White_FC

Either you have never had a carby turbo motor tuned (without blowing it up ) and have no idea how long it will take to get right, or your tuner is incompetant(sp?)
at tuning an EFI system... thats all there is too it, sorry.

Regarding the price, I recently picked up a 2nd hand fuel and ignition microtech digi 1 pro EFI computer to go in my FC, this cost me around ~$100australian, $60?US? this may be far from the best EFI computer out there, but it still offers FAR superior mapping capabilites than any carb will ever hope to manage... for a fraction of the price...



I disagree, I'm pretty sure 4 brand new injectors(+ even a 2nd hand EFI COMPUTER!!) will cost ALOT less than a brand new carby that would be suitable for a carby turbo rotor.



Sorry, I'm going to disagree here again.... I have 2 wires going to each injector, 3 wires to the TPS, 2 wires to the water and air temp sensors, a vac line to the map sensor and thats about all there is to my injection setup :-)

I too know what one i have under my hood and im not sorry for it either

RoninAutoBoX

Let's not go comparing second hand stuff to brand new equipment. Just because I can find a carb for free secondhand doesn't make it the going price.

You know as well as I do that aftermarket computers are very expensive and very expensive to have tuned as well.

I never said tuning either carb or EFI was easy, but there are far more steps that must be taken for EFI. The tuners of carbs that I have visited tune their carbs in times that most EFI guys agree is rather quick, but then again, the carb rotary tuners I know are also pro EFi tuners, so it is of no surprise.

Those few wires you have on your EFI are more components than there are to a carb system. That is for sure.

wpgrexx

I think EFI is in a perfect world the best way to go. But it is expensive. The biggest advantage of an efi system is that once its set, its set, go have fun. The carbs need constant adjustment depnding on the daily conditions

For bang for the buck for n/a guys, getting a carb may be the way to go. I think the argument would best be resolved by saying that each works very well for their desierd applications.

obviously carbs don't suck that bad or they still wouldn't be used to make ridiculous amounts of power in racing cars. But again the efi system, would probably get those race cars some extra mileage

NZConvertible

Why not? A 15yo injector can be made like new for $20. A 2nd hand computer that's a few years old will still perform exactly as it did when new. Carbs can also be reconditioned, so it's a perfectly valid comparison.
No they're not, even in the US. It may cost more than a carb, but in the context of the cost of modifying the whole car it's not that much more.
If you start with a completely untuned ECU then it will take quite a while. But most come loaded with base maps (or they can be easily found) that will be good enough to get the engine running. With a bit of fiddling it'll be driveable enough to get you to the dyno to finish the tune. Once on the dyno, final tuning takes considerably less time than with a carb because it's all done in real time simply be hitting a few keys. Not stopping and starting to change jets, etc. Yes, there is a bunch of other stuff that can be set-up too, like temperature corrections and ancillary devices, but it's this massive extra capability over a carb that make it worth the extra time and money.
I bet the stereo in your car has more wires but I doubt you complain about that. A mono AM receiver would be easier and cheaper to wire up, but would you?

In nearly all cases where carbs are used in organised competition, it is because EFI is not allowed by the rules.

wpgrexx

In nearly all cases where carbs are used in organised competition, it is because EFI is not allowed by the rules. [/B][/QUOTE]

that is true for a lot, but one exception is Trans Am racing, they have a choice, and I beleive their is only one car running EFI


If you could find me an EFi system complete with all sensors and wires that is price competitive with a carb, I would bet that a lot of people would jump all over it.

For me, my biggest obstacle is not having a laptop or palm pilot to program the systems. But when money is no object, an efi system with a TWM style throttle bodies is what i want. Very clean, little wiring, just effective. and you could turbo it a hell of a lot easier than it would be with a carb.

MPM

I just bought my fuel computer this weekend. $350 for an SDS EM-2. Sure its not the most advanced up to date and it doesn't control ignition but its better than a carb and cost less. I can use the factory intake and get rid of the AFM and still gain 15HP if not more with proper tuning. Were will I get my proper tuning? At the chassis dyno, the same place the carb guys tune. How much will it cost me to tune my car there? Less than the carb guys because i can tune in real time. No need to shut the car off numerous times to make changes.

And my engine compartment is not cluttered up now with all the vacuum lines. Just a small hand full of wires. Instead of the 6 I had with the carb setup I now have 12. OMG I just doubled the number of confusing wires.

wpgrexx

that sounds like a good deal, I have never heard of that brand, what functions does it have. Aside from being able to remove the afm, what advantage does it give you over a piggy back computer like an Safc or a power fc?

The microtech also sounds like they are cost effective or the mega squirts(i remeber hearing that megasquirt has a new model out)

I got a racing beat holley carb for 250 (used though), it comes ready to install, racing beat modifies it for you. When I install it, I will let everyone know what my feelings are on it. For the price I got it for, I couldn't pass on it.

RoninAutoBoX

because it is not fair to mention secondhand prices. If you want to compare secondhand prices, then doing a carb setup is actually free for me and therefore totally smashing EFI out of the water. It is stupid to compare prices in that fashion. We all know that you can get extraordinary deals that are stupid low out there, it doesn't mean that such a setup is therefore cheap. If an aftermarket ECU were dirt cheap and so easy to find, we would all have one and haltec, Motec, and all of the others would be out of business with no more customer base. I don't agree with everything you have said, but you have at least been reasonable. Secondhand prices cannot be used as a comparison, because there is no comparison, they can vary as widely as the imagination can conjure up, and nothing secondhand is guaranteed to work properly. I mentioned new prices fopr the carb setup to be fair, so stay on track. If you want to keep mentioning second hand channels, then I can tell you about a carb setup that will not only cost you no money to make, but you will actually get paid for the conversion. Wish to continue?

Quote:

No they're not, even in the US. It may cost more than a carb, but in the context of the cost of modifying the whole car it's not that much more.
If you start with a completely untuned ECU then it will take quite a while. But most come loaded with base maps (or they can be easily found) that will be good enough to get the engine running. With a bit of fiddling it'll be driveable enough to get you to the dyno to finish the tune. Once on the dyno, final tuning takes considerably less time than with a carb because it's all done in real time simply be hitting a few keys. Not stopping and starting to change jets, etc. Yes, there is a bunch of other stuff that can be set-up too, like temperature corrections and ancillary devices, but it's this massive extra capability over a carb that make it worth the extra time and money.

Are you kidding? You act as if EFI tuning is all done in a single pull. Do you want me to pull up the rpices for aftermarket EFI tuning from some websites? Or the Steve Kan tuning posts in our SE Forum? Let's go and see just how cheap and easy it is. Let's see how few runs it takes to set up an aftermarket EFI computer with those great baselines that barely give the engine enough reference to start and get up to 20 mph. I am very familiar with these base setups. I drove a Starion with TEC2 that had a baseline. It sucked.

I don't call several dyno runs "a bit of fiddling" by any definition, unless you've got Dynapacks sitting in your garage.

Quote:

I bet the stereo in your car has more wires but I doubt you complain about that. A mono AM receiver would be easier and cheaper to wire up, but would you?

A failure of my stereo, if I had one, would not cause my engine to shutdown or blow up, therefore I could care less, obviously demonstrated by the fact that I do not have one at all.

Quote:

In nearly all cases where carbs are used in organised competition, it is because EFI is not allowed by the rules.

In nearly all forms of competition you will find successful race teams forced into EFI from carbeurators. Saleen comes to mind just as an example.

MPM

The SDS EM-2 is comparable to the Megasquirt on functionality. You don't need a laptop to program the SDS, it has a handset you use to change the parameters in real time. But I did consider building my own Megasquirt but decided against it due mostly to my skills or lack of. I've seen what an engine can do with this unit on it and I was impressed.

I feel right now the Microtech is the way to go(not that I own one). Great price and it does more than most people will ever use. Support for it keeps growing and thats a plus. Eventually I'll end up with one as money permits.

For more info on the SDS goto www.sdsefi.com even though I'd recommend the microtech since it controls ignition.

RoninAutoBoX

Sounds good. I'll give that a try too. I'm considering all options. The handsets are a lot more convenient. With second hand units as cheap as they are, I may stay EFI. Just because I can see both sides of the coin doesn't mean I'm going to trick the flip.

White_FC

We're all getting a little off track here and forgetting a few things....
Like namely the fact that the guy seemed to want to make his 13bTURBO carb fed....

I'm still standing by my statement that an aftermarket EFI system will work out cheaper and considerably better than carby in this situation, wether it be 2nd hand or brand spankers.

Obviously no one here has tuned a carby fed turbo motor? takes alot longer in dyno sessions than any EFI technology would take to tune.

Less time = less money... much more cost effective solution...

Besides carby fed turbo motors are just plain wrong and shouldn't be around anymore at all since EFI is so cheap now.

anyway, late for my engineering lecture.. i must be off,

cheers, Nathan.

RoninAutoBoX

I think you are also forgetting that a performance carbeurator is a full performance fuel system capable of supporting a considerable amount of power. Throw in aftermarket injectors and the like, and the so-called cheap setup of EFI(which it really is not when you add it up) really isn't so cheap. At least if you want to try and equal the potential of a carb. A $200 carb has more potential hp in it that a $2000 set of injectors.

White_FC

Sorry dude, your just talking crap now

If your paying (im assuming $US?) $2000 for a set of injectors I think you have more deep rooted problems than just thinking carb would be cheaper...

You can buy brand new 1,000- 1,700cc injectors for like $150-200ea Australian

now... a $200 carb would be 2nd hand yes? right.. well... $200 can buy you AT LEAST 4 2nd hand 550cc injectors which is good for ~200rwkw on a 13bT(aussie dyno numbers).... I very much doubt a $200 carb could do this while retaining any sort of driveability at all on a turbo motor...

Think about the overall cost of ownership aswell, carb fed turbo motors have a terrible tendancy to chew fuel because of their VERY limited fuel mapping abilities for light load cruising. You would make your money back in fuel by just going EFI...

I really don't see there being any point at all to going carby, especially on a turbo motor.. makes no sense at all....

Makenzie71

I first have to point out that price is NEVER an issue...it's always preference. Always. So stop arguing the price issue because it's totally mute. I could get a brand new carb setup for $20...so?

Over 260 crank horspower? Where the hell does that come from? Our trannies don't take up that much power...

If you'll notice just a few posts above mine some one brought up just buying a TII instead.

I never said it was. Again...if you'll notice just a few posts above mine some one brought up just buying a TII instead.

There are countless factory original 30+ year old cars running around that will hand a TII it's *** in all but the tight twisties, and some that will nail a TII there, as well...funny how they all come with carbs. I never said carbing was better. I never said technology is bad. But technology isn't always needed. Plus the same technology that you're talking about has designed many modern day carbs that are almost or more efficiant than an EFI setup. The technology is better argument is mute as well. Again, that's preference.

Cool, I'm happy for you. Beings you're so lucky, maybe you can come figure out why my car idles at 4000rpm and doesn't rev or fall under that, because we're not all that lucky. In fact I've seen more problematic, actually about 4 times as many more, RX7's than ones that perform just as they're supposed to (modded EFI/fuel cars not included). No not all of the problems are EFI related but there are quite a few.

Some people already know how to work on carbs and EFI confuses them. It is just as easy to **** something up with a carb as it is with EFI but some people tend to be more attuned to grasping the idea and workings of one than the other. And I think you're both wrong about the reasons people swap to a carbed setup...it's not the price or the problems, it's the preference. I'm setting one of my sevens up with one for simple fact that I can...and I don't have enough EFI parts to spread around all three 7's.

So you're telling me that the UIM, LIM, and plenum are all emmisions related?!?!! Great!!! Can't wait to get all that crap out of there...lol. You're not grasping how clean a propperly setup FC bay is when carbed. I mean there's absolutely nothing there!

Some FCs and later FBs have a tone of problems because of their age and Mazda buying cheaply connstructed electronics. A lot of the reasons why the EFI RX7's have problems is bacause the electrical components were not put near the top of the list or prioraties, and therefore a vast number of sevens have poor wiring, devices that are not sealed from or at all from the elements, and in-general shaudy craftsmanship. Depending on how the car has been cared for the problems vary in severity from non-existant to **** like my 4000rpm idle. It's not a matter of the car "should have these problems" it's how common the problems are.

Also, carbing a turbo motor is stupid unless you're bored and have lots of cash and/or know-how. For the effort and price of carbing a turbo motor you really are better off buying a new turbo-back exhaust, FMIC, a SAFC, and maybe some injectors. If you've already got a turbo car and want to make real power then the EFI route is really a better platform to be on.

NZConvertible

Not fair? C'mon, that's a bit lame. If you find a good deal on a used ECU that suits your needs why wouldn't you consider it? Why is it any less valid? The point is EFI doesn't have to be expensive, even though it can be. WhiteFC picked up his ECU for A$100. That is very cheap! It doesn't matter if that's 100 times more expensive than a $1 carb, it's still cheap!
Please tell us more. How good can it be it they have to pay you to use it...
No, I don't think that at all. To tune an ECU from scratch takes many, many hours, but if you can get a good base map then it'll only take 2-3 hours. It'll take at least that to tune a carb properly.
So you had a crap base map. Look on the Hitman's site (as an example) and you'll probably find a set of Haltech maps close enough to your requirements to get the car running and driveable. Driven sensibly that will get you to the dyno.
Actually I was referring to before the dyno there.
My point is, having less wires is a pretty lightweight reason to want a carb.
Please explain "forced".

A 15% drivetrain loss seems to be considered the norm around here. 224 / 0.85 = 264
I assume you're talking about old exotics or cars with really big engines? That fact that they may be carb'd is completely irrelevant. You're basically saying an old carb'd Chev BB (for example) makes more power than a modern EFI 4-pot because of the carb, which is complete BS. We're comparing EFI vs carb on the same engine.
Please name one carb that's more efficient than EFI.
Does it stay that high if you unplug the BAC valve? If it does, it's got nothing to do with the EFI system. If it doesn't, you've found your problem.
Hey that's fair enough. But you can't just keep ignoring the dominant technology for ever. EFI is not nearly as complicated or confusing as some seem to think. There are plenty of books and websites that will give anyone a pretty good understanding of how it all works.
So carbs don't need manifolds now? I was referring to all of the emissions-related plumbing and wiring in the engine bay. If the car was to be emissions compliant all of that stuff would need to be there regardless of how the engine got fuel. Look in the engine bay of a completely stock 12A 1st Gen. It's just as messy as an EFI 2nd Gen.
For the third time, I've seen plenty of carb'd rotaries! I've also seen some incredibly clean EFI engine bays too. But why is that such an important reason for you to want a carb? As I've said, a few extra wires and lines isn't much of a reason to prefer a carb to EFI. And have you seen an aftermarket TB set-up? Wow, it looks just like a carb!
At least we agree on something.

Makenzie71

15% seems a bit much for a car that's only turning an alt and the tranny (elec fan/pump)....

Doesn't matter what engine. That statement was made because you're making it sound like carbs are evil and the gun equivelant of a stick with a pointy rock on the end. Same engine, same tranny, same body a carbed (insert engine here) will have more immediate potential than an ECU controlled EFI setup. But once money is thrown into it then that changes to just how much want either setup to accomplish. Any engine can reach the same performance with a carb setups as it can with an EFI setup...but once really huigh HP numbers start coming around EFI has an obvious advantage due to it's being able to adjust to given conditions. For the numbers most of us are trying to reach it doesn't matter what route we take and it's all a matter of prefference.

A stock FC with a Webber 48 and intake will make more immediate power (about 24fwhp) than with the stock EFI system and will get about the same gas mileage. I'd say that's pretty good. Different story with a holley or other carb though.

Stays that high no matter what you do. 4000rpm not matter what. Stays there like it was designed to be that way.

Again, you're making it sound as though carbs are the "string with six beeds on it" of computers. When our FC's came into existance the carb was still the dominant form of fuel delivery. Also, as simple as an EFI system is to operate, once you start modding it that system becomes kinna complicated. A carb can be as simple as "if it's running rich/lean just turn this screw til it's okay". Ease, simplicity, whether it's modern or not...that's all stuff a person considers when they make a preference. Either system can be simple. Either system can be technologically up to date. This is another argument that's mute, because, again, it all comes down to prefferenece.

I've seen plenty of clean EFI FC's. But if you're going for clean a carb setup can be as simple as 6 wires, four spark plug wires, one coil wire, and the carb. No EFI system can do that. Also, if you're worried about it being emmisions compliant you shouldn't even be trying to get ideas from this thread cuz almost any carbed FC would fail you so horribly that the guy after you would fail also.

See previous statement. It's important cuz I like it and it's my car...one of those preference things. Of course some people may find themselves in my shoes some time or another with not enough EFI parts for 3 cars.

And yeah, I've seen a couple aftermarket FI setups. They were really interesting looking, one was a the same webber 48 that I'm a fan of but with a plate between the carb and manifold to mounte the injectors in. That was a sweet setup.

That's because that's the only thing we've talked about so far that wasn't an issue of preference. It's just plain ***-wise to carb a turbo car. You couldn't reach much more than stock performance and it be drivable. Some people just don't understand how much air it takes to feed a turbo, and how that would effect a carburator.

RoninAutoBoX

I never said that injectors for an RX7 will cost $2000, I said a $200 carb can provide fuel equalling $2000 injectors, and yes, I have seen what $2000 injectors can do before. You could put $4 million dollar injectors that can go 120,000cc's and your 13BT will still shake its way through its dowel pins at 400-500 hp.

550cc injectors? Isn't that the OEM injectors for an S5 Turbo 2? Last time I checked they weren't exactly famous for putting giant numbers to the ground. A 200 carb will support over 500hp, brand new.

The fact is, once you get into injectors sizes this large, you really aren't going to see a difference in fuel economy. A car that extreme is just going to dump its gas, EFI< carb, or whatever, especially since any rotary that is actually powerful, and even ones that are not run rich as hell with a turbo setup.

I think a carb makes no sense to you because you actually know nothing about it.

RoninAutoBoX

It may be cheap, but that is not even a guaranteed product. If you want to go by second hand, you can call just about anything cheap. Turbos? Cheap. Aftermarket EFI? Cheap. Built engine? Cheap Intercooler? Cheap. Going by that point of view, everyone out there is mistaken, in reality, building up a full RX-7 project car is actually cheap and we've all been mistaken all along into thinking that it actually costs serious money to do a turbo rotary setup. Funny how in reality, it doesn't seem to turn out that cheap.

I guess Soul Assassin spent probably about what....$4k, maybe $5k on his car in that case?

Well sure! I can go down to my friend's shop and he'll give me everything I want totally free and then I'll sell my S5 parts and have money in my pocket. Comparing prices of second hand equipment is lame, not to mention that second hand equipment may not even be good anymore, assuming that in the process of buying it, that you ever recieve it.

AS it would with any major fuel system upgrade.

Those baselines, no matter which one you select will be no more than good enough to just that, get the car a couple of hundred feet to roll up the dyno. Those base maps are nowhere even close to what the engine will actually be running at once tuned, and they certainly don't come programmed with any of the information, such as boost control, AIC activation, or what not.

Oh, so with a bit of fiddling, a car can drive a few hundred feet and up a dyno ramp? Wow. What an age we live in.

I never said that wires were a tool of satan and that we must delivered from its shadow of fire. Obviously, iIdon'topen my engine bay every morning and start screaming. It's just a pretty good reason. Besides eliminating those few EFI wires, it also eliminates a great deal of other stuff too.

The rules one day say, run EFI or you're disqualified.

NZConvertible

I can't be bother replying to every point any more. It takes too damn long. So I'll leave it at disagreeing with all of these statements.
OK, that's not a problem with the EFI system, it sounds like a purely mechanical one. Air is getting past the throttles somehow. It shouldn't be that hard to trace, since there are only so many places it can do so. Pull the TB off and make sure all of the the plates are closing fully. Pull the BAC valve off and make sure it isn't jammed open. If you still have it, pull the AWS solenoid off and throw it away.

RoninAutoBoX

You said that's not a problem with the EFI system, but a mechanical one. I know for a fact that his problem could easily be caused by EFI issues, such as the TPS.

You give way too much credit to the stock components. Most of these components were made by names that I don't even recognize. Just who the hell is "Niles" anyway?

Makenzie71

not a TPS problem...though I can't set it propperly with an engine that won't idle below 4K...it's not an obvious mechanical problem either. 4 different throttle bodies achieved the same results, as well as 4 different intake manifolds. Believe me I've gone over it and over it and over it. I've taken every component short of ECU out and replaced with the same from one of my parts cars.

RoninAutoBoX

Belive it or not, I didn't think it was a TPS problem. That was just an example of one of many different problems that could cause it. I specifically mentioned TPS< because that caused my friend's engine to have a permanent 3500rpm idle. Once fixed, no problem.

It's like my freind told me about why he runs a carb for racing instead of EFI. With EFI, you have many types of problems that you can come across, most are difficult to fix in a set amount of time. It can be a sensor, the wiring going to it, the ECU itself, or the connections of thw wiring. With a carb, if you can't figure out the problem immediately in the pits, a racer will just slap another one on that has already been preset. Try doing that kind of swap with an entire EFI system. And yes, it is just that easy. Just ask any one of the muscle car road warriors who keeps a spare carbeurator in his trunk why he does so. Or an off-roader. Even EFI off roaders prefer a TBI style EFI so that way they can bolt up a carb if the EFI malfunction. The Holley EFI, one of the most popular sure enough uses a standard squarebore mounting, so it will bolt onto any carb manifold designed for a standard squarebore carb. You will find plenty of marine guys who use the same backup plan too.

EFi and carb have their advantages and disadvantages. EFI has in no way made a car obselete.

Evil Aviator

Not to interrupt our most recent iteration of the usual carb vs. EFI debate, but did anybody other than RETed consider that maybe the originator of this thread shouldn't be taking on any major automotive projects at this time?

Makenzie71

lmao...I can't remember who started this thread or why...

Most of the carb vs. EFI debate is just trying to prove that they have their places not that we think he/she should go with it.

Makenzie71

hmmmmm...I just noticed he was originally talking about carbing a TII...that's just not smart. Your better option would be for you to just give me your car and take one of my parts cars...

Now I'm hijacking..^..^..^..^..^..

Anyways, the carb setup I've used before was from an old pontiac including the fuel pump and such. Well, my fuel pump just burst into flames so now I need something else for when I actually have time to put it all back together. Could I use the stock EFI fuel pump? That would be great, what would I have to do?