carburetion |
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carburetion |
PCH |
Aug 23 2020, 12:44 PM
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#1
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Member Group: Members Posts: 143 Joined: 3-January 19 From: Santa Barbara Member No.: 22,772 Region Association: Southern California |
I've got about 10,000 miles on my engine (71 914-4 upped to 1911) with pretty much most the FI components being new or reconditioned except for the ECU.
Given the fact that the FI literally crapped out over night last weekend, I am seriously looking into carburetors. Don't get me wrong-the FI when it worked was a thing of beauty and I would love to stick with it. But, given the nonexistence of test equipment, and the fact there are no new ECUs available I have serious doubts of the viability and reliabilityof the old FI's in the future. I have pretty much read everything about the FI vs carburetor debate. I have read a lot of negative comments about converting from FI. But looking at lots of 914 pictures, I have noticed that there are a lot of 914s that run carburetors rather than FIs. I would love to hear from the those of you that have carbureted 914s and are happy with the drivability of your cars. It also would be interesting to see how you achieved those good results. Thank you, Peter |
SirAndy |
Aug 23 2020, 01:09 PM
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#2
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Resident German Group: Admin Posts: 41,681 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
The ECU very rarely goes bad. It has no real electronics in it.
Without knowing any more details, my guess is your problem lies elsewhere. But since you sound like you have already made up your mind, i can tell you that by far the worst experience i ever had with a 914 was my warmed over 2056 with dual carbs. Never could get that motor to run right. (IMG:style_emoticons/default/dry.gif) |
Mark Henry |
Aug 23 2020, 01:49 PM
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#3
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
They can work good but...
-linkage has to be set up perfect, from open to close in perfect unison without any flex, binding, etc. Hex bars suck so you have to buy something like a center pull or cable linkage. Even then getting it just right is a lot of fiddling. -you basically have to learn how to field strip, clean and reassemble the carbs. Best case you'll have to do this every 2-5 years. tiny specks of dirt are the enemy my /6 carbs has 3 filters in line to each carb, two common and one on each. -you have to learn how to set the carb float(s) and sync, for sync you need a snail sync tool. -you need a 3-5psi fuel pump, the FI pump won't work. -jetting, unless you want to be pulling and reading hot spark plugs on the side of the road or or can hear 14 to 1 atoms of air/fuel entering the carb you'll need a wide band O2 meter. -assortment of jets or learn how to use jet reamers. -depending on engine size you might want to change venturi(s). -really to do all this you need to read and learn, plus get your hands dirty. -Last but not least your engine has to be in good condition, if one cylinder is of poor compression you will have better luck slamming your beans and frank in the car door. Also the stock cam works but is sucky for carbs, I personally have only used carbs on performance engines with "carb" cams. The /6 is way more forgiving to linkage issues (etc) than the flat four, but it still took me a lot of time to get everything right. Including rebuilding, linkage, setting, floats, tuning, etc, etc, I probably have 60+ hours into my webers. Once set it's not anywhere near that bad, but there will still be maintenance and cleaning from time to time. |
Mark Henry |
Aug 23 2020, 01:53 PM
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#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
dp
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thelogo |
Aug 23 2020, 02:25 PM
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#5
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Senior Member Group: Retired Members Posts: 1,510 Joined: 6-April 10 Member No.: 11,572 Region Association: None |
I've got about 10,000 miles on my engine (71 914-4 upped to 1911) with pretty much most the FI components being new or reconditioned except for the ECU. Given the fact that the FI literally crapped out over night last weekend, I am seriously looking into carburetors. Don't get me wrong-the FI when it worked was a thing of beauty and I would love to stick with it. But, given the nonexistence of test equipment, and the fact there are no new ECUs available I have serious doubts of the viability and reliabilityof the old FI's in the future. I have pretty much read everything about the FI vs carburetor debate. I have read a lot of negative comments about converting from FI. But looking at lots of 914 pictures, I have noticed that there are a lot of 914s that run carburetors rather than FIs. I would love to hear from the those of you that have carbureted 914s and are happy with the drivability of your cars. It also would be interesting to see how you achieved those good results. Thank you, Peter Like marc said 4 is sensitive But if this is a (my 1st time /experience) working on putting carbs on a motor 914 may not respond well You gotta real know how to tune,tweek and setup But unlike djet . no witch doctor required (IMG:style_emoticons/default/poke.gif) |
fiacra |
Aug 23 2020, 02:47 PM
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#6
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Person.Woman.Man.Camera.TV Group: Members Posts: 347 Joined: 1-March 19 From: East Bay Region - California Member No.: 22,920 Region Association: Northern California |
I'm in the process of converting my 1973 2.0 that currently has carbs on it (done by PO) back to FI. That should tell you which side of the debate I will land on..... Couldn't stop the annoying popping and can't stand the smell of gasoline that you get with carbs. I didn't have any problem finding the needed components (thank you everyone who converted to carbs). Probably won't start the process for a few more weeks (the air in the Bay Area is too nasty to be out working in the garage) but I'll let you know how it goes.
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BK911 |
Aug 23 2020, 03:54 PM
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#7
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Senior Member Group: Members Posts: 672 Joined: 19-February 04 From: Rocky Top, TN Member No.: 1,674 Region Association: None |
I converted a 100k mile 1.7 about 10 years ago.
Every time I fixed the FI something else broke. Got tired of messing with it so converted to carbs. Been driving about 150 miles a week since with zero problems. Clean the idle jets every few years and that's it. Set of empi hpmx 40s right out of the box. |
GregAmy |
Aug 23 2020, 05:14 PM
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#8
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Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States |
I've got two 2Ls, one street with a stock engine and a Microsquirt conversion, one modified racer with dual Dellortos.
I'm giving very very very serious thought to converting the racer to Microsquirt fuel injection. The carbs are finicky inconsistent bitches. In fact, if anyone has any CB Performance TBs hanging around they're looking to dust off... |
jdamiano |
Aug 23 2020, 05:33 PM
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#9
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Member Group: Members Posts: 335 Joined: 18-March 18 From: Jacksonville Member No.: 21,981 Region Association: South East States |
I have the Weber kit from Redlne on my 2.0 with a Pertronix distributor and love it. The curve on the distributor pairs well. If you do it only use new parts and you will have reliably not possible with 50 year old FI.
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IronHillRestorations |
Aug 23 2020, 05:50 PM
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#10
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I. I. R. C. Group: Members Posts: 6,731 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None |
Injection is a better system, but carbs never left me stranded. The key is the right venturis, jets and linkage. When it comes to carburetion, bigger isn't better, correct is better.
I'd strongly suggest adding an O2 sensor, as it will really help getting the carbs set right. I like the CSP center pull bellcrank, but the last one I installed had some QC issues, and I had to putz with the location of the bellcrank to get it dead center. You'll also have to fabricate a cable bracket. The easiest to set up crossbar linkage I've used was not a hex, it was a round bar, which made setting up the drop links much easier. I purchased one just like it in the mid '80's from a place called Fast Freddy's |
Ansbacher |
Aug 23 2020, 06:42 PM
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#11
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Senior Member Group: Members Posts: 689 Joined: 4-July 14 From: Tampa Bay, Florida Member No.: 17,589 |
A carburetor got Lindbergh across the Atlantic in 1927. World War II was won on carburetors. Carburetors got me and my family across the Atlantic in a Douglas DC-6 in 1963. Yes, FI is a superior way to meter fuel (when it works), but I get a bit tired of carburetors being sh*t on all the time. They are/were wonderful marvels of engineering that do their job effortlessly via the laws of physics and fluid dynamics.
Ansbacher |
GeorgeRud |
Aug 23 2020, 07:07 PM
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#12
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
My only real issue with carbs is the fact that they were never designed for today’s fuels. The metal and gaskets don’t play well with ethanol. If an EFI system can be substituted for the original, it may be the best option.
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theer |
Aug 23 2020, 07:17 PM
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#13
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Senior Member Group: Members Posts: 677 Joined: 31-July 15 From: Dover, MA Member No.: 19,014 Region Association: North East States |
I’ve had my dual Webers 40’s for 30 years. Back then, the FI parts were Old (used) or expensive (New) and finding knowledgeable people to fix was difficult. Carbs were an obvious choice for me, so I changed the cam and put on 1.9 liter pistons during the rebuild. Cleans up the engine bay, too.
Get the jetting right (thanks, Tangerine Racing) with a good dizzy, and it runs very nicely. Gas mileage takes a hit, and it’s noticeably louder, but those are not a big deal to me. |
nditiz1 |
Aug 23 2020, 07:21 PM
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#14
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Senior Member Group: Members Posts: 1,191 Joined: 26-May 15 From: Mount Airy, Maryland Member No.: 18,763 Region Association: MidAtlantic Region |
I have much more experience with carbs and dual carbs especially on air cooleds.
I have only worked with FI when running djet on a 76 2 liter. It ran well except that it caused my to purchase a new battery after not realizing that one of the cylinders flooded due to a bad injector. Also the wiring harness was weak and I was constantly messing with the injector leads when down a cylinder. I actually kept trying to remove things to make it more simple, like the decel valve and the cold start valve. If I had to choose, I'd probably go carbs as long as the engine was correctly setup for it, Carb cam. OR go for an even easier FI system in the Ljet design. I think it has less pieces. Everything would need to be new as well and cost the same as new dual carbs with sync link ~$1000. Along the same lines of FI. My CIS on my 82 3.0 is European and is more simple than the US version and works every time. |
SirAndy |
Aug 23 2020, 08:13 PM
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#15
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Resident German Group: Admin Posts: 41,681 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
A carburetor got Lindbergh across the Atlantic in 1927. World War II was won on carburetors. Carburetors got me and my family across the Atlantic in a Douglas DC-6 in 1963. Yes, FI is a superior way to meter fuel (when it works), but I get a bit tired of carburetors being sh*t on all the time. They are/were wonderful marvels of engineering that do their job effortlessly via the laws of physics and fluid dynamics. The wooden wagon wheel got the settlers across the US to the west coast. That doesn't mean i would want them on my car though. Technology changes (usually for the better). FI is all around the better choice, no matter how fondly you remember the "good old days". (IMG:style_emoticons/default/shades.gif) |
ctc911ctc |
Aug 23 2020, 08:32 PM
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#16
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Senior Member Group: Members Posts: 893 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States |
The DJet is a wonderful set of well-engineered components, however, we tend to treat poorly what we do not understand. As a lad with a '70 1.7 stuck in an empty parking lot, Feb, Chicago with my dream date and the car turning over and not firing......long night - I found myself hating and blaming the computer.......what the heck is a computer doing in a car! At 18 in 1974 I was wondering what the hell is a computer! No one knew what those things REALLY did.
The Bosche team knew what they were doing, programmed analog logic using transistors and resistors to emulate logic gates. If _this_ happens then do _that_. Once the system is setup correctly, it is a dream. Which at one time in my life was also a nightmare. Never really figured out what kept the car from starting.........sigh......probably that damn computer! 1. Fuel Pressure 2. Vacuum leaks 3. Diaphram - MPS 4. Wiring Get those right and you are running, the rest will get it operating smoothly. A carburetor got Lindbergh across the Atlantic in 1927. World War II was won on carburetors. Carburetors got me and my family across the Atlantic in a Douglas DC-6 in 1963. Yes, FI is a superior way to meter fuel (when it works), but I get a bit tired of carburetors being sh*t on all the time. They are/were wonderful marvels of engineering that do their job effortlessly via the laws of physics and fluid dynamics. The wooden wagon wheel got the settlers across the US to the west coast. That doesn't mean i would want them on my car though. Technology changes (usually for the better). FI is all around the better choice, no matter how fondly you remember the "good old days". (IMG:style_emoticons/default/shades.gif) |
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