Thread: More Towing Fuel Economy with the 2.7L

Originally Posted by DiscoJeffster

Not that amazing. Cruise control.

Not worried about fuel economy though if (say) 91.5kmh was optimal for a triple or quad truck (mainly what we see on country WA roads) when burning the quantity of fuel they use (1litre/km or worse) . They stay Max on the legal speed limit 100kmh all the way whereas us holidayers write chapters on optimising theoretical fuel savings of $5-10/ 100km after spending $100k+++++ on car and equipment.

Time is money as they say.

Originally Posted by PerthDisco

Amazing how the big trucks keep it absolutely pinned at 100kmh towing their brick

Here,they mostly sit pinned on 105km/hr.

And that reading is off my Garmin,so accurate.

Originally Posted by scarry

Here,they mostly sit pinned on 105km/hr.

And that reading is off my Garmin,so accurate.

And do not appreciate the 90kmh ‘fuel economy obsessed’ caravan towing holiday maker one little bit.

Originally Posted by PerthDisco

And do not appreciate the 90kmh caravan towing holiday maker one little bit.

Correct,and the caravan towing holiday maker may actually be doing around 86KM/Hr.

This is an issue, Jo Average in their new car, more than likely is sitting on(or has the cruise set on) 100km/hr,but actually the real speed they are going is 95 or 96km/hr.
Most modern cars read around 4 to 5% less than actual.
So the truck driver will actually be doing 9km/hr more than Jo average,and won't take long to get frustrated,but Jo Average thinks the truck is speeding.
Well the truck is speeding,but not by much and probably won't get pulled over,only 5% over,not 9% over.

Even if the truck is doing 100Km/hr,its still 4 to 5 Km/hr faster than than Jo Average,who thinks he/she is cruising on the speed limit.

I drive by my Garmin street finder all day,and have for years,never had a ticket.
And some days i go through over 10 speed cameras,and a few cops sitting on the side of the road with speed guns,at least.

FWIW,and in my opinion,car speedometer read outs that are lower than actual are no real benefit,and are actually, in some ways,dangerous.

^ which is why I drive at 106kph when towing to be smack on legal (GPS reading at 100kph) which gives me a margin for error. Sometimes I do a smidge more too and set 110kph knowing it’s about 105kph and they won’t pull me for that. I have slim and relatively camper trailer so economy isn’t impacted much by speed

It's illegal for the speedo to show less than the actual speed. The vehicle is unroadworthy.
Radar is usually set to ping at 3km/h over the speed limit. If the vehicle is actually travelling at say 95 when the speedo says 100, then 95+5+3 = 103 actual speed, which could be 108 on the speedo, but I didn't say that.

Originally Posted by DiscoMick

It's illegal for the speedo to show less than the actual speed. The vehicle is unroadworthy.
Radar is usually set to ping at 3km/h over the speed limit. If the vehicle is actually travelling at say 95 when the speedo says 100, then 95+5+3 = 103 actual speed, which could be 108 on the speedo, but I didn't say that.

Speedometers tolerance under ADRs is +0/-10%.

Tyres between brands can be a significant variation in itself.

For camera tolerances Generalisations don’t work in AU.
In SA most cameras are +5km/h. In Vic it’s closer to +2km/h.

On SA highways it can (not always) be 10%.

Originally Posted by Tombie

Speedometers tolerance under ADRs is +0/-10%.

Yes under current ADRs but earlier than about 20 years ago it was +/- 10% so older cars speedos can show 100kph when you are doing 110kph.