Intercooler Colour
Great mag as always! I just read your
Ten Turbo Toying Tips and have a question about
something that was said. In the very first section of the article in the
intercoolers section you say "Intercoolers should also be painted matt black for
maximum heat dissipation." How does colour have anything to do with heat
dissipation? On top of that, wouldn't a coat of paint over the bare (or
anodized) aluminium hinder heat dissipation by forming a thin layer of
insulation? Thanks.
Tim Fulton
United States
In the same way that matt black better absorbs
heat, matt black better radiates heat. However, this effect is most pronounced
with radiation that is short wave (eg visible light) rather than long wave (eg
radiated heat from a hot intercooler). However, when we back to back tested an
intercooler (one that had previously been painted black and then stripped of
paint), we saw a slight increase in intake air temps. We think the insulating
effects of a light coat of black paint are trivial.
Aftermarket Variable Inlet Manifold
Re:
Breathing Deeply. I was just going to
share with you some info about the VW VR6 motor. The 12v VR6 has three different
styles of intake manifolds, all of which have different plenum sizes and hp/tq
numbers. An aftermarket company called Schrick makes a "variable geometry"
manifold, that splits the left and right cylinders....and at low rpm the left
cylinders draw from the left side of the manifold, the right draws from the
right, then at 4000 rpm a butterfly opens and both cylinders draw from both
sides. The results are roughly 20ft lbs of torque at 4000 rpm and roughly
5-10hp near 6750 rpm. It should also be noted that with the revised 24v
VR6 motor that VW has gone back and made their own two stage
manifold!
Aaron Jongbloedt
United States
All Captivas Not the Same
I read with interest your
Holden Captiva MaXX. Having not driven it
myself, I can't confirm or reject the findings of your evaluation.
I have driven the Holden Captiva LX and it is
nothing like the car that you described. Although your article referred
only to the MaXX variant, I think it unfairly omitted to explain to readers that
this was not typical of the entire Captiva range. While the SX, CX and LX are
manufactured alongside the MaXX at the GMDAT plant at Bupyong, they are two very
different vehicles. The Holden Captiva was heavily developed by GM Holden
from its inception but had no input into the MaXX which is in fact not a Captiva
but an Opel Antara.
I just hope that readers who are more likely to
buy the 7 seat CX and LX don’t get the wrong impression.
David Field
Australia
Fan Aero
On Michael Knowling's piece on aerodynamics
(see Aero Basics), there is a minor
error in the article. The "Fan Car" from the ground effects era, the fan was not
universally used, it was only used by Brabham (BT46B), which used an Alfa Romeo
engine. The reason was that Brabham (and Ferrari) used a Flat 12 engine, which
made undercar venturis pretty much impossible. As such, they lost a significant
amount of downforce compared with cars that did have the venturis. The fan was
Gordon Murray's attempt to get around the problem (he used the argument that the
fan was not a movable aerodynamic device, but that more than 50% of the effect
was for engine cooling). The car only participated in one race, if memory
serves, and won that race.
Dennis Jensen
Australia
Supporter
Loved the new car test
Holden Captiva MaXX, don't think Holden will
though... It's refreshing to see that some parts of the media are willing to say
it like it is instead of re-hashing the manufacturers' propaganda during
supposedly independent tests. If it's good then it's good, if it ain’t then it
ain’t - can't be any simpler really?
My 2c on other comments regarding content and
credits for articles: I have been a follower of Julian (& Co) from Zoom
through to AutoSpeed and I have found that things are credited as to their
origin and editorial view except where a mistake is made. From my
experience in those situations, mistakes always seem to be corrected and
a statement is made detailing this. There is no secret made of the fact
that views stated are the opinion of Julian (& Co) whether they are
favourable or not. I feel that AutoSpeed goes out of their way to state this in
all their articles; witness the negative feedback regularly posted on
your site. If it were just a chest beating site, would these comments
be there? I feel that the majority of subscribers are more than
happy with the site, going by the quality improvements that have
been happening over the years. You guys will always have my
subscription.
Darren
Roles
Australia
Departed
I have been a regular reader for the last 5 years
and will no longer continue to subscribe to this website due to the repeating of
articles I have read. There is no longer daily enjoyment to see what
article is there as most are re-hashed.
Ashley Quinn
Australia
Thanks for your support over the years.
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