Engine Efi To Carb Convertion

Pichette129

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Hi I have a 1987 gt Foxbody and I'm taking the efi off and going to a holly carb I was wonder about for the aod tranny cable that goes to the throttle body is there an adaptor for carb or just moch something up ?
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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That could start a discussion.
Look up lokar, maybe lrm has something, they have a place in the vendors forums and they give out discounts.
 

jrichker

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I'm building a race car and carb is more consistent
If carb is more consistent why does all the new Ford stuff run EFI and makes such fantastic HP from 302 cubic inches? It runs great no matter what the density altitude, temperature or humidity.

Let’s take the race to Pikes Peak and expand it a bit…

One of the important things is consistency: that’s why automatic transmission cars are so good at bracket racing. With a little effort on the driver’s part, they get off the line the same every time. Transport that idea to EFI and carbs: the EFI system is like the auto trans, and the carb is like the 5 speed. It can be much more difficult to get consistent 60 foot times with a 5 speed than an auto trans.

Large changes in temperature or barometric pressure can affect power output due to the change in air/fuel ratio in carb systems. EFI takes care of that problem by getting input from the sensors and adjusting the injector pulse duration .

Sample examples:

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…

EFI: Your new EFI 351 is all ready to go, hot HCI combo,70 MM TB, 36 pound injectors, 80 MM MAF, built C4, stock computer and a lot of time and effort. A trip to the dyno is scheduled and it’s a fine day, 60 degrees outside and bone dry. You pull up to the dyno shop and are greeted by a little guy with frizzy red hair that looks like an explosion in a mattress factory and is wearing a T shirt that says “DynoGuys” on it. He seems a little weird, but he is supposed to be the best. Five minutes later, he has a laptop connected to the computer port and is ready to roll onto the dyno and prep for a run. Tires, timing, fuel pressure & idle are checked and pronounced acceptable. First run is a baseline and shows there is more on the table. “DynoGuy” shakes his head, mumbles something and does a tap dance with his fingers on the laptop keyboard. Two more up and down runs, and he smiles, showing the braces on his teeth. The engine returns to idle and it seems a little rough. “DynoGuy” dances on the keyboard some more and things smooth out. Another run up and down and he hands you the dyno sheet and asks if that was what you had in mind. You say yes, he shuts everything down, disconnects the laptop and heads for his office. Five minutes later he is back with a little black box that the plugs onto the car’s computer where his laptop was plugged in. He plugs in the black box, secures the loose pieces and kick panel. So far so good – then he hands you a bill for $475. You look and see $300 for the dyno, $50 worth of his time and $125 for the custom chip he just installed. Ouch! Well, at least your air miles on your credit card just went up.
Weeks pass and the miles go by. The car even passes the gas stations, something it never did before. Several trips to the track prove fruitful, the car just keeps getting better. You decide to make a July 4th bonus race, even though it is 95 degrees and so humid that even your cat is sweating. Off to the track: first run good, second, third and forth runs are good too. You look in the glove compartment at your previous time slips. All are tightly grouped with about a 1/10 of a second between the highs and lows. Bonus time comes up & you win $75 for the most consistent times for the season.

The point is EFI is a consistent performer, hot or cold, rain or shine. Differences in temperature and humidity are accommodated by the computer’s programming. No jets to change, no linkages to adjust, no power valves to tinker with. No getting stinky smelly from gasoline while playing with tiny parts that seem to want to run away and hide from you.

Consistent all weather performance, good gas mileage, and no failing the smog check because of non standard equipment are the pluses of an EFI car. Cars that were EFI and have been converted to carb will not pass smog testing. That may not be a problem now, but if you move or sell the car to someone in an emissions regulated are, it will be.
 

Pichette129

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Look guys I'm putting a carb on the car there both good but I'm 19 and don't have money to get all new injectors and figure it out. I have a budget on the car and efi don't fit in tht . And if efi is better why do all the top bracket racers run carb
 

a91what

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They dont. ALL the top racers in my area run EFI.
ALL the top racers in professional racing run efi.

Efi is not difficult it's very simple. In fact the eeciv that you are abandoning is one of the most flexible when you start modding the car.
If you are making less than 300rwhp the stock injectors will support that just fine.

My advice... stay of of Facebook ... there are alot of dumbasses giving out false/bad information.

Now if you are dead set on moving 40 years into the past with a carb, you can get the kick down cable for a 79-84? Mustang they came factory with a carb.

Good luck with the build.
 

Pichette129

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IDK where you are from but here in Wisconsin one week it's 50 degrees and dry and next day it 80 and 95% humidity and my dads falcon runs a holly 950 carb and his car will run the same number all day and night. Last year was my last year in a jr dragster and I made it to the world finals and all the dragsters and door cars and even the super Comp and all those guys ran carb Plus I plan and putting new stroker crank and new heads and cam so I'm gonna be well above 300 by the time I'm done if everything goes well.
 

a91what

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I'm not saying your exaggerating but I grew up at the drag strip. I know what it takes to make a carb run consistently and that's why I now build efi systems and tune them.

Alot of work goes into a carb'd combo, keeping logs of air density and temperature, track conditions, fuel pressure.... ect ect.
You need all of these for fine tuning as conditions change.

With efi I just set the timing curve and AFR to what I want and let it eat, air temp and density are corrected for automatically.


Now enough about the great debate, it can go on forever if we let it.

Do you need a link for the cable or did you find it with google???

What's your combo? Hundreds of years of experience on this site can help you make wise decisions when purchasing parts.
 
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CarMichael Angelo

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Look guys I'm putting a carb on the car there both good but I'm 19 and don't have money to get all new injectors and figure it out. I have a budget on the car and efi don't fit in tht . And if efi is better why do all the top bracket racers run carb
Ahhhhh here we go then....
Because they bracket race. They cannot afford to compete in an actual drag race. It's also a simpler solution to just tear off all of the stock induction and put a carb in it's place. That includes the 10 pounds of wiring harness and ECU. It's also a simpler solution to gut the car, remove the glass, and put lexan in it's place w/ screws, and throw a cheap assed plastic racing seat in place of the nice one.

It's real simple to take a nice car and turn it into a turd.

Bracket racing exists because somebody in the 70's decided it was more about putting a 10 second car next to a 12 second car and seeing who got to the finish line first. That works, as long as the 10 second car doesn't mind sitting at the line for 2 seconds after the other car left. If that is drag racing, then I choose not to go. I also choose not to watch. Probably one of the most boring spectator sports left on earth to have to sit through after chess.
The words consistency, dial in, and break out don't exist in a real drag race,...The only time that an opponent has to lift at the end of the race in a real drag race is when he's suckering your ass.

Now to answer your question about why you see more carburetors on a bracket car than an efi equipped combo..
That is a fact that doesn't make any sense actually..An absolutely stock EFI equipped Fox mustang should be dead steady, and reliably consistent.

If the object is to be able to predict how fast your car will be so that you'll cross the finish line exactly at the time you've predicted, while at the same time not have to worry about tire spin, missing a shift, over revving the engine between shifts, or the engine running different in different air, and temps. Why not leave the car alone and dial in the combination based on a slow assed stock ET? Let the ECU correct for the air density and temperature, and put a weanie set of drag radials on the car to eliminate tire spin, put it in D and then go after it.

Then you'll actually win a race every now and then, proving to Buford an em that object in bracket racing is not about how fast and inconsistent you can make a car,...it's about how slow and consistent that you keep it.
 
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General karthief

wonder how much it would cost to ship you a pair
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Mike just has a way with words. I always looked at bracket racing as practice for the big leagues. Entry level way for someone to race on the cheap. A couple guys I know started bracket racing and got into super stock, one went on to race top fuel, you have to start someplace and hone your skills at the line.
 

CarMichael Angelo

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Mike just has a way with words. I always looked at bracket racing as practice for the big leagues. Entry level way for someone to race on the cheap. A couple guys I know started bracket racing and got into super stock, one went on to race top fuel, you have to start someplace and hone your skills at the line.
No silly Rabbit! Most bracket racers don't bother honing their skills at the line, they mat the gas and let a timer make up for their inability to cut a good light.
 
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Dart68

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Hi I have a 1987 gt Foxbody and I'm taking the efi off and going to a holly carb I was wonder about for the aod tranny cable that goes to the throttle body is there an adaptor for carb or just moch something up ?
I plan on racing my horse as well. The problem I am facing is that I have to keep it street legal and plated. That means I can't remove any of the emission equipment and it has to pass a dyno sniffer test. If I were trailering my car to the track I would probably go to carb as well. Considering the electronics of EFI on a 5.0, it's a more complicated system than a simple carb set up. The more complicated a system is, the more chances there are for a malfunction...and when I'm racing I want as little complication as possible. It's true that a good running EFI would run better than a carb but unless there is a DRASTIC change in the weather, I don't mess with the carb. It's WAY easier to change your dial in than the jets. And even if you do change the jets, the car still won't run the same. That's true of EFI as well but it may run closer.

If you have a good running EFI setup, why not run it at least to see how it performs? Maybe you won't want to switch to a carb.

And as far as bracket racing goes...bracket racing was invented so that persons of more meager means could race competitively. You only have $1000 to spend on a motor while Johnny Racer has a $100k to spend on his entire car. Bracket racing is more of a race of driver/crew skill than a race of pocket books. It's not how fast you go but how well you go fast.
 

Dart68

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No silly Rabbit! Most bracket racers don't bother honing their skills at the line, they mat the gas and let a timer make up for their inability to cut a good light.
You still have to "mat the gas" at the right time. The electronics do nothing to affect that.
 

General karthief

wonder how much it would cost to ship you a pair
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Flip a switch. Push a button. Mat the go peddle. Light turns green, let go of the button. Yea, thats race'n. Oh, I forgot, you gotta mash the brakes or you break out. Going too fast makes you a loser?
There is skill in bracket racing. No doubt.
But I don't get a kick out of electronic racing.