47 replies to this topic

[bmcecosse]

For a standard MG engine - the Weber idea is not great - and if you have to use the ghastly swan neck manifold - forget it. Jetting etc is well known - and yes they tend to use extra fuel because of the accelerator pumps. If you minimise that - then hesitation and spitting back will be your friend. Don't understand why twin HS2s can't work ? The engine is almost same spec as a 1275 S - so needles from that should be very close. However twin HS4s would be more closely suited to the engine for best power if you want twins. But overall the single HIF44 IS the carb to use - it's what Rover used!!

[Nightrain]

What a load of rubbish, webers can be just as efficient as the SU if set up correctly. They can also be adapted for pretty much any size of engine, for yours you want a 40DCOE. Which people don't seem to appreciate can take from a 28mm to 36mm choke iirc, which would be like twin 1.125" SU's to 1.4" SU's.

[mini7boy]

What a load of rubbish, webers can be just as efficient as the SU if set up correctly. They can also be adapted for pretty much any size of engine, for yours you want a 40DCOE. Which people don't seem to appreciate can take from a 28mm to 36mm choke iirc, which would be like twin 1.125" SU's to 1.4" SU's.

sure a Weber can be choked down and jetted down enough so that it will run on an otherwise stock engine. You could probably run split Webers on it as well. Go ahead.
Why stop there? Why not put fuel injection on it? Hang the cost and complexity.

But just because it can be done doesn't mean that it is worthwhile to do so.
There are lots of things that CAN be done, but that alone doesn't mean that such things are worth doing.
A single 1.75 SU is so much easier, cheaper, simpler and is more than adequate for this engine.

If clearance is an issue, than modify/build a manifold to adapt the SU to the head.

The energy and funds necessary to get a Weber working on this engine could be much better spent almost anywhere else.

[Nightrain]

sure a Weber can be choked down and jetted down enough so that it will run on an otherwise stock engine. You could probably run split Webers on it as well. Go ahead.
Why stop there? Why not put fuel injection on it? Hang the cost and complexity.

But just because it can be done doesn't mean that it is worthwhile to do so.
There are lots of things that CAN be done, but that alone doesn't mean that such things are worth doing.
A single 1.75 SU is so much easier, cheaper, simpler and is more than adequate for this engine.

If clearance is an issue, than modify/build a manifold to adapt the SU to the head.

The energy and funds necessary to get a Weber working on this engine could be much better spent almost anywhere else.

LOL @ calver, love the way a 40 weber is too much but a 44mm carb isn't. Webers are only complex if you don't understand them, they are a far more advanced carb than the SU and will out perform the SU on any vehicle.

Choking a weber is all part of the tuning process, granted if you find yourself running a smaller choke than 30mm you'd be better of with a 38DCOE. Likewise if you need a bigger choke than 35mm the 45 weber would be more suited.

Of course the other thing you haven't considered, is maybe you the weber is part of a larger plan and this is why the weber is been considered now !!!

Edited by Nightrain, 20 August 2009 - 09:35 AM.

[mini7boy]

sure a Weber can be choked down and jetted down enough so that it will run on an otherwise stock engine. You could probably run split Webers on it as well. Go ahead.
Why stop there? Why not put fuel injection on it? Hang the cost and complexity.

But just because it can be done doesn't mean that it is worthwhile to do so.
There are lots of things that CAN be done, but that alone doesn't mean that such things are worth doing.
A single 1.75 SU is so much easier, cheaper, simpler and is more than adequate for this engine.

If clearance is an issue, than modify/build a manifold to adapt the SU to the head.

The energy and funds necessary to get a Weber working on this engine could be much better spent almost anywhere else.

LOL @ calver, love the way a 40 weber is too much but a 44mm carb isn't. Webers are only complex if you don't understand them, they are a far more advanced carb than the SU and will out perform the SU on any vehicle.

Choking a weber is all part of the tuning process, granted if you find yourself running a smaller choke than 30mm you'd be better of with a 38DCOE. Likewise if you need a bigger choke than 35mm the 45 weber would be more suited.

Of course the other thing you haven't considered, is maybe you the weber is part of a larger plan and this is why the weber is been considered now !!!

[mini7boy]

sure a Weber can be choked down and jetted down enough so that it will run on an otherwise stock engine. You could probably run split Webers on it as well. Go ahead.
Why stop there? Why not put fuel injection on it? Hang the cost and complexity.

But just because it can be done doesn't mean that it is worthwhile to do so.
There are lots of things that CAN be done, but that alone doesn't mean that such things are worth doing.
A single 1.75 SU is so much easier, cheaper, simpler and is more than adequate for this engine.

If clearance is an issue, than modify/build a manifold to adapt the SU to the head.

The energy and funds necessary to get a Weber working on this engine could be much better spent almost anywhere else.

LOL @ calver, love the way a 40 weber is too much but a 44mm carb isn't. Webers are only complex if you don't understand them, they are a far more advanced carb than the SU and will out perform the SU on any vehicle.

Choking a weber is all part of the tuning process, granted if you find yourself running a smaller choke than 30mm you'd be better of with a 38DCOE. Likewise if you need a bigger choke than 35mm the 45 weber would be more suited.

Of course the other thing you haven't considered, is maybe you the weber is part of a larger plan and this is why the weber is been considered now !!!

Hey Smiffy, just which part of "A single 1.75 SU" wasn't clear to you? Did you forget that a Weber has two barrels and an SU one?
"Of course the other thing you haven't considered", Smiffy, is that the OP never mentioned future plans for the engine. You're assuming, with no basis at all, that he has plans to modify the engine further.
I never said that Webers are complex, so you'll need to redirect that comment elsewhere. A 1.75 SU is simpler, cheaper(tuned) and takes up less space than any Weber DCOE.
The OP says that there are vertical clearance issues. Fine, then modify or have modified an existing manifold to provide clearance. As long as it's for a stock engine, perfection is not required.

[Nightrain]

Hey Smiffy, just which part of "A single 1.75 SU" wasn't clear to you? Did you forget that a Weber has two barrels and an SU one?
"Of course the other thing you haven't considered", Smiffy, is that the OP never mentioned future plans for the engine. You're assuming, with no basis at all, that he has plans to modify the engine further.
I never said that Webers are complex, so you'll need to redirect that comment elsewhere. A 1.75 SU is simpler, cheaper(tuned) and takes up less space than any Weber DCOE.
The OP says that there are vertical clearance issues. Fine, then modify or have modified an existing manifold to provide clearance. As long as it's for a stock engine, perfection is not required.

LMAO don't want to tell you how a engine works calver, but each cylinder draws fuel independently. Because in case you hadn't noticed the A series has a shared port design, meaning each port serves 2 cylinders.

Now having a straighter inlet tract will decrease any fuel biasing, which in turn means more efficient combustion in each cylinder. More accurate tuning, better economy and performance !

[mini7boy]

Hey Smiffy, just which part of "A single 1.75 SU" wasn't clear to you? Did you forget that a Weber has two barrels and an SU one?
"Of course the other thing you haven't considered", Smiffy, is that the OP never mentioned future plans for the engine. You're assuming, with no basis at all, that he has plans to modify the engine further.
I never said that Webers are complex, so you'll need to redirect that comment elsewhere. A 1.75 SU is simpler, cheaper(tuned) and takes up less space than any Weber DCOE.
The OP says that there are vertical clearance issues. Fine, then modify or have modified an existing manifold to provide clearance. As long as it's for a stock engine, perfection is not required.

LMAO don't want to tell you how a engine works calver, but each cylinder draws fuel independently. Because in case you hadn't noticed the A series has a shared port design, meaning each port serves 2 cylinders.

Now having a straighter inlet tract will decrease any fuel biasing, which in turn means more efficient combustion in each cylinder. More accurate tuning, better economy and performance !

Hey Smiffy, what's that in English ???? If you're so concerned about "a straighter inlet tract", I guess you'll recommend nothing less than split Webers, right?

It's a stock engine, remember? Fuel biasing in that context is mostly irrelevant. How many millions of Minis have served, and continue to serve, their owners quite well with a single carburetor on a stock engine?

Why don't you just focus on helping the OP rather than trying to impress him with your talk of fuel biasing and straighter inlet tracts.

A simple 1.75 inch SU setup will serve him very well even up to the hypothetical point where he improves the engine via head, cam, etc.

Edited by mini7boy, 20 August 2009 - 11:47 AM.

[Frog]

Can anyone advise me whether I should put a Weber 40 on my MG Metro (standard) engine or whether I should hold out for a 45?

How easy is it to find out what the appropriate jets are for my engine?

Anything else I need to know?

Cheers.

Hi there, fitting a 40 or 45 weber to a standard 1275 is a massive over carb, I used to run a full race 1293 on a 45 & granted it went like stink but webers are well known for washing the bores with petrol which inturn gets into the oil meaning more oil changes etc. Can't see why a set of HS2's wouldn't work or HS4's, but if it is simplicity you want then fit either a HS6 or a HIF44, get either one of these set up correctly & produce just as much power as you would with the weber if not more.

[Nightrain]

Hey Smiffy, just which part of "A single 1.75 SU" wasn't clear to you? Did you forget that a Weber has two barrels and an SU one?
"Of course the other thing you haven't considered", Smiffy, is that the OP never mentioned future plans for the engine. You're assuming, with no basis at all, that he has plans to modify the engine further.
I never said that Webers are complex, so you'll need to redirect that comment elsewhere. A 1.75 SU is simpler, cheaper(tuned) and takes up less space than any Weber DCOE.
The OP says that there are vertical clearance issues. Fine, then modify or have modified an existing manifold to provide clearance. As long as it's for a stock engine, perfection is not required.

LMAO don't want to tell you how a engine works calver, but each cylinder draws fuel independently. Because in case you hadn't noticed the A series has a shared port design, meaning each port serves 2 cylinders.

Now having a straighter inlet tract will decrease any fuel biasing, which in turn means more efficient combustion in each cylinder. More accurate tuning, better economy and performance !

Hey Smiffy, what's that in English ???? If you're so concerned about "a straighter inlet tract", I guess you'll recommend nothing less than split Webers, right ?

It's a stock engine, remember? Fuel biasing in that context is irrelevant.

LOL @ calver so in your mind a 5 port A series engine suddenly becomes an 8 port, you only have to look at the spark plugs in any A Series engine to see that is rubbish.
Basically what your saying is an identical engine with a straighter inlet tract will not outperform one with a biasing towards a couple of cylinders.
Am I understanding you correctly here ?

[Nightrain]

They'll only wash the bores the same as any other carb frog, if there not set up correctly.

[Frog]

They'll only wash the bores the same as any other carb frog, if there not set up correctly.

Sorry beg to differ with you, raced in grass track for 10 years had several engines set up on rolling roads including SLARKS & they told me the exact same thing. Webers are great if you want just balls out power but for an everyday driver I definately wouldn't recommend one.

[Nightrain]

Hey Smiffy, what's that in English ???? If you're so concerned about "a straighter inlet tract", I guess you'll recommend nothing less than split Webers, right?

It's a stock engine, remember? Fuel biasing in that context is mostly irrelevant. How many millions of Minis have served, and continue to serve, their owners quite well with a single carburetor on a stock engine?

Why don't you just focus on helping the OP rather than trying to impress him with your talk of fuel biasing and straighter inlet tracts.

A simple 1.75 inch SU setup will serve him very well even up to the hypothetical point where he improves the engine via head, cam, etc.

Whoops see you've added to that last post, well seeing as Paul asked about the weber he obviously has a reason. Maybe he already has the carb or has been offered one. The simple fact is he asked a question and all the replies only told half the story. Everyone said it wouldn't work including yourself. Which quite frankly is just rubbish !

Too set the record straight and as usual you've taken it personally and launched it the usual torrent of abuse. Turning this thread into a slagging match, you may see it in your mind calver, but every post I make isn't about having a go at you !!!

Even though some would say, you are a very easy target........

Edited by Nightrain, 20 August 2009 - 12:18 PM.

[mini7boy]

Hey Smiffy, just which part of "A single 1.75 SU" wasn't clear to you? Did you forget that a Weber has two barrels and an SU one?
"Of course the other thing you haven't considered", Smiffy, is that the OP never mentioned future plans for the engine. You're assuming, with no basis at all, that he has plans to modify the engine further.
I never said that Webers are complex, so you'll need to redirect that comment elsewhere. A 1.75 SU is simpler, cheaper(tuned) and takes up less space than any Weber DCOE.
The OP says that there are vertical clearance issues. Fine, then modify or have modified an existing manifold to provide clearance. As long as it's for a stock engine, perfection is not required.

LMAO don't want to tell you how a engine works calver, but each cylinder draws fuel independently. Because in case you hadn't noticed the A series has a shared port design, meaning each port serves 2 cylinders.

Now having a straighter inlet tract will decrease any fuel biasing, which in turn means more efficient combustion in each cylinder. More accurate tuning, better economy and performance !

Hey Smiffy, what's that in English ???? If you're so concerned about "a straighter inlet tract", I guess you'll recommend nothing less than split Webers, right ?

It's a stock engine, remember? Fuel biasing in that context is irrelevant.

LOL @ calver so in your mind a 5 port A series engine suddenly becomes an 8 port, you only have to look at the spark plugs in any A Series engine to see that is rubbish.
Basically what your saying is an identical engine with a straighter inlet tract will not outperform one with a biasing towards a couple of cylinders.
Am I understanding you correctly here ?

I'm sorry,Smiffy. I only understand English. Why don't you try it for a change.
This is a stock engine we are talking about. We are not debating Engine Design.

In answer to your question, you don't understand ANYTHING about what this forum or this thread is for.

[mini7boy]

They'll only wash the bores the same as any other carb frog, if there not set up correctly.

Sorry beg to differ with you, raced in grass track for 10 years had several engines set up on rolling roads including SLARKS & they told me the exact same thing. Webers are great if you want just balls out power but for an everyday driver I definately wouldn't recommend one.

Thank you very much, Frog. Another voice of reason is a welcome addition to this thread.

Now, if you could just get through to Nightrain, you'd save me the bother of dealing with him.

Does anyone see a pattern here?

Frog and I have made the very reasonable(and obvious) point that paulrockliffe would be better advised to put a single SU carb on his STANDARD engine.

Instead of agreeing with this completely OBVIOUS concept, Nightrain has to be his usual abusive self and try to convince us all that he's quite an engine expert.
He does this by stating facts which should be obvious to anyone with even a modest knowledge of A-series engines.

as in: Stop Press !!!!! Nightrain reveals that A-series engines have siamesed intake ports !!!! No shot, Sherlock !!!

What a breakthrough in automotive engine design !!!! Somebody had better tell the Queen about this immediately.

Edited by mini7boy, 20 August 2009 - 03:17 PM.