Looking to replace the existing Webers on my 1976 2.0 liter. The existing set are mismatched, 1 old style and 1 new style. Just rather put a fresh pair on. What is the difference/preference between the 44 idf and the 40 idf carbs ? I recently purchased the car and the po said the motor has a slight overbore.

Not mine:

http://www.914world.com/bbs2/index.php?showtopic=236327

Ok to be up front, I have a pair of 44s for sale that would be perfect for your car. Not selling them to you just being clear.

I checked with various experts and I was told that 40s or 44s did nit really matter for a 2.0. What matters is whether the Venturi's are sized correctly. If a 32 vent works best for you application then the results regarding flow and performance are the same if that 32 is in a 40 or a 44. As you move to a much larger displacement than a 2.0 or a 2056 in my case, a 40 can become a limiting factor. I was told that a 32 in my 2056 was more than sufficient in my 44s for my 2056. I have no testing to back up what I was told other than when I had the 44 carbs adjusted correctly they performed well. But because I had the stock FI cam in my car I was never going to get all the 44s (or even 40s) could deliver from my engine.

So unless you know the cam has been changed then you will always be leaving some performance and HP on the table with either.

I have the 44s on my 73 2.0, and it runs real nice when I am racing it; but kind of poorly for leisure. It's better to starve it a little than it is to feed it too much.

44 uses same casting as the 40. All the same parts with the exception of a 44mm bore and butterflies. Do yourself a favor and go with the 40's. You'll have a much easier time tuning it and getting a nice transition. It can be done with the 44's but it's frustrating for most.

The only advantage to a 44 or bigger throat is when you run a really large choke for racing.

You don't need it.

On say a 40 with 36 chokes. The choke becomes so thin that you loose the Venturi effect and you loose velocity in the intake air
I considered 46mm carbs on my 2.0/6 because of the loss of velocity with 36 chokes and mid range stumble on the race car. Luckily we solved our problem with exhaust changes. But that is race only at 7800 rpm.

What would "you" ( a person with knowledge) Recommend for a street DD 2270cc.

(People who don't have knowledge can chime in too, just point out that you don't know what you are talking about.)

















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I'm not an expert on big 4's. But as a street car without FI the 44s are needed

Looking at the specs from Weber the main difference between the 2 carbs are the vent size 28 vs 36 the main jet size 115 vs 135 and the air corrector size 200 vs 175. Changing jets is rather simple and inexpensive the venturis not so much. As I understand the motor has only a slight overbore, possibly 2056. Seems most of you agree the 36 venturis are too large for this motor.

Yes, the 28 the vents would be better with a street driven 2.0. You look at CC's per cylinder and max RPM along with where the engine will live. For a race engine that sees 6K and WOT the larger vents are a better choice. On a street driven engine low RPM drivability and fuel mileage would suffer. The 40's would be a better compromise. IMHO the 115 mains are a tad small with 28 vents and the F11 ET. Buy the Weber Tech manual by Bob Tomlinson. Read it 5 times at least. Rember that it was wriiten when gas was cheap and over carbing was the rage.

I'm not trying to steal this thread but...I have a 2056 with a Raby 9590 cam. I'm a bit on the fence with the D-jet FI because I just cant get it right. If I was to go with carbs, What would you suggest.
Thanks_Bob

I think the perception is that carbs are plug and play and the only decision to be made is what size carb. First off it takes time and understanding to get the idle jet, main jet, AC jet, ET tube and vent sizing "right" (right = a compromise you can live with). Then you need a good linkage and get it adjusted. Then, when you get it running good your subject to the usual nuances of carburetors. The jets get plugged up, accel pumps and float bowl get gunk in them, floats need adjustment, the linkage needs to be readjusted, in short they require continual maintenance.

With that said I like carbs (Webers specifically). The only reason being is that it took a lot of time and experience to be somewhat decent at tuning them. FI is way better, I'm just hesitant to start on page one again.

I believe Raby supports his products well. A phone call might yield all you need as far as size and jetting. He also used to have a forum where his clients could ask questions such as this (no idea if he still does).

Anyhow, on a street driven 2056 (similar to the OP's) I'd go with 40's.

IIRC the 9590 cam was designed for D-Jet compatibility. It is not a carb cam. Tune your D-Jet.

I have a 2056 with the stock cam. Carbs were fun but not the real kick I wanted from a 2056. Took me a while to get the FI right. But with the fuel pressure at 31, new injectors, new TPS board, and AF guage to adjust the MPS, it runs very well now.

The stock cam just did not let the engine do what it needed with carbs. Don't get me wrong, the carbs worked and ran good. But there were just more on the upside with the FI if you keep the stock cam or a cam designed for FI.

What are your issues?

I thought the 9550 was the FI cam. No idea what the 9590 is. Anyhow, I believe his best option is to talk to the Raby folks.

I think the 9590 is the high altitude version of the FI cam
its only minorly different, with some exhaust lobe change as I recall

of course this is all from my poor memory so could be wrong

The 9590 is a FI cam. It was an upgrade from the 9550. That's about all I think I know about it. It was in the car when I bought it. I'm not sure if it's ideal for carburetors.

Good news today. It turns out the intake gasket #3 is leaking. I guess that would rob a few ponies. I'm getting closer.

Hi,

In my experience, Delloto's are much easier to tune than Webers and generally work better.

1, Dells have a right and left hand casting. Webers have one.
2. Dells have much better transition off idle because they have 5 progression ports. I believe that Webers have 3. Makes it much easier to tune a street car.

See this link for 2056 jetting2056 dell jetting

That being said, I'm retiring the drla 45's on the 2270 this winter and going micro squirt.

Carlos

Unless you consider having the drip a great thing I'd say no with the Dells. They will at some point drip, they're infamous for it.

Weber IDF's are a breeze to set up. Just finished dialing my 2056cc T-4 (72 Westy tin top) with an LM-2 ended up with the following:

28 vents
F11 E-tubes
50 idles
125 mains
180 air correctors
Float height 10.45mm
Float drop 32mm

That was at sea level and will put you right in the low 13's AFR.

Engine specs:

96m AA Biral P/C's (CR 7.8:1)
71mm stroke
New AMC heads re-worked by Headflow Masters (42x36mm)w/Porsche swivel adjusters
73 Web cam w/Web solids
Dual 40mm Italian Webers
Bosch SVDA
Pertronix module
Pertronix Flamethrower
NGK B5ES - .028
Bosch wires
S&S 4-1 header w/Walker quiet pack

I have 44's on my 2056 with and E cam in it. I swapped the vents for some 32's from CB Performance. I like the all around power it has and it pulls hard up to 5k.

Excellent information here. It would be nice to have a carb thread sticky with known good setups (with AFR data to back it up) to provide folks with a starting point.

I lost count of how many times I've told people to ditch the 115 mains that come with the carb out of the box. Not a big fan of the F11 either but that's another story.

I prefaced my post "in my experience". Have you ever installed and tuned dells? I have done both weber and dell in engines from 2.0 to 2.270. In my experience Dells work better.

Explain to me why less discrete progression from idle to main jet is superior to more discrete progression from idle to main. Tell me more about "Dells always drip". I have run dells since the early 80's. I have never seen a mystery drip. If I had 10 cents for every dollar that I wasted on mods/upgrades that peeps that where before I realized regurgitating a post that they read somewhere on the web as gospel, I'd have a 914 -6 in my garage. instead of 2 73 4 bangers.

My point is don't take options off the table based on some post you read somewhere unless you have direct experience. Convince me based on science or experience.

All that said, after this driving season, I am going microsquirt, after I plastidip the 928. Flame me now.

I've done a few Dellortos now, but to my knowledge, the Dellorto Drip is limited primarily to the DRLA 45s. The 40s apparently don't have the same problem.

The issue is caused by corrosion forming inside the idle circuits around the plug separating the circuit from the bowl. Carbs that have been abused or sat with a lot of water in them are particularly suspect.

The fix is to gain access to that circuit and remove the lead plug and reinstall a new one. While not impossible, it requires a few specialty tools, time and patience.

FWIW, I prefer the simplicity of Webers, even with the tradeoff in progression circuit operation. Easier to tune and maintain in general.

When you get the opportunity put some DRLA's on your car and live with them a while. They're much better than the IDF's, you'll see.

dopplepost

But since I'm here might mention that I grew up in the A/C VW world, and the standard Weber used on otherwise stock 1500 or 1600 engines are 40 IDF's with 28mm venturi's. At low RPM's it's perfectly fine and will give great MPG, but a larger engine needs more air, unless you're limiting the RPM's. And to confuse things a little further 40 DRLA's flow about the same as 44 IDF's with the same vents. Mention that just as another point of reference.

Are the Dell DLRA's still available new? When I just looked, the only one's I saw were in Europe and the vendor stated "limited supply." I have no experience with them but I've heard good things about them.

When I was in the drag bug scene the IDA was king. When they became scarce most of us went to the IDFs. Weber was just what we knew.

No, CB was the U.S. importer and the DRLA's are NLA for probably 15 years now, but they still turn up and are coveted. And IDA's are still king on the aircooled drag strip and still crap on the street, that hasn't changed. Last weekend was the Spring Bugorama in Sacramento with hundreds of aircooled IDF, DRLA and IDA cars, so it's pretty easy to see what works... and what doesn't.

Boy this got off track!
To the OP: You have a 76? the PO says it has a "slight" overbore?
No info re Cam change?

If it were me Id consider going back to the OE FI.

If to be believed, "slight overbore" I would interpret as a 2056.
The OE D-Jet will handle that change with out much tweezing.
If the Cam had been changed thats another story.
But I think more often than not Carb swaps occur W/O splitting the case.

OH & full disclosure ... I have a COMPLETE D-Jet setup off of a 76(CA car) FS