load on the engine increases. Dual planes can work fine with throttle body EFI, but it does come with potential downsides as mentioned. I basically see the same negative with both carburetor and throttle body EFI system since you can't precisely control fuel flow to each cylinder.

 

If you have good knowledge of carburetors and can work on them and tune them properly, a well-tuned carb [and engine] will perform just as well as EFI.

If you are not skilled at working on carbs and have the money to burn, go with the EFI system. Once it is set up properly, it will make life easier.

 

Is this setup better than the Eddy Pro-Flo in some way? The Eddy is a complete package, so no chasing parts...
The pro-flo also offers a front mount throttle body, which might work better on a low profile hood?

 

From what others have told me, the advantage would be tunability and look. Someone asked if there was a blueprint to tuned port injection that kept more true to the Gen 1 SBC. That is an option. That single plane manifold is no higher than an air gap manifold.

This setup would retain the holley terminator architecture which is extremely versatile. From what others have said, the proflow is more rigid in terms of user changes and input. I don't have personal experience there, but I am offering alternatives if people are interested.

 

There isn't an LS swap that will only cost me $1800 like my Sniper 2 did. No way in hell. Even if the engine was free you'd still spend more than that just getting the free LS in and working correctly.

 

Not for nothing but so was the $2,000 system I linked above with controls timing and all.

 

I sort of agree with that. I have 25 years of carburetor experience and 5 years of EFI experience. I've had quadrajet, Holley double pumpers, Holley with vacuum secondary's, experience over the years. I didn't get a ton of quadrajet experience in my early 20s, but I played with the Holley's a lot over the years, jetting and re-jetting for my various applications. I've had 4 different engines in my vette over the 30 years of ownership. A well tuned carburetor will perform acceptably in most situations. Not ideally. It has no mechanism for feedback correction. It has no feedback for engine coolant temperatures or inlet air temperature. It has no feedback for atmospheric pressure. Most people who know how to tune carburetor, jet it and forget it. Maybe they change an accel pump cam, maybe not. Most carburetor users bolt a carb on and leave it as it came out of the box. Does a knowledgeable carb tuner re-jet a carburetor when he/she drives up into the mountains? No, no one does. Additionally, a carburetor cannot data log your drive, and offer quantitative analysis on how your engine is truly running. Your carburetor can't run accessories based upon conditional circumstances... The list goes on and on. A carb is great and reliable no argument there, but it's not nearly as capable as an EFI system, period. We would be falsely advertising if we said it was.

Again, I am neither for or against any particular fuel delivery system. I am against over simplification of carburetors vs EFI systems. I am against users who bolt on EFI systems and treat them like carburetors, because that truly is a waste. I go back to my initial statement: EFI vs Carburetor is a mixture of personal preferences and technical preferences. If you like the simplicity of a mechanical fuel delivery system that works good in your environment, go with a carburetor, and keep it simple. If you want something (at a cost) that gives you everything a carburetor can give you, and many more capabilities, go with EFI - but only if you engage that technology. In the end, it's a personal preference. I know of users who got frustrated with the EFI experience, and went back to a carburetor. I know of other users who embraced EFI and all of its offerings and would never go back to a carburetor.

To add value to the OP, or other users, what is your intended usage? Do you want a simple mechanical device that controls fuel to your engine, or do you want a device that does that (but better) and a whole slew of other things as well? If you just want something that you bolt on and move on, get a carburetor. If you want something that wants you engage and make your system run better, get EFI.

 

All good points.
1 thing I have not seen mentioned in this thread is that gasoline has changed in the last 44 years since mfgrs do not make carbs anymore.
Todays gas is made for the higher pressures of fuel injection, not carbs.

The black parallel lines are the expected range of fuel psi in an EFI car. Today's fuel is designed not to vaporize under that pressure, of 29-87 psi.
The problem is carb fuel systems operate under much lower psi. 6 psi fuel pump pressure is 20.7 psi absolute pressure. (Orange lines and circle)
And at hot underhood temps the vapor pressure of today's gas could easily be 7-17 psi. (Green circle)

This 7-17 psi fuel vapor pressure poses no problem in an EFI system with over 30psi pressure in the lines. But in a carb system, it is very close, with a slight temp increase (parked, hot-soak) or a vacuum on the fuel pump suction side, or trying to run that old tank of winter blend in July, vapor forms in the fuel lines, as some of the liquid boils and turns to vapor.

That is what leads to many of the running and starting issues with carbs on todays ethanol laced gasoline. Getting the same car, to run as good on today's gas, as yesterday's gas, becomes a heat control challenge.

The pressures, temperatures, and vapor return lines have to be dealt with carefully, then most of the new gas issues can be dealt with and worked around, with a carb.

Some find it easier to spend their money for an EFI system, because they tune so much differently that a mechanical system.

I am not one that agrees there are large HP of MPG differences either way, but regardless, I agree the tuning differences are radically different.

 

After taking a closer look I kind of regret not going with this sequential setup now which with one of the 10% off you tube discount codes would only be $1,440... https://acesefi.com/products/wild-ca...41248171098318

 

Sequential along with a coil-on-plug ignition system and a transmission controller if automatic is the top level and would be what I would do if I went fuel injection

 

Thanks Leigh, and there's the fuel consideration too.

There shouldn't really be a significant difference in HP or MPG from one well tuned system to another. In the end, the work being done by the engine determines the energy required to do that work. How efficiently you get that energy in there to do work will help make a difference if any. As discussed, tuning is different, but unlike the carburetor, the EFI tuning via closed loop compensation is continuous. Even if your base tables aren't dialed in. It would be like asking a carburetor to re-jet itself as air temperature or atmospheric conditions changed. There lies the root of the EFI advantage. Even if you take away the timing control, accessory control, data logging, etc... EFI simply maintains the AFR at what you desire it to be, and if it's not there, it corrects the fueling to get you there. It does that for ALL load conditions in ANY atmospheric / air / engine temperature variables you throw at it. A carburetor - even a well tuned one - is tuned at a given set of conditions. It can't adjust to a new set of conditions - unless the user re-tunes again.

So, I think when someone asks us as members "EFI vs Carbs" we can't just say that they do the same thing but one fueling method cost more than the other. I think this particular thread addresses a lot of the over simplification of those very generic statements.

I think I've beaten the horse dead at least twice over. I'm also pretty sure anyone following this thread is tired of me beating the dead horse...

 

Dead horse though it may be, I copied this from Quora where it randomly showed up. I have not read this entire thread but hope to get to that so forgive me if this is extraneous, it seemed relevant to your discussion

What is the advantage of a carburetor over fuel-injection in a car engine?Since the OP asked for the advantages of carburetion and not the advantages of fuel injection, I'll give you the simple answer that no one else has. Carburetors as a system are simply…simpler. A carburetor is essentially a calibrated fuel leak that is released into a stream of air. It has jets and metering rods that change how much fuel it releases based on demand. Aside from production carbs that were made in the early 1980s, they require no electronics, no computer, no sensors, no wires, and are completely self sustaining. They need very little line pressure from the fuel tank, and are very tolerant to dirty fuel. Finally, because of their simplicity and lack of supporting systems, are the cheapest and easiest way to fuel an engine, which is why they are still used in power equipment engines. Depending on what you want, this could be the best way, or it may not. Fuel injection is more efficient, produces more power, and is more precise, but the tradeoff is complexity and cost.

 

 

"...the difference is in complexity and cost"

And how you go about tuning it!
ie: computer vs screwdriver

 

Dont forget a key benefit of the efi always adjusting itself for changing conditions like temp and elevation.

 

Exactly!

 

I just wanted to make sure the kids in the back of the room heard it!

 

Parts began to show up. Waiting on spacer, fuel pump, distributor and ignition coil and a couple other accessories. Quality of this build is absoulutely fantastic. Held some cheap car parts before and these aren’t them.

 

[QUOTE=augiedoggy;1608100592]After taking a closer look I kind of regret not going with this sequential setup now which with one of the 10% off /QUOTE]


Here's the thing. A true sequential port injection system with a separate map for each individual cylinder is a better system.
On Harley's we have a separate fuel and ign. map for each cylinder. This is fairly easy as we only have 2 cylinders. And I can assure you there are differences in the maps for each cylinder. And change the exhaust, and that changes air flow which dictates different fuel mapping.
Putting on 8 injectors spraying directly at the intake ports of the heads. And then running all 8 injectors on the same map being controlled by one wide band O2 sensor isn't really much of a difference from the 4 injectors in the throttle body. Also running on one map.
Now, if you have a O2 sensor for each cylinder, (like a Harley) and a computer that can run 8 different maps. with one main map controlling things like idle speed control, tip in fuel, tip out fuel, start fuel, warm up fuel, accel pump sensitivity. Accel pump amounts, etc, etc, etc.
Yes, then this 8 injector setup would be great!
haven't seen the 8 individual wide band O2 sensors yet. Perhaps I haven't really looked however.