> > > >> >> Paul wrote:
>> >> >>
>> >> >> Hi, Paul. I noticed on the Racing Beat website that
they claim the
>> >> >> peripheral ported 13b with a Weber 51IDA is good for 300
hp. Any idea
>> >> >> what rpm they need to turn to get that kind of hp?
>> >> >> Also, I have noted that some of the Weber carbs are mounted
>> >> >> vertically, and some horizontally. Does "side draft"
Weber indicate
>> >> >> that
>> >> >> it can be installed horizontally?
>> >> >> I see that they also have a "down draft" Weber, and
that is the
>> >> >> one
>> >> >> that is pictured mounted vertically. I assume that the internal
>> >> >> workings
>> >> >> must be different, as the float inside a carburetor
>> >> >> is typically orientated horizontally.
>> >> >> Last question....have you ever seen a successful
modification to
>> >> >> add
>> >> >> a mixture lever to a Weber? Sorry for the barrage of
questions, but I
>> >> >> was hoping you might be able answer some of these
>> >> >> questions. Thanks in advance for your reply. Paul Conner
>> >> >
>> >> > My guess the HP peak on that engine is right around 9500 RPM.
>> >> > You will need slightly longer pipes for 7500 RPM max.
>> >> > providing you have a 2.85:1 gear box. My guess would be
250 to 260 HP
>> >> > at 7500 RPM.
>> >> >
>> >> > Wow a 51 mm dual Weber! That is just about exactly 2 inches in
>> >> > diameter.
>> >> > Does that
>> >> > sound familiar or what? :) Side draft and down draft
never the twain
>> >> > shall
>> >> > meet.
>> >> >
>> >> > Back in the 60's Weber made a dual 58 mm side draft carb.
>> >> > When I was working for Chaparral we wanted to run four
Weber carbs on
>> >> > our
>> >> > big block V8. We wanted to run something like them in
down draft mode.
>> >> > So
>> >> > the
>> >> > Rochester Carburetor Division of GM copied the 58 mm side
draft Weber
>> >> > but
>> >> > converted it to a down draft version for our use only.
You should have
>> >> > heard our Group 7 competitors complain.
>> >> >
>> >> > It is a float bowl orientation problem Paul.
>> >> >
>> >> > Paul Lamar
>> >
>> >> Thanks for that information, Paul. Only one question
missed....ever hear
>> >> of
>> >> a successful mixture lever mod to a Weber? Thanks again.
Paul Conner
>
>
>> > I know it has been done with a Holley but I never heard it done
>> > with a Weber. I guess it is possible. I think the guys running Ford V6
>> > are using some sort of mixture control on their carbs as I recall.
>> >
>> > BTW I can understand why you are interested in carbs. What are your
>> > thoughts on this subject? Just for the record.
>> >
>> > Paul Lamar
>
>
>> Hi, Paul....the primary reason is simplicity. I realize that the EFI has
>> distinct advantages, such as being able to control the exact
amount of fuel
>> injected at various rpm's, and carburetor icing is not a
concern (with the
>> exception of the long intake runners that Mistral experienced
icing in). My
>> problem is with it's complexity....It requires two high
pressure fuel pumps,
>> expensive injectors that can clog, programming maps, and a
fuel return line
>> for unused fuel. The system also places considerably more
current demand on
>> the electrical system. (Important if you should have an
electrical failure,
>> as it shortens the distance you can continue flying to an airport). The
>> complexities of setting up proper maps for an ECU can also be
time consuming
>> and at times frustrating. I have found it difficult to find
anyone who could
>> assist in programming maps into my ECU. (Every A&P mechanic at
our airport
>> could help out with a carb).From what I am reading, there
seems to be a lot
>> of people using Webers on rotary powered cars, with many sites revealing
>> proper tuning techniques/jetting, etc.
> >
>> There are advantages and disadvantages to both systems,
obviously. I am
>> personally drawn toward the simple nature of the beast, and I
have had a lot
>> more experience with carburetors on aircraft (all 7 of my
previous aircraft
>> had carbs). I was pleased with their performance and reliability. Just
> > needed a throttle and a mixture control. If I could get the
same kind of
>> performance and reliability with a carb on a rotary, I would be just as
>> pleased as I was with my previous Lycoming powered
aircraft...No, make that
>> MORE pleased, as I would have a carb equipped rotary instead of a carb
>> equipped hand grenade. Just my opinion, and I could be wrong. (Again).
>> Take care. Paul Conner
I have run a Weber on my coot now for 1300 hrs, I used a 51 mm DCOE
side draft for about 1000 hrs but switched to a 48 DCOE, they also
make a 55 mm DCOE and the best place to get Weber's is at Performance
part warehouse in New York.
I switched to the 48 as it runs very smooth at the bottom end
compared to the 51 but I did lose some power on the top end but I do
a lot of slow speed water taxiing so its a tradeoff I will except.
Also for leaning I use a controllable air ram that creates a
pressure difference between the float bowl and the Venturi thus
leaning the fuel mixture.
I am with you on the simple thing, just hook up a fuel line and a
throttle cable and go fly, if you need jetting info I can give you
the jet numbers to put it dead nuts on.
I have thought about playing with injection but I will use a Weber
as a throttle body so the if something goes wrong with the injection
I can just flip a switch to the Weber fuel pump and keep flying on
the Weber and worry about fixing the injection I get home or whenever
I get around to it.
Ken Welter
Heck you can use this system as a back up. Second picture.
--
Paul Lamar
I don't want something to just safely get me to the ground I want
something so that I can keep flying and fix the injection when I get
home and I fly way out in BFE and I don't want to be fixing something
out there.
Like I said flip a switch and keep flying and if home is a week away
its no big deal.
Ken
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