Makenzie71

bumpity

NZConvertible

For production cars, carbs were obsolete 15 years ago. While this may have been emissions-driven initially, there's no way cars would have the performance they do today without EFI.

In racing the only formulas that force the use of carbs do so because either it's easier to police the rules, they're trying to limit performance or they're trying to reduce the costs of entry-level competition.

A popular racing class over here called SS2000 allows any NA piston engine up to 2000cc with whatever fuel system you want OR a 12A with a stock Nikki or severely choked Weber and a skinny exhaust. The fastest pistons are all EFI, but the rotaries are still dominant.
Yes, but you'd need to find a pressure regulator that can drop ~70psi down to ~5psi. It's been done before so I guess they're out there.

RoninAutoBoX

Well no kidding, because of emissions. I don't think it would be too hard to make a 340hp V8 or a 130hp 4 cylinder using a carb.

Uh......no. saleen ran carbs long after everyone had changed over to EFI, then the rules made him do it too. I wouldn't exactly call him a budget racer. he doesn't seem to have hard time coming up with cash. The S7 doesn't seem to be slapped together out of cardboard.

Ok........

NZConvertible

Why is it that peak power seems to be the only thing carb proponents ever mention? I said "cars would not have the performance they do today wthout EFI". Performance is much more than just peak power. It's about spread of torque, throttle response, consistancy, fuel consumption and volumetric efficiency to name just a few. These are all areas where EFI is far superior.
So? He's one out of thousands. That fact that he was the only one should be a clue...

And in case you missed it, the racing class I mentioned was an example of carbs being used to reduce performance, in this case to enable the 2L piston engines to compete with the rotaries.

RoninAutoBoX

You don't know much about carbs do you eh? I bet you think that a four barrel is the most advanced design ever made huh? I bet you don't even know what makes a true Predator carb so special.

he wasn't the only one, he is thousands out of thousands who wouldn't quit with the carbs. And he had no problems kicking everyone's *** on race day. They made him convert over to EFI because he was too fast and too reliable with the carb.

because they specify an OEM carb? Considering that most 12as came that way, it is not surprising. Most classes require you to run an OEM fuel system in order to restrict you to a certain class, and just about any 12 a came in carb. It is not very often, even if a class allows fuel injection that they will allow you to upgrade an OEM carb engine to EFI. besides, one simple governing body if racing is not the end all to be all of racing experts. I think the fact that a stock carb or a choked carb are going to be the biggest limiters of performance rather than the fact that they are carbs by themselves. You can have a supercharged turbo engine with nitrous and alchohol injection running rocket fuel, but if you can't get the right amount of air in, the engine will fall flat on its face. Something tells me that carbs that you describe with your own words as being choked, or an OEM carb which probably has about as much racing in its design as the window wipers wil do nothging compared to a 600 cfm Demon or a Holley square bore 650cfm.

Slap some real carbs on those engines and I bet the cars themselves would have to be banned.

Any more useful information you care to contribute?

Makenzie71

You guys seem to be getting way too involved in a pointles debate...

MPM

NZConvertible - Mallory has a great regulator for high pressure to low pressure. Its made for FI cars that are now running a carb. Do a search on Mallory 4309.

RoninAutoBox - What year Saleens are you talking about? I'm not a big fan of Mustangs but didn't they quiet using carbs in the late 80's or are you refering to some racing series that the Saleens ran in? And I've included a link for you to read. Its a test, carbs vs. FI. Guess who wins?

http://www.twminduction.com/ThrottleBody/carb_vs_fi.pdf

RoninAutoBoX

Quite using carbs in the 80s? I think not. He was using carbs until about 2 or 3 years ago.

Why are you sending me a link of carbs versus EFI? I never said that carbs were better than EFI, I merely said that they have a useful place in the automotive world because of the advantages that they offer. I certainly never implied that carb ownz EFI or anything like that. It certainly will deliver more power than our OEM EFI, but that is a given, or so I thought everyone already knew.

I can't believe that there are people out there who are so ignorant to pre-existing technology that they automatically assume it to be old garbage, and that any mention of its advantages is automatically a holy war against EFI. That is the same ignorance that has people talking about how rotaries burn out after 20 thousand miles, and that rotaries "unscrew themselves" (real quote) because they rotate elliptically instead of pump.

To anyone: If you don't like carb, and you don't understand it, then don't touch it! You'll probably destroy more motors than a junkyard anyway. But don't act like its a worthless POS just because you don't understand it.

My argument all along has not been that carbs are superior, which would imply total dominance, I have only pointed out a few ways in which they are superior, which they are, and these few ways make them totally valid and earn them a place in today's performance world.

But makenzie is right, this a pointless debate, because the truth is in the many carbed rotaries that are already out there, and anyone with opinions as negatively strong against carbs as NZ, certainly isn't open to any info supporting the usefulness of a carb. We're just going to keep hearing story after story about how hooking up aftermarket EFi is a breeze and a piece of cake, how diagnosis and troubleshooting is like shooting fish in a barrel, and how despite the fact that most RX-7s carrying aftermarket EFI are money pits, the whole sport is actually as cheap as visit to Six Flags.

Funny. I've talked to some of the best tuners that there are in my area, and they all got a great laugh out of this post. Seems that i can't find anyone who actually agrees that owning a highly tuned EFI rotary is cheap or easy. Go figutre.

mwatson184

Wow it is interesting to see how undeducated people are about carbs. I will admit that there are many advantages to EFI, but there are with carbs also.

I have owned a carbed TII for over two years now and am scraping the 400 hp barrier, so I know it is good for power. It has great throttle response, and since when have efi cars had better VE NZconvertable? It is a fairly cheap, practically pocket change compared to standalones, and I tune myself (sits at mid 11's afr at WOT across the rpm band) at the dyno. Not many people are able to tune there own efi cars, so there is some more money saved. For absolute all out power EFI might be a better choice, but carbs leave money for other power adding modifications.

-Marques

White_FC

I can't believe i'm going to waste some MORE time replying to this thread..

Marques, just interested in your car, your making 400hp? (i'll assume its on one of those dodgy over optimistic USA dynos again.. ) not a bad effort at all mate, what have you done to the engine? have you set it up as a suck through setup or blow through?

oh... and whats the fuel consumption like?


I don't consider myself uneducated about carbs...
however, i really can't see one positive thing going for carby fuel delivery...
You want a better flowing intake? righty o, get some ncie throttle bodies (or even a gutted out webber or the like with some injector mounts welded in...)
and hey-presto, you got yourself a great flowing intake still with all the advantages of EFI..

But sorry, carby fuel delivery is obsolete.... you can make power with them, sure.. you can also make some very impressive power with pure mechanical injection aswell...

But there is no way in hell you'd see me driving a car with a carby fuel delivery, over a car with EFI.....

EFI is simply just so cheap now, you can pick up fuel only ECU's quite *cheap which will have infinitly better fuel delivery than any carb over the whole rev range (very important thing if you wanna drive your car around town believe it or not..)

*cheap, cheap to me, I don't care what anyone elses definition of cheap is, im talking in relative terms to the overall TCO of a carby purchase.. so before anyone replies saying a carby is "cheaper" STFU

Makenzie71

Carbing is cheap to me. The money value of either setup is bullshit...stop using it...it doesn't matter. Any option you wanna throw in I can beat with the price of another...it means ****...

NZConvertible

These sorts of comments are only meant to be inflammatory, and don't contribute anything useful. I was trying to keep this discission civil. The least you could do is do the same.

And you are very wrong on all three points.
Carbs work by putting a restriction into the airflow. Without it there's no fuel flow. With EFI, no chokes and venturis in the way means less pumping losses and higher VE.

A good comparison is the Weber carb vs a Weber-style TB. Everyone knows the bigger the carb is, the better it will run at high rpm and the worse it will run at low rpm. So for example changing from a 48IDA to a 50IDA will increase peak power but at the expense or power at lower rpm. With Weber-style TB's 50mm would be considered a minimum on a ported engine, but that will have much less effect on the the engine's low-rpm performance than a similar flowing carb.

I've seen several cars with grumpy BP's changed from Webers to EFI and make significant gains through the rev range, as well as being much nicer to drive, idling lower and using less gas.

I've never said carbs are crap, or they don't work. But there are very few things that they can do better than EFI.

Makenzie71

I'm tired and it's late but for my love of argument I'm going to contest this statement...cuz it's the easiest to contest...actually I think it was the only on...ummm...anyways...

That isn't exactly true. Only the old school two barrel square bore style carbs were very restrictive. Modernized (and by modernized I mean made after 1940 ) carbs are actually quite free-flowing, and very dependant on that flow to operate normally. If a carb was restricive then the vacume process that actually operates the fuel delivery components would be weakened. Next time you get a chance to examine up close and personal a good 40 year old or younger mikuni, webber, or hell even a holley, do it and really pay attention to how it works. A lot of carbs, such as the Webber 48, is no more restrictive than the throttle body already used on the car.


Yeah, I think you did say that carbs were worthless...not quite those words, but similar...I'll put my foot in my mouth tomorrow if I'm wrong...:p

RoninAutoBoX

Stop shaking your own monkey tree. This is a funny comment coming from you. You are the first person to tell someone that they don't know what they are talking about, yet if I say it to you, suddenly I've slapped your mama? Come on.

If i am wrong on all three points, then please tell me how. You do know what a true Predator carb is right? Have you ever driven a car with one?

VE has absolutely, positively nothing to do with chokes and venturis. It has to do with overall manifold and intake design as an overall. A carb tunnel port system with a tunnel ram will aproach nearly 100% VE up to and over 9000rpm, an M5 or even an RX-7 with no internal modifications with any type of EFI that you could dream up, will never achieve such a goal. In order to achieve proper VE, one must design an entire engine, intake, and exhaust to do so. It matter not a few intake pieces by themselves. If it is a performance design, it will perform, if it is not, it will not. Carbs delivered enough VE even back in the day to give the Boss 302 and Chevy DZ302 enough VE have 8000rpm redlines, something which most engines wish they could do today. There were big block 427 cammers street driven that would easily hit 9. It takes a great deal of sustained VE to make a 2v engine rev like that.

You want to know what's really bad for VE? A VAF, an MAF, 5 throttle plates in a single throttle body, and an intake system that makes a 180 degree, and a 90 degree turn before delivering the air into the engine at another 90 degree turn.

NZConvertible

Anything that presents a restriction to airflow lowers the engine's overall VE. Anything. Using my earlier example, why to you think a 50mm Weber-style TB flows more than a 50IDA? Same size throttles, but nothing in the way!

For the zillionth time, I'm not saying carbs are crap or worthless or can't do what you say, just that EFI can do it better. If your EFI manifold is a restriction then get a better one. Take a step forwards instead of a step backwards in time. All your examples are from decades ago when carmakers could do what they please, so they're pretty irrelevant now.

Yes I know what a damn Predator is (second time). If they're so great, why aren't you using one?

Makenzie71

you keep saying there's something in the way in a carb....what is it? I"m looking at my Mikunis, my webber 48, and a holley and there's nothing in the way...except the butterflies, but EFI TB's have those too...

NZConvertible

Without a venturi (a narrowing of the bore), a carb doesn't work. EFI TB's don't need or have those.

Makenzie71

yet the area of the narrow end of my Webber 48 is actually larger than that of a 13B throttle body...I'm still not seeing a restriction...

White_FC

Another silly analogy(sp?)

No one has said anything about the stock manifold flowing as well as a set of aftermarket throttle bodies, wether they be carb or EFI...

NZConvertible

Manifolds aside, your 48mm Weber probably has 42-42mm venturis right? The stock TB has three 45mm bores. That's bigger. A lot bigger.

But my point is, for the same size bore, a Weber (or similar) carb will have venturis in it, but an EFI TB won't. A 2x48mm TB will flow more than your 48IDA.

And that's about all I can be bothered adding to this thread. Enjoy your carbs gentlemen.

Makenzie71

you may say you're not going to answer anymore but you'v said it a couple times so far :P...

anyways...no, the manifold side of my 48 is 48mm. That leaves a total area on the manifold side of the carb at 36 square centimeters. The 13B TB has about 47.7 square cm. However, a stock 13B TB has two of those butterflies closed throughout the low RPM range reducing it to about 15.8cm2, of course it's something that can be fixed. Also, the three outlets cause a great deal of turbulance whereas the 48 is a direct path to the cylinder...however, like you said, the argument's mute. I feel like each has their place and each has their abillities and each has tasks that it dominates...we'll leave it at that.

White_FC

There are just so many mistakes in all of that.. and i wont even mention you said cylinder

Anyway,
Doesn't matter about the 'manifold side' of your throttle body, it is the smallest restriction point in the system that is what is at question here...

And the three throttle butterflys on the 13b's all open up at exactly the same RPM.... you can have them all 100% open at 0-RPM if you want..

The two secondary port throttle butterflys however are totally closed until around 15% throttle is used, this is to allow the small duration center port to be the only one open, hence giving better fuel consumption and emmissions..

Makenzie71

Bite me...I'm sorry that you don't have the luxury of trying to help and explain **** to people who have other types of engines...you know what I meant get over it...

It only matters what end is the smallest, huh? Well no ****...guess which end of an IDA is the smallest...and what part it bolts to...

Yeah, again, no ****...I mean I wrote that but I'm must not have known what I was talking about to need you to say it again.

Actually, no it wasn't. If you remove the secondary butterflies it's not going to change a damn thing at any point in the RPM range except low range torque and startup...maybe a few other quirks but has nothing to do with emmisions or fuel consumption. The same amount of fuel is burned reguardless of how open those butterflies are and emmisions are tested throughout the RPM range. Think of something else...and maybe you can start the post in a manner a bit less pompous...

White_FC

So the smallest part that air flows through your carb is the manifold side? I find that very hard to believe, see NZconvertibles posts re: venturis.


Er.. no.. you didn't write that.. you wrote... "However, a stock 13B TB has two of those butterflies closed throughout the low RPM range" which is markedly different to what I wrote...
Bzzzzt wrong answer, not true at all. I'm talking about the secondary throttle butterflys, not the 6-port actuation system which is what your talking about, these (at least in america/australia/japland/most other countries) are NOT butterflys at all... and are irrelevent to what we WERE talking about anyway.

Makenzie71

I'm holding an IDA in my ******* hand, I can tell you which end is smaller.

What's the difference? It's like me saying 2+2=4 and you followed with 2+(44*((3.14-2)/3))-14.72=4

Bzzzzt...you obviously don't know what I or yourself are talking about. Who here mentioned anything about the 6-ports???