[AlanHo]

My new i30 1.6 CRDi Style  is spending today at the dealership having "proper" front parking sensors fitted.

My courtesy car is an old model i30 1.6 CRDi Comfort which was built in January 2012 and has 4020 miles (6470 km) on the odometer.

It is very revealing to go back to a car mechanically identical to my previous 2010 1.6 CRDi Premium model - except that :-

The loan car has 16" rims and Hankook Optimo 415 tyres
My previous car had 17" rims and Yokohama Decibel tyres.
My new 2012 car has 16" rims and Continental Contact 2 tyres.

My initial impressions are:-

The steering on the loan car is much heavier than my new i30 set at "Normal" mode. In fact it feels heavier than the new car with the steering mode set to "Sport".

Cabin noise is much higher than my new i30 - a decibel meter check indicates that it is about the same as my previous i30 Premium.

The loan car has a slick gear change - the equal of my new car. My previous i30 was notchy in 1st and 2nd gear

The loan car is far less refined than my new i30 - the speed bumps and potholes on local roads bear full witness. It feels the same as my previous car (which had 17" rims)

I have checked the gear change indicator and can confirm that on the loan car it tells you to change up at 2300 rpm in 1st falling to 1900 rpm in 5th. This is identical to my new car. However, because the gearing in the new i30 is taller – the car speed at the gear change points is also higher in the new i30. 

Using the motorway marker boards and my Sat-nav, I determined that the odometer in the loan car was 3.6% slow. (ie: if the odo trip shows a distance covered of 100 miles – the car has actually travelled 103.6 miles). In my previous i30 Premium the odo was 2.5% slow and in my new i30 it is 1.8% slow. This needs to be taken into account for brim to brim economy calculations.

Despite the odo error – the speedometer in the loan car and the speedo in my previous car were both dead accurate compared with the sat-nav. In my new i30 the speedo reads about 8% fast.

I carrried out an acceleration test in the loan car using the same method as I earlier tested my new i30. The result was the loan car did 0 to 62 mph in 11.9 seconds compared with 10.9 seconds in my new i30. Despite this - the loan car felt more spritely but I have now sussed out why. When driving the loan car on the motorway I kept trying to change up into 6th gear - only to find that I was already in that gear. 6th gear in the old model is the same ratio as 5th gear in the new model - so if you drive in a lower gear through the range, the new car is as lively as the previous model.

Now for some bad news that has got me more than a little concerned.

From previous threads you will be aware that I have a personal test route which I use to check fuel economy. This route is a round trip of 41 miles of which 14 miles are urban with several junctions and traffic lights – the remainder is motorway.

I took the loan car around the test route at the same speed as I used for my previous i30 and the new model. This is the result :-

                                          Mpg       l/100km        Avge mph   Avge kph      Air Temp

Previous i30 Premium           54.4         5.2                42.7         68.7             13°C
 
New i30 Style                      64.9         4.35              41.6          67.0             15°C

Loan i30 Comfort                 66.9         4.22              43.0          69.2             16°C

I am unhappy to see that the loan car was more frugal that my new model. I am also concerned about the economy comparison with my previous i30 Premium. Members will know that I ofen remarked that the economy of my car, compared with others on the forum, was so poor.  This test has highlighted it again and makes me wonder whether the DPF was in a permanent state of regeneration.

However - it has been an interesting day - and has reminded me that no matter how much I feel the new i30 to be a substantial improvement over the previous model. They are both in their way excellent cars.

[Doggie 1]

A great comparison.
Despite the slight differences in economy, I still think you'd have to be happier in your new car considering the greater refinement and advances in other areas.
I hope the new sensors work out well.

[Dazzler]

A great comparison.
Despite the slight differences in economy, I still think you'd have to be happier in your new car considering the greater refinement and advances in other areas.
I hope the new sensors work out well.

  No wonder we get on so well Dave (you quoted my thought almost word for word) 

[Doggie 1]

  

[TazManiac]

A very good write up. Thanks for the comparison.

[eye30]

I carrried out an acceleration test in the loan car using the same method as I earlier tested my new i30. The result was the loan car did 0 to 62 mph in 11.9 seconds compared with 10.9 seconds in my new i30.

Well you heard it first on here ---- AlanHo is an Old Boy Racer in his new i30   

[baroudeur]

Using the motorway marker boards and my Sat-nav, I determined that the odometer in the loan car was 3.6% slow. (ie: if the odo trip shows a distance covered of 100 miles – the car has actually travelled 103.6 miles). In my previous i30 Premium the odo was 2.5% slow and in my new i30 it is 1.8% slow. This needs to be taken into account for brim to brim economy calculations.

Despite the odo error – the speedometer in the loan car and the speedo in my previous car were both dead accurate compared with the sat-nav. In my new i30 the speedo reads about 8% fast.

Apparently sat nav mileage will always be less than actual owing to linearisation** although I cannot find out to what percentage this would amount.  Presumably it would vary depending on how "windy"  were the roads  involved.

** sat nav measures straight lines between consecutive points.

[AlanHo]

I have tested my sat-nav against the motorway distance posts over a distance of 133 miles on the M5 south and it was bang on correct.  I did it again on a trip from Scotland on the M6 over 142 miles and again it was proved to be accurate.

In any event - I checked the odo against both the motorway distance posts and the sat-nav to determine the error.

[Phil №❶]

Without getting too carried away here, I would always expect a minor degree of error when comparing geodetic points to actual driving. Every little undulation causes the vehicle to travel further than a flat line, eg a sine wave is obviously longer than the 0 reference on an oscilloscope. I think over 100 miles  a small % wouldn't be out of the question at all. In fact, I'm surprised Alan's results are so close. 

[asathorny]

Without getting too carried away here, I would always expect a minor degree of error when comparing geodetic points to actual driving. Every little undulation causes the vehicle to travel further than a flat line, eg a sine wave is obviously longer than the 0 reference on an oscilloscope. I think over 100 miles  a small % wouldn't be out of the question at all. In fact, I'm surprised Alan's results are so close. 

'solutly....  why didn't I think of that  Duuuuhhhhh   

[AlanHo]

Apparently sat nav mileage will always be less than actual owing to linearisation** although I cannot find out to what percentage this would amount.  Presumably it would vary depending on how "windy"  were the roads  involved.

** sat nav measures straight lines between consecutive points.

I have no doubt that you are correct in what you say. However - my checks were carried out on motorways which are generally straight with a few very bends - and the bends are very gentle so errors would be minimal because the NUVI has very short intervals between log points.

However you have put some doubt in my mind.

I have just returned home after a round trip to Tewskebury down the M5 so I decided to check the car odo and the sat-nav yet again against the motorway distance boards which are set at decimal kilometer distances apart ( even though in the Uk . Previously I have left the sat-nav units in miles - but today I changed it to Kilometers to get sightly better sensitivity. The car trip is in miles so I have converted the recording to kilometers for comparison.

I noted the distance shown on the first motorway board I passed after joining the M5 and the last board before the the exit ramp in each direction.

Travelling south
Distance between motorway distance boards : 50.8 km
Sat-nav trip distance                                   : 50.7 km (difference -0.2%)
Car odometer                                             : 49.2 km  (difference -3.3%)

Travelling north
Distance between motorway distance boards : 50.5 km
Sat-nav trip distance                                   : 50.4 km (difference -0.2%)
Car odometer                                             : 48.8 km  (difference -3.4%)   

Hence on this journey the sat-nav did indeed under-measure. But only by a very small percentage.                     

[baroudeur]

Thank you Alan


Obviously, motorways will produce the smallest error.  A   trip over a mountain range with short tight bends  might produce some anomalous figures.
My Garmin sat nav has a programme which measures every  trip and  the fuel consumed and, so far, it agrees with car's computer figure for mpg albeit over relatively short journeys. 
My next  really long, non-stop, trip on a motorway will be the A75 from Clermont Ferrand to Pezenas, just under 200 miles so it will be interesting to compare the brim to brim, car computer and the Garmin figures for mpg and distance at around 70 mph average speed . I will also record the overall figures for the complete return trip which will probably be in excess of 1700 miles.

[Dazzler]

For Alan's next trick he is going to drive in a straight line between Manchester and Liverpool .. Don't worry about the debris (billboards and fences which will become attached to the car) he will weight these and take the extra weight into acount when comparing his fuel economy calculations ...

[Doggie 1]

Manchester to Belfast by the shortest possible route would be interesting. 
Although, I hear it can be a little wet at this time of year.

[AlanHo]

For Alan's next trick he is going to drive in a straight line between Manchester and Liverpool .. Don't worry about the debris (billboards and fences which will become attached to the car) he will weight these and take the extra weight into acount when comparing his fuel economy calculations ...

I could walk it (along the Manchester ship canal)...............

[eye30]

For Alan's next trick he is going to drive in a straight line between Manchester and Liverpool .. Don't worry about the debris (billboards and fences which will become attached to the car) he will weight these and take the extra weight into acount when comparing his fuel economy calculations ...

I could walk it (along the Manchester ship canal)...............

M62 would be the best straight line

[AlanHo]

M62 would be the best straight line

My wife reckons I could walk on water - so I will stick with the canal..............

[Dazzler]

M62 would be the best straight line

My wife reckons I could walk on water .

Maybe she just wishes you would