David,
Thanks - that's very helpful. Seems to be performance and response are the
factors. I understand that with the carb I also have to change the
exhaust. What has to get changed to help choke diamter? Knowing this
group, I'm guessing somewhere there's a recommended "List of Things To
Change When Converting from a Zenith to a Weber". Know where that list
might be?
However, going to a Weber will wait until I put OD in. That's a definite
priority.
I know Weber makes it harder to pass emissions. We don't have emissions
testing in my area, but I'm not looking to make some belching air-abusive
car either. I'm not an enviro-nut, but I try not to be overly
disrespectful either. What emissions part is the Weber particularly bad in?
Thanks for the informative answers...
- Tab
At 11:08 PM 8/5/00 +0100, David Hill wrote:
>Hi, Tab.
>
>Carbs all do the same job, though not necessarily in the exactly the same
>way. Sometimes, the stock carb is restrictive so a larger choke diameter
>will allow the engine to breather better at higher revs. However, there is a
>great danger of overdoing this, so the gas speed is reduced to the extent
>that the fuel doesn't atomise properly.
>
>Engine tuning is essentially about getting a bigger bang to happen faster,
>which is why much of the work involves allowing mixture to get in, though
>and out of the motor as quickly as possible. This is why cam profiles and
>exhaust/inlet flow get so much attention.
>
>The other element of tuning is accuracy-i.e. balancing combustion chambers,
>tweaking advance curves, etc. so as to make the events in the engine happen
>in under tighter control. In this respect, a Weber is, arguably, a better
>unit than a Zenith, in that its provision of the right mixture for different
>conditions is more accurate.
>
>Remember, though, a Weber on its own won't make a huge difference and the
>additional mods depend on numerous factors, including choke diameter.
>
>Hope this helps,
>
>Dave H.
>
>
>----- Original Message -----
>From: Tab Julius <tab@penworks.com>
>To: <mgs@autox.team.net>
>Sent: Saturday, August 05, 2000 8:23 AM
>Subject: What are the true benefits of a Weber carb?
>
>
> >
> > Today, a gorgeous day, I met two (count 'em: 2!) MGs driving in my town, a
> > small town of 3000 people where I probably have the only one, unless
> > someone else is keeping theirs tucked away.
> >
> > One was a B, the other a Midget. I talked to guy with the Midget, who was
> > just passing through, and he told me how he had reconditioned his,
> > including replacing the Zenith with a Weber. He said it was a definitely
> > noticeable major difference, although he didn't elaborate (and by then we
> > were out of time). I have a '78 B, and now I'm wondering, if I moved to a
> > Weber:
> >
> > 1) What significant differences would I see?
> > 2) What would be involved? Is it just changing the carb, or do I have to
> > do the muffler too, or what?
> > 3) For those of you who moved from a Zenith to a Weber, what did you
> > think? How much did it cost, and would you do it again?
> >
> > TIA,
> >
> > - Tab
> >
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