I've had 2 Tr6s that while not new, neither had more than 12,000 miles
when I purchased them and both (74.5 & 75) would run smoothly up to 5000
rpm with no problem. My others had more miles but would all readily run
up to 5K rpm. I recall this from passing experiences (remember two lane
highways?), where I would run up to 5K and hit the overdrive switch,
which meant I was between 52-5500 before the o/d engaged. Never had a
noticeable high rpm flat spot on these cars and certainly not on
slightly modified CF38690UO, which revs up to 6K strongly, if a little
noisily.
Jim Davis
Fortson, GA
CF38690UO
CF37325U
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of Jim Swarthout
Sent: Tuesday, June 24, 2003 12:03 AM
To: 'Ted Schumacher'; 'Sally or Dick Taylor'
Cc: 6pack@autox.team.net
Subject: RE: Problems at 4500 RPM
And a stock engine does not go flat at 4500+. Add another 700 rpm and
they will start to soften but sitting new in our showroom they would
easily turn past 4500 rpm. Ted
Ted,
Interesting! Let's hear what actual drivers have to say!
Acceleration flattens out at 4400 rpm and nearly disappears at 4800 (in
3rd
gear it takes a long time to go from 4800 to 5000 rpm).
The same thing happens in second gear but is less noticeable. I
couldn't
sense anything in first gear (I guess because it all happens too fast).
I
didn't have a place to test it in 4th gear, but I'd imagine it to be
*very*
definite (and therefore easier to measure).
Test conditions (since an earlier message mentioned some effect of
temp/humidity):
temperature: 51 F
humidity: 81%
elevation: approximately 100 feet
Stock '69 engine, but with lightened flywheel, electric fan, and Crane
XR700 electronic ignition)
I'll be interested to hear how my results compare with everyone else's!
Regards,
Cregg Cowan
71 TR6 (w/ 69 engine)
Referencing Page 10,Figure 3 in the Triumph TR6 Competition Preparation
Manual (which compares dyno runs of a stock TR6, TR6 w/10:1CR, TR6 with
S2 cam/10:1CR, and TR6 with S2 cam/10:1CR/Header) , the stock tr6 makes
max HP at 4700 RPM (103 HP) after which it falls off sharply. Therefore
I would say (according to the chart) that one should use 4700 RPM as the
max shiftpoint (although personally I prefer 4500)
Hugh Barber
Hollister, CA
I would have to say "peak " horsepower is reached at 4500 rpm, for later
models @ 104hp. After this the hp falls off even though rpm's still
climb.
Mitch Seff
Oceanside, N.Y.
75 TR6
In a stock car, I'd have to say things "stop happening" at around 4500,
more or less. Change to K&N's and it does up a tad, maybe 150 RPMs.
regards,
Bob "seat of the pants" Lang
Jim Swarthout
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