If you own a car with an automatic transmission, you’re probably aware that
it requires routine trans fluid changes. Most people will drain the fluid from
the oil pan, refill ‘er and give themselves a pat on the back for a preventative
maintenance job well done. Well, unfortunately, this only a half-measure – it
doesn’t flush the fluid lurking in the torque converter, cooler and cooler
lines. A proper transmission flush should involve removing the filter (where
fitted) and ensuring all fluid is replaced. One approach is to disconnect the oil cooler pipe returning to the transmission, run the engine for up to a minute or until no more fluid is discharged from the pipe, switch off, drain the pan and refill. No fancy pump required.
If you’ve got a V-configuration engine and you’re looking for a bit more
grunt, it’s worthwhile considering the asymmetric turbocharging principle as
used by Saab in the late ‘90s. This system, where only one bank of cylinders is
used to drive the turbocharger, simplifies manifold construction and can
potentially save a lot of money. However, you’ll need to consider the
relationship between compressor and turbine size – you need a compressor big
enough to provide your desired max power but a turbine small enough that it’ll
spool up when required. You might also encounter tuning issues relating to
variation in backpressure and heat. There are some hurdles but it’s a very
interesting concept that deserves exploration.
Another interesting approach to forced induction is twin-charging – using a
supercharger to provide ample low-down grunt and a turbocharger to provide a
more efficient top-end. We’ve recently been asked the best way to set-up such a
system – and the answer is to copy Nissan! The late ‘80s Nissan March Super
Turbo is one of those rare production vehicles with a twin-charger setup. At low
revs, the Nissan turbocharger blows through the working supercharger while when
engine rpm and load increases, the blower’s electro-magnetic clutch is
disengaged and the turbocharger provides boost to the engine via a supercharger
bypass passage. Airflow through the bypass is controlled by a differential
pressure valve which starts to open as the turbo nears operating rpm. In
standard guise, the supercharger is used to deliver 7 psi boost and the turbo
forces 13 psi. Food for thought!
Oh, and when embarking on a custom turbocharger fitment, you might also be
interested to learn that ball-bearing turbos can survive on a much reduced oil
pressure/flow than conventional sleeve bearing turbos. In fact, given generous
water cooling, it’s quite possible a ball-bearing turbo will survive on only
around 10 psi oil pressure (depending how hard you’re working it). This means
you can configure a stand-alone turbo lubrication system that uses a relatively
low power electric pump and, where space permits, a sump. This avoids dumping
excess turbo heat into the engine’s lubrication system and can make installation
easier.
Although widely seen as a relic of ‘80s turbocharging, the humble over-boost
pressure relief valve (aka pop-off valve) deserves attention. We’ve recently
heard of several engine failures related to turbo over-boosting caused by
sticking external wastegates and inadequate turbo hose systems. In each of these
cases, a relief valve would have vented excess boost pressure and saved the
expense of an engine rebuild. Not a bad investment, given an over-boost relief
valve might cost only a few dollars... One approach is to modify the relief valve
fitted to early Nissan turbo engines (such as RB30ET and E15ET) or you can fit a
different spring to an aftermarket blow-off valve – as detailed in Venting Boost, Part 1
Weight reduction is one of the easiest ways to improve the performance of
your car - but how do you reduce weight if you don’t want to sacrifice all the
mod-cons that come standard in today’s cars? Well, you can typically shed a few
kilograms by switching to a smaller dry-cell Odyssey battery and removing the
spare wheel to carry an electric air compressor and puncture repair kit (as
found in some European vehicles). You’ll also be surprised how much weight
you’ll save by replacing the factory exhaust system – a standard S13 Nissan
exhaust weights more than 25 kilograms! Oh, and relatively small diameter alloy
wheels also weight considerably less than some of the tasty looking aftermarket
jobs on the market.
With most new cars of the last five years employing a variable intake
manifold, there’s a great opportunity to pick one up cheap from a wrecker and
adapt it to fit an older engine. If you’ve got a straight six, the variable
length manifold from a post-EF Ford Falcon is probably one of the best
bang-for-buck propositions. If you’re after something smaller, pretty well all
of today’s four-cylinder engines have ‘em – Mitsubishis, Hondas and Toyotas. In
the V6 segment you should look at the high performance version of the new Holden
V6 (however, the Holden system merely alters plenum volume rather than runner
length). Also check out the dual throttle intake manifolds fitted to Japanese
import VG30DE engines. Sure, you may need to make some elaborate manifold
adaptors, play around with the dual-stage switch-over point and throttle
linkages but there’s certainly an opportunity to achieve substantial gains.
AutoSpeed has always promoted taking measurements to find out whether its
worthwhile upgrading your car’s exhaust, air intake or throttle body.
Unfortunately, due to the wide range of test pressures, it’s been necessary to
collect a range of different gauges. Well, now there’s a single hand-held
digital meter than can measure positive and negative pressure (vacuum) up to 30
psi – it’s ideal for automotive testing. You can also select your preferred unit
of measurement and use the handy max/min hold function. See our full test at Handheld Digital Manometer
For anyone reacting to the recent increase in fuel prices, it really does pay
to do some sums before buying a used ‘economical’ car. In many instances, you’ll
find that diesel or small, fuel-efficient vehicles cost substantially more than
large petrol-engine’d vehicles that might’ve cost twice as much at the
time of release... It’s quite conceivable that you’ll sell your up-market family
sedan only to step into a bare-bones hatch with hubcaps and wind-up windows! In
addition, there are times when the figures simply don’t add up in your favour –
take into account the reduced fuel consumption bill and compare it to the amount
extra you’re paying for purchase and it’s sometimes not worth it. Don’t get
caught up in the hysteria!
If you’ve read the press release on the Mitsubishi 380 you may have noticed
the hoo-ha surrounding the use of pulse width modulated thermo fans. Compared to
a basic on/off wiring arrangement, pulse width modulated control improves
electrical efficiency and there’s no annoying fan cycling. Well, for a few
bucks, you can introduce pulse width modulated thermo fan control to your car!
Using the Silicon Chip Nitrous Fuel Controller you can control fan speed
up to a maximum rating of 10A. For more, see The Nitrous Fuel Controller - That's Also a Lot More!
|