A Matter of Manifolds
I have been enjoying all of your junkyard and low budget
tech articles for the past two years. I have even been adapting some of your
ideas to my own turbo project car - a 1977 280Z with a 1982 280ZX turbo motor. I
recently decided to run the stock cast manifold due to its durability and I was
wondering if you guys are planning a test between cast and tubular manifolds?
We have done a couple of stories covering cast and tubular
manifolds (see "Buncha Bananas", "Out the Exhaust - Part Three" and "Spool Time").A
side-by-side test would be almost impossible to perform.
Down with the Drone!
I was just reading Response at and came upon "Damn Drone!"
from Gordon Pieterse, South Africa. I think I know exactly what he
The short answer is to mount something like the Moroso
Spiral-Flow or a Flo-Pro Twister muffler immediately after (or in place of) the
cat converter. Follow this with an effective straight-through absorption muffler
like those made by Borla.
The Moroso and Flo-Pro designs are very similar and very cost
effective. Each uses two different length flow paths for the exhaust - one path
is around the circumference, the other is straight through a centre pipe. The
length of these two paths allows destructive interference of the acoustic waves
as specific frequencies. This can be very efficient at reducing loud resonances
IF they are tuned fairly close to the offending frequencies.
Word on the street (and track) is that the Moroso Sprial-Flow
muffler is very good at reducing cabin resonance in cars with large, open flow
exhaust system with or without turbos. It offers less restriction (it seems)
than chambered mufflers, but is very effective where most resonance occurs
(about 3000 rpm).
I wanted to contact Unorthodox Racing at their website after
reading "Michael's Speed Zone".
There seems to be no email and I was wondering if you knew how to get a hold of
them? I'd like a crank pulley for a 1999 Mazda 626 2.0-liter 4 cylinder.
There's a Contact Us box on the site.
Excellent timing on the intercooler article
("The World's Biggest Intercooler Comparison - Part One")! I am just about to purchase
a JDM Galant VR4 (another excellent article by you guys!) and the info on the
intercooler was a real eye opener. I had always thought that bigger was better,
but please bear with me on this... The mass of the core is important in regards
to dissipating heat while intercooler flow is important in regards to spooling the
turbo up? Does that mean if I intend to use the car for occasional track days
that mass or flow is more important? Additionally, is there any way to improve
the flow or do you just ditch the 'cooler and throw in another one? Keep up the
The mass of the intercooler is important for absorbing short
stints of boost, which is typical in point and squirt traffic conditions. The
biggest advantage of a high flowing intercooler can be found at high rpm and
load, where the engine is consuming a huge mass of air. A good 'cooler will pose
minimal flow restriction between the turbo and engine, while a poor flowing core
will require you spin the turbo harder (and generate more charge air heat) to
achieve the same manifold pressure. It's difficult to improve the charge-air
flow through an intercooler without inserting a new core and/or end-tanks - you
might as well "throw in another one" in most cases. For track work - where boost
is sustained for long periods - the cooling volume of the core is most
important. Bigger is generally better in this regard (ignoring internal design,
I am playing around with a dyno program from the 'net - www.tweecer.com/StreetDyno/The
program requires detailed specs on the car such as gear ratios, Cd, etc. Do you
know where this sort of info can be found? I notice most of your articles quote
this sort of information, but it is not in my car's user manual and I can't find
it on the 'net (I have a 1992 Mazda 323 Astina SOHC). Any leads will be
figures and other tech data are often quite difficult to find - particularly as
the car gets older. The best way to obtain this info is to look back
through old car magazines (accessible at a public library near you) and search
the web (as you've already tried!).
Come to Me, Cdti...
I would like to know if there is any way to get an Opel CDTi
1.3 litre Ecotec 4-cylinder diesel engine in Australia and what would be the
best way to get it.
Try Holden Australia or Opel dealers overseas - maybe some
readers can help out?
HSV Holiday #1
Re Julian's visit with HSV "The Spin Circuit"... All very valid observations
from another who is perhaps cynical of marketing spin. Just because it's new
doesn't mean it's better. I read with utter confusion why a manufacturer might
say that the new car has x% better torsional resistance, x% better power, x%
better this that and the other. Does this mean the previous model is a heap of
sh*& and should be sold immediately before it kills you? I think not. Why
else would we restore older cars? It's all about what appeals to you. Why else
would there be a '67 Alfa GTV in my garage when my daily cars have been more
modern (fuel injection, turbo, electronics, etc)?
I hope that Julian isn't a victim of a company shutting down
freedom of speech and that more journalists get to the real questions. Who cares
if their green is better than yours, or worse "they aren't even on our radar"?
HSV Holiday #2
I've written to AutoSpeed briefly in the past about little
things, but I wanted to convey my thoughts on the article "The Spin Circuit". The Spin Circuit is,
possibly, the best technical-or-not thing I've read on AutoSpeed since I began
reading. It had everything - from the marketing crap, to who'd speak and who
wouldn't, other journalists' behaviour and more.
I just have two points to make - first, I hope the candid
material you got from those sadly rare interviews sees the light of day in
future articles. And, second, did HSV fly you business class or economy? That'd
be an interesting footnote to add to the article. That said, though,
congratulations for continuing to try and raise the ethical standard by noting
Julian was flown economy class and, yes, there will be stories appearing
from those interviews