Carb To Efi

85rkyboby · Aug 11, 2014

I have searched through a few previous threads about swapping carbed cars to EFI. Most end in it's not worth the money for your circumstance or they end up talking about swapping EFI to carb. I have an 84 that I'm considering swapping to EFI. The car will be running a Dart 351, currently it's an old non roller 302 (80's full size Ford motor to be exact). Now I'm wondering what all needs to be done? I am really in the dark and to be honest, a little intimidated by the swap. Well the computer part at least. My biggest concern is, say after I swap to EFI then I have to have someone tune it. Who the hell can I trust to work on my car. I'm in Georgia and don't know of any GREAT tuners. Any help would be appreciated.

-Garrick A.R.

Dan_Soprano · Aug 12, 2014

It's a bit pricy, but have you looked at the FAST EZ-EFI setup?

84Ttop · Aug 12, 2014

Dan_Soprano said:
It's a bit pricy, but have you looked at the FAST EZ-EFI setup?

EZ EFI will only work if you plan on never using a power adder. The FAST Sportsman XFI would be the next step in that direction and really works well. You will ultimately need to find a tuner for this as well though.

Lets start here... What are your power goals? I'm assuming with a dart 351 build you will be looking to make some real power? This one decision will lend towards using or not using the EEC IV factory style computer system or not.

jrichker · Aug 12, 2014

You're either going to be a terrific junkyard digger or have deep pockets.. Either way, one of the prerequisites is a knowledge and skill with electrical things.
If you have a Clevor, you'll need a set of adapter plates to make the 351 EFI intake manifold fit. Or see http://www.summitracing.com/parts/tfs-51611116 $777

The harness kits you buy new are probably easier to install, less cut and connect. They are also somewhat expensive -$525-$750.

A junkyard harness is going to be cheaper, but will involve a lot more labor. My experience with removing an EFI harness from a 5.0 Mustang was that it was a little like wrestling with a python. Once you get it out, you will probably need to cut or enlarge a hole in the passenger side firewall to feed the harness through into the engine compartment.
Computer:
A9L (5 Speed) computer from junkyard $100-$150
A9P (Auto or in a pinch, it will work in a 5 Speed car) computer from junkyard $100-$150

.
Here's what the harness looks like outside the car:
Diagram courtesy of Tmoss & Stang&2birds
Main Computer harness this is for 1989 model 5.0 Mustang, and is the best choice for simplicity's sake.:

Engine mounted EFI harness for fuel injectors and engine mounted sensors:

O2 sensor harness:

Beware that the O2 sensor harnesses are specific to the type of transmission in the car. Use an automatic trans O2 harness with an automatic trans and A9P computer. Use a manual transmission O2 sensor harness with a manual transmission and an A9L computer. In a pinch and A9p can be substituted.

36 LB injectors, Calibrated matching MAF or custom tune, 190 LPH fuel pump.

I can post more information that you will need if you are really interested. Fuel pump & injector sizing, EFI harnesses from junkyard cars, fuel tank & fuel gauge information.

85rkyboby · Aug 12, 2014

84Ttop said:
EZ EFI will only work if you plan on never using a power adder. The FAST Sportsman XFI would be the next step in that direction and really works well. You will ultimately need to find a tuner for this as well though.

Lets start here... What are your power goals? I'm assuming with a dart 351 build you will be looking to make some real power? This one decision will lend towards using or not using the EEC IV factory style computer system or not.

Yes, that's what I was originally looking at. Until I realized it wouldn't work with a power adder or that much power. I'd be happy at around 900RWHP through an automatic.

@jrichker I'm comfortable with running wires, soldering, making circuits, and diagrams for them. My dad's always been pretty good with computers and electrical stuff. That EFI manfifold says 1,500-5,500 rpm range, should I have that ported to gain more rpm out of it? Or is it impossible to get more rpm out of it.? Another question. That diagram of the main harness, would that harness be in the passenger footwell even on a factory carbed car?

jrichker · Aug 12, 2014

85rkyboby said:
Yes, that's what I was originally looking at. Until I realized it wouldn't work with a power adder or that much power. I'd be happy at around 900RWHP through an automatic.

@jrichker I'm comfortable with running wires, soldering, making circuits, and diagrams for them. My dad's always been pretty good with computers and electrical stuff. That EFI manfifold says 1,500-5,500 rpm range, should I have that ported to gain more rpm out of it? Or is it impossible to get more rpm out of it.? Another question. That diagram of the main harness, would that harness be in the passenger footwell even on a factory carbed car?

There is very little of the wiring in the front section of the car that will be reused. I would advise you to carefully read the Main Computer harness description to get a mental picture of what connects to the engine and where on the harness the connectors are. The Main Computer harness does not connect into the lights, heater/AC fan, or charging system. You will have to leave the existing wiring harness in place to make connections to the systems I just mentioned.

85rkyboby · Aug 12, 2014

I'll check all the connectors tomorrow. I just didn't think I would have that harness in my car, but I def. have a 60-pin connector.

84Ttop · Aug 12, 2014

If you are seriously trying to make 900rwhp an aftermarket fuel injection system is more than warranted. Xfi, BS3 or Holley are the only 3 choices in my eyes. Sourcing the factory wiring and PCM and getting it to work at that level is not advisable.

85rkyboby · Aug 12, 2014

Ok, that makes sense. Alot less wiring right

84Ttop said:
If you are seriously trying to make 900rwhp an aftermarket fuel injection system is more than warranted. Xfi, BS3 or Holley are the only 3 choices in my eyes. Sourcing the factory wiring and PCM and getting it to work at that level is not advisable.

Which of those would you choose personally and why? The XFI 2.0 seems good alot less wiring and can handle boost/nitrous. What do people do when they want more than 1000hp, EFI management wise.

84Ttop · Aug 13, 2014

85rkyboby said:
Ok, that makes sense. Alot less wiring right

Which of those would you choose personally and why? The XFI 2.0 seems good alot less wiring and can handle boost/nitrous. What do people do when they want more than 1000hp, EFI management wise.

I personally like the XFI 2.0. I am using that system in my race car and it has proven itself to work very well. I am using 235lb injectors and the car can start at the flick of a switch and idles with great manners. The same tuneup was still able to safely lay down 1,576rwhp. The amount of control that you have over then engine is incredible. The system is among the easiest to use in my eyes as well. It has a ton of great features and will really work with any power adder that you would want to run. The install is very straight forward as well.

85rkyboby · Aug 13, 2014

So can you up the HP capabilities of that system or is their 1000HP rating just a safety precaution?

84Ttop · Aug 14, 2014

There are no real limitations for an aftermarket fuel injection system as far as hp is concerned. The questions become more the ability of the tuner than the computer

RacEoHolic330 · Aug 14, 2014

After getting my feet wet in the aftermarket EFI world, I would never consider using a factory setup for any EFI conversion anymore. The processing speed and ability of aftermarket systems is incredible. They can literally do as much as your wallet is willing to spend. They can replace a whole slew of other aftermarket systems. Boost control, ignition, traction control, electric fans, water pumps, nitrous, meth injection, etc can all be controlled from the same ECU. That can make the initial sticker shock of an aftermarket setup not seem so bad once you realize how much less you'll spend on other controllers.

Most only use a wideband O2 and don't have a mass air meter. They are amazingly simple, yet so capable. I have Holley EFI and the factory support online is very impressive. It was a major factor for me choosing that system. Tons of people use it, so forum support is great too.

85rkyboby · Aug 14, 2014

Thanks you guys! I'm sure I'll have more questions to come soon! Still waiting on the shortblock to arrive, just trying to cram as much info into my head as possible. I'm assuming you guys are running fuel cells and not a factory tank? @RacEoHolic330 @84Ttop @Dan_Soprano

RacEoHolic330 · Aug 14, 2014

My tank is a sumped stock-style aluminum tank made by Behind Bars Race Cars. 14 gallons. Mounts like stock and accepts the factory fuel level sender. It's honestly a hand-welded work of art. Lol

84Ttop · Aug 14, 2014

I have a fuel cell that I custom made. 17 gallons and recessed half in the floor. Making a stock tank work with a mi I tub is not the easiest task lol

85rkyboby · Aug 14, 2014

84Ttop said:
I have a fuel cell that I custom made. 17 gallons and recessed half in the floor. Making a stock tank work with a mi I tub is not the easiest task lol

Ah, haha that's a good thought. How possible is it to get the traction without a mini-tub? Seems like that would be a necessity. Although @RacEoHolic330 is making high numbers without one, I do understand his isn't the all out racecar like yours Nick.

This car is going to be my "fancy" street car. It will see passes here and there but is by no means an all out dragger.

84Ttop · Aug 15, 2014

85rkyboby said:
I know yours was a factory efi car. I'd assume I should get the factory efi tank right?

Ah, haha that's a good thought. How possible is it to get the traction without a mini-tub? Seems like that would be a necessity. Although @RacEoHolic330 is making high numbers without one, I do understand his isn't the all out racecar like yours Nick.

This car is going to be my "fancy" street car. It will see passes here and there but is by no means an all out dragger.

For what it's worth, If I was building another car I would not mini tub the car. From the time when I started my build until now, a lot has changed. With rolled fender lips and a little massaging of the inner wheel wells, a 275/60/15 tire will fit on a 10" wheel. This is more than enough to handle some ridiculous HP so long as the rest of the suspension is up to par. The mini tub requires the inner plastic panels to be cut, requires coil overs and trunk pan modification and is just a ton more work all together.

85rkyboby · Aug 15, 2014

84Ttop said:
For what it's worth, If I was building another car I would not mini tub the car. From the time when I started my build until now, a lot has changed. With rolled fender lips and a little massaging of the inner wheel wells, a 275/60/15 tire will fit on a 10" wheel. This is more than enough to handle some ridiculous HP so long as the rest of the suspension is up to par. The mini tub requires the inner plastic panels to be cut, requires coil overs and trunk pan modification and is just a ton more work all together.

Alright, thanks for that insight. I'll probably try to steer clear of the mini-tub. Not to get stray to far off topic. Is there anywhere y'all know of that rents out a fender roller? I used a bat last time, I can't seem to find any wooden bats for sale locally.

85rkyboby · Aug 19, 2014

@RacEoHolic330 I just took a look at the behind bars race cars tanks. They look soooo good!!! I have a question though, my car is a 84 so obviously the sending unit that comes with those tanks won't work with my factory gauge. Cheapest way around this I can figure would to be buy the Speedhut gauges so it will work. Their fuel gauge comes with a sender that you program for empty then you fill the tank and program it for full. Any opinions?

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