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Subject: Carbs
Date: Sun, 2 May 1999 11:21:25 EDT
<<Maybe there is a mindset with those that install Webers but all of those
so fitted drove like... a truck. 
None of the SU fitted cars reacted that way but they felt like they had
a tad less 'grunt' as well. So, listers... are these first impressions 
correct or did I just catch a bad batch?  I bought my little yellow beast 
WITHOUT Webers BECAUSE of this impression.>>

No, you have it about right. 

First, I have nothing against Webers - I use them on my TVR race car on a 
Derrington crossflow head, and on my Twincam race car.

On my street cars, I use SU's, though often H or HS 6. They are easy to set 
up, and don't go out of tune easily, contrary to popular stories. For me, 
they are the best combination of driveability and performance - if you have a 
tuned engine, fit the 1 3/4" variety, if you race you can use 2" (although 
many engines that have these applied don't really need them - another story 
for another time).

The DGV Weber is a waste of time, and inferior to an SU - usually sold to 
someone with worn out SUs that wants the vicarious 'racy' feel that having a 
Weber gives them. They'd have been better off just rebuilding the SUs.
No improvement in power, often have flat spots. 

The Strombergs are a pretty decent carb and actually have slightly more 
accurate metering than the SU. Problem is that most are CDSE series without 
adjustment. If you can get an older 175 CD series, from an older TR4 or 
suchlike, you can do a decent performance set up. Just don't perforate the 
diaphragm (sound like a father sending his daughter out on a date, don't I?).

The side draft Weber is a proper performance carb. Problem here is that they 
come with certain standard jet settings, as built for a particular 
application, which you can bet your boots was for some oddball Fiat or other, 
that usually bears no resemblance to what you want to fit them to.
Once you get them right, they are very good, but the fact that so many 
installations have driveability problems indicates that few people can tune 
them properly. Usually, they get them so that they don't put out black smoke 
at idle, and don''t totally crap out at full throttle, and then quit while 
(they think) they are ahead. If you have someone that can tune Webers (REALLY 
tune them, which not every clown named Luigi can do) by all means try them, 
but do not bother doing this for a street stock car. Your gains in power will 
be so small as to be undetectable and will all be at the top end at full 
throttle, where you never are, though you might like to think that you drive 
that way all the time (if you _do_ drive that way on the street, stay the 
Hell away from me!)

When I rebuilt my wife's MGC, I did it with SUs, not Webers. I saw one guy at 
a show that had triple Webers on his car, with everything all cad plated. He 
was obviously pretty impressed with himself, and spouted on about how much 
horsepower he was sure it made. I asked him what the mods had done to his top 
speed, a pretty accurate way of measuring increased power. He said that he 
didn't know as he'd never had it over 80 mph! Wanker!  I opted for 3 HS6 SU's 
on her car, with craftily done manifolds in cast alloy and some tricks to get 
the third carb to clear the bonnet. It looks right, and after it was broken 
in we had the chance to run on a newly opened section of highway with no 
company but my buddy in a V12 E type. The C did an honest 130 mph, about 5 
below what that Jag could do, but right on what he was willing to do that 
day, much to his surprise. Again, SUs served the cause very well.

Just my experience with this stuff. But then I'm clearly a maniac - I once 
built a TR engine with 4 H4 SUs instead of Webers, just to see what would 
happen. Also had one running with SU DU6s, a double barrelled carb that I'd 
wager none of you have ever seen in the flesh, unless you have been looking 
at a Cooper Climax at Laguna, or some such. Should have kept those carbs to 
hang on the wall, I suppose.

Bill Spohn

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