Dave M. commented on possibly having a Horsepower competition at a car
event...
Funny you should mention this. I've been tossing around the idea of doing
just what you suggest with our club. The difference would be - instead of
every body getting speeding tickets from the local gendarmes - we would
arrange to have a rolling dyno at the location (or we would go to it) and
then figure out how to award folks by measured output. The problem is - how
do you select winners??? I mean - a Spitfire has no chance of building the
kind of power you can get with a really tweaked-out TR8 motor. I'm talking
Woody Cooper's "Bad 8" here. That sucker's making some serious power!
Oh well. I'll figure it out one day.
On a related topic, someone posted a question regarding what sort of power
a warmed over TR6 motor might make. Good question, and as several folks
have pointed out - pretty hard to answer, especially because we have no
idea what tweaks are done to the cam. Our hint is the .014 valve lash -
this would indicate a slightly warmed over cam, not a really hot cam like
an S4 or the Kent Road/Rallye cam.
But all that aside, figure the following _gross estimates_.
Note: this is a US spec car with low compression and the US spec cam. FWIW,
72 is the best of both worlds - higher compression, longer intake runners
and the best cam combo. All others (earlier or later) are less than ideal.
Stock - 104 HP (more or less)
Warmed over #1 - header, K&N filters, free flow exhaust - 115-120
Warmed over #2 - #1 plus port matching - maybe 125 HP
Warmed over #3 - #2 plus fan removed (and an electric fan installed) -
maybe 130. Supposedly, parasitic loss from the TR6 fan is up to 8 HP.
That's a lot!
Note: a tuned exhaust may provide slightly better numbers. A really good
header helps a lot. I have no empirical data for this, but JK Jackson has
said this to me as well as Dave Hogenbush from TRF. They don't give any
numbers but they do indicate that this is generally true.
The PI cam is better and non federal TR6's run higher compression. Think
150 HP or more if you free up the air intake and exhaust, but not a lot more.
Remember: if you plan on "playing" with your car (road racing or autox) the
rules are pretty specific about what you can do to tweak the car. This
means that in the US, PI cams are not stock and put you in the "prepared"
or "mod" classes and raising the compression a lot is a def. no-no for the
stock classes. However, VTR rules are pretty much different than SCCA, so
if you follow those rules, you could build a pretty quick car... but I
won't give any secrets away. ;-)
At any rate - there's some fuel for the discussion.
Bye,
rml
TR6's
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