Roger,
RE:" I do not know of any other major manf using such an ill
thought out contraption...[vacuum retard unit]"
Actually, they copied it from a Chrysler design developed in the
'60's. I think it's a great idea myself. What if the Triumph folks had
never used it, and someone came on the list and said "hey, with $20 of
junkyard parts, I can help you rig a system that will get you past idle
emissions easily, but won't change the performance of your engine one bit
above idle speed. You won't have to retune your entire engine just to get
through Smog Check." That lister would be a hero, I think. He'd be invited
to present his invention on the VTR pages, and even the skeptics would
probably take him seriously enough to at least hear him out. But when the
Triumph engineers do the same thing, we get posts like "Vacuum
retard=miserable '70's emissions control device, vacuum advance=more
power". (Not you Roger, I know you understand the system).
RE:"Say I downshift to 3rd to be ready to pass on a 2-lane road,
now change lanes and kick it... now count to 10 as the darn timing is 14
rear of where its supposed to be and doesn't correct till moments "after"
the pedal is punched."
Now really, Roger, count to 10? On my car the timing change is
almost instantaneous, try it with a strobe and see.
RE":I think this is a result of the engine running at maximum
efficiency, instead of choking it by firing the mixture 4 degress after TDC
(actually more due to the proprogation delay of the burn, see engine books
for details). By turning both idle screws the same amount
counter-clockwise this can be easily corrected. Above assumes idle timing
12 BTDC @ 800 RPM"
What I was referring to is the fact that in some later cars, it
seems like you run out of idle speed adjustability once you advance the
idle timing 14 deg. Of course the speed goes up due to greater efficiency,
I know that without checking "engine books" for details. But the problem is
that with the idle adjustment screws backed all the way out, later carbs
don't seem to have the throttle butterflies as completely closed as carbs
on cars intended to run with advanced idle ignition.
With regards to your very manly Autocross challenge, we all choose
to enjoy our TR's differently on this list, from daily driver to autocross
to concours d'trailer queen. I fall somewhere in the middle, but I prefer
to do my aggressive driving in cars that were produced *after* the Beatles
released the White Album, so I'll pass.
Best Regards,
Tom Marincic
CD3574L
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