I agree that the use of FR rams does indeed act 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.'
I also agree that '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.'
SO, it seems to me that even agreeing with what you say Mike, the FR rams are
likely to be a big part of the solution BECAUSE they negate a choking effect
and by doing so maintain good gas flow velocity and venturi effect, to use
your own words. This is particularly and I suppose obviously the case at low
engine rpm where the gas speed is low, at high rpm it makes less difference.
I would also say that typically the full radius ram will allow a larger main
venturi to be used in a DCOE, all things being equal. Theory aside they work
well with a correctly calibrated carb in my experience.
I see your point about less power with 32mm chokes as oppose 34s but was
coming from the point that I considered a 266 cammed A-Series with the spec
detailed to be such that 32mm chokes would flow less air than the car would
need at 6,000 & + rpm and would thereby limit power.
Are you using full radius type rams on your car's engine Mike?
(www.twminduction.com)
Nik
In a message dated 23/11/01 14:10:25 Pacific Standard Time,
mikeg@vicnet.net.au writes:
> 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.
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