DPF Advise

[Krankin]

well they reckon adding 2 stroke to the tank gives great power and economy, not to mention advanced fuel system lubrication,
he can try that as well as driving like an old moll,
and with the spare cash savings why not add a hiclone...that'll just top off the the whole package, complete system.

 

[Old.Tony]

Apart from the DPF ... automatics will ALWAYS use more fuel than a manual - but that gap is closing.

In a manual, every single turn of the crankshaft of the engine is directly translated into a single turn of the gearbox input shaft because the clutch drive is solid - there's no slip, except when taking off. At all other times, consider the drive to be 100% solid.

In an auto, the drive isn't solid - it's actually called a fluidic drive, where the rotation of the engine is transferred to the gearbox via the shearing forces imparted through the oil in the torque converter. One turn of the engine is NOT one turn of the gearbox - in my car (and every car is going to be very slightly different) at 1500rpm of gearbox input speed my engine is turning over at about 2000rpm.

How do I know? That's easy. One of the nice things about the Nissan torque converter is that it has a clutch that, under certain circumstances, engages the input and output sides of the torque converter turning it into a solid drive. At about 80km/h as I'm just holding the vehicle's speed with 2,000rpm this clutch - called a TCC - will engage and reduce the rpm to about 1500. I've watched it happen dozens of times.

So, that's 25% of my rpm being wasted on turning the torque converter over - so 25% of the input to my engine is wasted compared to a manual. Until that converter locks.

Once the TCC locks I'm on par with the manual.

The automatic has an advantage over the manual on takeoffs (where fuel usage is very high, getting all those tonnes moving). Whereas you'll ride the clutch and get a LOT of revs out of the engine, the auto will start moving the vehicle at a lot lower rpm - it transfers power more efficiently than a slipping clutch. You have to be pretty good with the manual clutch to match the auto's performance here.

In the long run, the auto is only marginally worse than the manual in performance. It really comes down to driver, environment, fuel choice, tyres and load.

And just to provide a real-world understandable example: if you drive from Sydney to Perth (4500km) and use a whole extra litre per hundred km of fuel, that's 45 litres more for the entire journey. The automatic costs you about $70 extra to get it across Australia ($675 for the manual @ 10LPHK, $742.5 for the auto @ 11LPHK).

It's not that big a difference. And with technology like the TCC, the difference between auto and manual in terms of economy is getting smaller all the time.

 

[merchant]

and just a small side note....removal of the DPF is illegal....
your choice...just puttin out the info

Ha, it's only illegal if you get caught.

 

[KraftyPg]

I still say it's a crock that all autos use more fuel and say it's the driver that wastes the fuel not the car but people always want something or someone else to blame so if it makes them feel better to blame the car or the bits on it for economy that is not what they expect then so be it.

 

[Old.Tony]

I still say it's a crock that all autos use more fuel and say it's the driver that wastes the fuel not the car but people always want something or someone else to blame so if it makes them feel better to blame the car or the bits on it for economy that is not what they expect then so be it.

My contention is that if YOU drove a manual you'd get slightly better fuel economy than in the auto simply because of the physics involved.

And I further contend that the only way I'd get better fuel economy than you is to tow my Navara, or take a bus.

 

[KraftyPg]

But manual drivers can be just as heavy footed as auto drivers thus over riding any perceived benefits of having the manual box to begin with. The argument that one is ALWAYS worse than the other is incorrect, the argument that many drivers can't make an auto as economical as a manual might have some truth too it but it's still not an ALWAYS case.

I can travel at up to 100kph (not many 110 zones in my daily travels) and I can do that with figures up until recently of just above 10LPH and now below 10LPH, it's not impossible sure it takes some effort to get used to but it's definitely not impossible to do and it;s something most others could do if they tried.