jonmac and List,
I get the impression that in Europe and the UK it is felt that the SU's
are much better than the ZS. For example, Roger Williams suggests the
replacement of the ZS with SU.
This doesn't seem to be common practice here in the US. I have the
general impression that many in the US don't see a big difference
between the SU and ZS.
Would anyone care to comment as to why this difference of opinion exists?
Don Malling
jonmac wrote:
> At the risk of arriving late in this topic (I'm only in digest mode) some
> thoughts of PI cars based on personal experience and ownership of them for
> thirty odd years. The power difference between injected and Stromberged cars
> was, as someone has already pointed out, not just the addition of a Lucas
> system. I'm not at ease with some of the highlighted differences but it would
> be entirely possible to extract the same or closely similar power output to
> the injected car by using injection components and no Lucas system - i.e. two
> 1 3/4" SU's, properly jetted and needled would suffice and without recourse to
> Weber or Dellorto carbs - as the factory proved on engineering development
> cars. This is what many European enthusiasts have been doing for many years
> when buying carbed TR250/TR6's from the US and 'upgrading' them to extract
> closely similar injected engine power. Also, it should be remembered the
> injection system itself was hardly rocket science. The exactitude of precisely
> metered fuel delivery for optimum performance, economy and what-have-you
> really existed in the minds of the sales brochure authors. In reality, the
> picture was very different. There was no engine management system of any sort
> that we accept as the norm today and the injection engine was so 'dirty' in
> terms of emissions, that it would be banned from use today - almost anywhere.
> The set-up of the metering unit in terms of tracking the fuel delivery curve
> across a variable range of engine speed and loads requires a fuel injection
> flow bench - and even then, it's a hit and miss affair in contrast to modern
> systems using mono or multipoint injectors. Perhaps the worst aspect of the
> Lucas system is it had no altitude compensation and only operated at its most
> "efficient" at sea-level conditions or close to them. That's one of the
> reasons why former US cars are so popular in Europe. The steering is already
> in the right place and only the engine needs attention to uplift its power. If
> you put all these variables into one pot, all you have is a TR5 or 6 or a
> 2.5PI saloon that is faster than its contemporaries, is fun and quirky - and
> by no means devoid of its own unique problems in the diagnostics department.
> It also has a rather unique noise from the exhaust and air intakes and can be
> most encouragingly fast when pressure is applied with the right foot. In
> short, it's a Triumph - warts and all.
>
> Jonmac
>
> "In the Shadow of my Father" aka "Life at Triumph"
> Still a few copies left. Still time to catch the Christmas mail
> http://www.toolbox.ndirect.co.uk/triumphbook
>
>
> ---
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