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Spitfire Which carburetor is the best?

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FlyingCat

FlyingCat

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I'm ready to purchase a carburetor for my 1980 Spitfire (Federal). Right now I'm pretty well sold on the Weber DGEV, unless somebody has a better idea. (The original ZS carburetor is long gone.) I live in the Willamette Valley, so it never really gets that cold in the winter (it's rare to get below freezing), and it doesn't get that terribly hot in the summer -- 90 is about tops. I do, though, have mountains all around me. I'm not sure if any of that makes a difference in what carburetor I get. On the Weber, I know that I can choose either water, manuel, or electric choke. Which is best? Thanks!
 
There are lots of options and lots of opinions.

Start by asking if you are going to have to pass emissions testing when you put this car back on the road. Some locations require original equipment intake and exhaust (emissions) components.

If you are allowed to change the carb, some of the common choices are a replacement Stromberg, a single SU HS4 (with MGB needle and slightly modified mounting holes), a Weber, or the European dual SU HS4 carb package. I cannot comment on the Weber but I know it is a common choice. Once properly jetted they are supposed to be great. We ran the single HS4 on our 1500 all the time we had it. It worked like a champ and gave no trouble over 6 years. The dual SU HS4 package is supposed to be a nice setup but I have no experience with it either. Apart from those interested in originality you probably won't get many endorsements for the single Stromberg.

Again, start by looking at your local regulations.
 
I would be tempted to look for a dual SU setup, rather than the Weber. But that's just me. I don't know much about the DGEV, and I'm a lot more familiar with SUs.

My preference would be manual choke, since it lets you adapt directly to conditions. If the engine needs just a bit more choke under some circumstance; pull the knob out a bit. Getting an automatic choke adjusted just right can be tricky sometimes.

For example, on a cold morning, my TR3 (with dual SUs) will idle smoothly with less choke (just the fast idle cam really) after a mile or two (from my house to the freeway ramp), but needs a bit more fuel to make full power going up the ramp to the freeway. No way an auto choke can cover that.
 
Emissions requirements is definitely something to consider. In Oregon, we have the DEQ -- Department of Environmental Quality. They apparently don't care if your car will stop, only if it doesn't pollute. Thanks!
 
FlyingCat said:
Emissions requirements is definitely something to consider. In Oregon, we have the DEQ -- Department of Environmental Quality. They apparently don't care if your car will stop, only if it doesn't pollute. Thanks!
Click to expand...

If that's so and the car has to pass a 'smog inspection' they may not be happy with anything other than what the car was born with.
 
I think some phone calls are in order.

Oregon Overview Link:
https://www.oregon.gov/deq/Vehicle-Inspection/Pages/Portland-Required-to-Test.aspx

From the above...
Vehicles required to (emissions) test
All 1975 and newer cars, trucks, vans, motor homes and buses powered by gasoline, alternative fuels (such as propane) or hybrids registered within the Portland testing boundaries.

and (test methods)...
https://www.oregon.gov/deq/Vehicle-Inspection/Pages/Test-Methods.aspx

Oregon DEQ Vehicle Test Methods
Tailpipe emissions test
(1995 and older model years)
At a Clean Air Station, a DEQ inspector places a probe into the vehicle’s tailpipe to ensure vehicle emissions are not exceeding standards


I did not see mention of "original equipment" but it is probably required... and worth a phone call or two before you buy any new carb(s).
 
Just a quick update. I spoke with the folks from DEQ, and all they are interested in is that the car has a catalytic converter (because it originally did) and that the tailpipe emissions are within range. They not only don't care if you have the original equipment under the bonnet, they aren't lifting the bonnet to see. The fellow I spoke with said that as long as the carburator is set correctly and the catalytic converter is new, then I shouldn't have any problems. Let's hope he is right, because that emisssions stuff is really expensive... if you can find it at all.
 
I had a GT6+ which a threw away the emissions control junk. Big mistake. Ended up having to buy it all again. That's California though. The TR3 doesn't even need a smog check due to age.
I've heard that the SU carburetors produce more power but the Strombergs are more reliable.
 
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