Emissions Info
The recent article Emissions Regulations - Part Two made for interesting reading given my recent experience with the
IM240 test. Attempting to get my Mazda 929
(Series 4 13B turbo engine with exhaust/intake/FMIC mods) through this
test resulted in the following results:
Run #THC
(g/km) NOx(g/km)
CO (g/km) CO2(g/km) Test Result
1. 4.35 0.49 54.52 70.3
FAIL
2. 6.61 0.34 83.1 247.1 FAIL
3. 0.84 1.42 6.7 326.9 PASS
Between runs # 1 and
2, four new injectors
and an air pump were fitted to reduce emissions.
Instead, they
increased! The only change
between runs #2 and 3 was
the fitment of a
new catalytic converter (the old cat was a mere
1.5 years old)
just four hours
before the test. It's
amazing just how much difference a cat can make, and how quickly they cease to be effective!
Damien McKay
Australia
2 or 2+2?
Re your article RB26 260...
Great article - I am a
big fan of these cars and have been for some time now. However, the
article mentions that the back seats are now non-existent! The Datsun 260Z was strictly a 2 seater - there was another model (the 260Z 2+2) which you may be confusing it with. The photos indicate this car is definitely a 2 seater due to the small
gap between the rear shut
line of the doors and the wheel. The 2 seaters have become more desirable cars having a lower
curb weight. Otherwise thanks for the great article and hopefully
we will get an update when
the RB30/RB26 engine is fitted!
Dale Everett
Australia
Very well spotted! Article now
corrected.
Re New Car Tests and Feature Cars...
I've been a regular reader of AutoSpeed for several years now and, is it just me, or has there been a
noticeable decrease in new
car reviews? Also, the
modified car reviews are getting to the point where you can have a template that goes like
this:
[Insert Name]
bolted on
[X Go-Fast Parts]
onto
[his/her]
[InsertCar]
and it's all good. They reckon that it's good for a
[Insertnumber]
quarter
mile run.
It would be nice
to see some more owner modified cars and more new car reviews.
That said, reviews where you look at a particular model of car
over several
years (like in The Sporty Magnas)
and articles like the Prius modding ones are good
reads. Keep up the good
work.
Daniel StreefkerkAustralia
Points taken. Unfortunately, most of our new car tests rely on manufacturers making
cars available – and there haven't been many available lately. Re owner modified
cars – we love those cars too but DIY cars that are genuinely well presented are relatively
thin on the ground. We feature them whenever
we can.
Pick a One-Box
I’ve been reading with great interest your
articles on the Estima The Extraordinary Estima
and the Custom vans Hi-Ace Hankering
and Van Fan
and have a few questions for
you:
1 - Which would you
choose out of the three you drove and why?
2 - How would insurance
be on them - especially the body kitted and18 inch wheeled Estima?
3 - What about the
later (mid ‘90s) Delica -
they seem to be VERY available but I haven’t been able to find
any real info on them!
What would be awesome would be a comparo on
a few of them - would make for very interesting reading!! Thanks again for an awesome online read!!
Cameron Tuesley
Australia
Tough choice. For sheer interior space the Hi-Ace is superior to the Estima. But the
Estima comes with 4WD, looks and feels much more modern and drives better. Overall, we prefer the Estima. We have not yet tested the later series Delica. We don’t think there will be a problem
insuring the Estima with a body kit and wheels – but you’d be wise to ring
around insurance companies before buying.
Relocated AFM Benefit
Re "Move the
AFM?" in Response...
Moving your AFM closer to your throttle body should give better throttle response and more accurate
mixtures, as it's measuring the air that’s going
into your engine 'now' rather than the air that will go in after about .1sec.
Kent Slaughter
Australia
Re Braided Brake Lines #1
As a long time reader of AutoSpeed I always enjoy your ability to evaluate modifications using quantifiable data rather than
just word of mouth and
company press releases. Your recent article on braided brake hoses Braided Brake Lines was great in this respect
- but I just wonder
if the calculation method
was correct? When measuring the change in brake hose diameter should you not be calculating the
increase in cross-sectional area rather than a straight lineal change? Using this approach sees a change of 4.9% for the
old rubber hose, 3.47% for the new rubber hose and 1.2% for the braided hose. Keep up the good work!
Davin Field
Australia
Re Braided Brake Lines #2
Your article on braided brake lines Braided Brake Lines is interesting but it misses the
point analytically. I have braided lines on my track car because it is the thing to do - but I have always been a bit
sceptical about the
benefits. Your article gave me a chance to crunch a few numbers which actually support the braided
argument quite well. The
problem with your numbers is that you look at percent diameter change instead of percent volume
change. Given a few
assumptions that I had to make (but could be verified with the hoses in hand)
the results are interesting.
Assumptions:
1 - There are four lines
- each 440 mm long
2 - All lines have an internal diameter of
3mm at zero pressure
3 - The change in internal diameter under
pressure is the same as the change in external diameter
Based on these assumptions, the volume of the lines at zero
pressure and at test
pressure is:
Old lines - 12.4cc and
17.5cc
New lines - 12.4cc and
14.0cc
Braided lines - 12.4cc and 12.8cc
If we further assume that the master cylinder has a bore of 2.5cm, the stroke required to expand these
hoses is:
Old lines - 1.03cm
New lines - 0.31cm
Braided lines - 0.07cm
One would need to know the pedal ratio to know how much pedal travel is
associated with this piston stroke. Also, of course, the test pressures were artificially high but the
stroke reduction resulting from using braided lines should be quite apparent
at high brake pressures based on this
analysis - and it serves
to illustrate why a simple percentage change in OD analysis is not
particularly useful.
James Mewett
Canada
Re Braided Brake Lines #3
Regarding your Braided Brake Lines article Braided Brake Lines - I am surprised that
your (perfectly valid)
testing showed such a tiny improvement.
I had my 1991 UZZ32 Soarer upgraded just before Christmas 2003
and the pedal feel was
transformed. But,
then, it probably had
the original hoses and I
did have EBC GreenStuff pads fitted all-round as well as EBC rotors on the front - so I would have expected to feel a change!
Although, just last
week I changed the (probably) original hoses for braided lines on my 1988 Alfa 33
and, with no other
changes, there was that
pedal feel transformation again...
I say "no other
changes" but, of
course, the fluid had to
be changed so maybe
changing the fluid is the biggest single improvement that can be made? Like so much (all?) of the
braking system in cars, fluid largely gets
ignored - despite the recommendations of the manufacturers.
Barry dal Herbert
Australia
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