14 replies to this topic

[Spinksta]

Not really a specific mini question, but indirectly relevent..

I've been browsing the fleabay and have 'stumbled' across a page of weber carbs.

Now there are plenty on there but they're all for different makes of cars, but most of them look pretty much the same (doesn't mean a lot, I know). There are some ones that look very different but I'm excluding those from my question below.
Now my question is:
Is a weber a weber and the only reason they're for different cars is because they each come with the relevent manifold for that car, or are the weber carbs for a nova subtly different to the ones for an MG and even if you put the MG manifold on the nova carb, it still won't work in the MG? Or would you not even be able to put the MG manifold on the nova carb? Because like I said, the carbs all look roughly similar with similarly shaped manifold ports.

Just a random question, but if they are interchangeable between different cars then that might be a dangerous thing to know (for my wallet at least...)

Cheers people, sorry for rambling

[benpopham]

A weber is a Weber.. you have 2 main types DCOE 40 or 45.... and will fit on any car you just have to get them jetted to suit your mini

[The Matt]

Basically, a Weber is a Weber.

The ones that most mini peeps go for are the DCOEs, these are sidedraft (they suck in vertically, rather than downdraft).

I'd say most mini folk use either a 45 DCOE or a 40 DCOE, the 40 being more suited to owt that's not too racey. Then you need a manifold to suit, your car (in this case a mini) and also the carb will need jetting to suit your car and will possibly need chokes to suit your car. All in all, unless it's a bargain, it's probably best to get one that is set up for an A series engine of a similar size to yours.

[benpopham]

yeh what he said!

[Dan]

Oh no that's not true at all. There are many, many, many different types of Weber carburettor. There are down draft and side draft carbs, single, dual and twin choke carbs, different sizes, different layouts. All kinds. Weber are just a carb manufacturer, they made carbs as OE for a few companies and they made carbs as OE service replacement (usually as a way of ridding a make or model of car of a particularly dodgy auto choke system, as with the Mk2 Astra) for many different cars because they were cheaper than a new genuine carb from the main dealer. Very few types of Weber carb are specifically designed as a performance carb. Performance units are generally twin choke, side draft types but there are some down draft ones. The dual choke (where the chokes are different sizes with a progressive throttle action) are not performance carbs, these are the service replacement types. If you just find 'Weber carb' on E-bay you could end up with anything from any car. Maybe a performance carb, maybe not.

One thing is common to all Webers though, they are horribly inefficient at using fuel. Kind of like using a fire hose to supply the petrol to your engine.

[mini93]

just reading the yellow bible for the 1st time properly(tuning the a-series) there are lots of different webers and i now want an IDA downdraft weber, the book says it suffers above 70 because they stick out the bonnet and the turbulent air flowing over the top. this can be sorted by making and air scoop filter whih slows the air down (diagram in the book kinda looks like the one off a ERA turbo mini (bacward facing scoop) if you have tuning the a-series page 85 fig. 7.5

[Dan]

That carb also suffers from terrible carb icing for the same reason.

[benpopham]

Well iv just bought a Weber DCOE 40 for my 1048cc, with a stage 3 1275 head, will this be ok?

[Spinksta]

OK that's great, cheers everyone.

Just to confirm I was indeed on about the side draught, twin choke ones that are a popular upgrade with many a mini owner. Probably should have said that in the first post! Oh well.

OK then, new question(s):

If the Weber would need new chokes to suit the car, is that dependent on the size of the engine, the bhp / torque, or what?
And how much, ballpark figure, would it cost to get a Weber 'jetted'? I assume it's a fairly standard procedure...

Mmm, firehose...

[mini93]

would that be cured by the scoop? it says in the book the cooler charge should help the engine
*trying not to take it off topic too much* i want it, but its going to be used in rally events (if regulations allow me to put one on and mod' the bonnet) its not going to be used on long steady runs, vairying speeds should help stop it?

[alexcrosse]

why, u get less performance because u dont have a straight through choke! An IDE has a 90degree shoulder, no advantage atall. Just designed for other cars and pointlessly adapted for mini's. If you want good perforance get DCOE. Rather than buying the wrong carb and adapting it to fit and run badly! =p

[mini93]

read the yellow book? the manifold is aparntly very well flowing even considering the bend (which i do admit is dodgy) the graphs show the comparisons its the lenght in it which effect the different changes in flow

[Dan]

would that be cured by the scoop?

I've seen these having to be fitted with a steel shroud around the forward half of the air filter as well as a rear facing scoop on the bonnet to overcome icing. The draft under the bonnet from the grille can ice it up so the filter gets protected from all forward facing air by a combination of the shroud and the scoop. And it's proper carb icing too not the inlet manifold condesation that many people confuse with carb icing. The kind of thing that Supermarine Spitfires had oil heated SUs to avoid as in the throttle and float frozen solid. There was one in Mini Mag a few years back, might have a photo somewhere.....


As for the cost of modifying Webers, talk to Webcon. They are in West London I think and are the main UK people for Webers. To my knowledge all Webers are now out of production so all parts are in limited supply unless people like Webcon get them re-made. That may have changed recently as I think they were trying to re-start main line manufacture of the DCOE types.

Edited by Dan, 25 June 2007 - 06:54 PM.

[mini93]

if you could get a piccy..couldnt imagin the manifolds being heated aswell, the book says theres very rare now so aproach maniflow for custom manifold...ooooh the price! i guess i could stick to my dellorto i already have. still interested about these tho

[ginigwunkle]

a weber isnt really just a weber,

i have the weber haynes guide and theres 13 chapters each with arround 4+ carbs so thats like over 50 different webbers!

which is a few saying su only did 5/6!

now each weber arround 90 internal parts that can be changed and swapped to suit each individual engine, not just the a series.

then theres the manifold's, long short swanneck........ good airflow usually means no dash left inside the car! and an airbox with cutting of the bulkhead needed too keep some fumes out!!!

i know someone thats just changed 246 parts on each of his two twin dcoe 45's on a 1460cc 8port monster! thats a staggering 492 parts

so a webers not really just a weber!