Classic Mustangs (Tech) Technical discussions about the Mustangs of yester-year.

Throttle Body vs. Carb

Old 05-29-2007, 04:56 AM
  #1  
KBunny
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Default Throttle Body vs. Carb

Ok, so I have a friend who is going to have a 302 with throttle body fuel injection (computers, wiring harness and all other components) removed from his late 80's T-Bird and had asked if I would be interested in it.
I have a 289 carbed but I don't think that extra 13ci will make much of a difference.

What will be the MPG, HP, and Drivability difference between TBFI and Carb.
Is it worth the hassle?
What would something like this be worth given everything is in working order?
Pros and Cons for the Carb and the TBFI.

I had also thought that when doing this to put some heads and a mild cam with the throttle body or do the heads, cam, and my carb setup... but If I go the carbed route I might as well get a 302 block from a Junk yard and fix it up.... the only reason I would use his is the fact I know the owner, know the engine works, and I know its condition.

What do you all think?
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Old 05-29-2007, 05:00 AM
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atomsk680
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Default RE: Throttle Body vs. Carb

i think its too much work to get a little better fuel efficiency
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Old 05-29-2007, 05:06 AM
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KBunny
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Default RE: Throttle Body vs. Carb

I probably should add the fact that my stock 289 needs rebuilt and so eventually it is going to have to be pulled and either replaced or rebuilt.... at which point I would have an opportunity to drop that 302 TBFI in or do something else, that's why I bring this up.... however its not that big of a deal because if it works out like most of my ideas and deals that come along then nothing is going to happen.
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Old 05-29-2007, 05:13 AM
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atomsk680
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Default RE: Throttle Body vs. Carb

its not that the FI parts are hard to piece together, its the computer you need to install and all the connections,and those are not easy to do, with the time and money costs it will probably be cheaper and easier to stay carbed
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Old 05-29-2007, 05:14 AM
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superdavid
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Default RE: Throttle Body vs. Carb

One question: how good are you with wiring?
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Old 05-29-2007, 12:09 PM
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my77stang
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Default RE: Throttle Body vs. Carb

if your looking to use it for a cheap engine replacement, use the 5.0 long block with your old intake and carb and be done with it
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Old 05-30-2007, 02:37 AM
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GypsyR
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Default RE: Throttle Body vs. Carb

IIRC, the last CFI Tbird was 1986, that engine is now 21 years old. You say you know the condition, so OK. It's a 5.0, so a swap will require a 50 ounce imbalance flywheel/flexplate appropriate to your transmission among a few other things. Lots of folk have done similar swaps so there's plenty of info out there on putting a 5.0 into a 289's clothing, which is how I would do it.
The CFI setup is very limited. It won't respond to any performance modifications beyond exhaust headers. About it's only good points would be better cold weather starting and possibly slightly better mileage. A carb engine can easily make more power with a few addons and modifications. Don't confuse the CFI (throttle body) setup with the "true" EFI setup Ford used in 1989 (Mustangs, in particular). It WILL respond to mods and even supercharging and nitrous. The SFI system used in '87-8 (Mustangs and Tbirds) can be modified fairly easily to a true EFI setup, but the CFI setup can't. You'd have to pull and discard almost every bit of it if you wanted to upgrade to the later style fuel injection. I just can't see it being worth the bother.
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Old 05-30-2007, 03:42 AM
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andrewmp6
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Default RE: Throttle Body vs. Carb

it all depends on the carb and throttle body injection theres 2 different styles efi a throttle body injection and a multi port injection throttle body is like a carb the multi port has fuel rails and a injector pre clyinder
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Old 05-30-2007, 01:13 PM
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Norm Peterson
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Default RE: Throttle Body vs. Carb

Been there.

You're right - the 13 cubic inches isn't enough reason by itself to do the swap, at least not for daily street driving or weekend cruising.

For simplicity, I'd basically go with what GypsyR and my77 have already said - and either install a carb intake on the throttle-body long-block or (if your current carb is a 2V) I think you can just bolt your carb up to the TBI manifold. From, or upgrading to,a 4V, the swap could be either your carb/manifold or an aftermarket upgrade.

Consider swapping the water pump (rotation direction issueIIRC) and accessory drive over to V-belt if the 302/5.0 is a serpentine arrangement, as that's simpler than swapping direction-sensitive accessories. The new(er) engine probably has hydraulic roller lifters - that's a good thing, as you usually get slightly better torque and HP than with a flat-tappet cam of similar lift/duration.

The TBI should have somewhat better driveability, going from a stone-cold engine to warmed up (especially during the winter). But in terms of power output, I don't think the TBI is much better than a 2V up at the higher rpms.


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Old 05-30-2007, 02:13 PM
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Stevetra
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Default RE: Throttle Body vs. Carb

I have done some similar investigation and I am curious about 1 claim made by another restorer I met last week.
He believes that a TBI system adds life to an engine because there is no cylinder washdown when the engine is not running.
his claim is that a carb will leak fuel into the intke and strips oil from the cylinder walls, causing excessive wear at startup. A TBI system dosnt do this, so the engine will last longer.
Can there be any truth to this statement?
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