> Hi,
Hi.
>
> I've just returned from an Open Super-Sprint event at the local track
> and need some help in setting the '6 up properly. I don't have any
> problems with the engine - it revs to 6500 - no problems - plenty of
> power.
Being from the 'states, I'm not sure quite what a super sprint is, but I'll
assume you are road racing or time trailing... is this a good assumption?
> What I need help on is the handling side - tyre pressures,
> front end camber settings, size of front/rear sway bars, brake
> settings, shock settings, tyre size and type etc... anything that
> will make it handle better and safer.
In order: tire pressure: talk to the manufacturer of the tires. If you are
serious about performance, you need to get good tires. In the states, a lot
of racing classes specify Department of Transportation legal tires... that
means they could be registered and used on the road, but they would not
last very long! At any rate, the tires pressures depend on the weight of
the car and the cornering forces. It's safe to say that you need more air
pressure than you might on the street, but we have some racing radials in
the states that use similar tire pressures to what you might use on the
street. If you are doing serious high speeds, I'd stray away from "street
tires" and go for slicks - depends on what you are doing.
Camber: if you are running bias ply tires, then you probably want to stick
closely to the factory specs, -.5 camber and zero toe. If you find that
zero toe does not provide adequate "turn in" then you should consider
adding a bit of toe _out_. Maybe 1/16 inch... If you are running radials,
you need more camber. To get a lot of camber on the front of a TR6, you
might have to resort to some magic, but 4 or 5 shims can get you in the
-1.0 to -1.5 degree range. The way to check this is to get a pyrometer and
spend some time at the skid pad measuring the tire temperatures: you want
even temps across the face of the tire after a spirited run on the skid pad.
Bars: 7/8 inch on the front and 3/4 inch in the back. Addco makes a bar
available in the states. For tuning the car, you might need to modify the
Addco bar for "no sway bar pre-load". This will make your car more balanced
on turn in for both left and right turns... this will help you drive more
smoothly.
Brakes: not knowing what you are doing, this is tough to offer advice.
Racers like "harder" pads, so you might look for some metallic linings. If
you are doing "real road racing" a higher temp pad might be the right way
to go. Talk to other racers about what they are using. The back brakes on a
TR6 are problematic. The cast iron drums expand quite a lot and this will
cause some loss of pedal if the brakes are adjusted too loose. If you rules
allow it, you should give serious consideration to "alfin" drums (the 240Z
drums can be made to fit with a small amount of machining). Ideally, you
can increase the front calipers and move the stock front calipers to the
rear for 4 wheel disk brakes. If you do this, you need to dunp the stock
master cylinder and replace it with two seperate masters with a "balance
bar" or proportioning valve so that you can adjust the brake bias. If you
go this route, you're starting to get "serious".
Shocks: Spax or Konis are adjustable. I use Spax - they are less expensive.
I set 'em "hard" all the way and then soften them up till the understeer
goes away. This works okay for me. In the rear you can modify the damping
rate of the lever shocks by playing with the internals... don't use really
thick oil in them or you'll wreck the seals! There are conversion kits for
telescopic shocks for the rear. Be careful if you go this route: some of
the kits bolt to the body (very bad) and some interfere with the inside of
the rear wheel. If you're really ambitious, you convert to coil-overs on
all four corners - but that is a really serious excercise in engineering!
Tires: this is a possible religious thing for many. I run 225/55-15's on my
TR6. I have to use 1/4 inch spacers to keep the rear from rubbing the inner
fender on really hard cornering. I'd recommend 6 inch or wider rims for
tires of this size - this year I'm going to use 7 inch "revolutions"
because I got a real deal on them. I suspect these wheels and the tires
that I'm using will not cause any problems. I prefer radial tires because
they are really responsive. A lot of folks like bias racing tires... it's a
matter of preference. I use Hoosier D.O.T. approved radials in the "road
racing" compound... they stick really well.
> Any one with experience in racing these things (especially in Aust.)
> like to impart a bit of knowledge and help me out? My '6 is road
> registered and needs to be 'street legal'. All suggestions would be
> appreciated.
I hope this helps a bit.
I would also suggest that you get a book like "How to Make Your Car Handle"
by Fred Puhn - some consider it THE bible for exaplaining handling
characteristics... also get a copy of the TR6 Comp Prep book by Kas
Kastener, it has a lot of good stuff in it. If you are really adventurous,
try to find a copy of "Tuning Standard Triumphs Over 1300 CC" by David
Vizard. There's lots of trick stuff in there on how to make Your TR go!!!
It's been out of print for 25 years, but its a pretty good resource.
>
> TIA
regards,
Bob Lang
TR6's
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Bob Lang | Editor | New England Triumphs
Phone: 781-438-2568 | |
FAX: 617-258-9535 | |
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