Dual carbs vs Injection questions., YEs... It's another 914 N00b. Options

[FEF]

All,

I've been haunting the forums here for a few weeks. I've found the information sound and well reasoned. Well, for the most part. (IMG:style_emoticons/default/wink.gif)

I have the chance to pick up a '75 with the 1.8 (I believe) and dual carbs that's been sitting for about 3 years. I'm told it ran well when it was parked. Here's the thing... I can get it for $600. If it passes the folding car rust test, I may pick it up as my dailydriver beater car. If it ran well enough when it stopped, I should be able to get it going again. But what do I do after It's running????

I've read in other places that the dual carb setup is not good. Now, I'm trying to understand why. Sure, they require 2x the timkering of a single carb, and more electrosavy (Ya... I made the word up) then the EFI. But, is it really that bad? I will not likely race it (Although, I was known to autocross and rally a bit), so high HP is not my goal. I am looking for a fun car that's reliable and has modification possibilities. (IMG:style_emoticons/default/cool.gif)

I'm not saying that I want to bo back to EFI. To me, that's not an option. Before I do any engine work, I'll convert it to an Electric Vehicle. I've seen one move. It don't stink.

Why are dual carbs so bad? Why did one guy say he's only seen one good setup, and it was on a race car with a HUGE budget? I have experiance with 4 carb motorcycles, so multi carbs don't scare me. Should I be afraid? Should I plan on trying to get a single carb intake for the sake of simplicity?

It all sounds kinda odd.


Thanks in advance

[ArtechnikA]

Why are dual carbs so bad? ... Should I plan on trying to get a single carb intake for the sake of simplicity?

first - absolutely avoid a single carb - not worth the bother, they just don't work well on these engines.

next - dual carbs are NOT Bad. look at every car that predated the 914 - and the 914/6.

the thing about carbs is that they are not better. people put them on thinking they're going to see huge power gains "due to limitations in the stock fuel injection" and it just doesn't happen. minimum - you need to change the cam to take advantage of what carburation -can- do for you, and that is not a trivial change in any 914 engine.

i ran dual Dellorto's on my 1,7 a l-o-n-g time ago and they were fine. carburation is -not- a place where bigger is better. even tho i ran 40mm Dells i ran comparitively teeny venturiis at the recommendation of the salesman (there's a rarity ...) and he was absolutely correct.

properly sized and tuned QUALITY carburetors like Webers or Dells will work just fine - assuming you're in an area where you have no worries with visual emissions inspections - in which case - you'd be toast no matter how clean you were able to make 'em run ...

the OEM Injection was very well sized and tuned for the stock engine - and when everything's working correctly, it is unsurpassed in emissions and power. some of the components are getting hard to find and debugging it if it's acting up can be a challenge. lots of people hate carburation. i tend to like it, but there's room for all manner of varying opinions. most of all i like the MFI on my car, but that's not really an option for most...

[Dave_Darling]

Single carb setups are much worse than duals on a "flat" engine like ours. Particularly one that was not designed from the outset to run a single-carb setup. (Note that there are no "heat risers" or other manifold heating systems on our engines. Nor any provision for them.)

Duals are far preferred to the single-carb setup.

I prefer FI, most particularly on a stock or near-stock motor. For a highly-modified motor, I think programmable aftermarket EFI is the way to go. But some are more comfortable with carbs.

If the carbs are street legal for your area (e.g., if you're not in California), and the car is solid, go for it.

--DD

[LvSteveH]

The poor reputation of carbs is largely undeserved, but as they pointed out, there are many misconceptions concerning them. If carbs were so very bad, then they wouldn’t be so successful on the 914-6 and countless 2.7-3.2L upgrades throughout the years. Basically you have to choose your poison, if you are more electrically incline, then staying with the factory setup is probably the way to go. If on the other hand you are an electrophobe, and shutter at the thought of testing various sensors for proper operation to debug a high idle, yet are perfectly happy splitting the engine case to throw in a more aggressive cam and some larger pistons and cylinders, then carbs may very well be for you. EFI and Carbs both have an art to proper tuning and maintenance, some very lucky guys are good at both, but most of us have a preference one way or the other.

That being said, as Dave mentioned, the best solution is without a doubt a modern fully programmable system. It will provide maximum efficiency, power, and engine longevity. Unfortunately such a system is not readily available and affordable. When that time comes, I will gladly hand over my carb jets and ohm meter and enjoy the relative ease of having a microprocessor take over. We’re not talking George Orwell here. It will just take a little initiative for someone to come up with a simple system that should work on a wide variety of engines. A mass airflow meter, and O2 sensor, a few others will do the trick. There are a few systems on the market, but none that have sufficiently impressed me to order one. I’m not an electrical guru by any means, but I’d think a simple retrofit could be made from a modern car with all the hard work already done by the guys with deep pockets.

[jnp914]

The Harley aftermarket guys have produced a couple of retrofit FI units for hogs. It seems that one of them might be the closest fit for a similar application (air cooled, low revs by todays standards, an example of early to mid 20th century engineering.)

[ChrisReale]

If it ran well before it was parked, why was it parked? Just consider that when it comes time to buy.

[FEF]

If it ran well before it was parked, why was it parked? Just consider that when it comes time to buy.

Excelent question.

My friends father-in-law sold it to my friend when he got his other Porsche. My friend was going to put a V-8 in it and was gathering parts for the conversion. Now he's working on a big turbo mustang he wants to run and is looking for a few bucks. Well... That and his wife it tired of looking at the 3 other project cars. (IMG:style_emoticons/default/blink.gif)

As one that has a few projects, I can understand how 3 years can slip away while completing other projects. I can also understand the need to make the wife happy, too. (IMG:style_emoticons/default/smile.gif)

I have to be able to fire it up, or I can't bring it home. That's the deal I made with my wife. If it don't fold up on me when I get in, and I can fire it up, I can't see how I can loose.

[rhodyguy]

hope it fires up for you. i think i see craig circling for the kill all the way from tacoma. get a friend to let you stash it for a week. get it running, THEN take it home.

kevin