Was just reading an article in a mag. They did another EFI vs carb test. They used a 454 mild-*** crate motor with a converted Vic Jr manifold. They used a Demon 850DP/mechanical dist in one test, then an Accell 1250cfm TB, cc-dist, complete DFI, in the same manifold for that portion of it. They mentioned that they spent some time dialing in the EFI, but didn't say either way about the demon.

Keep in mind, this wasn't some OEM TPI or TBI based crappy system. This was a full aftermarket DFI multiport system. More or less top of the line available. Total price as tested, $5,500 for just the induction. As opposed, of course, to about $500 for a Demon and manifold.

The results are: the carb beat it at every RPM in both TQ and HP, from 2300RPM to 5800. Peak difference was about 9 in both. Yes, the carb even had more low end.

I really would like to see some more tests on this. I mean EFI TB had a friggn 400cfm advantage..what would happen if they put a 1250 King Demon on it?. Plus the motor was so mild..I would have liked to have seen what would happen if they stabbed in a halfway decent cam.

Did I ever mention that EFI SUCKS?
EFI SUCKS

 

you sure you arent talking about the article in car craft? because that sounds just about the same as that article only it wasnt a victor jr converted.. it was the single plane for the EFI system. And no that didnt spike the test because the single plane for the efi system with a carb on top made 20 more hp than the dual plane that came in the crate. The initial efi test with the stock tb had about a 9 hp difference but when they busted out the even bigger TB the numbers were virtually exactly the same.. atleast within the dynos error margin anyways. The charts posted show an obvious advantage in low end torque in favor of the EFI.. at the start of the test the efi had a 7 lb foot advantage.. and peak horsepower was EXACTLY The same at 454.4.

Doesnt tell me anything I wouldnt have guessed beforehand. Stab a big *** cam in that rat and lets see which system wins on average torque.

as for the system costing so much, you were primarily paying for the name brand and electronics.. the mechanical aspects are virtually the same as a gM efi system adapted to a 250 dollar holley single plane with efi injector bungs allready installed. In fact, id say the dfi system electornics/software is less capable.. perhaps more user friendly but definately less capable than say for instance a 730 gm ecm in the hands of a knowledgeable tuner

so, ding dong you are wrong

 

That EFI single plane IS a Vic Jr. Accel just modifies and reboxes it.

That second TB is a custom prototype, you can't get one. That doesn't exactly count in the name of comparing apples to apples. Even if they could, It gained a whopping 1 ft-lb of Tq and equal Hp to a carb 400cfm less..want a cookie?

Then you're gonna tell em that EFI is better because a Vic Jr gained 20hp over a stock GM dual plane? Do you just throw arguments out your a$$ for the hell for it?
And if you think you can make a super EFI system for a few hundred bucks from a stock GM ECM..good luck. Oh yeah thats right..you tried it..gave up and converted to carb yourself. Then you're still gonna come here and argue that EFI is better? Please..spare us. Go back to the TBI board where such stupidity can go unnoticed.

 

I agree Jester. A carb and EFI do the same thing, they add fuel to the air being sucked into an engine. All other variables equal, they will produce about the same power and efficiency. Assuming both are tuned as good as they can be tuned.

 

Agreed, but the point is what it took to GET them equal on a very mild street motor even. $5,500, complete DFI system, plus prototype not even commercially available parts. On store bought parts, even very expensive ones, they couldn't get it to put out the same power at any RPM.

People 'round here seem to think that thier siamesed base TPI with an SLP stage 6.9 chip is gonna do it for them. just doesn't work that way.

 

Ah, the money thing. I wonder how many times I can rebuild my Holley, and/or replace it when it finally wears out with the money it costs for a good FI set-up. Considering I haven't had to rebuild my Holley, and it's far from needing replacement, I would say it would take quite a few lifetimes.

 

I read a FI vs carb article (not sure if it's the same one) a while back. It was kind of funny because after the dyno numbers proved the carb is completely superior, they still tried to argue the reverse. They said something like, "well, the torque converter was too high for the application. If we had used less stall, the better torque of the FI would be apparent. And we stopped the test below the RPM when the high horsepower of the FI really begins to shine. So even though the carb got higher numbers, FI is really the better performer."

People just believe what they want.

 

The money issue got me too. I actually was wanting to keep the TPI at first. Once I realized I ordered a cam that would not have had enough manifold vaccum to properly operate the SD system, I considered a carb. I thank G0d I did. The induction alone to support the power I have now would have been $1050, I paid $310 for the carb, and intake. Yeah, I would have spent less on gas, and been able to start it in the winter, but I have driven it 1200 miles in 7 months. And I would not even consider driving it in the winter. FI is nice when it fits the situation, but a carb is all I need.

 

Read this before after Pablo's reply, but I got kicked over here today by... well... Saving that for later.

Pablo, et al, lets take a look at this:

Its a magazine article. I had someone ridicule me because I told them to look at this specific article, specifically because it was in a magazine. I tell you what, you go find an article of any sort, in a magazine, book, SAE, whatever, a true back to back dyno comparo that shows EFI with an advantage in a WOT setting. I've seen enough articles in and out of magazines and enough data to support that at WOT, the game is over. Any advantage FI had went right out the window. And for you nuts out there, I'm talking about wet flow EFI (wet from the sense the valves get sprayed with fuel, I cant remember the technical name right now)... not direct injection which is a whole new ballgame. What happens if both are setup correctly and arent a hindrance to flow (like TPI), is theres NO advantage. I dont care what side of the fence you are on. I havent seen a single piece of information to refute this, and as such I find it to be an accurate assessment.

So here's the real results, cost aside: (HP, TQ)
Carb peak:
454.4, 490.3
EFI peak:
445.1, 481.2
EFI with custom one off TB:
454.4, 491.8

Know what, so far it looks pretty damned close to me. Heres more: (HP, TQ)
Carb av:
355.6, 462.3
EFI av:
348.1, 453.0
EFI with one-off:
355.8, 462.9

See that average, with the one off TB? Notice how close it is to the carb? Like too close to call? This isnt a freak accident. You dont like the results of this article, go find another. You'll find the same thing. In a WOT setting thats just what happens. In real life, its much easier to get a carb setup right at WOT in a range where you race at. In real life, most carbed cars beat the EFI stuff. This is not always the case, I have seen enough bad running carbed cars leaking gas all over the intake that are just like mistuned EFI setups. Ideally, equal. Period.

Ok, lets continue.
This article is infested with them wanting the EFI to perform as well. Does anyone really think they didnt spend alot of time to get the EFI near equal? They even threw a different TB on to try and see if they could pick up some more power. Know whats really funny? The top of that TB looks like a carb. I seriously doubt the results are unfair. I also seriously doubt theres any significant difference below the 2300rpm they started at. Many are arguing FI is so much better at low RPM's, well at WOT I dont think so, and really... it doesnt matter! We are talking about race stuff here, WOT... who spends any time under 2300? I dont know about you, but my TPI car hits 2000 at launch.... somehow I dont think 300 rpm less is any factor here. And isnt it about the average power you put down? Well the numbers are there, clear as day. These arent unusual results either. Ive seen it time and time again.

So whats the conclusion? Conclusion is, at WOT its a moot point. Pick one. If you have $5500 laying around burning a hole in your pocket, maybe the FI will float your boat. For those of you wanting to spend less, the carb is your solution. And thats the article. Period.

Now onto other things:

The only real advantage FI has over a carb is idle. Read that again. The only real advantage FI has over a carb is idle. Thats one of the main reasons FI is on new cars. Emissions. EPA. Fuel efficiency. In city driving, cars spend entirely too much time parked at lights idling. This is the least efficient area of vehicle travel, carb or not. FI has a distinct advantage here, as it is not sensitive to vacuum and doesnt need it. You can mess with a carb and get it really close, but it will not be equal. For most purposes, it doesnt matter. From a mass-manufacturing standpoint of millions of cars that will not be maintained, its a huge problem. Massive. And hence, FI. Easy and effective solution to a complex problem. Would have been my choice too.

Those of you wanting to argue other advantages of either, go right ahead. I'm not even going to address the whole part throttle/crispness BS. I too am not touching the low/high altitude issues. Really, how many times do you drive under the ocean one day and up Mount Everest the next? Its such a rare occurence, to me, its hard to place a heavy value on it. Most people stay at the same sort of elevation probably 99% of the time. Even if I am generous and say 5% is spent elsewhere, its still not enough for consideration.

I own a mix+match of cars. I dont rip FI off FI cars, nor rip carbs off carb cars because I think one is better than the other. I have one thats converted to FI from CCC, and another that I was Edelcrock's QC department away from going from FI to carb. I choose what I figure is the best idea from different standpoints, and thats what goes on the car. I could really care less what it is, as long as it does what I want it to.

 

Bravo!!! Very well stated!!

 

I'm just curious... Did they state any fuel economy figures in that article? I mean, did they drive it through a tank of gas to see what the mpg would be? Again, I'm just curious because WOW if it was even remotely close (ie within 5 mpg or so) then I feel much, much better about staying carb.

Steve

 

No, they didnt. The engine I think was on a stand and never saw a car, so that would be kinda hard to do. I'd imagine, as a wild guess, the EFI would be slightly better. I doubt it would be significant though. My old carbed car runs the same ET's as another guy who has FI instead but the motor itself and drivetrain is pretty close. I'm not sure if his car is much heavier than mine, but its not more than a couple hundred pounds if it is. I'm getting the same gas mileage as him.

Would be nice to see a comparo on that though. That and low RPM emissions just because it will show where there will be a difference.

 

i think that post by madmax should be saved in everyones computer and in their favorites.because lately this FI vs. CARB,and it always ends up a cats game.back and forth and nobody ever wins the argument.why?because as madmax stated,there is no winner/loser when it comes to this topic.its always a fun one to discuss,but theres never an outcome that either side likes.i think this line sums it up PERFECTLY.
me,i DONT have the money and/or time to spend on fine tuning an FI setup.i DONT want to sit in front of my computer figuring out countless combinations on a chip,and i DONT want to spend the money on the materials needed to do so.and i definetely DONT want to buy a laptop to use just to scan my cars ECM in real life just to see if its running right.to me,its a big waste of money and time.i would rather turn a wrench or a screwdriver and have fun tuning my car,AT my car,under its hood,not at my computer desk.and i want to mod my car and know that i dont have to sit inside on a sunny day burning a chip to get it to run right after i put a new cam,new heads,or a power adder on it.all i gotta do is take it for a ride,check the plugs,and rejet the carb.hell maybe even GTECH it to see what helps.
Again,this is ME.this is WHAT I prefer.and CARB is what i pick.not yet,as i dont have the money because im in between jobs right now.but in a few weeks when i start receiving a steady paycheck,you can be damn sure im going to carb.
just MY $.02

 

There IS a winner in the Carb vs. FI argument. The winner is the guy who READS and LEARNS from posts like this. Not the trash-talking and instigating trolls looking for an argument. The REAL DETAILS and the subtlety that goes along with answering a very blunt question like "which one is best."

Here's the plain truth of it all:

EFI will not make any more HP than a good carb setup. Sorry if you thought it did- it doesn't. Not even a little tiny bit. This thread is just more evidence of that.

However, here's what FI does better than a carb:

Cold start/smoother operation under extreme conditions
Emissions
Taming a lumpy cam and getting a good idle out of it
Building extreme low end torque with a lumpy cam.
Fuel Economy
Working well in blow-through forced induction applications (turbo/centrifugal supercharger)
Packaging well under a low hoodline

The downside is, of course, a considerably higher cost and the fact that very few people really know how to tune them (or even posess the equipment required to tune them).

Which is best? Well, What are you looking to do?

 

Now thats funny.