Damian, I'm not a TR6 owner but I do have experience in upgrading the
performance on a number of different vehicles. It all depends on what area
of performance you're talking about, what is the vehicles intended purpose
and how much time and money you have. Personally, I would tackle the
handling aspects of the vehicle followed by the engine performance but
before I started, I would take a close look at the overall condition of your
ride. You're not doing yourself or the car any favours (Canadian spelling)
if your doing mods on a car with a rotted frame or a sick engine. The
engine part is particularly important as increaing horsepower will put added
stress on all the components creating a potentially unreliable vehicle.
Make sure your rings and bearings are fine before you start. Having said
all this, here's the order in which I'd tackle things in order of personal
preference:
HANDLING
Tires - This has been noted by numerous magazine articles as giving the
biggest improvement for your dollar. I would suggest that you stick as
close to possible to the original aspect ratio (70 series I believe).
There's not much available up here in a 70 series performance tire but I
think you have it a bit easier in the States. I currently run BF Goodrich
Comp T/A 185/70VR15's on my vintage-race prepared TR4A and they're great.
An even hotter set would be the Comp T/A R1's. Be forewarned that you
generally sacrifice wearability in exchange for performace (i.e. the better
performing the tire, the quicker it wears).
Shocks - I believe there's quite a selection of good, adjustable shocks
availble for the TR6. Stick to the name brqnds like Koni, Spax or Bilstein.
Consult with your retailer on the pro's and cons of gas vs. hydraulic. I
use Koni hydraulics up front and stock lever shocks with heavy grade
motorcycle fork oil in th rear.
Sway bars - Depending on what you're doing with the car and the condition of
your present shocks, you may want to go straight to these and forego the
shocks. Sway bars tend to reduce weight transfer during cornering without
sacrificing a lot in terms of rideability.
Springs - Heavier springs tend to be shorter than stockers and as a result,
will lower your car slightly. They work in conjunction with your shocks to
keep the tires pasted on the pavement over the various undulations.
ENGINE PERFORMANCE
Sparkplugs and cabling - Buy yourself some Splitfires or similar plug and
make sure your high tenion leads are in good shape.
Header - allows the engine to breathe more efficiently. I have a header with
2 1/2" tubing straight back to a Supertrapp. The header and 2 1/2" tubing
was recommended in the factory race preparation manual. Coincidentally, you
can probably pick one up for the TR6 through Moss or one of the other larger
parts companies.
Headwork - Porting and polishing the head also helps with engine breathing.
I did mine myself. It's a relativly simple job as long as you're patient
and don't get too carried away. A three-angle valve grind is also
recommended (probably best done by the pros).
Webers - Coining a phrase from Porsche, "There is No Substitute." Of course
this will involve a multitude of other parts. You'll need an electric fuel
pump, fuel regulator, and an intake manifold. Before you put attach the
Webers to the manifold, port and polish it as well, paying particular
attention to the areas where the carbs attach and where the manifold meets
the head. The idea is to reduce/eliminate any ridges or differences in
inside diameter between the various components. Also, if you're going to
put all this effort into helping your engine to breathe easier, spend the
extra $100 on some K&N air filters.
Camshaft - Again depends on your application but if your going for the
Webers, get the cam.
Distributer - Well if you're going this far, you may as well throw in a
Mallory dual-point distributer without vacuum advance. This will help your
engine respond much quicker to the much greater amounts of fuel and air
it'll be getting.
Well, that's it for my suggestions. Hope this helps. I'd be interested to
know what you decided to do. Oh, something just dawned on me with regard to
engine mods. Living in California may prohibit you from doing a lot of
these mods. CHECK WITH YOUR LOCAL AUTHORITIES BEFORE YOU PULL OUT YOUR
CHEQUEBOOK!!! Good luck!
Dave Page
'66 TR4A IRS
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