white2001s10

iTrader: (4)

negative

joecar

Yes, you're correct (air-fuel emulsion).

Note that some EFI systems are wet flow (GM TBI, Holley Pro-Jection, ...).

The job of both carbs and EFI is to produce an air-fuel mixture with an AFR suitable for combustion under the instantaneous current condition; as a bonus, EFI can also control ignition (like a distrubutor with many sets of instantly available springs and weights and vacuum advances, plus knock retarding).

whether that's done by emulsifying or spraying doesn't really matter (although each has it's own pros/cons);

the selection of carb vs EFI comes down to the intended application: 1/4 mile monster, road racer, weekend warrior, daily commuter, ...

sprayinss

iTrader: (2)

it will always be a debate its really whichever u know the best,me its both but u may be diff

stevieturbo

Im still waiting of one example of a carburettor engine that can produce in excess of 200bhp per litre, nevermind 300bhp/litre, yet still remain a perfectly useable and fairly economical road car for every day use. If carbs are better than efi, there should be loads of examples.

As it is, there are none. Carbs can perform good within certain criteria. But efi can perform good under any criteria. The only limitaitions are with cost to build the system. Carbs are simply limited by what they are capable of..

white2001s10

iTrader: (4)

There are many blow-through turbocharged carb engines 350 ci through 400 ci that are producing between 1200 and 1600 horsepower and are still streetable.
I don't know what you're getting at with this.
You don't allow FI? well then there are nitroused monsters that are streetable with the same HP level.
You don't allow any power adder? well then go climb a rope.
I'm pretty positive that you don't own one example of any of the above, so I can't see why you'd argue that as a point.
I don't know anyone else besides you that requires 200bhp per liter from their own daily driver, or even shoots for that. That kind of goal would be plain stupid as the project would be a money pit just to prove a point.
The fact is that there are tons of carbureted engines that are perfectly streetable, get great mileage, and could still beat anything that you'll ever own. All I can figure is that fact just hurts your feelings. I'm sorry about that.
My last carbureted engine was a 383 that ran 10.9@124 NA, and averaged 24 MPG on a 625 mile highway trip. It was a perfect daily driver. Of course it could've been better, but it was a very low budget project, and that's the point. EFI would've cost a whole lot more and introduced more variables that would've reduced reliability.

Don't get me wrong, I do like both carburetor and EFI, but you people that dog on carburetors and think EFI is God, simply don't know what the hell you're talking about when it comes to carburetors. Reading about how they work on an internet site doesn't count. That's just straight up ****** style.

stevieturbo

Who said I dont allow FI ?? I was actually referring to turbocharged engines in particular.
Yes, I do also own a Subaru producing just under 400bhp, which is almost 200bhp/litre.
I also own a turbocharged mini, with a very simple SU carb making 200bhp from 1300cc. It works very well, but as I built it over 10 years ago, I know I could do a lot better with efi. It does have compromises and was very difficult to get the power from it. But that was a long time ago.
I ran a blow through Holley on my old twin turbo Rover V8 for about 6 years before going efi. It made power, and drove very well, but it was anything but economical. It drank fuel at an alarming rate. Perhaps this was in part as I am not an expert with carbs, but otherwise all other aspects of it worked good. My mpg almost doubled after I went efi, and overall driveability was improved, although outright power would have been similar. The savings in fuel costs would make up for the cost of converting long term.
Given many Subarus, Evos etc etc are peoples only car, and daily driver, 400bhp from such a car isnt really that much. So giving an example of these, 2000cc cars that produce, 400, 500 and in some cases 600bhp yet are still totally useable and economical road cars is very valid.
There are many thousands across the world that do have those sights in goal and do achieve them..
In fact, just recently, although I am a little sceptical of it myself I read about a Toyota Starlet in Australia. This car is still a road car, although extensively modified. It is producing 348bhp at the wheels from its mere 1300cc, which is almost 400crankhp from 1300cc which is over 300bhp/litre.

Im not ******* carburettors, as I said they do work for certain applications, but they dont have wide ranging ability efi offers for pretty much any application. Carbs here in the UK are now a rare sight. Most people in all forms of motorsport have moved on and realised the benefits of efi. It is probably only the drag racers that are holding onto the carbs, but they do work very well for them.


Are there even any new cars produced in the US that are fitted with carbs ?

critter

iTrader: (9)

It might be more interesting if you were speaking to the origional question. It was:
but you seem to ignore this. Carbs are proven to make more power than EFI in a max effort N/A application. This is undeniable. I agree with you that EFI is much better for the street, but that is not what the question was about.

rob_v

efi !

stevieturbo

Ok, looking at it from a motorsport point of view. I still disagree.
Do any Formula 1 cars use Carbs ?? Being at teh pinnacle of motorsport, I would think they are a max effort n/a car, which make about 800bhp from a mere 3000cc. If carbs were better, Im sure they would use them ??

The only top form of motorsport that uses carbs are drag racers. All others, unless dictated by rules, use fuel injection.
If carbs were indeed better for max power, then surely there would be more using carbs ?

Do you disagree with any of the above ?

How many forms of motorsport at the top level still use carburettors ??
Drag engines are the only one I can think of. Virtually all others have converted to fuel injection.

white2001s10

iTrader: (4)

They used to. Rules changed.
It's also easier to fuel a boosted application with port injection.

Ask David Vizard to set up the same 3000cc engine with carbs to make the same power and he could do it. It's just more work in that application.

critter

iTrader: (9)

Unless you define "better", you can't even discuss the issue. Better in what way? Max power? I would be quite certain that F1 owner/drivers are more interested in lap times than max power, so I think the proper definition of "better" is lap times, which is more closely related to drivability and many other factors than max HP. Ergo, carbs are not better for F1 cars.
See the above. Since you aren't specific about the other "top forms", I can't be specific, but I am quite certain that drag racing is the only one in which max HP is an important variable. Ergo, carbs are probably not right for the "top forms of motorsport" other than drag racing

Right. Because drag racing is the only one where absolute power is an important part of the equation.

Since you are fond of motorsport examples, Harold Martin runs EFI on his Pro Mod (a drag car) but he struggled for years to make it work good enough to be competitive, and it is only competitive. It is clearly not dominant. But if you want definitive proof, hit the net. You can find both evidence of and rational for carbs being superior at making horsepower. And you can also find evidence of and rational for EFI being better at everything else. Google is your friend

stevieturbo

Ok, you are saying that Carbs are better for producing maximum power only, fair enough, I'll accept that.
You are also saying that maximum power only doesnt always make for a fast car, which is definately very true, pretty much with the exception of drag racing. I'd agree with that.

Better is a general term. If a carb setup only makes more power at max rpm's but less power and torque everywhere else while using far more fuel. Then I wouldnt say it is better.
better is an engine package that makes a car go very fast, has a good spread of power, and still give good economy ( relatively speaking )

As for top forms of motorsport. I mean any form of motorsport at the top level. eg F1, F3000, WRC rallying, Le Mans/GT cars, Touring cars etc etc.
Not your Joe average cheapy weekend racing where they come last every event type of motorsport, on a shoestring budget..

Bowtieman4life

iTrader: (1)

Doesn't Nascar use carb's? Also, Hot Rod recently had an article where they compared the Ls1, Ls6 and the new Carb intake for LS motors. The Carb set up won hands down.

Max power= carb
Daily driver and 4 wheeling = EFI

Remember that as the angle on the road, trail or hillside gets steeper the distribution of fuel changes in a carb set up. The rear cylinders get more of the fuel and the fronts get less which = power loss, lean and rich conditions. Overall, early engine wear and failure.

Look up the article.

stevieturbo

Nascar use carbs as rules dictate they must.

I have seen articles testing a carb setup vs a stock LS1/LS6 setup. but thats my point, its a stock LS1 setup. The carbs replacement is designed to produce power. The factory LS1 intake has cost, emissions, power etc to take into account as it is a production item which must abide by certain rules.

If you were to test it against an efi system with multiple throttles ( US Kinsler style ), then I would be pretty sure efi would win. Has anyone tested such a system on an LS1 ???

critter

iTrader: (9)

Win? You mean most power? No, the carb would win. Like I said, research it. One of the reasons is air density. The latent heat of evaporization of the gasoline reduces the temperature of the incoming air more with a carb because of the more complete evaporation of the fuel. Lower temp air is more dense and that means power. The fact that the gasoline is more completely vaporized gives a better burn, and thus more power. You can find the rest on the net.

Having said that, it is clear that port injection EFI or Kinsler style will give more even fuel distribution more easily than with a carb. Even distribution can be done with a carb (and in fact is necessary for max power) but it is much more difficult. EFI is the clear winner for probably every application except max power as in drag racing. Here the best carb setups beat EFI.

Bowtieman4life

iTrader: (1)

DITTO!!!!!!!

stevieturbo

So you now agree that for about 95% of cases efi is better ??

For the drag racing fraternity, the carb seems to win as it may be capable of producing slightly more maximum power only..

You can get systems where multiple carbs are used, such as Weber sidedraughts or down draughts, or indeed Dellortos. These used to be very popular over here on many engines, and could indeed make a bit of power on a lot of engines, and offered performance advantages over a factory efi setup.. But with these you had to make big compromises as to what you want. If you were to aim for big power, you had to use large carbs, with big chokes, so airspeed was high enough to draw fuel properly at high rpm's without offering an airflow restriction. Then low down power and torque suffered heavily.
Efi in similar circumstances ( ie throttle/cylinder ) allowed the use of smaller throttles/bores that flowed more air ( it was the choke size in the carb that dictated airflow, not carb barrel size ), with massive gains over carb low-mid range perfromance, but with all the gains up top end.

critter

iTrader: (9)

LOL!!! I never said it wasn't! In fact the number is probably more like 99.9%, but once again, the quesion was:
and the answer is carbs make more power, and it looks like his definition of "better" is more power.
Uh yup. That was the question and that is the answer.
You are preaching to the choir! But all that is irrelevent to the question this thread is about!

stevieturbo

Ok, Efi is better, as it will usually make more power/torque over a wider rpm range, which makes for a faster car, even if it may lag behind slightly on maximum power...

Carbs have potential for more maximum power only for reasons others have stated.

Is that a suitable answer ?

critter

iTrader: (9)

LOL! Stubborn one, aren't you?
I agree with that unless I am going drag racing.
I didn't say that, and would have to think about it. I don't think that is necessarily true.
Again, I didn't say that. It sure isn't true for a ProStock car. Probably wouldn't be true for a Cup car. Might be true at Le Mans, but I haven't seen any real evidence - only anecdotal examples.
Now that is what I have been saying. I definately agree with that.
Suitable for what?