Fuel injection VS carb. 500hp engine.

A friend of mine has a speed shop, builds all sorts of exotic street machines. He figures a daily driver is a toss up, but when going for extreme power the carbureted engine has an edge. He should know. He has a chassis dyno built into the floor of his shop, so he can maximize power with the hood up, and all diagnostic equipment connected.

EFI would have been nice on my supercharged setup, but really, the cost difference from carb to EFI is ridiculous. About 1000 for carb, about 3000 for EFI. A no brainer at this point. Maybe some day ill switch, but i hate wirering, so i doubt it.

Id also like to see how many people that vote for EFI actually have it, or just think its cool on a old car.

I vote efi as well, you dont have to spend 3k for efi, I have one of these going on my 408 but the earlier one that controls igniton as well........Retrotek - Powerjection III System

I have efi on my car and can say that you need to be realistic about the intended use of the car before making the decision.

Power and torque will be about the same at the end of the day.

EFI will yield better fuel economy in real world day to day driving. But if all you do is take the car out on weekends to cruise or pound on it, what do you care about mileage?

EFI will start everytime at any temperature with the twist of the key, no stomping the gas pedal, no fooling with the manual choke. But if you only drive in nice weather, who cares?


EFI has unlimited tuning capabilities, but the learning curve is very steep.

Production based EFI systems weigh considerably more than carb setups so if weigth is a big deal for you, recoginize that.

And by the way, I get many, many more people that think I've ruined the car versus those that think the efi is cool.

My car puts maybe 275 HP to the wheels and I drive it probably 3 days a week to work and open track it occasionally. It drives just like a modern car with 20 to 25 mpg if I don't beat on it too bad.

But if I had to do it again, id probably have to go with a carb. But that's me.

Good luck...

I love EFI and I've even done an EFI conversion on a carbed car, but IMO unless you drive the car all the time and many short trips it's not worth it. I don't really like carbs but they are a lot cheaper.

Of course unless you tune on a dyno or have wideband O2 sensors on the car you will never get a carb tuned as well as EFI will naturally tune itself. That also means you will never make as much power with a carb unless you do the extra tuning work. Also, a carb will make great power right after it's tuned but it won't self adjust like EFI. Just realize a carb is cheap and easy to install but not as good as EFI in power, fuel economy or driveability in the real world. I would go with a carb in a summer only car, but not because I think it works nearly as well - just because it's cheaper.

htwheelz67 said:

I vote efi as well, you dont have to spend 3k for efi, I have one of these going on my 408 but the earlier one that controls igniton as well........Retrotek - Powerjection III System

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What does it cost? From what I see it is $2500 for the TBI? MS is way more capable and could be done for that price including buying a TIG welder and building my own intake.

I got mine used for 1300.00 used for 3 months and the guy decided to go stacks,

http://www.autopartsdealer.com/professional_products_powerjection_iii_kits_70026-p240053-p.html
or you can go port injection

Professional Products Powerjection II Kits 72003

These new self tuning "TBI's" will give port injection a run for the money, unlike the old type TBI these run 45-60 psi fuel pressure giving great atomization and wide band 02 sensor, its a proven fact that the further away the injector from the port will give more power except for direct injection of course.

I have seen a few dyno runs comparing the powerjection tbi and powerjection port inj and they were almost exactly the same, also the EZ-efi TBI versus the fast port injection and the same results less than 10% difference in hp gain and the ez-efi tunes itself.

You can spend hours of tuning on a carb and match the hp of efi but the throttle reponse and most of the time TQ will be much better with efi as well as fuel economy and efi compesates for hot/cold weather, altitude, humidity and it will make a lumpy cam idle much smoother, I have personally experienced this with efi in the past.

htwheelz67 said:

You can spend hours of tuning on a carb and match the hp of efi but the throttle reponse and most of the time TQ will be much better with efi as well as fuel economy and efi compesates for hot/cold weather, altitude, humidity and it will make a lumpy cam idle much smoother.

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Aside from drastic altitude changes (we ain't got that problem here) I have none of those problems using a carb(s)

Regardless of how well you tune a carb, real world fuel efficiency will never match any modern efi system.

I will grant you that at cruise you will be able to match efficiency with a very well tuned carb but at every other point, which is where most driving occurs, efi will win.

In closed loop my 20 year old EEC system is always trying to hit a stoich burn at any throttle position less than 50%, always.

A carb simply cannot match that.

Carb N/A
Fuel Injection turbo/supercharger

I personally hate the look of fuel injection setups on old cars. There are a few that mimic a carb and look stock, which i a nice way to go. 5.0L intakes just look out of place in a classic IMO, kinda like the modern 5.0 wheels with the goofy wheel offsets.

I have efi on my car off a 91 GT.I'm using a tweecer rt tuner and it's really not user friendly, but its a cheaper solutions than going with acell or a fast system.

phutch11 said:

Regardless of how well you tune a carb, real world fuel efficiency will never match any modern efi system.

I will grant you that at cruise you will be able to match efficiency with a very well tuned carb but at every other point, which is where most driving occurs, efi will win.

In closed loop my 20 year old EEC system is always trying to hit a stoich burn at any throttle position less than 50%, always.

A carb simply cannot match that.

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So tell me what the exact power output difference is between the two at any given RPM ?