Over Weight And Over Heating

Over Weight And Over Heating



Vehicle weight is​ a​ major issue that many Four Wheel Drive owners are often unaware of​ or​ just ignore. This is​ not only a​ performance issue but also a​ safety issue and not just for the​ vehicle owner but also for other road users. at​ Berrima Diesel Service ( www.berrimadiesel.com.au ) they usually see half a​ dozen 4WDs in​ their workshop every day for tuning,​ performance problems or​ turbo charging. During the​ process of​ their work they weigh the​ vehicles as​ part of​ the​ job. They do this as​ they have most vehicles coming in​ for a​ power gain. it​ might end up with the​ power gain at​ the​ wheels,​ but it​ may not push the​ vehicle as​ thought. This is​ where the​ weighing process comes in,​ sometimes with surprising results. They utilise a​ modern electronic weighbridge that is​ accurate to​ within 10kg.

Considering that the​ average 4WD wagon only has a​ payload capacity of​ just over half a​ tonne,​ it​ doesn't take long to​ swallow that up with 2 or​ 4 occupants,​ oils in​ the​ engine,​ diffs,​ gearbox,​ fuel in​ the​ tank/s,​ the​ normal accessories like bull bar,​ towbar,​ heavier suspension (big springs and shocks are literally heavier). Even different tyres can weigh substantially more than standard .Generally,​ the​ big wagons have a​ maximum GVM (max loaded weight) of​ 2.9 tonne to​ 3.1 tonne. Berrima Diesel see the​ average ones weighing 2.9 tonne to​ 3 tonnes and they are certainly not loaded for a​ trip. When they get the​ accessorised big wagons in​ they start to​ reach towards 3.2 tonnes and they have seen the​ odd 100 series Landcruiser in​ their workshop,​ obviously with a​ lack of​ power problem,​ weighing in​ at​ 3.5 tonnes. When you talk troopies,​ they regularly weigh over their GVM as​ they are stacked up with all the​ heavy gear needed for the​ trip. Large steel fuel tanks not only carry a​ lot more fuel (weight) but weigh in​ surprisingly more than the​ factory poly or​ tin tank. One recent GU Patrol went over 3 tonne and the​ vehicle wasn't what you would call heavily modified,​ just the​ usual 'steel gear'.

A big problem arising from the​ ever increasing weight of​ 4WD's is​ fuel consumption. a​ standard 4WD diesel can start off with a​ happy consumption figure of​ around 10-12 litres/100km only to​ have it​ blow out to​ 16ltres/100km once modified.

Tyre blowouts are common on​ a​ lot of​ trips and this is​ an​ area that weight can have a​ huge effect. Standard tyres are designed to​ work within the​ working parameters of​ the​ vehicle but once it​ is​ overweighted the​ standard tyres are often working very close to​ their maximum weight limit. Throw in​ an​ extremely hot road and the​ working weight of​ the​ tyre gets lower. When considering loading up next time,​ check the​ loaded weight of​ the​ vehicle and check the​ combined load rating of​ the​ tyres. Make sure you have a​ good percentage of​ difference between the​ tyres and the​ weight of​ the​ 4WD they are carrying. Eg. probably 20% to​ 30% less weight of​ the​ vehicle than the​ maximum tyre carrying load.
Wheel bearings are another thing to​ consider. Make sure that they are greased if​ you are carrying weight.

Overweight vehicles are the​ main reason for performance problems. Not only that but they are often illegally overweigh. Ask the​ people how much they think their 4WD weighs and the​ general answer is​ 2.2 tonne or​ 2.4 tonne. When Berrima Diesel explain that it​ weighs in​ at​ 3 tonne or​ more they have trouble believing it!! Add to​ this the​ 2 tonne trailer and you have,​ for example,​ a​ 3 litre Nissan trying to​ move a​ combined weight of​ 4.5 to​ 5 tonnes!!

Overweight vehicles can also become an​ insurance issue in​ the​ case of​ an​ accident. a​ listed weight,​ initiated by the​ accessory manufacturer on​ accessories,​ would be of​ a​ great benefit to​ people.

Some other areas to​ consider that can effect vehicle weight areas steel refrigerators,​ larger tyres,​ upgraded suspension also lends itself to​ more weight as​ well as​ thicker springs,​ storage drawers,​ roof racks,​ dual batteries,​ different seats,​ HF radios. People usually need these for trips but at​ least an​ awareness of​ where the​ weight is​ coming from can help with controlling it.

Find a​ reputable weigh bridge or​ just turn into an​ RTA truck weigh bridge for free and get ready for a​ possible shock!

Radiators and Air flow:

* Consider a​ larger radiator. Some Factory radiators are a​ 2 core and can be increased to​ a​ 3 core radiator.
* Please… resist fly screens where possible.
* Consider the​ size and positioning of​ driving lights,​ winch,​ number plates and particularly bull bar air flow.
* Check to​ make sure air conditioning condenser fins are clean!!
* If an​ Intercooler is​ mounted in​ front this can add considerably to​ hot air flow over the​ radiator and restricting air flow to​ the​ radiator.
* Consider installing a​ few small bonnet vents on​ the​ left and right of​ the​ rear region of​ the​ bonnet. This has proven to​ be a​ popular addition and has huge effects on​ under bonnet temperatures. Considering how tight most engine bays are after a​ few accessories are added,​ this venting addition can reduce heat stress on​ a​ variety of​ products under the​ bonnet.

Engine set-up:

* Over fuelling is​ usually the​ major cause of​ high combustion temperatures.
* Make sure the​ fuel injection system has been thoroughly checked and setup correctly.
* If the​ vehicle is​ fitted with a​ turbo or​ super charger,​ over fuelling may be the​ cause. it​ is​ very easy to​ over fuel a​ diesel once plenty of​ air is​ available as​ possibly no smoke under load may be visible. Visible smoke under load can be a​ warning of​ over fuelling!

This article and the​ technical advice was taken from an​ interview with Andrew Leimroth of​ Berrima Diesel Service. Andrew is​ one of​ the​ Diesel Experts who have been working exclusively on​ diesels since 1965. His wealth of​ knowledge and skill with problem diesels is​ well known in​ the​ automotive industry.




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