ejm

hey i am wondering what engine has more potential such as horespower and torque but also in acclertion and top end, a carbed or fuel injected. Which one would be cheaper to mod including any computers/computer tools required for fuel injection.

88IROC350TPI

They both have the same potential powerwise but from a cost standpoint fuel injection is gonna cost you thousands of dollars more, be harder to tune, harder to troubleshoot, and as I said harder on your wallet.

hydric

100% agreed witht he top post...

if you have a chance to eliminate the computer, you'll see a less gain in gas mileage but a huge gain in everything (sensors) kicking you in the *****.

1983Fbody

I think the fuel infection would be better if you can afford it: more torque, better mileage

A carb is cheaper and performs better for the money up to a certain point for example projection costs 1400-- vs. a carb costs 300-- so go figure what you can do with 1100-- you'll save by buying a carb.

I'm sure even the most diehard carb guy would (in a heartbeat) never go back to carbs if they could afford a system like electromotive offers: http://www.directignition.com/mpi_kits.html

hydric

in my opinion, you couldn't be more wrong... when tpi was set-up on my car, i was replacing sensors like crazy... some of them arent cheap

if you can tune a carb, you can be very happy with its performance... fuel injection is just another way to spend more $ when something breaks i think... a carb rebuild is damn near cheaper then having your injectors tested if you suspect one of them is bad...

i'll never be a TPI or any electronic bs kind of guy for my baby =]

dimented24x7

iTrader: (2)

Ive never had a lick of trouble with my TBI system. No MAF and no useless stuff to break. Got rid of everything that I didnt need.

Ill be the devil's advocate and cast my lot in with the efi. Theres also no need to spend thousands of dollars. A good carb intake, used 4 bbl or large monobarrel throttle body, wire harnes + a few sensors, fuel injectors, and a SD TPI ecm is all you really need to get a good efi system going. Machine the intake for inj. bosses and put eight (or six, or four depending on the motor) quality injectors in and your in buisness. Theres also no need to be a computer programmer or an electrical engineer to tune it. Just need some knowledge of engine theory and some time to tune it. Its now easier then ever to tune as well. More people are into tuning with efi and the software to tune it is all point and click. Hell, you could even go get a monkey from a zoo and teach him to burn chips. The hard part is what to put in to make the engine run the way you want it to. The tricky part is what to put into the prom to make the engine run the way you want it to. Thats teh part that alot of people tend to get stumped on. Hence the need to know soem engine theory when it comes time to tune.
Another great aspect of efi is the fact that the engines fuel and timing can be tuned point by point which means that the engine can be tuned very precisely. I personally dont have anything against carb and Id be more then happy to run one on a car but efi has its advantages as well.

88IROC350TPI

I feel yet another heated carb vs EFI debate about to form....

Please explain to me how EFI will give a motor more torque and better gas milage compared to a properly selected and tuned carb? Yes EFI can precisely meter fuel but a properly tuned carb can do almost the same... the milage difference would be maybe a half mile less a gallon if that...

1983Fbody

The question asked was "what has more potential" not what is more reliable, easier to tune, etc.

I was quick to say more torque, better gas mileage because thats what the magazine articles say so IT MUST BE TRUE. lol i'm sure you'll love that statement. Well I'm just thinking about a injector spraying a fine mist of fuel at high pressure vs. a lower pressure carb sort of pouring the gas in.

88IROC350TPI

The question is also "Which one would be cheaper to mod"

Well, hands down the carb has more potential per dollar per horsepower. There is absolutely no disputing that.

five7kid

iTrader: (14)

Yes, this could easily get out of control. So, keep it civil, boys, or it's lock-city.

Closed-loop is better than open loop, assuming the controls have adequate range. MAF TPI is an example of inadequate range.

High-pressure to low-pressure fuel injection will produce a better air-fuel mix than a carb. That makes for better fuel economy and reduced emissions, and typically better idle with more radical cams.

Dry vs. wet flow - all sorts of effects there.

Cost - it's no contest - carb is cheaper. But, EFI can certainly reduce operating costs in the long run.

I know of very few FI or EFI cars at the track. However, I know of one particular race-dedicated '89 Vette with Miniram'd 406 that is amazingly consistent. I've seen him run in multiple classes, going deep into the rounds, not bothering to hose or spray it down between runs, and not changing his dial-in between rounds. Multiple class season champ for several of the last few years, in fact more than 50% of the years he's been racing. Amazing car. Very expensive car.

1983Fbody

I have to agree doller vs. performance, carb is king and that is the exact reason I run one

dimented24x7

iTrader: (2)

Ehh... no need to get hot under the collar.

It can because of the 02 sensor forms a feedback loop with the ecm so it can compensate for changes in weather and such. The effect wont be huge but it can really make the difference if one has emmisions testing to deal with. With efi one can get the little bit of extra power because the timing, fuel, etc. can be set at individual points of the engines operation so it can be more precisely tuned to optimize the engines operation to its fullest. Again, this isnt large, and is probably quite small compaired to a properly tuned carb + ignition. One of the real reasons ive stuck by the efi and not gone the carb rout is the fact that here in jersey, we were posting some of teh worst pollution numbers in the country over the summer and theres been some distant rumblings of tighter emmisions standards. Possibly as the population density increases we could be looking at california style emmisions standards in the future. Probably be hard to sneak a modded engine + carb past the sniffer. Not imposible to do but efi makes it a bit easier in that respect.

hydric

i will give you that one... most carb cars that have some mods will have to be fondled to pass emissions, i know that I have to tear down and replace my size shooters and retard my timing/use low octane gas to get her close to passing. but at the time, my cam was too big, with my new cam i'm sure i wont even have to mess with my jets or timing....

again i stand firm.. if you can devote some time to learning your carb and how to tune it properly, it will be the best thing on earth money wise and performance wise...

holley

:hail: :hail: :hail: :hail:

dimented24x7

iTrader: (2)

In that respect, hed be blind to which system to go with. All have equal ammounts of potential

No... My borther had the same engine that I have in his f-body and I can get a few more mpg then he could get with his setup, which was tuned properly. His ran jsut as good but I can squeak out a few more mpg then he could. WOT is a different story. Even though my AFR's are hovering in the high 12's the engine still seems to empty the tank in nothing flat with some spirited driving.

dimented24x7

iTrader: (2)

Yep, like the carbs and hot engines, too. If only there was no such thing as OPEC and smog testing.

ejm

can a fuel injected be changed over rather easily or is it better to find an already carbed car. thanks eric

88IROC350TPI

Easy as easy can be. I could convert a fuel injected car to a carbed one in 2 hours taking my time and paying attention to detail

1983Fbody

Everything I've read has said that EFI makes more torque than a carb on similar applications. To make it fair they also stated the carb has more horsepower potential. I've always been told that torque is what wins races. How can a carb atomize the fuel better than injectors?

88IROC350TPI

Thats backwards... Horsepower is what always wins races, not torque.

1983Fbody

Bench races?

dimented24x7

iTrader: (2)

The torque or the horsepower really isnt a function of whether its efi or carb. Thats really dependent on how the induction system is set up, like what kind of intake is used, the volume of the intake, flowrates, etc. Thats what determines, in conjunction with lots of other stuff, how much torque the engine makes at a peticular rotational speed, which in turn determines how much horsepower the engine makes and what its power band is. As far as fuel is concerned, the real difference is that the carb is a wet flow system while most efi setups are dry flow.

dallam1

To me, the biggest thing about EFI is drivability. No more pumping the gas pedal umteen times and then having the engine roar to life and spit, sputter, cough and belch for 10 minutes until it warms up. And if I don't take a full ten minutes to warm up completely, theres a cloud of black smoke following the auto. No more smelling exhaust fumes with tears in your eyes at the stop light because of a low vacuum causing cam, needing the carb's " gas flood gates open" to make the motor idle. With EFI, the idea of bearly touching the starter then having the engine come instantly to life and immediately settle down to a perfect idle makes life so much better. Not to mention better gas milage too. As a matter of fact, because of EFI, I've lost a few pounds and my sex life is better with the misses and my kids are getting better grades in school!

Air_Adam

The way I see it, the fewer parts you have, the less can go wrong. Thats why I like carb'd motors. There aren't sensors everywere, no injectors, no electronics, etc etc... so you have alot less that can potentially go wrong.

Power-wise, I'd have to say a carb and a high performance EFI system (not TPI) are about equal.

EFI does have one small advantage though, in that it can make some really big cams a bit more streetable (tamer) than a carb can, but the difference, most of the time, is not nearly as big as alot of people think.

EFI is also alot more expensive to 'build' than a carb'd engine is. There is the cost of a carb ($300-500) and manifold ($100-150) for the carb'd motor and the same for the EFI motor ($1000-2000). BUT, the EFI motor also requires alot of sensors as well as a place to install them, which means you have to get a set of headers with a place for the O2 sensor, which aren't cheap, usually over $300.

You also cannot use solid lifters on most EFI systems because they will play mind games with the knock sensor.

88IROC350TPI

There someone goes spitting untuned carb-slander. Thats 110% false. Heck, my car doesn't even have a choke on it and I can fire it up in the dead of winter rev it to 3000RPM once and it'll idle and drive around ...But who with any kinda performance car would drive around on cold parts? Its definately NOT good to fire your car up in the freezing cold and then the second it starts throw it in gear and take off down the street, regardless of how good it runs due to its fancy EFI.

five7kid

iTrader: (14)

A carb'd engine that starts up and runs cold without a choke cannot possibly be tuned correctly.

Okay, this is getting outside of what can be considered reasonable tech discussion. My recommendation? Run what you've got, make improvements to it. Have a carb? Keep it carb and fine tune it. Have TPI? Enjoy, make mods to it that will improve it (I've seen a sprayed stock '88 350 TPI run 13 flat at 5800' Bandimere - that ain't shabby).

Have TBI? Well, you've got other "issues", but you've also got friends on the TBI forum.

Say Good Night, Gracie...

five7kid

iTrader: (14)

Some good comments from MrDude_1 that I'll add:

"the POTENTIAL (1st thing he asked) is higher with a FI car... because you have finer control over the fuel and with a dry flow manifold, you can shape the manifold to something that packages and works better then what a wet manifold could flow... think LS1 manifold... or SHO, or the BMW rotating drum one.... more POTENTIAL..

the best power per cost, is carb... because $300 gets it running and while it may not be perfect everywhere, you can set it up for max power and get it... think tunnel ram... carbs are cheaper, and work... however they are also a compermise, and thats the reason for the whole debate.. personally i think for most street, N/A engines, either is fine, and its more a problem of money then anything else...."

hydric

about the start-up and drive deal and not have to pump a car...

well thats just insane, on a cold day with a cold engine, the oil is thick which takes more time to run throughout the engine... to start any car up whether it fires up or not n put it in gear is crazy.

Money is a major factor but why spend it? I think we all can agree that gas mileage is about the only thing here IF you can set-up your carb correctly.. And for giggles, smoking and gas fumes cause it has a carb is bolony as well... I know people who are excellent mechanics who I know keeps their cars in A-1, even their winter beaters, and their TPI 305's pump out black smoke... its not cause you have a carb/EFI/TPI that a car smokes, its cause something is in need of fixxing... dont bad-rap a carb cause it is more likely to dish our the fumes cause of incorrect tuning...

For a price of a NEW TPI system, possible sensors going bad and u replacing them/labor to do so if you cannot do it yourself (I know i wouldn't want to replace the o2 on the cat on a cold winter day) and all the bs along with those systems, you can buy a nice demon/holley carb, a nice intake for it to bolt on, and rob a HEI distribuator if you have to change the TPI system over (as stated its pretty simple from carb to tpi, same applies to TPI to carb)

Good discusion though after all... but if money is tight and you want something that will be as good if not BETTER then EFI, go get yourself a carb.

thanks five7 for let me get my 5 cents in (again)

MrDude_1

i think you missed the point......

TPI is basicly crap.... and so is a from the box holley..

niether works well for a performance motor...... they have to be tweeked to work well..

lets assume the FI owner knows how to tune the car, and ditches the TPI and uses a aftermarket non-tpi manifold to unleash its full potential...

lets assume the carb ower knows how to select the proper intake manifold and tune his carb.


lets assume they're both new and maintained so we arnt worried about sensors failing or powervalves blowing out...



then we can begin a civilized conversation.




now theres 2 parts to this conversation.



no holds barred, the FI has more POTENTIAL...... if thats used or not, isnt the issue... the POTENTIAL is there.


the cheaper one is carb.. hands down...



so now tell me, WTF are you guys arguing about? you're both right.. its just that the carb guys are only talking about cost and the FI guys only about potential...


now keeping in mind EVERYTHING i just said, is any of it wrong?

five7kid

iTrader: (14)

I had originally typed in something to the effect that the questions asked don't have a single answer, and the server barfed, lost my reply, and I forgot to say that when I retyped my reply.

With these last few comments, I think we can say, "Enough said."

"Good Night, Gracie."