Author Topic: better mileage (Read 4912 times)

Benjamin · « **on:** January 25, 2007, 10:47:26 am »

hi guys, i know there is said much about how to make a economal diesel engine, but i wonder there is not a faq.
my car is stock and the mileage is bad, my powerfull engine use less with more hp... :cry:

Do i need to increase or decrease the timing, wich injectors, high turbo boost for less egt's...? talking about IDI and TDI-m

Greetz, Benjamin

jtanguay · « **Reply #1 on:** January 25, 2007, 10:53:27 am »

TDI-m is the better way to go for better mileage & power.

burn_your_money · « **Reply #2 on:** January 25, 2007, 02:19:26 pm »

More boost with the same amount of fuel theoretically yields better mileage because the fuel has a higher probability of being burnt

Slave2School · « **Reply #3 on:** January 25, 2007, 07:33:40 pm »

Too much boost and the back pressure is needlessly high and you get poorer mileage

3bar map in my car makes for better power, but incredibly poor fuel economy.

jtanguay · « **Reply #4 on:** January 25, 2007, 08:52:04 pm »

i would have to say that off boost would yield the best mileage, but the worst performance. either way you look at it the VNT turbo system is the best in a turbo application.

our cars only need about 40-50 hp to move along at around 100km/h but when the boost starts coming on our cars are pushing 70-80hp moving along at 100-110km/h. extra hp requires extra fuel :wink:

vnt system allows you to get that extra hp you need for passing/merging. once thats done you could just keep the vanes open to let the engine breath a bit easier. if you reach a hill, just depress the pedal a bit and the turbo will kick on more increasing the boost to let you get up the hill. power on demand is a great thing

Benjamin · « **Reply #5 on:** January 26, 2007, 03:42:21 am »

should a VNT turbo be better than a normal turbo, and what should be the best: k14 or k24?, offcorse when driving normal. My car use +-8L/100km (thats much) (weight: 1000kg) when i'm just driving normal, even when i drive the slowest i can, i cant get 7l/100km :cry: i rather wanna reach 6l/100km or so with my IDI

and what about static and dynamic timing for best mileage?

what rpm for better mileage?

Greetz, Benjamin

burn_your_money · « **Reply #6 on:** January 26, 2007, 04:38:37 am »

Quote from: "Benjamin"

what rpm for better mileage?

Drive according to the road conditions. If you are at too low of an RPM your pump is just going to dump in more fuel and get the turbo spooling

jtanguay · « **Reply #7 on:** January 26, 2007, 05:32:16 am »

generally keep it below 2800, but like burn said, downshift going uphill to use more of the engine's hp to move it along.

its also wise to know when your engine is working too hard and not burning all the fuel. if you notice that you are accelerating at a certain speed and depress the pedal further, but still not accelerating then release the pedal a bit because its just wasting fuel. the motor will usually start vibrating a bit more which you should then clue in on... no sense in pushing it further than it can go right? all you get is black smoke :twisted: