OK
the idea is certainly not original as I have spied it on a car in
a Hot VW's article from the early 80's but many people have asked
me how it was done, why and what's it run like! so here goes.
Originally
the later model type 3's ran twin solex carbs for improved performance
over the earlier single solex carb. The airflow was drawn from outside
vents through a sealed air filter / oil bath arrangement to the
carbs, this allowed cooler air rather than that from the engine
bay to be used. My own carbs were re-jetted etc. to suit my engine
and the car ran well.... when the carbs were in balance and the
linkages were the correct length!, I also wasn't all that keen on
the size of the air filter covering the engine. Back to that Hot
VW's article!
Getting
the Weber carb was easy as I picked up a 45mm DCOE side draft in
very good condition for a reasonable price, Getting the manifold!
well this had to be made up with the help of a few people. I was
lucky enough to pick up a manifold for the same size carb but for
single port heads, this helped a lot otherwise I would have had
to make a base plate to suit. All that was needed to do with this
one was to change the ends to suit twin port heads, with the help
of a few mandrel bends and an Auto my manifold was complete, it
was then bead blasted and painted to clean it up a bit. Now to fit
it and see if it works!
Most
people will agree that Volkswagen knew what they were doing when
it came to tinware and airflow, so to remove the air filter system
and the associated tinware??
Out
it all came and on went the new set-up, bolted up no worries! now
the fun part to sort out some cabling. The fuel line was no worries
just a single line from the pressure regulator instead of using
the T-piece for twins. As the balance tubes were removed (air tubes
from the lower manifold half from left to right) these were blocked
off as well. The accelerator cable required a bit of sorting out
and relocating in the engine bay, the outside casing was lengthened
by about 1 inch so it would run smoothly and the cable holder which
it runs through the tinware was moved. Weber carbs like most aftermarket
carbs have several options for accelerator cables, it was just a
case of working out the right setting to allow full throttle as
well as closing off! and sorting out a return spring, no real problems
here. Now the carb I picked up had a manual choke on it as well,
so may as well hook it up!
With
the help of some creative brackets incorporating a hidden return
spring and some bike cables and casings I connected the choke to
one of my heater box sliders near the drivers seat.
Now
clearance can be a bit of a problem on type 3's but this carb arrangement
fits no drama's, however I was a bit concerned about airflow into
the carb as the oil breather sits close to the left hand ram tube,
so I looked up the Hot VW's article yet again to see the owner had
made his own oil breather to get around this.
A
few plumbing supplies and an alloy plate later it was finished,
the hard part was making it neat as possible. The big question now
was would it all work?? Turning it over for the first time it started
(my first big surprise) and ran while I tried to check the tuning
since I know little in this area, what size jets it had etc., so
I decided to see if it would drive OK which it did! (my second big
surprise)
I
then drove it down to another Auto shop to sort out some final tuning.
Now how does it run!
Inlet
temperature was probably my main concern but this was easy to check
as I have had a temp sensor in the car for some time, interestingly
the temperature went down when compared to the twin set-up!, pleasing
result. Torque seems up on standard, again another plus!, whether
this is due to the longer manifold length or the carb I'm not sure.
Finally
overall running has improved as well as having that great Weber
intake sound!
The only problem that was experienced was a few hundred km's down
the track.
My home-made oil breather was not up to the job and increased pressure
in the case blowing oil out the pushrod tubes, so it was back to
the original breather for better oil pressure. Airflow and performance
was not affected so this is where it currently stands.
Bernie
