Hi,
The initial question was (paraphrased): "will a twin-pipe system (72 and
later) fit an early car."
Short answer: yes.
Will it make more power?
Short answer: not necessarily.
There can be some benefit from using a single pipe, sized correctly. That
benefit comes from the scavaging effect of the "other three" cylinders. If
you've read the TR6 Comp. Prep. Manual, you'll no doubt notice that it says
to use a 2.5 inch pipe from the collector to the back of the car. There's a
reason for this.
The dyno doesn't lie.
Most of the twin-pipe systems don't share any space with the front three
cylinders and the rear three cylinders. This has some drawbacks, namely in
the form of less power potential.
By way of example, take the Group 44/ ex-PLN TR6. While all the pictures
show that there are two pipes coming out the back, you might get the
impression that two is better than one. Well, careful examination of that
particular car reveals that just after the primary tubes end, the pipes are
all tied into one "box" and then the two pipes split out to the back of the
car, and those impressive MEGAPHONES. To say the car sounds impressive is
an understatement.
So what? you ask. How about 230 HP on the dyno.
I don't have any numbers handy, but figure a twin pipe system without a
crossover tube would yield something less - figure under 220 for the same
setup. But that's a race engine, and not likely how you'll be using yours.
So, what should you get?
Depends what you want to do. If your goal is only power - get the nice
header from TRF (TRFCD4) and the SS "sport system". If you want better
power (I think the single tube part of the exhaust kits from the various
manufacturers are a little on the small side), then have a custom setup
made and use 2.5 inch pipe after the collector, and split it out if you
want into two mufflers if you wish. The kits like the Monza kit or the SS
kit from TRF seem to use a glass-pack first and then a resonator. I've seen
a few installations that just use a hi-po resonator only (like a
Flowmaster) and the car isn't too-too loud. Unless you tromp on it. They
don't call it the LOUD pedal for nothing.
But - remember that if you wind up using mufflers of any type, you'll be
cutting your power, in some cases by a lot.
As another point of reference, most of the "temple of triumph" guys use a
straight pipe with a few of the faster ones using a megaphone to get the
most power. But those babies are LOUD and def. not suggested for a street
machine.
So, if I were you, I'd go for the "early" header, and a custom setup. If I
didn't want to play around with that, the next best thing would be to get
the SS setup that you initially referred to - again, I'd go with the
earlier setup, but that's my preference.
If you really want to drive your neighbors crazy, put on the Monza setup.
They're LOUD.
If I get some money put aside this year, I intend to get my TR6 on a dyno
with the Monza setup to get a baseline number and then later on when I get
a custom system on there to get another set of numbers. I'll be the Monza
system does not really help all that much.
Oh well. Enough rambling. It's your car, dowhatchawanna.
rml
=====================================================================
Bob Lang | TR 6 Guy | Editor: New England Triumphs
Phone: | 617-253-7438 (days)| 781-438-2568 (eves)
Occupation: | ComputerZ | TR fixer-Upper
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