Fuel economy with 3.2 DID

User avatar
peterpot
Country: SA
Vehicle: 2009 Pajero 3.2 SWB
Location: Pretoria
Posts: 343
Joined: Wed Jan 27, 2016 3:42 pm

Fuel economy with 3.2 DID

Wed Oct 24, 2018 2:06 pm

With the latest and future fuel price hikes I thought it might be in some owners interest to get the best fuel economy from their 3.2 DID. Sure they are not the most economical vehicles but with the fantastic reliability, safety, "towability" and versatility I am happy to live with that.
Having had a Gen3 and now a Gen4.1, by comparison, I can say that the Gen4.1 3.2 is not an easy vehicle to drive economically. Likewise I see the Gen4.2 3.2 owners are also getting far better fuel consumption.

Sweet spot. All vehicles have a "sweet spot". This is where the vehicle seems "at its happiest". It is a balance of wind resistance, engine performance, load, etc. Find your vehicles "sweet spot" for best economy. My Gen3 had a bullbar, air inlet modification and otherwise std. I found my best economy at about 95km/h. I could get 11.5 km/L without really trying. My Gen 4.1 has raised suspension, bullbar, air inlet modification and 73mm freeflow exhaust and its sweet spot is 100km/h. I can get 10.5 km/L but only with a lot of concentration.

Tyre pressure. I run my tire pressures at 2.5 bar on tar. I found this pressure counters the excessive wear on the outer edge of the tire due to a heavy vehicle and heavy cornering :mrgreen:, plus it helps with fuel consumption.

Air filters have a serious effect on fuel consumption. Avoid free flow air filters and keep to the OE system. I fitted an air filter restriction indicator to my Gen3 and again to my Gen4.1 vehicle. This allows you to monitor the filters efficiency and change only once economy is about to be effected. They are available from Donaldson Filtration. Use the progressive one (goes up in clicks / shows red when due) and make sure you get a diesel one as petrol engine indicators are different. I fitted one to my Gen3 and immediately noticed a restriction. This is how I came across the fact that the turbine system just prior to the air filter causes a slight restriction (thread on Community 4x4). The turbine helps in extreme / very dusty areas. I removed mine on my Gen3 and my Gen4.1, as I seldom drive dusty roads plus I keep an eye on the indicator and fuel consumption is critical to me.

I find the speed control can have a serious negative effect on fuel consumption and I only use it on long flat open stretches. If the speed control is left to accelerate and change gears on inclines it well have a serious negative effect. If I see any possibility that my speed might change, I cancel it and once over an incline engage it again.

Long open stretches the 4.1 is happy with and I can cruise at 100km/h comfortably. Keeping to 120km/h has quite a big negative effect. I find once the 4.1 has to start working harder the fuel consumption takes a serious dip. For this reason I try and get a bit of a run at a hill and will slowly increase my speed so that to get up the hill I have to use the very minimum of acceleration, The harder you have to accelerate to get up the hill the worse you consumption will be. Getting a run up helps a lot but this is a problem if there is a lot of traffic (which is why I choose to travel without other vehicles close to me. I find it too dangerous to travel at night now :x , so I try and select the least congested / quietest possible day and time of day to travel.

Plan your trip. Do research check road conditions. Establish where and when you are going to stop. Drive consistently and safely. Drive so as to accelerate and brake as little as possible. Some people have told me my brake lights do not work and when tested they see they do in fact work. Time your overtaking so as to make the action as smooth and safe as possible making hard braking and acceleration as gradual as possible. Keep your distance behind the front vehicle so that your braking and acceleration is minimal and this will allow you to predict his actions so much easier.
User avatar
peterpot
Country: SA
Vehicle: 2009 Pajero 3.2 SWB
Location: Pretoria
Posts: 343
Joined: Wed Jan 27, 2016 3:42 pm

Re: Fuel economy with 3.2 DID

Wed Oct 24, 2018 5:23 pm

Something I forgot to mention was that fitting a new MAF sensor (fits on the air filter housing) had a big improvement on performance and fuel economy. For the R1 500.00 odd it was a good investment and made a fantastic improvement. The faulty MAF sensor was not picked up by the engine management system or vehicle diagnostics.
User avatar
Mitsu Fan
Country: South Africa
Vehicle: Pajero Gen 4 2015
Posts: 80
Joined: Tue Oct 29, 2013 4:50 pm

Re: Fuel economy with 3.2 DID

Sun Oct 28, 2018 7:01 pm

Thank you Peterpot for the tips.

I wont be doing any serious mods as my Jero is still pretty new, but the travelling tips made me realize how bad my driving habits really are.

Cheers
Chris
Country: RSA
Vehicle: Pajero GLX
Location: Boksburg
Posts: 77
Joined: Wed Jul 27, 2011 1:02 pm

Re: Fuel economy with 3.2 DID

Mon Nov 05, 2018 7:33 pm

Thanks for some usefull tips. I removed my raised suspesion and improved the consumption by 1 to 1,5 l/100km. I fail to understand why such a big difference but have heard of several other Paj drivers who confirmed it to be true
Chris
User avatar
peterpot
Country: SA
Vehicle: 2009 Pajero 3.2 SWB
Location: Pretoria
Posts: 343
Joined: Wed Jan 27, 2016 3:42 pm

Re: Fuel economy with 3.2 DID

Wed Nov 07, 2018 7:57 am

Now that is interesting!.

Return to “Engines and Engine Management”

Who is online

Users browsing this forum: No registered users and 2 guests

Login · Register

Latest Posts

Login  •  Register