Dear fellow English car buffs,
I have been thinking of some modifications to make to the
somewhat restrictive engine breathing (intake & exhaust) system of the
jag, and I've received a few good suggestions over the NET.
I decided to start by enlarging the air intake ducts that feed
air into the air filter boxes. I saw that Lister Performance offers a
larger X-section intake stack, about 3"dia. as opposed to the 1.5"dia.
that is currently on the car. There are 2, one for each bank of 6
cylinders. Note, the intake throttle bodies are about 3" in diameter,
and are mounted immediately behind the air filter element.
Being a tinkerer, weekend welder, college student and cheapo, I
decided I could make what Lister offered for cheaper than $50, and
probably make it better. Sunday, Dianne and I fabricated 3" stacks and
welded them to the factory airboxes, in place of the 1.5" stacks. The
difference in high-rpm power of the engine is noticeable, however there
is an increase in full-throttle engine noise.
The whole job cost me under $3, and looks almost factory. What
I'd like to do now, both to cure the noise at full throttle, and to boost
performance, is to make two cutouts in the small shroud above the
radiator. From these I could run 3" flexible piping back to the 3"
stacks. I think that flexible aluminum dryer ducting painted flat black
with black clamps would look unobtrusive, and even perhaps professional.
This way, I would get COOL air to the intake, and have some
degree of muffling for the intake passages. I bought the stuff for this
job too, and it was under $4. However, I won't be back at my shop till
spring break, so it'll have to wait.
But even now, the increased performance of the car is most
noticeable at high speeds on the freeway, and it's more fun to drive.
I just thought you might like to know.
Greg
Greg Meboe meboe@wsunix.wsu.edu
Dept. of Mechanical and Materials Engineering
Washington State University, Pullman, Wa.
'85 XJ-12 H.E. (daily) '67 Spit-6 '74 TR-6
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