Real World Test

It came as an afterthought.  It was never my direct intention to have done what I made.  I had initially made a Secondary Intake for reducing fuel consumption of this car.   See my previous article.  Then I wanted to make the spoiler adjustable so that it can actually be useful.  This was on my previous thinking that the spoiler functioned as perceived.  That it provided down force and that if I took it out, the handling would suffer.

This then changed somehow without any premeditated intentions.  What I have right now is a combination of efficiency solutions.  The secondary intake initially showed that I could save money in the movement of the throttle.  That was fine.  Then the aerodynamics were sorted.  Never did I thought the two combined mods made significant fuel saving changes.

I did a test run yesterday for 230km in total.  This was a return trip on the North South Highway.  It was to test the Deflector at speeds above 90km/h.  It performed admirably by registering an Indicated average Fuel Consumption (FC) of less than 5.0 l/100km. You can see the YouTube video here . Yes, this means I now have a YouTube account.  Forgive me I am rather slow at 46 years old.  I have only now found the use for it.

During the same journey I made similar tests for speeds of 100, 120 and inadvertently 130km/h.  All of these test results were on solid straight roads with the AC switched on.  I plotted the values which I had observed on a spreadsheet.  I had expected a exponential curve from 100 to 130km/h.  But I could not get it.  The only time I observed a high FC is when the car was being driven at 100km/h up a 20 degree incline.

capture_11092014_004322The table is now UPDATED on 9 November 2014.

The data is based on observed data from factory standard equipment.  They are not absolute and the value is AVERAGE Fuel Consumption.  The last data if drawn to scale should be closer but it should also be higher.

A few things floated in my mind.  As engineers we are told that aerodynamic load is very much affected by speed of the object or vehicle.  This aerodynamic load increases .  Fuel consumption will increase dramatically as speed increases.  Perhaps it is too early and too easy to say that somehow with the combination of both modification, we have come to a point where the world is no longer flat.  I might need to spend more day trips to Melaka to do more tests.  One might say that these values at these speeds are insignificant as the speeds are low.  But these speeds are what normal people are driving at.  This is the whole point of doing these modifications.  It is so normal people could save money driving normally.

Should anyone ask about performance degradation; I simply did not see any.  The maximum top speed is still attainable.

Deflector Part 2

Just a quick one as I do not want to give away too much.  Finally managed to do up the fibre glass work with Chooped Mat and Roving.  The Roving is better suited to hold the surface on the edges as it is stronger.


Producing the top surface Needed to brace this securely on this working design.  I would not need to get a really solid grip on the production model as it will totally be fibre glass.  As it is now, wood is used as the main structural material.  I would only need this working design to make some sets of mould.  The finished product would therefore be much lighter and look nice.

Deflector mounted on car

Deflector mounted on car

Had a spin around Putrajaya.  About 45km distance.  First round registered 4.3 l/100km while the second registered 4.5l/100km.  Will keep doing test and maybe try to add more surface area on the bottom.  I am very happy as it is, there was little effort to try and clean it up.  Not even fillers and it still meets the target.  Probably I might get better results with the extension.

The Other Car

People Mover! I hear you shout.  Truly agreeable with you on that one.  It is NOT a car.  Its a bus.  Initially it was an embarrassing idea to have one.  Yet I have a family with three above average size children with above average appetite.  Plus we used to have a lived in maid from Indonesia.  Therefore, it is a must have.  It is a Hyundai Trajet GLS circa 2002 but we bought it in 2004.  The only automatic transmission car that I own.  My wife actually owns it.  I just pour in the fuel and pay the monthly dues and do all the maintenance on it.MyTrajet

A bit of history.  Hyundai made this to compete against the Toyota Estima, Honda Oddysey and the GM/Opel Zafira.  Wherever they meet.  I would think Asians would be the preferred market as the Europeans are dead set on station wagons.  Aisans tend to have a sizeable family extended or not.

It drinks a lot.  Petrol I mean.  Wherever you go except for national highways which seem to be just about ‘ok’.  The fuel consumption is a real issue when it does not travel in one huff.  Stop and Go traffic is stressful on the heart and the wallet.  It does not have a fuel consumption meter.  Which makes it hard to guess how efficient it is at doing its thing.  However, big lugs like this are the ones that supposed to get the highest attention.  Reducing fuel consumptions on behemoths should be the main focus of car designers.

Therefore, in the spirit of chasing efficiency, I plugged in the washing machine hose thingy into the airbox.  Drilled an M25 hole and simply push it in.  The other end with the funnel could be placed anywhere.  So I did.

Airbox mod

Interface done with airbox

The Trajet's turn

Secondary Intake for Hyundai Trajet

I had it go through various orifices.  I had to remove the front grille to make my hand accessible to where I want it.  I then decided to run it through the bottom grill.  I found this not to be the ideal place.  The wake from the bumper would have a slight pressure drop where I had it.  It ws a bit lengthy and would cause some measure of pressure loss.

Since then I had cut it up and placed it just over the left light cluster.   What I do want to see is using a snorkel and mount it right over the radiator.  That would be Trajet Snorkel 2.0

I still have no clue if there was any improvement.  I leave that one to faith.

Secondary Intake Pt 3

At the end of this project, I remembered when I was roughly 12 years of age, I was into making model spaceships.  I had picked up a magazine about Scratch Building.  Initially it was to make a diorama for my scale models.  But it grew on to making a complete spaceship out of two aluminium cans and one plastic cap.  The cap became the engine exhaust.  I had painted it white and took a picture of it with black paper as the background.   That was my experience with working with house hold items.

View of internal of air scoop.

What air would see before being sucked

I wanted to cap off this project with something spectacular.  But then I kept reminding myself of the reason why I did this.  It is to make things as simple as can be.  Hopefully it would inspire ordinary men on the streets to come out with their own ideas in increasing efficiencies of anything they have.  All the items I used can be bought from the nearest hardware store.  Even the tools; which is a knife.  That is the beauty of science; it does not limit to rich people, it does not want to burden people.  In fact it enlightens to those who seek it.  It does not provide the glitzy glamour of a high priced premium aftermarket which endears the modding community here.  But it does save money for the rest of the working people.  If they could only open their eyes to possibilities.

I decided to increase the intake are of the flexible pipe by having a scoop.

Recycle Reuse Reborn

If you are like me, I have a shed which I keep all chemicals, paint, thinner and lubes stored on the top shelf.  I had a small bottle of Automatic Transmission Oil which is quarter full.  The shape of the bottle was interesting.  It had a sloping line before it meets the cap.  It also had different radiuses as its edge.  This was significant to meeting my requirement.  The hole where I inserted the front end of the intake has a matching shape.  When I tried it on it was a perfect match.

I had to cut the hose further as the bottle will be using up the length.  I inserted into the bottle’s neck and taped it with Electrical Tape.  I then inserted this below the headlight cluster and left it there.  It fit snugly and there was no need to tie down the white hose further.

While feeling satisfied at how the project turned out, one can never truly be complacent.  What was very apparent from the beginning was that I was toying with household items which others never think of being an engineered product.  What may be difficult to find 10 years ago, has become common and the price of these have gone down.  While I would be most challenged to make a purpose built equipment, nothing beats simplicity.  This mod project truly embodies the reason for this blog.  Anyone could do this project.  He doesn’t need to have an AutomotiveFits nice and snug

Engineering degree.  Its just a matter of wanting and how bad you want it.
Tonight I took the family out to take an opportunity to test the set up with full load.  It was satisfactory.  “Sorry bout that Mr. CR-Z! I’m doing an experiment!”


I am just about finished with this project.  Even though its a relatively short testing period, I am well convinced that it has met its objective.  The objective was to reduce average fuel consumption.  The method is not new but I believe it is for this Proton model.  People may think that just because it works for a highly engineered product that it will not work on others.  They are well and truly misjudging its benefit and impact.  An engine in an old car is still an engine in a new one.  The fundamentals remain the same.  I have now increased the fuel efficiency of the car by 30% in Highway mode.  It should reflect a fuel saving of not less than 20% on average through the entire journey.  But I seriously doubt  it could improve the FC during idling.  That is a project to be done in another day.  I look forward to working with others on a similar project.

Secondary Intake Pt 2

It is hard to write down the results of the test on the road.  It is hard because I have been very ecstatic about the results.  It has been two days of consecutive tests.  Repetitive results would provide an assurance that the reading was not a fluke.  And that is exactly what has happened.  The first day and second day results were the same.

Testing method was by observing the onboard Fuel Consumption meter, having the car maintaining 80km/h speed.   Location of tests were two; from Putrajaya to LDP Toll on my drive to work and from USJ exit to

PutrajayaTest 3 results Toll on the Elite Highway.  After two consecutive days, we can safely say that both readings were the same.

Putrajaya to LDP: 4.0l/100km

USJ to Putrajaya: 3.5l/100km

I use two different route as my daily travel plan on weekdays.  Therefore the test would provide me estimates on the effect of the modification towards my daily travel costs.  The second day of tests, I had become impatient on the way I should do these tests.  So on the return trip.  I did two separate tests; one at 70km/h and the other at 80km/h.  I had video taken to show that the consumption was 3.3l/100km when driven at 70.  Which is even more fuel savings.
Some friends were concerned about the fuel savings on actual performance.  I cannot say if there was any negative performance effect as I wanted to do this mod for Economy and not to increase power.  But I must say that the question has intrigued me. I look forward to making my own video stand to clamp on the seat headrest.  This will provide datalogging capabilities.

Debunking Myths

Some people I know do not want to take the reading seriously as many doubt the accuracy of the onboard computer.  Some would want me to do the ‘Fill up full at the Tank’ method.   When we take measurements, we need to reduce variance as much as possible to get closer to the truth.  Setting the datum at the petrol kiosk has several fundamental problems.

a) How do you know that you are actually filling up to the full?  An empty petrol tank can only be found on a car that is not running. A partial tank in reserve can contain 5 litres or less.  How much less?  We cannot possibly know.

b) When you fill up to the max, there’s two problems one is engineering wise and the other is behavioral

i)  You can never know whether a pump has delivered the correct amount of fuel you require by measuring at the fuel tank scale.  The scale of the meter is huge compared to the resolution we are trying to find out.

ii) If you are driving on full tank, then you think that this is just a game.  Someone who drives will a full tank all day is bringing with him weight that he does not need.  Carry only what you need.

They probably need to know how the FC reading works.  Its is pretty much simple.  The ECU controls the triggers to the fuel injectors.  All it needs is to count how many firing of the injectors were done since the event of the reset button press.  It multiplies the number of firings against the number of injectors, multiplies it against the flow capacity of the injectors and take the trip meter reading since button press.  The trip meter or distance measured is based on a magnetic pickup on the driven wheel which is fed directly to the ECU.

If you limit the use of the FC reading to measuring at constant speed and relatively short distance, then it is good enough.