Custom carb or EFI

[c1500sbc]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

[ClassAct]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

Mark Whitener Lightning Carbs
Dom Thumpr Carbs
Tuner here on ST can fix most anything.

[steve cowan]

Mark whitener is on this forum
WWW.racingfuelsystems.com and forum name JMARKAUDIO send him a private message
Braswell make excellent carbs as well

[Tuner]

If OP still retains virgin status he can jump right in the volcano with EFI. That's the ticket.

[Mike Laws]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

Both.

Still a best kept secret: https://www.knfilters.com/eci

[c1500sbc]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

Both.

Still a best kept secret: https://www.knfilters.com/eci

I saw this the other day but didn't pay much attention. Have you used it? To me it just seemed like a computerized power valve/accelerator pump

[c1500sbc]

I mean, it looks cool, I get the idea behind it. If you were able to lean out the mixture at WOT say to 13.5:1 and set the ECI system to enrichen the mixture to make it 12.5:1 then I could see the benefit. Or also use it for cruise AFR in the same way. Lean the mixture out with the carb and let the ECI enrichen it to the desired AFR. That would be cool as long as its accurate.

[rebelrouser]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

Both.

Still a best kept secret: https://www.knfilters.com/eci

Summit says that unit is almost $900.00 I got a Fitech that controls the timing and the air fuel is self learning, for just a little more. Seems a waste to not just do the full injection system.

[digger]

Has anyone used a custom carb company? If so, how were the results. I have a previous post on here about tuning in an Edelbrock 750. With y'alls help I got it mostly dialed in. I'm still not completely happy with it though. There are custom carb companies that claim to build a custom carb, built off a particular engine build, that yield 20-40 hp gains over a typical self tuned off the shelf carb. I got a quote from a company called Pro Systems carburetors for a really nice looking carb. Everything sounds great about the build, but i'm unsure of the actual gains from the "custom carb"

EFI is certainly an option, top choice would be a Holley sniper system, but they seem to be pretty glitchy and when people have an issue with them it seems to take weeks to get it rectified. I don't want my truck down that long. Carbs are much easier to get parts for and repair but it's certainly intriguing to put an EFI system on it.

Anyone have possible some opinions or even better, some dyno results of a custom carb?

Both.

Still a best kept secret: https://www.knfilters.com/eci

Summit says that unit is almost $900.00 I got a Fitech that controls the timing and the air fuel is self learning, for just a little more. Seems a waste to not just do the full injection system.

a carb makes more power at WOT than 99% of EFI systems though, so the EFI only needs to take control when the carb cant do as good as a job as EFI. if you dont have an ignition box sure thats a benefit for a slightly smarter system

[David Redszus]

a carb makes more power at WOT than 99% of EFI systems though, so the EFI only needs to take control when the carb cant do as good as a job as EFI.

With all due respect, I beg to differ.

While a well developed and tuned carb will outperform a poorly or under-developed injection system, that
is not an apples to apples comparison. The reverse is also true.

Carb manufacturers have many years experience with their products installed on many vehicles.
They can provide insight and assistance that is often lacking with EFI sellers.

The first task is the proper selection of EFI which includes the ECU, for the application.
There is a very large difference between throttle body injection and port injection.
While both may be called EFI, throttle body injection actually resembles an electronic carb.

With an ECU, mixture can be varied according to atmospheric conditions automatically, for TBI or port injection.
One substantial advantage of EFI port injection is the improved manifolding design that it allows.

But, correctly mapping an ECU is much harder to learn and to perfect than changing jets. There are
many more variables that affect the fuel and timing maps, to understand and consider.

Fuel injection has replaced carburetors in every high performance application, starting about 100 years
ago with aircraft engines; where and when the rules (or budget) allowed.

And now, direct injection has the potential to make our brains hurt once again.

[digger]

a carb makes more power at WOT than 99% of EFI systems though, so the EFI only needs to take control when the carb cant do as good as a job as EFI.

With all due respect, I beg to differ.

While a well developed and tuned carb will outperform a poorly or under-developed injection system, that
is not an apples to apples comparison. The reverse is also true.

Carb manufacturers have many years experience with their products installed on many vehicles.
They can provide insight and assistance that is often lacking with EFI sellers.

The first task is the proper selection of EFI which includes the ECU, for the application.
There is a very large difference between throttle body injection and port injection.
While both may be called EFI, throttle body injection actually resembles an electronic carb.

With an ECU, mixture can be varied according to atmospheric conditions automatically, for TBI or port injection.
One substantial advantage of EFI port injection is the improved manifolding design that it allows.

But, correctly mapping an ECU is much harder to learn and to perfect than changing jets. There are
many more variables that affect the fuel and timing maps, to understand and consider.

Fuel injection has replaced carburetors in every high performance application, starting about 100 years
ago with aircraft engines; where and when the rules (or budget) allowed.

And now, direct injection has the potential to make our brains hurt once again.

I'm talking about fuel delivery only (assume already has a box that can get a decent timing map) in that case a carb that puts either generic FI as either PI or TBI onto the same single plane style carb manifold. A good carb makes more peak torque and peak power at WOT . There is not an advantage to going FI as the carb can get the fuel volume close enough but the preparation and lower temperature seems to trump any adjustability aspect. An engine doesn't need the fuel volume to be particularly precise

Not saying you cant make more power than a carb but rarely does the average guy do what it takes to make more power. Yes it is not apples to apples but its a real world scenario.

[David Redszus]

A good carb makes more peak torque and peak power at WOT.

I completely disagree. But I would like to hear your perspective as to how or why that would be possible.

There was a time long ago, when embryonic automotive fuel injection systems, produced a sub-optimal
spray pattern with a range of droplet sizes much like a carb does with wall wetting.

And there was a time when carburetor performance was favorbly compared to throttle body injection performance.
Those days are gone. The reduction in air mass flow with a carburetor vs port injection is hard to overcome.

There is not an advantage to going FI as the carb can get the fuel volume close enough but the preparation and lower temperature seems to trump any adjustability aspect. An engine doesn't need the fuel volume to be particularly precise

Fuel mass delivery is much better controlled by an ECU and port injection. Particularly when the engine
must operate over a wide rpm range. Irregular fuel delivery is one cause of cycle to cycle combustion variation
that reduces performance. Inlet air temperature and fuel density variations, knock detection and correction,
and several other variables can be compensated dynamically. And soon, combustion pressure data will be used
to alter fuel and timing curves, cylinder by cylinder on the fly. Fuel injection is not an overpriced main jet.

Not saying you cant make more power than a carb but rarely does the average guy do what it takes to
make more power.

Now we agree completely. Nor does he attempt to use data collection to ascertain what is actually occurring in the engine or its performance. Micro tuning of old technology is not making progress.

[digger]

A good carb makes more peak torque and peak power at WOT.

I completely disagree. But I would like to hear your perspective as to how or why that would be possible.

There was a time long ago, when embryonic automotive fuel injection systems, produced a sub-optimal
spray pattern with a range of droplet sizes much like a carb does with wall wetting.

And there was a time when carburetor performance was favorbly compared to throttle body injection performance.
Those days are gone. The reduction in air mass flow with a carburetor vs port injection is hard to overcome.

There is not an advantage to going FI as the carb can get the fuel volume close enough but the preparation and lower temperature seems to trump any adjustability aspect. An engine doesn't need the fuel volume to be particularly precise

Fuel mass delivery is much better controlled by an ECU and port injection. Particularly when the engine
must operate over a wide rpm range. Irregular fuel delivery is one cause of cycle to cycle combustion variation
that reduces performance. Inlet air temperature and fuel density variations, knock detection and correction,
and several other variables can be compensated dynamically. And soon, combustion pressure data will be used
to alter fuel and timing curves, cylinder by cylinder on the fly. Fuel injection is not an overpriced main jet.

Not saying you cant make more power than a carb but rarely does the average guy do what it takes to
make more power.

Now we agree completely. Nor does he attempt to use data collection to ascertain what is actually occurring in the engine or its performance. Micro tuning of old technology is not making progress.

Get the AFR in the same ballpark the Inlet air temp due to evaporative cooling is better with the carb even compared to throttle body injection. Its enough to overcome the loss of airflow required to get a carb responsive

Ask yourself in this situation Why would fuel injection make more power

[My427stang]

First, on my carb builds, a tuning a tunable carb makes a HUGE difference. In fact, in terms of power, it is not unreasonable to see small changes work out to be 10 hp at at time, often multiple gains. That's a clunky but decent carb with tuning along the way. I would put an Edelbrock 750 in most cases, a clunky but decent carb. Depending on the build, likely some gains there, although Edels are usually pretty nice to drive

Second, it needs a good guy to tune to a knife edge, which isn't me. However, for Holleys, QFT, etc, I use Scott Perkins (Bowling Green, KY) on the fancy ones and he does great. In fact, sometimes magic.

Then, a good carb is a good carb, but it will never be as responsive to environmental conditions or cold starts etc, as an EFI that controls timing as well. My own car was dialed in very nicely and idled at 1100, fussy when cold, but once warm was very nice. Now SEFI since 2009, turn the key half a turn and drive away like a modern car. Also, I was able to tune injector timing to match cam events and it dropped the comfortable idle down to 950 RPM. Although not dyno'd back to back, it doesn't feel like it lost, and my feeling is the port injected single plane gained mid and top end, and the ignition control bought back some low end

So, good EFI or good carb, carb is easier to replace, but don't be scared of EFI, lots of goodness for the part throttle, cold start drive and can make power with the big dogs

[Mike Laws]

Both.

Still a best kept secret: https://www.knfilters.com/eci

I saw this the other day but didn't pay much attention. Have you used it? To me it just seemed like a computerized power valve/accelerator pump

I've installed several. Have dyno tested and tuned on race and street cars. Works very well. It's basically a supplemental-EFI system w/o ignition control. I have very limited EFI programming experience but figured this out quickly.

From Summit's description: "The system consists of a carb spacer plate with a fuel block and injector, an ECU, and a wide band O2 sensor. The plate has a provision for the fuel injector. When needed, the injector squirts atomized fuel into the air stream passing through the spacer plate. In a way, the ECI system works like an EFI system that reads the air/fuel ratio fed to it from an included O2 sensor that you install in your exhaust. Where this differs from EFI, is that it is used in conjunction with the carburetor. Any time the system detects a lean condition, the injector will kick on to bring the AFR back to spec, but the engine is still fed primarily by the carb. The ECI acts as a supplement to your existing carbureted setup, rather than a complete replacement system such as EFI or TBI. The ECU programming is as simple as answering a few questions and setting 5 parameters with a laptop. However, if desired, the user can dive deeper into the ECU and set more parameters for the system to follow. Some of these include injector pulse width, shot volume, progressive injector firing, and minimum/maximum RPM range in which to operate."