Decision time, Fuel injection or carb(s) Options

[r_towle]

If you enjoy tinkering, carbs are fun.
You can make more power with a carbbed camshaft, but you must like cleaning carbs, tinkering, and being pretty careful with fuel additives to keep the fuel from going sour during long winter storage.

If you want to walk out, start the car and drive somewhere, whenever you want, no waiting....stick with FI.

Rich

[srreality]

The overwhelming vote is for FI, which is what I expected. "Back in the day" we always thought FI was a step up from carburetors, so that's the way I was leaning. I've never done much with FI, so I have a lot to learn and will need professional help, but I'll get it done. Thanks to all of you for taking the time to comment.

[Spoke]

I'm starting to think part of the carb smell is the engine breather. Typically the engine breather is re-cycled in FI , but in a carbed car its dumped to atmopshere. I currently have my breather dump into a can in the rear trunk and have a lean/normal a/f at idle and the smell isn't that bad with my carbs. But don't put anything in the trunk (IMG:style_emoticons/default/smile.gif).

I'd like to see your set up. I have carbs on a 2056 and the breathers definitely stink up the engine compartment. The breathers also stink up the interior when I put heat on. I need to find some way to get the breather fumes back into the carbs or out of the engine compartment.

(IMG:style_emoticons/default/hijacked.gif)

[stugray]

Where in Colorado are you located?

I have a car with Carbs and two complete FI systems (one 1.8L and one 2.0L) that I don't need.

[Dave_Darling]

What do you know? What do you like working on? If you're not going to be the one working on it, what does your mechanic like working on?

Both can work well. I think the FI is better, but it's pretty subjective.

BTW, the Le Mans-class-winning 914 had carbs because it was a SIX. Apples and oranges.

--DD

[rhodyguy]

You have to figure out a way to hookup a charcoal canister and draw off the fumes. An open evap line in the engine compartment doesn't help.

[somd914]

No gas smell from either of my teeners with carbs...

As for adjustments, a snail gauge (synchrometer) is $40-$45, so not an expensive tool.

I found moving from a cheap hex bar linkage system to a CSP bell crank system made synching much easier and holds adjustments better - hex bar had too much slop and difficult to adjust. The car I purchased last fall with a 2258 has a hex bar system that will be replaced either with the CSP system or Tangerine Racings cable system which appears to make synching a cinch.

But yes, I'll agree carbs require some tweaking and tinkering to be at their best, but I had a time consuming and expensive time attempting to get my D-Jet sorted out before moving to a 2056 with carbs.

But is there a "right" answer to the FI or carbs debate? I don't think so. As with so many other aspects of these cars, everyone has the personal opinions, many based on personal experiences, some not. Do what you think is best to make you happy - both can be decent setups, both can be poor setups depending on implementation.

[Bleyseng]

Where in Colorado are you located?

I have a car with Carbs and two complete FI systems (one 1.8L and one 2.0L) that I don't need.

It came with fuel injection for a reason.

And the 914 that won its class in Le Mans had carbs for a reason too.
(IMG:style_emoticons/default/cheer.gif)

What reason was that? It was a race prepped 2.0L six ... (IMG:style_emoticons/default/confused24.gif)

[r_towle]

I'm starting to think part of the carb smell is the engine breather. Typically the engine breather is re-cycled in FI , but in a carbed car its dumped to atmopshere. I currently have my breather dump into a can in the rear trunk and have a lean/normal a/f at idle and the smell isn't that bad with my carbs. But don't put anything in the trunk (IMG:style_emoticons/default/smile.gif).

I'd like to see your set up. I have carbs on a 2056 and the breathers definitely stink up the engine compartment. The breathers also stink up the interior when I put heat on. I need to find some way to get the breather fumes back into the carbs or out of the engine compartment.

(IMG:style_emoticons/default/hijacked.gif)

Gas tank breather, hose out under the car following the same path as the drain tube.

Valve cover head breathers, either don't use them at all....which works, or add brass fittings to each air cleaner and blow the fumes into the air cleaner. The fittings will fit underneath for a stealth look.

As far as th oil smell when you turn on the heat, try cleaning your HE, and redo the valve cover gasket and push rod tubes......sumpin is dripping oil onto the exchangers

[MarkV]

I guess I have been lucky or something because I never have to tinker with my Delorto carbs. My previous car was a 74 1.8 L-jet that was a constant pain in the butt. It doesn't get much simpler than a set of carburetors...think 356. If you vent the breather lines back into the air cleaners you wont have a problem with fumes. Look at the front page of the web site on any given day and notice how many threads are open regarding FI problems. Its not like the factory fuel injection is anything like modern fuel injection. I have all the parts to convert back but why go to all the trouble if the car runs great the way it is. (IMG:style_emoticons/default/popcorn[1].gif)

[Mark Henry]

I'm starting to think part of the carb smell is the engine breather. Typically the engine breather is re-cycled in FI , but in a carbed car its dumped to atmopshere. I currently have my breather dump into a can in the rear trunk and have a lean/normal a/f at idle and the smell isn't that bad with my carbs. But don't put anything in the trunk (IMG:style_emoticons/default/smile.gif).

I'd like to see your set up. I have carbs on a 2056 and the breathers definitely stink up the engine compartment. The breathers also stink up the interior when I put heat on. I need to find some way to get the breather fumes back into the carbs or out of the engine compartment.

(IMG:style_emoticons/default/hijacked.gif)

Sealed breather box a few baffles help, top outlet goes to one carb (or both), bottom drains back to case or into a puke bottle. All the vents go into the middle of the box.

Charcoal filter, hook up stock with a separate fitting leading into a carb air cleaner .

[damesandhotrods]

Where in Colorado are you located?

I have a car with Carbs and two complete FI systems (one 1.8L and one 2.0L) that I don't need.

It came with fuel injection for a reason.

And the 914 that won its class in Le Mans had carbs for a reason too.
(IMG:style_emoticons/default/cheer.gif)

What reason was that? It was a race prepped 2.0L six ... (IMG:style_emoticons/default/confused24.gif)

The 914/6 was sold with the 911T engine; the carbureted engine was chosen to ensure that the 914/6 would be slower than the 911. That 914/6 engine left Stuttgart with carbs. So it had to race with carbs, even though Porsche had long before switched to mechanical fuel injection for its race cars. From a technical stand point, fuel injection has always been the superior way to mix air and fuel…

[Mark Henry]

Carbs have their place, they are easier to tune with wild cams and can be made to work well.
Like FI most bad experiences have been with improperly set up systems, mostly due to lack of knowledge or poor mechanicals.


That said I do like FI (IMG:style_emoticons/default/shades.gif)

[stugray]

BTW, the Le Mans-class-winning 914 had carbs because it was a SIX. Apples and oranges.

What reason was that? It was a race prepped 2.0L six ... (IMG:style_emoticons/default/confused24.gif)

But WHY did the six have carbs instead of FI? You think the engineers just picked that option at random?

damesandhotrods might be correct that it was to make them slower than the 911s, but I think it was to give them maximum tune-ability for racing.

Carbs have their place, they are easier to tune with wild cams and can be made to work well.
Like FI most bad experiences have been with improperly set up systems, mostly due to lack of knowledge or poor mechanicals.

That said I do like FI (IMG:style_emoticons/default/shades.gif)

This was the correct answer. They used carbs because you can adjust them to fit any needs as you tinker with the engine.
Back then you could not easily tinker with the ECU in the FI systems.
Now that teenagers can understand a Megasquirts and we can tune our hotrods with our phones we forget that.

[Justinp71]

I'm starting to think part of the carb smell is the engine breather. Typically the engine breather is re-cycled in FI , but in a carbed car its dumped to atmopshere. I currently have my breather dump into a can in the rear trunk and have a lean/normal a/f at idle and the smell isn't that bad with my carbs. But don't put anything in the trunk (IMG:style_emoticons/default/smile.gif).

I'd like to see your set up. I have carbs on a 2056 and the breathers definitely stink up the engine compartment. The breathers also stink up the interior when I put heat on. I need to find some way to get the breather fumes back into the carbs or out of the engine compartment.

(IMG:style_emoticons/default/hijacked.gif)

I just recently bought the pmo vapor recovery kit, it made a huge difference! I would recommend this, not sure it it will work for your application, but it can easily be made or modified. It just routes the engine vapors into the carb hats.

http://youroil.net/k_n_vapor_kit.html

[Dave_Darling]

But WHY did the six have carbs instead of FI? You think the engineers just picked that option at random?

The race car had it due to homologation. The purpose-built race cars had been running MFI for a while by that point.

The street car had them because they pulled the motor out of a 1969 911T, which had carbs, and stuck it into the 914 to make the Six. It was cheaper to use what they had on hand than to re-engineer things for the motor they decided they were putting into the car.

They kept the carbs in the 911T model through the 1971 model year--it was the cheap 911, and they used the cheap way of getting fuel in. The higher-performance 911s (the 911E and 911S) both went over to fuel injection in the 1969 model year! They were charging more for those, and they expected more performance out of them--so they went to MFI instead of the cheap and easy carb setup.

Carbs were used because they were cheap. FI was used when the system needed to be better--offer better throttle response, better power, maybe even better fuel economy...


Now, that does ignore the fact that the 911's MFI setup is rather different from the D-jet used on all 1.7 and 2.0 914s, and the L-jet used on all US-spec 1.8s... But that is a different argument.

--DD

[stugray]

But WHY did the six have carbs instead of FI? You think the engineers just picked that option at random?

The race car had it due to homologation. The purpose-built race cars had been running MFI for a while by that point.

The street car had them because they pulled the motor out of a 1969 911T, which had carbs, and stuck it into the 914 to make the Six. It was cheaper to use what they had on hand than to re-engineer things for the motor they decided they were putting into the car.

They kept the carbs in the 911T model through the 1971 model year--it was the cheap 911, and they used the cheap way of getting fuel in. The higher-performance 911s (the 911E and 911S) both went over to fuel injection in the 1969 model year! They were charging more for those, and they expected more performance out of them--so they went to MFI instead of the cheap and easy carb setup.

Carbs were used because they were cheap. FI was used when the system needed to be better--offer better throttle response, better power, maybe even better fuel economy...


Now, that does ignore the fact that the 911's MFI setup is rather different from the D-jet used on all 1.7 and 2.0 914s, and the L-jet used on all US-spec 1.8s... But that is a different argument.

--DD

Hmmmm..... Then maybe I should take the carbs off my 2056 race car and put the D-Jet on it?

Why not? Its better.....

[Mueller]

I have a complete running Megasquirt EFI along with a complete known good L-Jet for my soon to be installed 1.7.

If someone offered to trade or give me a properly sized dual Weber carb setup that allowed some upgrades in the future I'd jump on the offer just to be able to install and play with the carbs.

There is no right or wrong unless building the car for a specific race or show class that prohibits one or the other.

Go with what you feel comfortable with, tell the naysayers to suck an egg!

[green914]

Keep the fuel injection. (IMG:style_emoticons/default/agree.gif) I have had both, and would take the factory fuel injection over carbs.

[Dutchdriver]

Have double carbs on my 2.0, since previous owner installed it.
Have original FI in parts as well, planning to install it in near futire. But only after I have driven the car for some time, because I just got it.
I love originallity, so therefore FI