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MG MGA - Switching to a Weber

I know this is a subject that stirs a lot of polarizing views (I searched the archives), but I'm considering switching over from the original SUs to a Weber sidedraft 45 DCOE carb. My mechanic (MG-only) swears I will see an improvement, and he specializes in tweaking these things. Every other MG owner or mechanic I've ever talked to swears by SUs, saying if they are properly set up they'll outperform a Weber. But my car has a wonky choke (no fast idle control, difficult to fix); I ALWAYS encounter vapor lock when restarting the car after it is turned off for 5 minutes; and since the PO installed a Nissan 5-speed with the 4.1 differential, you gotta wind the engine up pretty high before engaging 1st gear. Not much "off the line" power that might be helped by switching to a Weber...also maybe more passing power at highway speed.

Two questions
- anyone else running a sidedraft? I know there is only a small power improvement with a stock engine, but interested in your experience.
- anyone got one for sale? :)
Jim P

Jim,
I used a 45 DCOE on my 1500 and with decent extractors got about 10bhp more.

Basically SU's are as good, but they don't have a pump jet, so can't deliver the instant squirt like a webber. Down side is few economy though.

Here's some jetting I've managed to gleam over the years.

If you've only got a 1500 or 1600, then a 40 DCOE is plenty but setting are harder to find for those, so you end up down choke-ing a 45 anyway.

Wrap the exhaust in that heat proof tape and you'll get rid of the vapour lock no matter what carb you use. It has down sides though in terms of manifold life, other than that, all good.

http://freespace.virgin.net/marka.hester/RaceStuff.htm

Cheers <MARK>
Mark Hester

I use a holley 1904 - car goes like stink
dominic clancy

Dominic ... that's because you have a supercharger!
Richard Ross

Jim,

I changed my original SUs for a 45 DCOE side draft
and cured my overheating problem instantly.
The car has improved acceleration and the overall
fuel consumption is about the same.
There is no vapour lock.
Downside is that you have to have the carb set up
by someone who knows what they are doing on a rolling
road,which costs money and you can hear the induction
noise when accelerating hard.
You will need a swan neck inlet manifold not a straight one.
Remember you can keep your original carbs and if you
ever wanted to sell the car the new owner has a choice.
I would not change back.

David
David

Richard- Is that the big black thing by the carb?

dominic clancy

Dominic,
And here's me thinking it was something to do with the spin cycle - certainly sounds like a washing machine.
Richard Ross

Oh,
With both my MGA's with 45 Webbers.

I have had the inlet manifold milled a tiny bit to angle the manifold up more to give extra clearance with the body work.
I've also fitted an MGB spacer under the Left Hand engine mount.. AHH6992

No 13 here.
http://www.moss-europe.co.uk/MossUK/ProductList.aspx?SubSubCategoryID=MGB_DS004A

If you want to use ram tubes on the Webber, then you may need to get a large rubber hammer and give the bodywork on the inner guard some small persuasion. Only about 5mm or so is enough.

Hope this helps.
<MARK>
Mark Hester

This thread was discussed between 19/04/2006 and 20/04/2006

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This thread is from the archive. The Live MG MGA BBS is active now.