Variable Nozzle Turbo Boost Control
In response to
Brilliant Boost, I don't think this
approach will work with variable nozzle turbochargers (VNT). My car (Ford
Focus turbo-diesel) has one, and boost is controlled by varying the angle of the
turbine nozzles which vary the angle of impingement of the exhaust gases onto
the turbine blades. This is I think is supposed to increase the range of engine
speeds over which effective boost pressure is available. The vanes are
controlled by the ECU and there is no wastegate. I assume in these
cases the boost would need to be raised by remapping the ECU. VNTs can usually
be identified by the actuator linkage and pivot attached to the turbine
As you have said, a pneumatic boost control
modification is not suitable for a variable nozzle turbo. By now you will have
Turbo Diesel Hilux Power!
which covers the
power-up of a diesel engine with direct ECU actuation of the turbo geometry.
In reply to Peter Bodon's
Response, diesel tuning
is already big business in the UK and Europe, since around a third of cars sold
here are now diesels, mostly turbocharged. Tuning generally takes the form of
chipping, adding on a tuning box or remapping, with or without a rolling road
Companies often quote increases of 20-30% in power
or torque available without resorting to further mods such as free-flow intakes
or exhausts. Check out companies such as Superchips (www.superchips.co.uk), Tunit
(www.tunit.co.uk) and Van
I'm sure at least some of these type of products must be available in
I've driven the Prius a few times - we have a
number as pool cars at work - and also various turbo-diesels (I own a Ford Focus
TDCi) and, for me, the effortless low-to-mid-range punch and relaxed high-speed
cruising of a modern turbo-diesel beats the Prius hands-down every time. Open
road fuel economy is pretty similar as the hybrid gives its best results around
I write to offer an observation on repeated
articles. Whilst I would rather not see them, that is not the main reason for my
I note that recently you have published a number
of letters offering negative feedback regarding repeat articles, but none
offering positive feedback (that I could see, anyway). Either you are choosing
to only publish negative letters, or you have not received any positive ones.
Whatever the case is, it's not a good look when you are constantly publishing
only these negative letters and then defending them, and in one recent case,
quite abruptly (the “vote with your money” response). I do note that you have
subsequently removed it. All I am suggesting is that you give consideration to
balancing the negative feedback by publishing some letters in support of the
repeated articles, if you have received any.
You have stated that you are unlikely to change
this editorial policy, and at the end of the day, it's your magazine and you can
publish what you like. As a long-time subscriber, it won’t cause me to
discontinue my subscription; I just fear that if you are seen to be resisting
frequent calls to reverse the policy, it might give the perception that
AutoSpeed is not giving what the readers want. I'm sure this is not the case,
but as you are well aware, what the public see and what is the reality can be
very different things. In closing, despite my feedback above, I believe
AutoSpeed is a good alternative to the mainstream car magazines (to which I no
longer subscribe), and while it remains that, I'll continue to be a
PS: Please, please, please give consideration to
bringing columns back. When I do read a mainstream car magazine, I always go and
read them first.
The reason for the existence of Response is to
allow readers to complain, state where corrections need to be made – and yes,
occasionally praise us. To suggest that “it’s not a good look” when we publish
criticism is to completely miss the point of why Response exists. Incidentally,
we have not removed the reply from the previous Response that, should a reader
feel sufficiently aggrieved with our editorial changes, they have the option of
withdrawing financial support. Nor do we consider such a sentiment abrupt: it’s
a fact that should be stated.
We have received no letters specifically in
support of repeat articles. That’s not surprising since contributions to
Response are limited to subscribers - and long-term subscribers are those most
likely to have previously seen the repeated material. Instead, to gauge the
popularity of repeat articles, we refer to Reader Ratings (ie the score
subscribers can give by clicking on the numbers at the end of the articles) and
actual readership page views, which include both subscribers and
non-subscribers. As we have previously said, both sets of stats show that repeat
articles are popular.
Re the columns: where have you been? The
columns were dropped about 5 years ago....
I fitted the Jim Mock Motorsports exhaust to
my 94 NC Fairlane in combo with existing Pacemaker extractors about 18 months
ago. This was followed by a 10,000km "test drive." The improvement in power off
the mark and through to 4500 rpm is awesome. There are no droning noises and the
exhaust noise is well within legal requirements. It is easy to forget the
improved exhaust is fitted until you put your foot down. Power uphill is
dramatically improved and overtaking is a breeze. Average fuel consumption
improved from 11.5 l/100km to 10 l/100km. Considering this was with a fully
laden car with four adults on board (about 2 tonnes all up) and driving through
days up to 39C heat, I reckon the exhaust was worth every cent.
be interesting to see the results of the same exhaust fitted to your test
Where are the Diagrams?
is a very interesting article, which is unfortunately let down by a lack of your
usual brightly coloured diagrams; this would greatly improve comprehension of
the systems proposed.
Fair point. The whole topic is very interesting
and is one we keep meaning to revisit with a fuel economy-based project. We
promise we’ll use colour diagrams then!
Diesel Emissions Technology
Your magazine is top shelf for technology reviews.
As such, I would love to see a review of the current diesel NOx abatement
systems, with and without urea injection, to meet the Tier 2 Bin 5 emission
requirements, including assessments as to hardware complexity
(maintenance/control), performance and/or mileage impacts, etc. Other diesel
emission abatement equipment assessments, such as particulate filters, would be
It’s an area we expect to do a tech article on
in the near future.
Something which has
always attracted me to AutoSpeed has been the constant source of new ideas,
innovation and the practical technical articles. However, I think some of the
latest changes are taking AutoSpeed into the territory of the boring monthly
magazines. As you have pointed out before, it is common for monthly publications
to repeat topics every two or three years as new readers come on board.
AutoSpeed's recent adoption of this principle has significantly decreased my
reading enjoyment! I for one would support increased subscription fees, or an
increase in site advertising, to support a return to the “one new article per
day" editorial policy. Yes, I realise I might not be in the majority with the
first suggestion, but I think its something which requires serious
Let’s be blunt: no modified car publication
in the world has over the long term a constant stream of new, worthy ideas and
innovation. Some can sustain it for a period; none can sustain it indefinitely.
We have never made any pretence that we are a “constant source of new ideas
innovation”. How many ways can you do a car exhaust? How many ways can you
do a car intake? How many ways can you do a turbo boost control?
But that said, in the same way that we have
been doing for the last 8 years, we strive to put a new slant on car
modification and technology. In just the last 8 weeks we’ve done stories
which, we think, you’d look a long way to find in any other modified car
publication. Stories like
Diesel Hybrid!, Building a Work Bench, Springs and Natural Frequencies, Common Rail Diesel Engine Management, Part 1 and Common Rail Diesel Engine Management, Part 2, Spring Swaps!, How Heavy's Your Knob?, The New Intelligent Intercooler Water Spray Controller, Part 1 and The New Intelligent Intercooler Water Spray Controller, Part 2, and The New Global Hybrid System.
Just wanted to comment on the excellent
article on fitting the exhaust system (see
Frank's Exhaust, Part 2). I have read
Julian Edgar's excellent book "21st Century Performance" recently cover to
cover. Finding AutoSpeed only recently and then the added bonus of his
articles that are not only informative but definitely focussed on the real world
of true motoring enthusiasts, made my decision to subscribe both easy and
rewarding. Back to the exhaust article: this has provided me with a lot of
information for some modifications I wish to make on my current exhaust
system. So a big thankyou.
Won’t be Coming Back
Your review on the new
Astra SRi Turbo is very unusual for a
so-called motoring expert web site. Also you say the Focus XR5 is
fantastic yet it is so noisy in the cabin (tyre and road noise), a just as hard
ride, no foot rest, no cruise yet you say it is fantastic. It has massive torque
and weight at the front. Like the Mazda 3 MPS, too much for a FWD.
When you give it a blast (like any other turbo) it will also give you 13L/100km.
Same performance as the Astra. Sure a good car but fantastic? I won't be
returning to your web site, not for me but some will like it.
Is it possible to print readable versions of the
thumbnail pictures that come with the technical articles?
In nearly all cases, clicking on the picture
will bring up a larger version.
Likes Audi Test
I just changed my vehicle from an '03 BMW M5 to an
'06 Audi S4 Avant and having had it for a few days and being rather disappointed
by the performance, decided to Google some reviews to see if it is just me or my
Audi S4 Road Test is absolutely spot on. I
have the exact same feelings about the curious throttle response, wooden and
understeery chassis and complete resistance to throttle steering. Add to that
list pedals poorly placed for heel-toe downshifts and slower than expected
acceleration and I’m starting to miss my M5, which did everything the complete
opposite. That was a far, far more thrilling car and just loved to hang the tail
The S4 is good for people who drive on part throttle and never
venture near the limits of adhesion. Driven in these conditions the S4 is in its
element. Beyond that, it falls apart and reveals Audi's real philosophy, even
for their S models: safety and security but zero excitement.
Some further Googling revealed that you are the
only magazine to REALLY say it how it is. These problems are barely alluded to
in other reviews and I appreciate your honesty. I have bookmarked your
Oval Shaped Chain-rings 1
In your latest driving emotion 'Engineering
innovation that leaves modified cars for dead' (see
Driving Emotion) you spoke of the oval
shaped chain rings and their lack of popularity in pedal powered machines. I own
an older model race bike which I received free from someone who didn’t want it
any more and noticed that the chain ring was oval. Because I had never heard of
this before I went to the bike shop to ask about it. The store guy told me that
this system is unpopular because it leads to knee injures so that would explain
the lack of popularity. All I can say is while I now have a new bike I haven’t
had any injuries after riding the oval for 2 years, and now my dad rides it and
hasn’t had any injuries either.
Hope this helps, and keep up with the
articles on cheaper fun cars for young people with no money!
Oval Shaped Chain-rings 2
Interesting what was written by about the oval
cogs for bikes. I had used these on a pushbike nearly twenty years ago. Yes they
are excellent but they have one major downside which caused me to remove them,
that being - every 13 revolutions or so, the whole pedalling process resets
itself. For one whole single revolution your legs completely 'free wheel'! You
can still order them from most bike shops in Oz but the bike sales staff will
more than likely try to talk you out of buying them. Surprised this
never got mentioned, that's why they never took off.
There is no reason why oval shaped chain-rings
should exhibit the behaviour to which you refer – and as far as we’re concerned,