> Once you go below 34mm chokes on a 45 to get the bottom end throttle response
> you want you need to be thinking about a 40 DCOE and not the 45.
>
Agree. 34 is OK with a 45 , but a 45 is wasted below that.
> If the car runs really well on the 32mm chokes it will certainly produce less
> rpm at the top end than with the 34mm chokes.
if and only iff, the 32mm chokes enable less fuel/air flow than the engine can
use.
>
> Personally I always think down choking a DCOE to improve bottom end response
> means sacrificing power for driving flexibility and cures symptons and not
> the problem. If you want cure the problem WITHOUT SACRIFICING POWER and
> improve the bottom end and top end throttle response and maybe gain some
> power you need the aluminium alloy full radius rams from ITG in whatever
> length you prefer (I doubt the 266 cam is that bothered what length it sees).
> All the standard steel rams are considerably inferior to the ITG items.
No matter how good these rams are, (and I haven't a clue about that brand),
they are not a cure here. What they do is to improve the air flow through the
carb
by eliminating the indirect restricting effect of air flow around a sharp
corner. The
sharp corner acts like a choke and the rams are essentially removing that
choke.
There are good diagrams in Vizard IIRC, along with features to look for.
The real issue here is that you want the largest chokes that still maintain
good
gas flow velocity and venturi effect, or put another way, the smallest choke
that
doesn't kill your top end. A few timed "drag" runs will give you a clue...
If you don't like the result and the tuning is all spot on, then you have
chosen the
wrong cam for the application.(Mind you inthis case, 266 is pretty mild)
You *can* tweak the result by shrinking the choke size, or playing with cam
timing,
but these are indirect solutions.
>
> I've assumed you have a decent inlet manifold and not something from Pierce
> or Canon because AFAIK neither has good product for the DCOE and a poor
> design will reduce air flow and cause fuel drop out(of the air).
>
The Wannaford long manifold (aka Redline now) is the best commonly available
Weber manifold. Russell Engineering in Sydney make an even better manifold, but
availability would probably be a problem.
I have the Wannaford on the bugeye and the Russell on my midget.
>
>
> Nick
>
> In a message dated 23/11/01 07:26:11 Pacific Standard Time, rbc43@home.com
> writes:
>
>
> > I have mostly completed the tuning of the 45COE Weber on my Bugeye. I have a
> > stock 1275 lower end, an aluminum head, a 266 cam, Isky valve springs, a LCB
> > header, 1-3/4 pipe to a Cherry bomb 22" long. I started with 34 chokes, 3.5
> > aux venturis, F2 emulsion tubes, 50F9 idle jets 50 pump jets 155 main jets
> > and
> > 170 air jets. After I found and repaired the cracked fuel line near the
> > tank,
> > we were ready to work on the Weber. I drove up to Russ's house at 9:00 AM
> > on a
> > beautiful fall day. Russ races a GT4 Toyota and uses Webers on his race car,
> > so he has some understanding of them. I used some settings I got from Rick,
> > who has a similar engine and settings from listers on this net. We set the
> > float levels at 4.5 and 15 mm with some tools Russ had made. they were
> > pretty
> > far off. We set the timing, and the idle screws and we were ready to start.
> > We
> > changed one setting at a time,( it's amazing what you have time for if you
> > are
> > retired). We would make the change, go out to the road and make a run to
> > test
> > the change. Russ drove each time. We would come back and evaluate the
> > change.
> > We made about 10 runs including lunch. Russ had a lot of parts, so this
> > reduced the cost of tuning. After about three hours of this, these were the
> > results: 34 chokes, 3.5 aux,f2 emulsion, 50 F9 idle 45 pump jets, 160 mains,
> > and 160 air. It would not take full throttle with out choking, you had to
> > add
> > throttle gradually. Our plan was to have me order some parts 32, 30 chokes
> > and
> > 40 pump jets and 160 main jets. One thing that bothered us was some times
> > the
> > tack would work, and some time it would not. We checked all kinds of things
> > and couldn't come up with the solution. So I installed an Ignitor system on
> > another 25D dizzy and put it in. the problem was solved! When I got the
> > parts,
> > I installed the 32 chokes. It was like a brand new car!! It loved those
> > chokes!. I hope to evaluate the 40 pump jets soon. And we have to go though
> > the mains and airs again.
> > It was nice to have the time to do this in a very methodical way. I now
> > have
> > a Bugeye that drives much better than before. Now I can plan the changes to
> > the engine (shaved head, 1.5 rocker arms, 40 over pistons, and balanced and
> > lighten rods and crank) and do it all over again.
> > Now to tune into Flounder Vision!
> >
> > Roger Cotting
> > 59 Bugeye Yellow Beauty
> > 60 Bugeye Ironhead
> > 60 Bugeye project car
> > 74 Midget for son
> > 80 TR 8
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