stevenb

I get half n half from my friends some say that carb is faster cause its raw power and some say its worse. What does everyone else think? I wanna know if its faster and if its more efficient? I know it hogs gas.

5678TA

FI is can be more fuel efficient while a carb can make more power.. but it can also be reverse..

my first 383ci w/ carb used to get 10-12mpg and my 91 4.0L(245ci) ranger w/ efi used to get 13-15mpg.. so FI is not always more efficient..

the thing about a carb making more power is that it is alot easier to tune and alot easier to make big numbers.. while FI, you need a computer to tune it and it takes more time to get to the same level of power.. FI can make more power too.. its just the time and hassle factor that some dont want to deal with..

84z28350

FI is the superior system. But it takes one hell of a long time of tuning to get it there!

With FI, you can have your cake and eat it too. You can make awesome numbers while still getting very respectable MPG.

A carb is alot cheaper and dummy proof, bolt it on, change the jets and rods and your laying rubber across town. But the downfall is the fuel economy...

ChillPhatCat

My '74 Camaro had a 454 BBC with 750 CFM carb and it got 16 MPG on the highway using the stock transmission (TH350) and a 3.08 rear end. It might not sound so great, but consider that that was at 70 MPH and 2800 RPM... If I had a .5 final ratio like a T-56, it could have probably gotten into the mid 20's in mileage. I'm sure if it were EFI it could have been tuned to get more power, it wasn't more than a 400 Hp engine, but I think it was quite impressive for what it was.

In the end I think it comes down to ease of tune, you can get decent mileage and quite impressive power with a carb and it takes very little time to tune; or you can get quite impressive power with EFI (slightly more) and even better mileage but it takes a while and a bit of knowledge to tune.

1BadaGTA

Well I was wondering the same question not so long ago. But after alot of asking around, watching some races and a ton of resreach. I found that no matter what people tell you fuel injection is superior to carb but carbs can make around about the same hp and tq numbers as the fuel injection and they are cheaper (right now) and like everyone else has said easier to tune. But that cheaper thing isn't going to last much longer because I work for an autoparts store and the price of carbs are going up really fast which means theres not a high demand where as the EFI is getting more and more common. So its not hard to figure out which is the more effecient.

online170

For the guys that drive their car year round with a carb, will realize that FI is the superior system. But full FI not just throttle body injection. The carbed guys will notice, that once autumn roles around, the car gets a little harder to start, and gets a lil rougher cuz of the colder weather, and the carb has to be adjusted a lil to fine tune for ease of driving.

Translate that into power, if at peak tuning your car ran 434 hp then each time you start it up with a carburetor, it will have lost its tuning a bit, due to the weather, humidity, driving habits, etc etc etc.... So you dont always have 434 hp, unless you pop your hood and tune the carb each time u go for a drive.

With FI, you get the EXACT amount of fuel needed every stroke, and with the help of the sensors, that fuel can be varied to deliver constant results. This results in efficiency and increased power.

Yea your gonna get some guys comparing their 70's impala, or cadillac, or galaxie, to an 80s EFI car, and say, ive owned both cars, and my carb ones WAY better on gas and powerful too, but thats not really a controlled circumstance comparison.

Sure some guys can get more power out of carbed cars, but just look at the car industry today compared to when these cars first came out. Back then it was all about displacement, cuz fuel was cheap. Then when it hit double digits per galon/litre, there was a big hype, and they started concentrating on efficiency, but not really. Now that gas is hitting triple digits, its a reality, so efficiency is the MAIN goal.

You can pull up next to a guy pushing 500-600hp with his carbed muscle car, but i bet it has one hell of a lumpy idle, and he can only race from one gas station to the next. Conversly, the new ford GT has the F-150 truck engine, thats supercharged, and its pushing similar figures but it sounds much more tame. The new mustang is pushing close to 300hp, and is very easily tuned. Any LS7 corvette that is coming out can be upped 100hp with a cam change and headers, according to hotrod magazine. The new camaro, and challenger soon to be produced, are gonna blow everyone away with their power figures in two years, etc etc.. The list goes on.

That little civic, is even in the figures that some v8's were producing in 70s and 80s.

SO... as big a fan i am of carburetors, you gotta face the facts. FI is the superior system, some may have their opinions, but you cant deny the facts.

izcain

I believe that this is a very big debate that often takes side roads lol. The answer is depended on what the primary use is for the vehicle. If it is a race vehicle then test have shown the carburetor providing more HP on similar setup FI race motors. But times have been changing as of recently so Im not so sure that a carb is always going to make more power. It will all depend on the setup.

online170

Izcain has a good point. The carburetor is a very basic setup, and will always remain the same. It can only be advanced so far. The jets, floats, cfm, and fuel flow is what makes the carb work, and tweeking little venturies etc can make the best use of the mechanical device.

But FI cannot simply be summed up like that. FI system, is starting more and more to control the rest of the engine as well, and it is always developing. It can control, amount of fuel, pressure of fuel, size of injector, how it injects (angles), fine mist, multi spark, electronics controlling timing, advancing and retarding for maximum power, displacement on demand, not to mention the 100s of sensors it uses to vary this stuff.

Soon enough, they will have fabricated something to allow an engine to run at one constant temperature with a much greater accuracy than right now, or with a carbed car, etc etc etc etc

It would be nice to actually see some results and time slips, or dyno tests contrasting this. I realize the question is very general, so the arguments are gonna be very opinionated, but we can learn alot from this thread.

z282slo

If you can tune a carb, your car will be faster with a carb.
If you can tune FI, then your car will be faster with FI.
If you can tune both, then you're not really human.

Sonix

iTrader: (1)

An FI motor is typically built different as well. Case in point - carbed, single plane intake, 106LSA cam, big solid roller. It's dyno chart looks a certain way. With a good shift kit, the right stall, it's terrifyingly fast.

The FI engine (and yea, TBI doesn't sound, we're only talking port injection here - REAL fuel injection) - needs a smaller cam, no solid cams or it'll throw off the knock sensor usually, wider LSA, etc. It's a whole different animal. Flatter power curve, but the peak isn't as high. It won't do the 1/4 mile as fast, but it's more driveable on the street. As things are right now, fuel injection costs a whole lot more, and you need more gizmos to tune it. Sensors, laptop, etc. I can tune my carb with... 4 screwdrivers and one wrench sorta deal.
As long as gearheads are typically not computer wizards, the carb wins. Carbs can be tuned to have good highway mileage, if the person is dedicated enough to take the time. Typically people with hot rods just want it fast, and don't take a lot of time to tune for good mileage. The main thing is the transition - FI has a very good side benefits. Good smooth transition from cruise to power, more efficient power etc etc. ie, no huge pumpshot, it's a smooth fuel addition curve.
Anyway, this is an age old arguement, nothing new here. Z282slo pretty much has it nailed - And i'm a carb tuner so...

stevenb

Is gas as bad as everyone says it is? I'm thinking about running a Holley 750 double pumper and I heard i would get like 7 MPG. Sound accurate or not?

Sonix

iTrader: (1)

Uh, no not accurate. Around town, if you're leaving a 10' streak of rubber at every stoplight, then yea, 7mpg.
If you're driving on the highway, doing the speed limit, not passing everything in sight, 17-21 MPG is reasonable. We're talking about a medium built 350 here. No OD you get closer to 17, OD and lazy highway gears gets you up in the 20's.
My medium 350 with no OD, tall tires, Q-jet, gets 20MPG on the highway.

Apeiron

A carburetor is more efficient in HP/dollar. Fuel injection is more efficient in miles/gallon.