>I've been leaning toward fuel injection because of the drivability. I just
>liked the way that FE looked with the Webers.
You can have the look of Webers and still have EFI. Here's a picture
of a Pantera with just such a system:
http://www.panteraPlace.com/images/PP%20Shop%201.jpg
The intake manifold is a Weber and the throttle bodies are from TWM and
look like Weber IDA's. The ones in the picture have stacks but a low
profile version without stacks will fit under most stock hoods. The
major difference will be the fuel rails. Typically, they will be run
in between the throttle bodies. The system in picture is from the
Pantera Performance Center and is around $5500 for a complete ready to
install system (wiring harness, Haltech computer, lines, throttle
bodies, air cleaners, etc.). A number of places will do something
similar for any engine that has a Weber intake. The driving factors
in the cost are the TWM throttle bodies and the computer. A number
of individuals are looking to have the throttle bodies cast elsewhere
(China or Australia) to keep price down and there are a number of
alternate computers that can be used.
Weber no longer manufucatures the 48mm IDA Webers that are typically
used on small block V8's. I'm not sure if Dellorto does or not. In
any case, 48mm IDA's are only sufficient for up to 350 cubes or so.
Above that, you really need a larger venturi. Some of the VW flat four
tuners make larger bore versions for race VW's. Gene Berg is one
of the sources and I think he has them in sizes up to 58mm, though he
also does EFI now.
>Webers do not have enough vacuum under the carb to operate anything,
It's not the carbs fault, it's the fact they are mounted on an
independent runner intake manifold. If you mount them on a
plenum intake, they'll provide vacuum signal like a four barrel.
That said, you can get vacuum enough to run power brakes with
proper plumbing in an IR manifold. The vacuum oscillates in an
independent runner with the positive and negative spikes cancelling
out. A check valve in the runner line will do the trick, I believe.
>Also you need a specific camshaft to work with weber carbs, the duration
>is more critical.
Properly set up, independent runner EFI (or a IR Weber) will allow a much
larger cam to be run than with a plenum intake. A friend street drives a
Pantera with 255 deg duration (at 0.050), 105 LSA, and 0.600" lift and
says it's just fine in traffic and will pull from 1500 RPM in 5th gear.
It was a real window rattler with a single Holley on a dual plane intake
and needed 3000 RPM to smooth out. With the IR EFI, he thinks it idles
too well so he plans on increasing the cam duration.
>Gas mileage...there is none, it's 1/2 of what it should be with a 4 barrel.
When properly sized, installed, and tuned, an IR Weber set up can yield
fuel economy very close to a 4 barrel but those are big if's when it
comes to Webers. David Vizard ran a set of Webers on a warmed up 350
Chevy in his work truck and pulled 18+ MPG, as good or better than he
did with a 4 barrel Holley.
>Good setup for racing, just alot more to go wrong on the street.
True, and given the cost, I'd go with a similar IR EFI set-up.
EFI isn't magic and you'll still need to tune the system properly
but it's a lot easier to do that with a lap top than a bunch of
jets, emulsion tubes, and the like (a selection of which is not cheap
for a Weber system, BTW). Also, a wide-band O2 sensor will make tuning
much easier. The DIY-EFI guys have recently brought an inexpensive DIY
wideband o2 to market.
>The injection was EFI but the management system was just a few dashpot
>adjustement screws. Their mechanics said they liked it much better than
>the speed pro computer.
If it only has a few dashpot screws, then it really doesn't have enough
adjustability to work over a wide range of applications. Some systems
use the screws for AFR trim but you still have control over the important
parameters in the control system. I've been looking over injection
computers for a friend's injection project (side draft IR EFI). There's
a lot of factors to consider in computer selection (method of control,
cost, ease of tuning, releiability, support, sensor selection and
compatibility, built-in test etc.). Interestingly enough, a hacked GM
or Ford computer is very attractive. Far better built-in-test than any
aftermarket controller I've reviewed, much cheaper spares (cheap enough
to keep a spare computer and set of sensors with you when you head out on
trips), and an ever expanding user base. With third party software,
tuning may be relatively straight-forward. There's also the Megasquirt
internet DIY EIF project. Also, the Haltech from Australia is relatively
inexpensive due to the current exchange rate.
Dan Jones
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