Big Daddy Mack
Re your idea in Driving Emotion ("An intercooler fan powered by turbo boost")...
A similar idea has been used by Mack trucks for many years. The 30 old Macks
that I have driven in the army use a tip turbine to power a fan that draws air
through intercooler. You can hear it coming in and spooling up when you are
trying to use high power at low speed. This was done as these old Macks spend a
fair amount of their time out in the bush using full engine power but at low
road speed. It’s not a bad setup for a 10-wheel-drive 30 year old truck that can
pull 8 ton onboard plus a 20 ton trailer... I’m not saying a Mack intercooler
setup would make it under your old Maxima but it could be a place to start
looking to see how they have done it. I am not sure if they are using boost
pressure to power the tip turbine or if it is inserted in the intake flow
somewhere. I’ll leave that up to you guys to find out!
Keep thinking outside of the square - this is what I like to see.
While I am at it, has anyone out there had any experience with supercharging
a 4.2 litre Jaguar XK engine? I’m interested to know if I am breaking new ground
or reinventing the wheel.
Robert Williams
Australia
Thanks for that, interesting stuff –
we’ll look into the Mack system a bit more. We haven’t heard of anyone
turbocharging the XK engine – anyone else?
Troublesome Trans?
I have a question to ask... I own a Holden VS V6 Commodore and have a problem
with what I think is the auto trans. When I drive the car, its power seems to be
all over the place with what seems to be gearbox slip. I have serviced the auto
and maintain the car very well. Lately, I have given it a carbon clean, replaced
the leads and put in a new set of spark plugs – and the problem is still there.
I have also installed a sports exhaust and cold air intake.
When you pull up (say, at a set of lights), you can take off with a lot of
revs but the car accelerates slowly. Other times the rear wheel break out in
wheel spin and acceleration is excellent – it can do 0 – 100 km/h in 6.8
seconds. It will run 14.7 – 15.1 second quarter mile times but when it’s going
like this it would have trouble doing a 17...
I have had the computer and sensors checked and they seem to be fine. I have
been told the MAP sensor is noisy but apparently this won’t affect the car’s
performance.
I am fairly sure it is the auto trans slipping but I’m not sure. Your
thoughts?
Brad Walther
Australia
Hmmm – interesting one. It’s hard to
judge without going for a ride in the car but it certainly sounds like there
might be an intermittent problem with the trans. We suggest installing an
air-fuel meter to make sure the engine isn’t doing anything whacky first, though
– see Smart Mixture Meter, Part 1
for details on the meter. It’d also be a good idea to take your local
transmission specialist for a drive and ask their opinion. You might also be
interested to read Auto Trans Dyno.
RS v GTi-R
Hey, your website is very informative - I always come on to find out the
latest in cars.
Just a question... I own a 1991 Subaru Liberty FWD and wanna buy a new car next
year. I’d prefer a turbo – I’m considering either a Nissan Pulsar GTi-R or a
Subaru Liberty RS turbo. If you have any advice, it would be great.
Scott
Australia
The GTi-R is a better package for
performance when left in standard form – but there’s no need to keep it
standard! We suggest the Liberty RS as the better option since there are so
many aftermarket and second-hand parts floating around to suit. New genuine
replacement parts are also readily available.
Read Pre-Owned Performance - Subaru Liberty (Legacy) RS
for things to look out for in a Subie RS. Also check out Supercar Steal
for our GTi-R buying used article – but keep in mind this article was written a
couple of years ago.
Clamp Currents
Just a quick tip regarding current clamps you mentioned in "Using
Multimeters, Part 3".
You rightly state that current clamps are inaccurate when measuring small
currents – however, the situation can be improved (at times) by passing the wire
under test through the clamp more than once. By placing more turns inside the
magnetic core, the clamp becomes more sensitive by a factor of the numbers of
turns present. Place the wire through the core twice and the voltage output of
the clamp will increase by two times. This technique can be used to successfully
measure small currents that would otherwise require you to break the circuit and
insert the meter's probes.
Cary Wintle
Australia
Front Diff Findings
I did a search of AutoSpeed and was not able to come up with an article on
adding an aftermarket front LSD to a car (such as a Subaru WRX). This
modification should improve AutoCross handling by reducing understeer.
If
you haven't done that article/test yet... well, add it to your list.
Mako Koiwai
USA
No we haven’t covered that topic. Good
suggestion - we’ll keep our eyes open and cover it if the opportunity becomes
available.
Pssstttt-ing Diesel!
After reading the "Electronic Blow-Off Valve" article The Electronic Blow-Off Valve! in your excellent e-mag, I
have gotta have one on my turbo diesel car. The problem is my car has mechanical
injection, so it doesn’t have a throttle potentiometer. Is there another method
of sensing the throttle position that can be used to signal to the Delta
Throttle unit that I am coming off the gas, thus opening the BOV? Could I
perhaps fit a micro-switch to the car's throttle lever?
Please help as I’ve gotta have that psssssssttttt noise on my car! Keep up
the good work on the mag.
Andy Birch
England
A simple 2-position switch won’t work
because the DTT looks at the rate of throttle movement – not throttle position.
You can, however, fit an OE throttle position sensor, feed it the appropriate
regulated voltage and then take the signal from it.
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