Greg---Cars that I've driven with the early cam shaft and the 8.5:1 CR
definitely feel to have more low end torque, (and also fade out more
quickly above 4500 rpm). Since the top end is of no concern to you, I'd
go with the 10/50 50/10 duration.
Advancing the cam timing a few degrees will help with low end torque
a bit more.
Roller rockers with increased ratios will get back some of the top
end breathing, but it is an expensive way to go, unless you feel you
need to replace worn out rockers and shaft anyway.
Advance the ignition timing a few more degrees, if you can do this
without engine ping. Higher octane fuel can help out with warding off
the pinging, but is not cost effective.
Lightening the car also helps to get up to speed quicker. See if
there's stuff in the trunk you don't need to carry.
Smaller tires, both in diameter and (wheel) weight, can make the kind
of difference you are looking for. Since you have OD, you might feel
this is a worthwhile replacement, when the time comes to replace them
anyway.
Dick
From:
rgperry@earthlink.net(Greg Perry)
Hello List,
First, Happy Independence Day weekend USA!
Since I have a stock 72 TR6 with carbs, A type overdrive and dual
exhaust, the highway rpm range is from 2100 to 3000 depending on traffic
and road conditions. I am interested in maximizing the lower torque
range from 1200 to 3000 rpm. I am not interested in HP ratings. Torque
gets you down the road. The web site Triumph 2000 Tuning website
http://www.kvaleberg.com/t_tune.html
has an extensive list of camshaft profiles for PI models. It seems
that the stock camshafts are better suited to my needs. The pre 72 USA
TR250/TR6 camshaft (10/50 50/10) has a power band 1500- 4800 and the
currently installed 72 onwards USA camshaft (18/58 58/18) has a power
band 2000-5000.
1. If the pre 72 camshaft is put into a stock 72 motor, what are the
opinions from the list about a possible torque increase and performance
if any?
2. Would I get a similar result by increasing the valve lift with 1.55:1
roller rockers on the currently installed camshaft 72 onwards?
3. Any other suggestions for increasing the low end torque?
4. Or am I just wasting my time and future money for a small performance
increase?
I am only considering options available in the future if/when I
need/decide to rebuild the engine. I could collect the parts when they
are on sale in the future. I will probably do a little autocrossing at
the local scca events after getting the suspension up to the task.
Thanks,
Greg Perry
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