Carbureted v. EFI

[85_SS_302_Coupe]

Bravo! more input!

Interestingly, no one has responded to my satement "The primary limitation of carbs is that they are a mechanical device, and have no way to compensate for changes in temperature and atmospheric pressure. These two items can limit the power of a carb’d car. A race to the top of Pike’s Peak on a hot summer day would be an example of how this will affect a race car. Or a trip down the drag strip at Denver, Colorado in the summer compared to one in Los Angles during the winter. Definite power differences would be seen & felt. Adjustments can be made, but it requires some small amount of wrenching to do." How do you make a carb do that on the fly? EFI is all weather, all the time, even while you are racing towards the finish line.

See people assume that i think carbs are all mighty....not saying you do, but i will say that EFI is superior....but i'm just arguing that carbs aren't as limited as they seem. True, they can't adjust to the atmosphere, which is one of their short comings, but i don't think many people are running Pikes Peak or something like that with a carbed car anyways..lol. If you have the cash for something that extreme then you need engine management anyways. For a street/strip warrior, there's not a whole lot that EFI has over a carb when you stay within a certain climate/altitude/season.

Hell i don't even change the jets in my car in the winter...i don't drive it that often, but you can find a sweet spot between hot and cold weather and have one set of jets all year and not leave that much on the table.

 

[EMW150]

Carb: You take your new hotwheels 351 with a carb, fancy heads, hot cam, built C4, etc., etc. to the local tuner whiz. He’s a little peculiar, one of those hair on fire, can’t stand still kind of guys, but he gets results. He also gets $100 an hour plus $300 for dyno usage, so wasting his time isn’t healthy for your wallet. It’s 60 degrees and dry as dust as you pull into the dyno shop. The first pull is terrible, and he shakes his head and makes some insulting remarks about your hat size. Out come the tools and 15 minutes later he’s ready for another run. This one is better but flattens out near the top. He’s thinking a different power valve is the fix. More tool turning, another 15 minutes and he’s ready to go at it again. Next run looks really good on top end power, but the mid range torque is down and isn’t what he wants. Time to change more parts… Out comes the jet kit and he finds the proper size, along with another 15 minute slice of your wallet. Fire up the engine, re-adjust the idle and accelerator pump linkage and run it up. This one makes him smile – a little. He tells you that this isn’t the ultimate, but it is good. Pleasantries are exchanged, along with $400 of your money. Weeks pass and spring turns to summer, along with several trips to the track. The track results have been good, but the times seem to increase as the temperature rises. Today it’s 95 and so humid that everything has a layer of sweat. First run, power is down, the car seems to bog, the trap speed is down and the ET is up. You check the timing, tire pressure, fuel pressure, all OK. Second and third runs produce similar results. Another run and you do a clean cut at the last light. Coasting into the return lane, your pit crew buddy meets you with a plug wrench and some extra bodies to push the car out of the way. Plugs come out, inspection is done and you conclude that the engine is running rich. A call to the tuner guy results in him digging out the dyno sheet and looking at his notes. More insulting remarks follow, and he asks you if you expected the same tune that ran good at a dry 60 degrees to run the same at a sweaty 95 degrees. You say yes and then he tells you to get a life and some more education on how temperature and humidity affect engine performance. He offers a retune for the current weather at a discounted $300 flat rate. A sudden pain in your wallet springs to life as your credit card starts to throb like a stubbed big toe…

That's funny. As far as tuning, they're not as hard as you think. I know my engine well and I know where the jetting needs to be under particular conditions. An EGT gauge helps with tuning and also warns of any problems.

 

[jrichker]

That's funny. As far as tuning, they're not as hard as you think. I know my engine well and I know where the jetting needs to be under particular conditions. An EGT gauge helps with tuning and also warns of any problems.

Looks like the carb guys are winning this one by sheer force of numbers...
Are there no other EFI proponents around?

The idea was to make more of an apples to apples comparison of the cost of a high end tune and the long term results.

Gross tuning on EFI can be done by simply changing the fuel pressure. However, that isn't effective to fix the rich at the bottom, lean at the top problems. That requires a dyno tune. To make the picture less lopsided, I described story that made a comparison of carb & EFI costs and the long term results. Short form, no retune needed for EFI due to changes in weather or altitude. EFI does all weather, all performance, all the time.

 

[Dean85GT]

Im gonna enter this debate, but I dont have the good tech info alot of you guys have too. First off lets say that my car has a carb from the factory otherwise I dont think it would have one. I think that carbs are better when the engine is more radical. What I mean is that for most people, the modding never stops and the car is never done. This is where a carb is better, (in my eyes) because the owner can make small adjustments with each change in the combo. Look at how many times alot of guys switch around there combo or keep going bigger and bigger. Basic carb knowledge will let these guys maintain a decent tune on the car. I hope that doesnt sound bias because I dont know to much about EFI besides a preference for it on street and daily driven cars

 

[85_SS_302_Coupe]

Looks like the carb guys are winning this one by sheer force of numbers...
Are there no other EFI proponents around?

The idea was to make more of an apples to apples comparison of the cost of a high end tune and the long term results.

Gross tuning on EFI can be done by simply changing the fuel pressure. However, that isn't effective to fix the rich at the bottom, lean at the top problems. That requires a dyno tune. To make the picture less lopsided, I described story that made a comparison of carb & EFI costs and the long term results. Short form, no retune needed for EFI due to changes in weather or altitude. EFI does all weather, all performance, all the time.

I'm more EFI than you think...i just go with what i can afford but i also stand up for what i know is right ya know? Having ran a carb now for about 5 years straight i know you don't lose THAT much. People think on things to an extreme when it comes to this subject. Even though NASCAR is held to the rule book with carbs, you can't deny how high tech those engines are and they run like a bat out of hell...all with a carb. Do you think they're worrying about jet changes in the middle of the race just because the temp outside changed? NO because it's not that crucial.

EFI is superior...i think i've said that in every post now. But, in the end it comes down to a whole lot more than what is truely superior and what you can live with giving up and/or working to achieve. With an EFI system, you pretty much tune it and forget it...it's sort of like the lazy man's system who doesn't want to be tinkering with their car to keep it running at it's best...and believe me that's one thing i miss sometimes. Another thing i miss is that you just about never get throttle hesitation with EFI...which you have to KNOW how to tune a carb and tune it well to get that same responsiveness, but it still can be done.


In that same magazine i listed above they have the '05 Performance Racing Industry show coverage, and in that article they have a picture and a small bit about BOSS 331 Racing's carbed 5.4 DOHC engine setup...talk about F'in badass...you get the awesome technology of duel overhead cams and badass heads, but with the simplicity of a carb on top. And the intake is just plain sick because of the way the intake runners are on the heads, the intake stands up off the heads like a spider (really just like a spider) and they have the coil packs UNDER the intake tucked away where you can hardly see them....talk about a clean show engine...no wires or all that other junk for the EFI, and you wouldn't even see a distributor or coil packs, and the plug wires tuck nicely behind the cam covers. Then if you run an electric water pump and manual steering (just to keep it as simple as possible) you'd have one single little belt up front for the alternator which is tucked down low almost under the engine. You'd either have the cleanest engine bay in the world or you'd have plenty of room for 2 turbos to run into a carb hat...

Here's an old website, i don't know if the guy is still doing this sort of stuff, but back in the day his little site was a great reference for the DIY home turbo kit....he's got (or had) a 10 second twin turbo Capri that ran through a carb...he started with a twin turbo 351W in a Thunderbird, and i think the whole engine/turbo setup cost him about 3k (the price of a decent supercharger for EFI). Ultimately i think that is the biggest gain you get from carbs is the price...and if you work hard to learn how to tune a carb and learn how to work on it, then you know how to keep your carb in tune so that you don't lose much when running against EFI.

I hope someone actually read all that typing...lol.

 

[85_SS_302_Coupe]

Im gonna enter this debate, but I dont have the good tech info alot of you guys have too. First off lets say that my car has a carb from the factory otherwise I dont think it would have one. I think that carbs are better when the engine is more radical. What I mean is that for most people, the modding never stops and the car is never done. This is where a carb is better, (in my eyes) because the owner can make small adjustments with each change in the combo. Look at how many times alot of guys switch around there combo or keep going bigger and bigger. Basic carb knowledge will let these guys maintain a decent tune on the car. I hope that doesnt sound bias because I dont know to much about EFI besides a preference for it on street and daily driven cars

Right man....think about it like this...i bought my 650 double pumper a couple years ago, and at that time it was too big for my mostly stock 302....BUT, with a simple jet change you can get it running damn strong and only have to deal with a slight loss of grunt down low (which believe me, you pick back up in the high RPM). Now, i've got a carb that's going to be suitable for my near stock setup and then all the way up to an aluminum headed 347 stroker, and then if the need arises i can jet it up more and support a mild 408 stroker as well, but then you start getting into the "dang i need a bigger carb" area....but you have cheap inexpensive options there as well.....a company called Proform sells awesome main bodies for carbs, and with a little wrenching you can change the 650 main body into an 850 main body (if you need that much carb) and all the other stuff from the carb switches over...and those main bodies are around 100 bucks....so basically you go from mild to wild for cheaper than an EFI cold air induction setup (which won't give you any more support when going from a 302 to a 408 than a hope and a prayer will).


If i had the money to convert my car to EFI, i would only do it to run a turbo setup with. You can run turbo/superchargers with a carb hat, but i personally like engine management when it comes to boost (unless we're talking about an old school roots supercharger/carb setup which is just plain awesome). I like the idea of having a laptop right there in the car and being able to monitor everything the engine is doing, and i don't even have to lift the hood to tune it....that's badass, but that's WAY out of my price range so untill i hit the lottery, i'll just have to lift the hood and get dirty

 

[Carb'dCobra]

Just off topic a little, I also like the way that you can change the appearance of carburetors. Sure fuel injection intakes are different but there's really no way to make them look trick. Add-ons such as the velocity stack can really bring a "trick" element to the engine. Not to mention hilborn and enderle style scoops.

 

[85_SS_302_Coupe]

If you can't decide between carbs or EFI, and you want the best of both worlds....get Webbers. Although they can be a royal pain to get in tune, they hold a tune really well and can be modified for any cfm...once they're running good they're awesome. I think the design of EFI originated from Webbers.

 

[Carb'dCobra]

Even more off topic, but hey 88, what's your wheel sizing and backspacing for all four?

 

[dragnazz5.0]

If you can't decide between carbs or EFI, and you want the best of both worlds....get Webbers. Although they can be a royal pain to get in tune, they hold a tune really well and can be modified for any cfm...once they're running good they're awesome. I think the design of EFI originated from Webbers.

like a carter AFB? or an edelbrock? all the same design. edelbrock bought the design

 

[loveblueoval]

If You want peak horse power go with a Carb, If You want more power under the RPM curve go EFI, Plain and simple.

 

[jrichker]

If you can't decide between carbs or EFI, and you want the best of both worlds....get Webbers. Although they can be a royal pain to get in tune, they hold a tune really well and can be modified for any cfm...once they're running good they're awesome. I think the design of EFI originated from Webbers.

Weber carbs are the ulitmate carb, but expensive - $3000 for 4 each IDA 48 carbs and a manifold. You can tune them for everything you can imagine. However, the complexity that comes with that would overwhelm the guy who swaps out his EFI for a carb because it is simpler.

Seehttp://www.carburetion.com/weber/wildv8.asp for more...

 

[85_SS_302_Coupe]

Weber carbs are the ulitmate carb, but expensive - $3000 for 4 each IDA 48 carbs and a manifold. You can tune them for everything you can imagine. However, the complexity that comes with that would overwhelm the guy who swaps out his EFI for a carb because it is simpler.

Seehttp://www.carburetion.com/weber/wildv8.asp for more...

Yeah, they're a whole different world of tuning. I have a magazine article on them and the guy talks about tuning them. He says the hardest part is getting the fuel pressures and idle screws matched to eachother. He did say that once you dial it in, it's pretty much set for life unless you need to change for a mod. They really scream in the high RPM range too because there isn't much intake runner, but you don't loose torque because of the way each cylinder gets it's own air and fuel...it's pretty ingenious. They were bad enough to be on the old GT40 racecars so that's pretty awesome!

Oh and i never heard that Edelbrock bought the design? Last i heard you pretty much had to scour the Earth to find a complete set of Webbers and an intake and even then you often had to rebuild/restore them. It would be pretty sweet if you could buy a brand new setup. If i were going to build a high RPM all motor setup and had that kind of cash, i'd definately get them, especially if i had a vintage Mustang. You just couldn't have an old Shelby without one.

Shelby GT350 with original Webber setup. That's one nasty little 289!