Help - Search - Members - Calendar
Full Version: Carbs VS FI
914World.com > The 914 Forums > 914World Garage
Pages: 1, 2
DBCooper
They're modern upscale carburetors: http://www.pmocarb.com/
So.Cal.914
QUOTE(Mark Henry @ Sep 17 2008, 09:01 PM) *

Now if your happy with a stock 80/95hp L/D-jet engine then I agree that stock FI is the best, but I'm not so then you're into carbs or PEFI.
Simple as that.

Carbs are not perfect but they can be tuned to a point of being comparable to FI and handle all sorts of mods to the engine. The 180hp (150rwhp) T4 I built runs just as smooth as a 95hp d-jet. My bus with a 2L T1 w/dual DCNF's runs better than stock 1600 with more than twice the power.
Most issues with carbs are user error, poor linkage set-up being #1, followed by engine faults (built bad or worn out) and poor choices on parts. With an solid engine, O2 meter and a set of jet reams I can set the A/F ratio right on the money. (I BTW I fine the A/f ratio more stable with carbs). Four years ago I drove my VW squareback all winter, no chokes on my dual weber's down to -25C, never a problem.

If we were talking /6's there is almost no FI vs carb debate..if there's no FI on that /6 then slap some weber's on that puppy.
Guys will spend $3k on PMO's


QUOTE

For modified engines when you have to remove the stock fuel injection then a modern fuel injection system running in closed loop gives even more advantages. Carbs don't change mixtures according to feedback from the engine like FI in closed loop, so they can't provide correct fuel/air ratio for every situation. It's impossible. They simply don't have the physical capacity to do that. You can get carbs to be good, no doubt, but never as good as well tuned fuel injection. Any new performance cars you know of being produced today that use carburetors? Highest buck, no compromise cars running carbs? Even as optional equipment? Why not?

Sure you CAN drive a carbureted car in the winter with no chokes, we've all done it. But you've got to admit that it was primitive and your engine wasn't real efficient or friendly until it was warmed up. And did you try doing that at 8000 feet? That's the whole point, fuel injection gives you the correct air/fuel ratio no matter what the situation. Carburetors don't. They can't.

Put on $3000 PMO's IF there's no FI on the 6? Vroom, vroom.


I do have a preference like alot of others here, carb or FI. This guy is like a Jehovah's Witness at your door, and no matter what my or anyone elses beliefs are HE IS RIGHT. Its like the neighbors chijuajua...bark bark bark bark bark bark.
QUOTE

See? One more useless thread about FI vs carbs. To each his own. Why get hot and bothered and call someone an dick just because they have a preference? Do you think the guy that drives a Porsche thinks another guy is a dick cause he drives a Ferrari? Bullshit! There are applications where FI works best, and of course, where carbs work best. Why not save your typing skills for something that really matters? If ya wanna argue about useless bullshit, go to the sandbox and post in one of the 1237 useless political threads?


Hey vsg914 'Blow Me"...
J P Stein
As the Canuck says, PEFI makes more power (& torque) and is more efficient than carbs....with all due respect to Pro Stockers who aren't allowed to use it.

Unfortunately it is more than twice as expensive for a top drawer set up (ie:one that works) than a new set of PMOs......this is 6 cylinder stuff....I dunno shit about 4 poopers.... cept they're slow. biggrin.gif
DBCooper
QUOTE(So.Cal.914 @ Sep 18 2008, 05:01 PM) *

I do have a preference like alot of others here, carb or FI. This guy is like a Jehovah's Witness at your door, and no matter what my or anyone elses beliefs are HE IS RIGHT. Its like the neighbors chijuajua...bark bark bark bark bark bark.

Convincing argument. Lots of good technical info there. rolleyes.gif

QUOTE(So.Cal.914 @ Sep 18 2008, 05:01 PM) *

Hey vsg914 'Blow Me"...

PMS?
nsr-jamie
Didn't the Euro 1.8 models come with carbs instead of injection??
underthetire
I voted FI, not stock, but I love to diagnose through the laptop and be able to make changes. It's also not bothered so much by bad/old gas and temperature.
JmuRiz
FI is the best, but I'm thinking more EFI...but that's $ to setup right. I'd love to have EFI on my WIP 6 conversion, but I couldn't pass up a full carb setup, manifolds, airbox, and linkage for under 1500...I'd have to pay double that for a nice ITB EFI setup.

Each setup has it's ups and downs. If you have a carb or FI setup that's working, just keep enjoying it. These cars are too much fun either way wink.gif
speed metal army
I voted FI,Its predictable,and performs well.I also like the idea od programmable FI.
Carbs are cool too.If I didnt have the bux to replace a totally malfunctioning FI set up,(or fix it etc)I'd run some carbs,cuz they are simple(ish)and fairly cheap.
914 shifter
up to 2056 original d-jet. shades.gif bigger displacement needs carbs or aftermarket fi yellowsleep[1].gif
Bleyseng
QUOTE(nsr-jamie @ Nov 25 2010, 08:54 AM) *

Didn't the Euro 1.8 models come with carbs instead of injection??

yes, 8.6CR plus dual Solexes like a VW Bus.
benalishhero
I've had three different set-ups on my stock 2.0: duel carbs, single carb, and currently D-jet. I voted for the latter because the performance and reliability does not compare.

I refrain, all with a stock 2.0.
J P Stein
Dueling carbs is a very common occurance around here. A syncrometer will cure that. happy11.gif
ME733
I voted for Carburators...........here,s why....The stock fuel injection is a first generation system., with limitations..With carburators you are NOT restrained within certain parameters for a camshaft choise., with fuel injection the duration and lift is limited as a practial matter., Carburators are a demand system.The more air and fuel the engine needs the carburator (s) will supply it no matter what RPM,s you use.....Camshaft selection is just a matter of the RPM ranges you intend to use...Carburators are simpler.(KISS). keep it simple stupid. Carburators are simpler, without the masses of high pressure fuel lines , fittings, temp senders,air box, air flow meter,etc etc...Over many years I have replaced the fuel injection systems with carburators.Every customer was satisfied and the engine ran better, had MORE HP. and was customer friendly....The OEM fuel injection is adequate for the limited power range and RPM,s in stock form., but after forty years practacially every component is worn out, and some of the replacement parts are getting EXPENSIVE...The OEM system, to me, is just not worth the hassle of maintenance....Carburators are the way to go.
Jake Raby
I provide engines with stock FI, programmable FI and Carbs..

I make the choice of which is the best to go with based on:

1-The purchaser's experience and skill level (I'll never give a newbie PEFI!)
2- Target engine output and desired displacement (If it's over 125HP or a 2056cc engine stock injection is out the window)
3- What I feel the purchaser's ability is to follow instructions
4- The application- if someone has a newly restored car they need simplicity because by the time the reach the engine install portion they'll be out of patience.

Lots of people live in a world filled with Unicorns and Rainbows and they want a system that falls into place, tunes intuitively and performs flawlessly.

Wen those guys come my way I tell them to go buy a new Porsche, because their 40 year old car isn't going to get them there here in the real world.

I like carbs and PEFI, I am not a fan of stock FI because it requires compromises related to engine design that aren't beneficial in any other way other than providing stock EFI compliance. Stock FI does have its place.



Gint
Yikes... Just when you thought that the only thing worse than another 4 vs 6 or carb vs. FI thread, someone votes in and bumps is a 2 year old carb vs. FI poll thread. happy11.gif
hashagen7
Click to view attachmentI will gladly trade this for your carbs.
chrisg
Maybe slightly off topic, but has anybody had problems with CA gasoline and carbs? I'm still not sure which way my L-jet stock 2.0 will go, but carbs run with CA gasoline have become a major PITA with my motorcycles if they sit for 2 weeks or so. I have not found an additive that works either. The small slow jets get jelled(?) gas that clogs them in that short period and the only way to fix it is to tear them down. I can't handle this if I decide to go with a motor combo that would dictate using carbs. I'm leaning towards a McMark/Jake 2056 with L-Jet but can't help wanting to go maybe 2270.
'73-914kid
I was having the same problem for a while.. It's kind of just part of owning carbs with crappy gas..
I did try one thing that worked. a shot glass of Marvel Mystery Oil in every full tank of gas has kept the problem at bay for 2 months now... Maybe something to try..
tradisrad
I like my d-jet set up. No cold start issues, starts in just a few cranks of the engine, good mileage, good power. Its been trouble free for 20 years.
benalishhero
Chrisg, does CA have E10? We run it up in Maine. Napa fuel additive with ethanol treatment works quite well to prevent jelling. Part number is 7800 IIRC.
Drums66
QUOTE(hashagen7 @ Nov 28 2010, 01:17 PM) *

Click to view attachmentI will gladly trade this for your carbs.


.....Now that you put it that way....I'll stay with FI biggrin.gif happy11.gif
carbs have their place ?(eat them all the time) chowtime.gif
seriously they do have their place pain30.gif
I 2nd the worthless thread opinion! yellowsleep[1].gif yellowsleep[1].gif poke.gif
Dave_Darling
QUOTE(benalishhero @ Nov 29 2010, 09:10 AM) *

Chrisg, does CA have E10?


Evidently we do, as of this year. Last year, it was (generally) E6, but they changed it.

--DD
ewdysar
Carbs are inherently better. That's why all modern car manufacturers use carbs to generate lots of efficient, reliable power. FI is just a fad.

(Getting ready to pul my SBC Holley 4bbl carb and install a MAF injection system.)
ConeDodger
I voted for fuel injection...

There is nothing wrong with a well set up carb system. My motor is modified beyond what the factory fuel injection will respond to so I either have to go to carbs or aftermarket fuel injection. I want the control that fuel injection affords.
SLITS
And the debate goes on and on and on and on ....

I'll take my 27 - 33 mpg and put up with fixing FI. If I want a sucking sound I will record it and play it through my stereo.

You can have your 12 - 17 mpg with carbs.
patssle
QUOTE
You can have your 12 - 17 mpg with carbs.


And I do! I get 14 mpg in city driving with my old bus motor and dual Webers. Even with gas approaching $4 I was still driving it to work while my 28 city mpg Mazda 3 sat at home.
76-914
FI baby. Why? #1 - When I was a 18 I worked in a carb shop. Even then (1969) it was obvious that carbs had run their course ( in stock applications).
#2 - I watched Lew (shewlew) piss and moan while throwing money at his carb set up over and over. Since he converted (or as they say in west TX "decided to get the shit out of his neck") to FI, I don't see poke.gif him anymore. In all fairness to carbs I believe most of their complaints arise from improper application (ie the FI cam) or after market POS set ups. IMHO, I believe America was the only one to get carbs right. And towards the end we began to complicate them w/ centerflow technology or worse, internal non serviceable metering blocks.
SirAndy
QUOTE(dbgriffith75 @ Sep 16 2008, 03:08 PM) *
Carbs VS FI, Which is better?

Yes ... biggrin.gif
al weidman
I'm an old guy and I would say it depends on either how smart you are or how much money you have. I am not smart enough to diagnose FI problems but there are plenty who can. My current 914 stopped on me five times and I had to be towed home each time. I replaced something different each time but it continued to stop. (just like someone turned off the gas) I put a set of del orto 40's on and have not had any problems since. By the way, last year at WCR I averaged 32 miles per gallon. It is a '75 2.0 with 195 X65 tires and runs at 75 mph at 3000 rpm. My original 914, that I special ordered new started having FI problems at about 1979. I put a set of 40 mm webers on it and it still has them and is owned by my friend Bob Scott in Washington. He would not sell me the car back when I wanted to get back in so I found my '75 instead. I do know several owners that have had their cars for many years without any problems. It all comes down to the reliability of the parts on your car and their failure or not. The new FI systems seem to be much more reliable, however, I would be behind the same tow truck if it broke. stirthepot.gif confused24.gif
Click to view attachment


Bleyseng
Well, after buying my 76 914 2.0l with Dell 40's on it in 95, I drove it for three years until I couldn't stand it any longer. Cold starts in Seattle sucked so I bought and re-installed the Djet without any of this Internet help available today. Best decision I made as its been trouble free since but it did have one CHT failure (wouldn't start in the driveway). That was a easy fix so I still don't understand why people say FI is so complicated and hard to fix as there is very few parts, its KISS.
Elliot Cannon
QUOTE(al weidman @ Jun 6 2011, 09:07 AM) *

I'm an old guy and I would say it depends on either how smart you are or how much money you have. I am not smart enough to diagnose FI problems but there are plenty who can. My current 914 stopped on me five times and I had to be towed home each time. I replaced something different each time but it continued to stop. (just like someone turned off the gas) I put a set of del orto 40's on and have not had any problems since. By the way, last year at WCR I averaged 32 miles per gallon. It is a '75 2.0 with 195 X65 tires and runs at 75 mph at 3000 rpm. My original 914, that I special ordered new started having FI problems at about 1979. I put a set of 40 mm webers on it and it still has them and is owned by my friend Bob Scott in Washington. He would not sell me the car back when I wanted to get back in so I found my '75 instead. I do know several owners that have had their cars for many years without any problems. It all comes down to the reliability of the parts on your car and their failure or not. The new FI systems seem to be much more reliable, however, I would be behind the same tow truck if it broke. stirthepot.gif confused24.gif
Click to view attachment

Nice wheels on that car. Where did you have them done? lol-2.gif
CrashDown
QUOTE(ewdysar @ Jun 5 2011, 01:31 AM) *

Carbs are inherently better. That's why all modern car manufacturers use carbs to generate lots of efficient, reliable power. FI is just a fad.

(Getting ready to pul my SBC Holley 4bbl carb and install a MAF injection system.)

I agree with the first aprt, but you get a WTF.gif on that last part

QUOTE(SLITS @ Jun 5 2011, 08:31 AM) *

And the debate goes on and on and on and on ....

I'll take my 27 - 33 mpg and put up with fixing FI. If I want a sucking sound I will record it and play it through my stereo.

You can have your 12 - 17 mpg with carbs.


I have Redline 40's on my 914. i commute 50 miles round trip. When i drive my Subaru RS (non turbo) if i top off on monday i'm filling up thursday.

in the teener with the archaic, fuel wasting carb set up, if I top off on monday, i'm still going the following monday. I belive that's what people call in the judging community, a win.


QUOTE(SirAndy @ Jun 5 2011, 08:54 PM) *

QUOTE(dbgriffith75 @ Sep 16 2008, 03:08 PM) *
Carbs VS FI, Which is better?

Yes ... biggrin.gif

I vot this for line of the day....

QUOTE(Bleyseng @ Jun 6 2011, 11:13 AM) *

Well, after buying my 76 914 2.0l with Dell 40's on it in 95, I drove it for three years until I couldn't stand it any longer. Cold starts in Seattle sucked so I bought and re-installed the Djet without any of this Internet help available today. Best decision I made as its been trouble free since but it did have one CHT failure (wouldn't start in the driveway). That was a easy fix so I still don't understand why people say FI is so complicated and hard to fix as there is very few parts, its KISS.

You sir, are a good man. lulz

For me it was easy, 4 injectors at around 100 bucks a peice, plus rebuilding the entire FI system i used to have, that had flat spots, wouldn't idle right, horrible top end was going to be atleast a grand, and that was MY COST at work.

So i just got a set of brand new Redline 40's and it ran me $650..... it runs great, lots of low end, doesn't have flat spots, lots of aftermarket stuff you can do to change them.

if you want to compare the two in terms of colleges;

FI = Oxford, welcome to dullsville
Carbs = Chico state, THE Party school. Now show us your tits....

-Matt
Bleyseng
$1000 to rebuild at YOUR COST at your work? Where do you work?

I agree with SLITS and couldn't put up with the sucking sound!
My MPG is around 30mpg on the freeway, in the city its a lot lower as I drive like its a AX reving to 6000 rpms thru the gears without any flat spots or crappy high end. Of course I do know how to tune Djet too by attending classes at the School of DIY.
Dave_Darling
QUOTE(CrashDown @ Jun 7 2011, 06:49 AM) *

I have Redline 40's on my 914. i commute 50 miles round trip. When i drive my Subaru RS (non turbo) if i top off on monday i'm filling up thursday.

in the teener with the archaic, fuel wasting carb set up, if I top off on monday, i'm still going the following monday. I belive that's what people call in the judging community, a win.


Funny, I would have called it "apples and oranges". Since the RS is heavier, has AWD (which takes energy to run), is not noted as a very efficient car, has a 2.5 liter engine, and what, a 10 gallon tank?

Versus the lightweight 914 with a 1.7 liter engine (or is it a 2.0?) with 2WD and a 16-gallon tank.

Tell me why you think that's a valid comparison again?

--DD
ewdysar
QUOTE(CrashDown @ Jun 7 2011, 06:49 AM) *

QUOTE(ewdysar @ Jun 5 2011, 01:31 AM) *

Carbs are inherently better. That's why all modern car manufacturers use carbs to generate lots of efficient, reliable power. FI is just a fad.

(Getting ready to pul my SBC Holley 4bbl carb and install a MAF injection system.)

I agree with the first aprt, but you get a WTF.gif on that last part


if you want to compare the two in terms of colleges;

FI = Oxford, welcome to dullsville
Carbs = Chico state, THE Party school. Now show us your tits....

-Matt


My first line was tongue in cheek. I was referring to the fact that virtually all new cars are FI, even the high performance ones.

As for my 914 SBC conversion, the holley has been problematic with cold starts, high side load stumbling and elevation changes (regularly more than 5000+ ft differences). I'm switching to the Mass-Flo system that is becoming more common on the big and small block Cobra replicas. Truly self tuning, the only change that I would need for future engine upgrades will be if the engine exceeds the injector's 450 hp capacity. which is past where I plan on taking the car. Easy cold starts, high mileage when driven mildly, ready to run at any throttle setting and unaffected on a quick drive from sea level to 7,000ft. I just don't see a carb being that flexible. When this is done, my only car with a carb will be my Model T. But on that car, 100 year old technology, i.e. a carb, seems appropriate. poke.gif

I don't believe that anyone will consider my car overly sedate (dullsville) after switching to FI. driving.gif

Eric
jzdu
If anyone is scrapping their D-jet, I need the auxilary air regulator. Please let me know if anyone wants to sell theirs.
PRS914-6
Well, the poll only asks FI vs. carbs so general question gets a general answer, not really 914 but general...

Years ago when FI first came out I didn't understand it.....it was voodoo to me. When I ran into problems I yanked it off and installed carbs. Had them all my life and they were easy to me.

Fast forward 30 years and you couldn't give me a carb.....You couldn't pay me to convert. Now I yank off carbs and install FI. I went all the way the opposite direction where I actually burn my own chips (Chevy) When you can drive down the road running your vehicle on a laptop making changes on the fly you realize the time savings and efficiency. Too lean in one area and you can richen it up with a click of the mouse. Ping in one area, retard the timing in that area with a click of the mouse. Want a faster idle, a mouse instead of a screwdriver! Too lean at warmup, easy to fix....all on the laptop. When you get it perfect, you burn the chip and you are done. It's unbelievable awesome to do tuning this way instead of jet changes and recurving distributors. Those are the positives. The negatives are one....a steep learning curve. Modern day electronics pretty much diagnose a bad component on their own (not our 914's)

The negatives of carbs.....

When the air/fuel mixture goes around a turn in a manifold it has a tendency to separate
Gaskets dry out when it sits
Warm up is problematic
Mixture gets heated in manifold
Big cams , their low vacuum and intake reversion drives you nuts
Don't adjust for altitude
Not accurate across the temperature spectrum
Don't adjust for a hot or cold engine or air temp
Float bowls are vented to atmosphere causing sludge when sitting
Lots of work to adjust for engine changes
Ice up without "preheat" air

A carb is perfect on Fred's car.....Personally, I would leave it there biggrin.gif
Click to view attachment
GeorgeRud
agree.gif

though I love the look of my Webers, PRS914-6 hit it right on the head with his comments.
stugray
Just curious then:
Why was the 914-6 GT racing car sold with carbs?

AND won 1st place in GT class at 24 hours of LeMans in 1970?


IPB Image

Musta been because FI was better, but they wanted the challenge of racing with inferior equipment.....

Just ONE of the answers is:
Because the carbs give an expert infinite (almost) adjust-ability.
But with 70s technology FI, you get what you get.
Now if the Poll had mentioned modern FI like the megasquirts, the FI wins hands down.

The stock FI on the 914 is an analog computer. Unless you know how to change the gains on Op-Amps, then you cannot change much at all.
If you increase displacement or change the cam you are stuck.

Stu
FourBlades
EFI for a daily driver because of its sealed fuel systems that don't suck up water like carbs do. Florida is especially bad for this problem with its constant high humidity.

E15 is coming and will make fuel problems worse for daily driver cars with carbs.

I would like to move to EFI for my driver 914s and keep carbs on my 914 IMSA car in which I will run race fuel from sealed containers. Expensive, but you know what you are getting and it will not turn that many miles per year.

John
Robert21
It will be eight years with my 914 2.0 Had troble with FiI at first, until got new wires and brain , Have not had any ploblem since then. that was 7 years ago. If works leave it alone. Run every time. no tow trucks. Go 80 mph down the fwy no problem.
gil914
F.I. any day. My WRX has fully programmable stock and a programmable TEC-II (redundant F.I. no less) switch back and forth as needed. My 914-6 has programmable Autronic with individual stacks. The new 2.0 has Webers but I'm trying to find a working stock 74 DJET. If not I'll fake it and put a Megasquirt hidden somewhere.

The tripple and double webers sitting in the garage sure are pretty though....
reharvey
[quote name='gil914' date='Feb 15 2012, 01:58 PM' post='1625932']


My D/jet 2056 with Webcam # 73 runs great but you need to know how to tweek the FI so it'll run well. I'm sure it's the same with carbs. So----maybe it's all in what a person knows how to work with. Ray
Dave_Darling
QUOTE(stugray @ Sep 6 2011, 10:32 AM) *

Just curious then:
Why was the 914-6 GT racing car sold with carbs?


Because that's what the street car was homologated with. If they could have put MFI on the motor and stayed within the rules, I'm pretty sure they would have done it. Most of the factory's full-tilt race cars used MFI at that time, and for quite a few years later.

--DD
914_teener
QUOTE(Dave_Darling @ Feb 15 2012, 02:55 PM) *

QUOTE(stugray @ Sep 6 2011, 10:32 AM) *

Just curious then:
Why was the 914-6 GT racing car sold with carbs?


Because that's what the street car was homologated with. If they could have put MFI on the motor and stayed within the rules, I'm pretty sure they would have done it. Most of the factory's full-tilt race cars used MFI at that time, and for quite a few years later.

--DD



Dave....homo what?

Nice.

Injection is great....it's the wave of the future don't ya know. My teener runs great with it. The car was homolagated with it...them German egeneers knew what they were doing.

This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2024 Invision Power Services, Inc.