Incredible fuel economy

[Kermodi wvo]

I just bought my 96 surf with 3 litre diesel and love it to bits, I got 35 mpg when I tested it on a 600 km trip only used 50 litres which I thought was good, now I disabled the egr by plugging the hose with the little ufo filter and went fishing out of town yesterday in the pouring rain with 4 people and all the gear stuffed in the back and what a difference I got 343 km on 1/3 tank I had to take a picture to prove it as I couldn't believe myself. It definitely is way smoother a seems I barely touch the peddle to maintain hwy speed. I am running synthetic oil in everything that holds oil including power steering. Tires at 42 psi and driving at 55 to 60 mph. Just guessing I would prob get over 700 mms on this tank. Should be over 37 mpg or more.

[AlexKzn130]

I just bought my 96 surf with 3 litre diesel and love it to bits, I got 35 mpg when I tested it on a 600 km trip only used 50 litres which I thought was good, now I disabled the egr by plugging the hose with the little ufo filter and went fishing out of town yesterday in the pouring rain with 4 people and all the gear stuffed in the back and what a difference I got 343 km on 1/3 tank I had to take a picture to prove it as I couldn't believe myself. It definitely is way smoother a seems I barely touch the peddle to maintain hwy speed. I am running synthetic oil in everything that holds oil including power steering. Tires at 42 psi and driving at 55 to 60 mph. Just guessing I would prob get over 700 mms on this tank. Should be over 37 mpg or more.

well done bud im jealous lol 42psi sounds a tad extreme what tires you running?

[NiftyNev]

well done bud im jealous lol 42psi sounds a tad extreme what tires you running?

I've always thought you guys run low pressure. I have 31x10.5s and always have them at at 38 - 40 PSI.

Nev.

[AlexKzn130]

I've always thought you guys run low pressure. I have 31x10.5s and always have them at at 38 - 40 PSI.

Nev.

really hmmmm, i got 33 AT2's and run them at 32-34psi maybe im missing a trick here

TO GOOGLE!!!!!

[NiftyNev]

Google the 4 PSI rule.

Nev.

[AlexKzn130]

Google the 4 PSI rule.

Nev.

ok so your saying be careful cos if i crank it upto 50 in the morning in the afternoon it could read 52-55psi?

i just read my side wall and on the max load section it states max load 1000kg at 35 psi, so i think 40-50psi doesnt apply to my tire

[NiftyNev]

Not sure about your tyres. What brand are they? Simply put, if you inflate your tyres cold to 34PSI for example, check pressure when hot. If pressure reads 4PSI above cold pressure then cold pressure is correct. If pressure reads less than 4PSI above cold pressure lower cold pressure. If pressure reads more than 4PSI above cold pressure raise cold pressure.

A fair bit of the heat in a tyre comes from the sidewalls flexing, so if tyre pressure is too low a lot of heat is generated in the sidewalls, which is not good for the tyres. If you look at the above about pressures, you will see that lowering or raising pressure, allows the sidewalls to flex more or less to get the 4PSI difference between hot and cold. Hope I explained that ok.

Nev.

[Robot]

Tyre pressure is important for an awful lot of factors. The grip from a 42psi tyre is massively reduced over a ~30psi tyre of the same size due to the reduced contact patch and the grip of a 30psi BFG is bloody awful at the best of times. These are light 4x4s with big tyres. The correct way to identify the correct tyre pressure is to analyse the contact patch shape - the 4psi rule won't work for a vast number of reasons - heat dissipation depends on tyre type, size, speed of driving, rim type etc etc. It will vary from day to day, from drive to drive. If you were a racing team running a nascar on a constant loop in constant test conditions - sure. Hell, even the old chalk-line method is better IMO.

[AlexKzn130]

Not sure about your tyres. What brand are they? Simply put, if you inflate your tyres cold to 34PSI for example, check pressure when hot. If pressure reads 4PSI above cold pressure then cold pressure is correct. If pressure reads less than 4PSI above cold pressure lower cold pressure. If pressure reads more than 4PSI above cold pressure raise cold pressure.

A fair bit of the heat in a tyre comes from the sidewalls flexing, so if tyre pressure is too low a lot of heat is generated in the sidewalls, which is not good for the tyres. If you look at the above about pressures, you will see that lowering or raising pressure, allows the sidewalls to flex more or less to get the 4PSI difference between hot and cold. Hope I explained that ok.

Nev.

I've got 33x12.50 general grabbers AT2's ill see what my pressure is in the morning tomorrow, if i remember correctly the last time i put air in was on my way home from work so maybe the tires were already warm when i done it giving me less psi the next day when cold

[Kermodi wvo]

I am running 265/60/16 and max pressure cold says 51 PDs cold so I put them to 42. When I got the surf they were at 32 I felt like it wasn't rolling easily so aired them up, you could really feel the difference seems like it's not working as hard. Also I have nitrogen in them instead of air except for the little bit extra I put in this way heat does not change the pressure in the tire. I am also running 50% veggie oil in my diesel tank that gets heated by a coolant heater, don't know if that contributes to the good mileage

[Bogus]

I use 78% nitrogen in mine, seems to work just fine

[Big dog]

Interested in disconnecting my egr , is it the only pipe that goes into the top that you remove , my surf is a 2nd generation 3ltr , thanks

[NiftyNev]

I use 78% nitrogen in mine, seems to work just fine

Me too. What's the point of using nitrogen if there is already air in the tyre before it is fully inflated.

Nev.

[Kermodi wvo]

It's easy to disable egr just remove vacuum hose that has little ufo filter on it cap both ends or put small ball bearing in vac hose and put it back on. Done takes 5 mins