Phil (R?), about what gas for your TR-6, use the best you can, like maybe
Sunoco Ultra, unless you find you can run with something of lower octane with
no pinging (or if you prefer, no pinking). The way I read it was that "back
then" they used Motor and Research octane without specifying which, though
they differed by as much as 4 points. Now, by federal law, they give the
simple average (R+M)/2 as described on all the pumps, so there may be a 2 or
even 3 point difference between what you can get now and what "they" always
said, and it is a safe bet that most gas manufacturers, if not also the car
manufacturers, used the higher of the two (which I don't remember now which
one that was, but it doesn't matter), so now you can figure your car's gas
requirments to be lower by several points. (whew) Depending on when this
great nomenclature switchover came about, and I don't remember that. About
lead-free, all US car were required to use lead-free gas beginning in about
the early 70's (I think) but I don't know for sure, and most if not all TR-6
engines are capable of handling lead-free anyway, aren't they, somebody? If
you really need the lead for valve lubrication, you might as well just run
it with no-lead and monitor your valve clearance carefully, and *then* if
you need to, take the head off and repalce the valve seats.
About all those prototypes, the Triumph books by both Robeson and (blank
looks all around - blank mind too - Charles somebody? argh!) discuss the
Fury and the Bullet and Lynx. The Fury might have been an interesting car.
The latest newletter of New England Triumphs has a piece about the TR-6P
(P for Penguin), a possible Stag replacement as a high-end luxo-sports car,
to be built on a TR-6 chassis, extended by another set of seats and doors
to make a TR-6 4-door/4-seater. It claims there were 6 of them built,
though not all necessarily all as 4-seaters, and the Penguine name came from
the marketing concept of having only two color schemes, black on white or
white on black. Seems some guy in California has one of them now. I wonder
if maybe mjb or R.G had anything to do with writing that report. It smells
kinda' Aprilly First-ish, if you know what I mean. Has anyone else ever
heard of these cars?
Speaking of exhaust systems and what *should* work better, last year I found a
book in a used-book store, published by Bentley in 1962 and also by Whitefriars
Press, London, called Scientific Design of Intake and Exhaust Systems, by
Phillip Smith. It is interesting because it is quite applicable to the sorts
of things that the typical British car builder was doing when our LBC's were
developed. It discusses the Jaguar head at length, the Herald intake system,
the BMC A-series (I think), and a whole gamut of experiments done to study the
how the exhaust and intake systems affect performance. The best summary is
that you want to maximize exhaust scavenging and cylinder filling (emissions
were not an issue then, I guess). The most important factors are the timing
of the pressure pulses at the exhaust valve from resonance in the exhaust pipe
and muffler as a system, plus lowest total backpressure. All this is rpm-
dependent, and practically nothing can be generalized. There was a chapter
on muffler design, and it showed by theoretical analysis and experiment that
the kinds of things that are "supposed" to work are not always the best. This
chapter went through a "design effort" for a muffler, and it turned out to be
not so simple, and not at all reversible. And it you put the same muffler on
a different engine or with a different set of pipe lengths or with a different
"resonator" (pre-muffler expansion box) etc., the power curve might be totally
different. About the only thing you can conclude if you want to find the best
solution for your own car (when the supposedly "optimal" factory setup is not
available) is that it is hit-or-miss. So it is not surprising that the
much cheaper "Super-glue" (or whatever) muffler worked better on a Lotus Eureka
(with apologies to Maynard G. Krebbs) than a more expensive "Free-Flow-Fine"
(or whatever).
Am I done now?
Jim Muller
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