Byron,
At 20:51 3/03/98 -0800, you wrote:
>
>My Bentley and Haynes manuals both say that the TR7 engine is a
>"detuned" Dolomite slant four. Okay so how do I tune it for max horse
>power "strictly for off road use of course".
The UK/Australian spec TR7 has about 105 hp; I think yours would be about
90. Low-compression pistons and emmission controls are probably the main
culprits.
Like any other car, you could increase the compression, port the head, fit
headers and a snorty cam, stiffer valve springs, bigger carbs or fuel
injection (I'm partial to Webers), and of course, blueprint and balance
everything that moves. If you go completely silly (ie. Stage 3 - full race),
you can get something like 180 hp, if you don't mind a rough idle (at 2,000
rpm minimum).
I started out with the Moss Tuning Manual, then joined the local Triumph
club, pulled the motor apart and decided what I wanted to do. I went for the
Dolomite Sprint head (16 valves/cyl) conversion, which offers substantially
more power at all levels of tuning. You can get a complete kit from Rimmer
Bros.
Of course, you can also go with the 3.5 litre V8, but the Sprint-engined 7's
hold their own on the track, and the conversion is a lot cheaper (the
sub-frame for the V8 is over $1,000 alone). Also, you can race 4-cyl classes
with a car that's capable of beating an 8!
Mine is only fast-road spec, but I can consult the racers in my club with
specific questions about race spec modifications.
Allen Nugent
Graduate School of Biomedical Engineering
University of New South Wales
Sydney 2052 Australia
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