hey this site and the
information is great. have been worried about the electrical side of motors for
a while and stumbled onto this site in a search session. awesomely informative
with good examples of application. Thanks again-Brilliant!
Hi there from the UK! I love
your site and I agree with your review on the Fiesta Zetec, its a great handling
car and was well reviewed here as well. I only drove one for a few days but it
was great, I went berserk on a favourite back road and it held its
composure much better than my old Fiesta, and even a Peugeot 306 I remember
driving. As you said the problem is they should have given it more power, but
the higher insurance rating wouldn't be friendly for young drivers here (we get
a slightly bodykitted 'warm hatch' version of the 1.6 Zetec as a Zetec S) and
also the gearbox can't take the torque. Really Ford should have designed a new
gearbox for the Ford Puma 1.7, as the torque was restricted in 1st gear to
prevent damage to the box. That's also why they had to put a completely
different gearbox/engine series in the 2.0 ST they market over here, with 150bhp
it would have been playing Russian Roulette with the old IB5 box. Sorry for such
a geeky response, keep up the good work.
Airflow Meter Change
The time has come to seek your expert advice.
I am about to replace the MAF sensor on my car with a MAP sensor. I read your
article on teh subject, and I know you do not recommend it, but this is last
resort. I have a 1991 Mercedes w124, 2,3L petrol engine with KE-Jetronic
continuous injection. It measures arflow with a vane type MAF. Problem is after
200 000 miles on it, the tracks on the little pot are gone, Bosch does not offer
the little pot as a separate part,and the whole MAF unit costs about half the
car - almost 1000 Eur. Buying a second hand replacemnet does not guarantee
trouble free installation. I have to adjust fuel mixtrue every day - after a
while the ECU enters into trouble mode, and I have to delete the 4 flashes
trouble code, and readjust mixture after that. I am planning to leave the vane
intact, as it is also mechanically coupled to the KE-Jetronic fuel distributor,
and use a MAP to measure air volume instead of the potentiometer. I measured 0.5
bar of vacuum at idle, will a 1 bar MAP work? Originally, at idle the pot should
give betweem 0,5-0,7, and about 5V at WOT
We've said it all at Why to Not Swap Airflow Meters
Referring to an article of Real World Air/Fuel
Ratio Tuning by Julian Edgar. The scope meter readings look as if they
could have been subjected to impulse or alternator noise, resulting
in incorrect values. Was the scope meter used as a scope or a meter (if
that is possible?), I am thinking here that the volt meter mode may sample at a
lower samples per sec? Was any averaging used?
The Scopemeter trace looks fine to us – in the
pic it is showing closed loop cycling.
I have been a keen reader of Autospeed for
quite a few years now. It's the only site I can think of where the "technical
info" presented isn't subtly linked to selling something. Reading your articles
on parts, books, new cars etc., makes much other motoring journalism seem overly
enthusiastic and conspicuously non-critical. I guess that's why you have a
longish lists of car manufactures that won't loan you cars! So long as your
opinions are based on your observations and facts, good on you. There is so
little non-commercially motivated information around as it is.
other thing I like about your site is the sprit of science that permeates it.
I'll bet at least one of you is an ex school teacher in science. (Or wanted to
Finally, re your "Autospeed in 2008" blog on December 17th,
2007. I believe your new approach is wise and very timely. For example, I
have a mildly modified R33 GT-R Skyline which I enjoy a great deal, including
its high performance and handling. Bottom line though, I am probably not going
to be able to justify that as a daily drive in 5 years, when I am semi-retired
and high octane petrol is between $3-$5 a litre. Consequently, my mind has also
turned to hybrid petrol-electric, ethanol and biodiesel as alternates. You are
also right that this is a very significant turning point in transport
technology. The world is changing irrevocably due to the impending end of the
age of oil.
At least until discarded fish and chip shop oil becomes
a valuable commodity, I like the biodiesel option the best. (I suspect if you
have a look at journeytoforever.org,
you inner science teacher(s) won't be able to resist it either fat fryer oil,
methanol and caustic soda yummm!)
So I thought, hmmmm, maybe I could buy
a cheap, second hand diesel car and give it a go running home made biodiesel.
(eg. rather than wreck an expensive new car.) My search on Autospeed led me to
one of your project cars, the Peugeot 405 SRDT. What was missing though - I
thought - was the “is biodiesel a suitable fuel" perspective.
for our collective benefit, you guys could take the next step and identify
common, affordable and robust second hand diesel cars, that best lend themselves
to running 100% biodiesel. You can see from the biofuel forums that the
issues of degradation of plastic and rubber engine parts, cold starts and
clogging fuel filters, seems to be critical issues. (Eg. See Australian Biofuels
that is another useful topic for Autospeed to explore in 2008?
best wishes and thanks for a really great automotive site, which is obviously a
labour of great love!
We expect to DIY cover bio-fuels in 2008.
Julian Edgar worked as a secondary school humanities teacher for 8
Re throttle body story,
"AUD$" is like "PIN number".
Hmm, AC current anyone?
Prius HV Batteries
Does Julian still have any NiMH bats left from his
attempt to charge his battery externally?
Some, but he is keeping them.
I was looking into the audi boost mod> The Audi's DIY Boost Control - Part 2 now
in article one, you say that you un-plumb the solenoid (n75 valve) but leave the
loom fitted, i take it that you then do not use the solenoids fittings at all
and dimply use it to say its still plugged in? but with air not going through
it, would the ecu not realise this? or do you put your regulators inline
with the solenoid. im getting kinda confused as you can tell
The ECU doesn’t know that no air is passing
through the solenoid.
I read your articles about ignition timing,
ram-air and closed-loop monitor with great interest! This is very good
I have a question about closed loop cars. Is every car with
an O2-sensor equipped with a real closed loop mode ecu? I heard about
self-learning ECUs, and that real-closed loop cars were built not before 1999.
Is that true?
Perhaps some early cars using oxy sensors for
closed loop did not have any self-learning (ie they just used a fast feedback)
but certainly most have long and short-term fuel trims (ie
Human Powered Vehicles
I have been reading your "Building a Human
Powered Vehicle" series with great relish. Julian Edgar has done a marvelous job
of communicating the ups and downs of creating what at first appears to be a
child’s toy but instead turns into an unexpected drama of applying
exuberant creativity and exhaustive energy to higher engineering. The highly
sought-after technical information for this class of vehicle is presented is
such a practical and matter-of fact manner that I sometimes forget that much of
it is over my head.
I hope Mr. Edger has come across the web site below
as it has a level of engineering sophistication that I have not seen elsewhere.
More academic yet lacking polish as the author was busy with school and real
life.I hope he comes back and finishes. zeept.wordpress.com
To the matter at hand, I can not find the
conclusion (i.e., part 8) of the first HPV series, No matter how hard I look! I
wish to finish the series before I go to the next one, "Another HPV". My son and
I are designing and building an HPV (maybe with electric assist). We want to
design it as "high-tech" as possible, yet still keep the project within reach of
an average DIY guy without a welder (I.e. me). Your HPV series has become
invaluable for us on many design challenges, especially suspension and
I am encouraging my son to continue his interest partly to
foster his interest in dealing with global warming, partly to have a tangible
teaching tool for math, science, geometry, physics and the like, and lastly
because my son has a dream of building a car (like I have always
Please send a hyperlink to the final installment of Building a
Human Powered Vehicle, Part 8 - conclusion. Then I can read Another HPV as soon
as possible to continue my HPV education.
We suggest you go onto the next series, which
is a much better design.
I read with interest the article on MODIFYING
THE COMMODORE'S LS1 5.7-LITRE V8 & am now wondering if I am wasting my time
with Over the radiator air induction,extractors,2 1/2 system etc ?? Every
article I read on otrai claims better performance etc !! Are they kidding
themselves? I don't want to waste money if it's a 3 day wonder ??
We’ve never seen an engine that doesn’t improve
in some way – be it fuel economy, power or throttle response – with better