Canopy and Economy

[JoeMorrison]

I have a canvas canopy on a cab chassis STX. For economy, is it better to leave it rolled up or should I let down the sides and zip it all up?

 

[Old.Tony]

Aerodynamically speaking, I'd imagine if the tailgate was catching some of the wind it'll slow things down - but I can't say if that's going to be worse than the vacuum created behind the truck by having a full canopy.

I've only ever removed my canopy when transporting a new air conditioner for my home (wouldn't fit inside the cabin) so I can't offer any consumption observations over time.

 

[JoeMorrison]

Aerodynamically speaking, I'd imagine if the tailgate was catching some of the wind it'll slow things down - but I can't say if that's going to be worse than the vacuum created behind the truck by having a full canopy.

I've only ever removed my canopy when transporting a new air conditioner for my home (wouldn't fit inside the cabin) so I can't offer any consumption observations over time.

Thanks Tony.

 

[Tms40]

Just get used to it. I have a big canvas canopy and keep adding extras. Next is a shower tent. Everything I add on reduces fuel economy by 200+ ml/100

 

[JoeMorrison]

Just get used to it? 15.5 l/100 km. Pretty hard for a pensioner to get used to that. I'm looking for ways to improve that not make it worse. Have you done anything that has made a positive difference?

 

[Old.Tony]

15.5LPHK is a little steep if you're not towing. Wait ... diesel or petrol? That's pretty typical consumption for a petrol V6. The diesels can get down to around 10-11LPHK.

 

[JoeMorrison]

Yes, diesel, Tony. I have a 4.5 tonne bus that gives better figures! No sign of DPF blockage so I'm not sure where to start. I am using the lightest foot possible to keep the revs down on the highway and as I'm rural and living on the edge of the highway almost all driving is on the open road.

 

[Old.Tony]

If it's a diesel then the economy figures are not very good. There are a few things to check:

1) How warm are the rear drums after a 10 minute drive?
2) Is there any significant black smoke when accelerating?
3) How long since the intercooler was cleaned?
4) Has the EGR been blocked? (what year model is yours?)
5) Manual or auto?
6) Are the brakes very effective or do they require a fair push to stop the car?

 

[KevinE]

Probably not comparable, but I used to drive Unimogs with canvas on the back & there was a very noticeable drag with the canvas down compared to the canvas up on the open road (Adelaide to Woomera/Murray Bridge etc) Maybe try both out on the Hwy & see how it feels?

Tyres also make a noticeable difference in fuel economy on my YD25 D22. Went from 265/70/R16 P construction to 265/75/R16 LT's & the fuel economy went south by a fair margin.

I tow most of the time & my figures towing a dual axle work trailer around town were about 12.5L per 100KM's with the 265/70's & have gone up to around 15L per 100KM's with the 265/75's. I'm sure that the change from P's to LT's compounded the issue because of the weight increase.

 

[JoeMorrison]

Probably not comparable, but I used to drive Unimogs with canvas on the back & there was a very noticeable drag with the canvas down compared to the canvas up on the open road (Adelaide to Woomera/Murray Bridge etc) Maybe try both out on the Hwy & see how it feels?

Tyres also make a noticeable difference in fuel economy on my YD25 D22. Went from 265/70/R16 P construction to 265/75/R16 LT's & the fuel economy went south by a fair margin.

I tow most of the time & my figures towing a dual axle work trailer around town were about 12.5L per 100KM's with the 265/70's & have gone up to around 15L per 100KM's with the 265/75's. I'm sure that the change from P's to LT's compounded the issue because of the weight increase.

Thanks Kevin. This vehicle has LT 265/75 so thanks for confirming that could be a factor. I have a new set of standard tyres on my older D40 which I could swap to test if that's a factor.

 

[JoeMorrison]

If it's a diesel then the economy figures are not very good. There are a few things to check:

1) How warm are the rear drums after a 10 minute drive?
2) Is there any significant black smoke when accelerating?
3) How long since the intercooler was cleaned?
4) Has the EGR been blocked? (what year model is yours?)
5) Manual or auto?
6) Are the brakes very effective or do they require a fair push to stop the car?

Thanks. Good questions. Have not seen black smoke. Will check drum heat. Don't know about intercooler. Vehicle is auto with 80k on clock so doubt it has been cleaned. Brakes aren't great. Do require a push. Don't know about EGR. Model year 2012.

 

[Old.Tony]

If the brakes need a fair bit of convincing to work, there's a chance that you have a slight vacuum leak - which may be causing your turbo to underperform, which will also increase your fuel consumption.

 

[JoeMorrison]

Thanks Tony, I'll have that checked.

 

[Billy54]

I just did a holiday trip to Tuncurry for a week away in my 2011 D40 [120k on the clock] with Aluminium canopy. 2 hours up the highway with some driving around during the week then back. i put fuel doctor in the full tank and got 9.23 LPHK. Lots of holiday stuff in the back including the dog on the back seat. We came back heavier due to the consumpion of fresh prawns and seafood. I sat on 100 KPH because of the number of patrol cars along that stretch. Listened to Billy Sherwood Prog Progressive albums the whole trip [very good driving music] I think it helped with the fuel consumption.

 

[JoeMorrison]

So Mick Jagger is to blame? No wonder I can't get no satisfaction!

I would regularly get consumption figures like that from my 2006 model D40. Fuel doctor may be worth trying. So thanks.