best mpg Land Cruisers? (1 Viewer)

[Dave 2000]

You are correlating an engines efficiency with electronic control and making the assumption that further electronic control will yield further benefits.
Where mechanical tdi engines have no problem matching an
electronic engine for absolute efficiency.

Absolutley correct I am doing exactly that! So, you are saying that if I remove all of the electronics from the latest diesel engine it will make no difference to it's efficiency right?


The gains made in fuel consumption are the following.
1. Direct injection not only giving better thermal efficiency, but an engine strong enough to take lots of boost.
2. Variable geometry turbocharging to provide more boost over a wider operating range.
3. The use of higher pressure turbocharging to deliver more from smaller engines (aka downsizing).
4. Gearboxes strong enough and with enough ratios to get cruising rpm way down. Passenger diesel cars are cruising around 1700rpm now, the current tdi v8 rangerover is cruising at 1400rpm. Courtesy of an 8 speed ZF auto.

So, you are saying modern engines/engineering has benefited in efficency right?


Badly written.
It is about how effiicent an engine is at cruising loads.

Who mentioned cruising loads. where did that come from?


4 cyls and 6 cyls are just as efficient at full load, but at lower loads the 6 has more internal friction, more heat loss and as a result lower efficiency. It's as simple as the internal heat loss and work loss being a bigger proportion of the total.

So, now you are saying 4 and 6 cylinders are just as efficient as each other however, only under certain conditions? So that is a variable right?

It's like trying to feed a family of 4 vs a family of 6. If you can keep all 6 working hard it's no different. But 6 doing the work of four gets expensive.

Good analogy but would it also be fair to say that if the 6 are fitter and stronger (more efficient) than the 4 you get the same work for the same food?

Again badly written.
The engine doesn't "work harder". Such a concept doesn't exist with engines. There is only the torque an engine produces, the conditions it does that under, how efficiently it produces it and how efficiently that power is put to the ground.

So it's false. A td5 does not and cannot work harder than a 1HD-T.
It's either a sick td5 or a badly driven one that drinks like an HD-T. Then again, "often get similar" means very little.

OK, I could have explained that better, try it this way. My friends engine has to consume more fuel to produce the same effort as my 6 cylinder engine making it less efficient?

I must say, you've mastered the art of writing down your nose quite well. I hope you can keep it up a little longer.

At this point Dougal I am going to call it a day with this topic, whilst I was enjoying this discussion and would agree you have some valid points I am afraid your last paragraph was uncalled for. I always thought I could recognise early when dealing with someone who lacks the maturity to have a sensible debate without lowering to comments such as this, clearly I was wrong about that.

regards

Dave

Unsubscribed.

 

[hedydd]

Don't worry about the dross, it is all part and parcel of the internet forums. Chin up.

Anyway, a six cylinder of equal design, from the same engine family, of 100hp, at the lower end of its possible rating spread, will almost inevitably be less efficient that a 100hp four cylinder. However, if the same six cylinder was rated 50% higher, at 150hp, then it is probable that it would be just as efficient in terms of specific fuel consumption, that is gallons per horsepower hour or grams per kilowatt hour, as the smaller engine.

Sometimes indeed, more is better. It is often observed that a chipped engine producing more power than factory set, can be make a vehicle or tractor unit more economical than before. That is because the engine is working easier after chipping. If all the extra power were used then it would use more fuel, but probably no more fuel than before in terms of units of work done per unit of fuel.

 

[crushers]

in my old powersmoke i decided to chip it, the power was wicked, the fuel economy didn't change and the smile on my face was worth every cent.

 

[Dougal]

There is no UK s****page scheme. It finished about two or three years ago.

Yes, same one.

One important point you have missed is the fuel injection system which is now overwhelmingly of the common-rail type. Not only is the injection pressure up to between 1500bar to 2000bar, depending on model, but the injection is made in stages with full computer authority in real time to provide an optimum combustion.

No, I haven't missed that at all.
The commonrail system isn't more efficient than mechanical direct injection. What it does give is better computer control over injection timing and multiple shots for decreasing NVH and giving an after-burn to clear DPF's.

The last of the 1HD-FTE engines were commonrail with a variable vane turbo. Toyota used the engine code 292F. Fuel consumption wasn't any better than the early ones, but they did meet a higher emissions standard.
The specific fuel consumption on a state of the art BMW 3 litre twin turbo diesel with over 200kw is 206g/kwh. This is only 4% better than my 25 year old 4BD1T.
In thermal efficiency 206g/kwh represents 38%. One landrover 2.5tdi was tested by a US university at 42% efficient. But they were low on specifics.

Low drag pistons, Nikasil coated bores etc etc have been with us for decades now. None of the recent gains in vehicle fuel economy are from within the engine.

Higher gearing.
Lower profile tyres which cut rolling resistance.
Better wind-tunnel testing and computer simulations for better aerodynamics.
Engine downsizing.
Better automatic gearboxes with more gears that spend very little time unlocked.
Auto stop/start.
Lower power drain on all accessories

If there was a 50% gain in fuel economy from the engine then we would have moved from around 40% to 60% thermal efficiency. BSFC would be down around 133 g/kwh.
Which hasn't happened yet and maybe never will. We may see 50% thermal efficiency in our lifetimes (BSFC 157g/kwh) for a production engine if we are lucky.

 

[Dougal]

At this point Dougal I am going to call it a day with this topic, whilst I was enjoying this discussion and would agree you have some valid points I am afraid your last paragraph was uncalled for. I always thought I could recognise early when dealing with someone who lacks the maturity to have a sensible debate without lowering to comments such as this, clearly I was wrong about that.

So you start with snooty comments like this:
[quote="Dave 2000]Without wishing to appear condescending let's break it down so it is easier to understand,[/QUOTE]

And then throw your toys because you think I'm lacking maturity. Bye Dave, I'm sure you'll be sadly missed.

BTW, taking the electronics off a modern engine will reduce it's fuel consumption markedly. It won't run.
Cruising load is the #1 determinant of fuel economy. I'm really surprised anyone would argue against that.

That blue font is terrible to read.

 

[hedydd]

Read all three pages and see how much effort has actually gone in to the latest generation to further improve the engine's fuel consumption as well as improved emission performance.

Features - Automotive Engineer

 

[canucksafari]

With my limited knowledge, I believe chipping gets rid of the settings which reduces pollutants, so in a way it turns it back into a more "old school" diesel, no?

 

[Dougal]

Read all three pages and see how much effort has actually gone in to the latest generation to further improve the engine's fuel consumption as well as improved emission performance.

Features - Automotive Engineer

I know how much effort goes in. They're spending billions and have some of the smartest engineers in the world.

In that article you see they managed to gain only 2% improvement on the test cycle. This is where engines are at in the development curve, all the big improvements are long gone, they are chipping away at 0.1% improvements and stacking them up to get overall single digit increases in engine efficiency.

While the whole vehicle gets 11% better fuel economy than previously (22% for the other mentioned), that's vehicle and accessory savings, they made only 2% in the engine.

 

[Dougal]

With my limited knowledge, I believe chipping gets rid of the settings which reduces pollutants, so in a way it turns it back into a more "old school" diesel, no?

Yes.
Typically chips are using the safety margins manufacturers have left, which is why most chips are advertising a 20% improvement. That's about the margin available before you melt holes in your pistons.

It's a safe bet that all chips will not meet the emissions level the engine was designed to meet. To get more power safely and cleanly you also need more boost which often requires bigger turbochargers as originals don't have that much spare capacity.

But that's too hard, so people fit chips which up the fuel and blow smoke. Which is bad for their engine, their wallet and unecessary pollution.

 

[canucksafari]

That is kind of a blanket statement about chipped diesels. I don't know if they all are blowing black smoke. I do know that quite a few chips are sold here, as BD Power is based here and sells all over the world. We have annual aircare inspections here and also mobile inspection units on the road which do and can pull over any vehicle pushing out lots of black smoke. That is the only contaminant they check for - opacity. Personally, I have seen many more TDIs bellowing out clouds of black diesel smoke than any of the likely chipped North American diesel trucks.

 

[crushers]

most chips i have seen have been 3 stage units (for the powersmoke you get 60 -80-100 increase) the 60 doesn't add any smoke that i have seen, the 80 adds a bit and the 100 is just too much fun. the 80 allowed me to tow 18,000 lbs across canada at 55 mph comfortable (yes, the trailer was weighed at a registered weigh station just outside Calgary).
would i recommend it? no.
would i do it again? probably not. although it was nice to know that old van could do it.

chips are like any other mod, you can over do it and kill the engine but once again it will be your right foot that kills the engine, not the mod.

 

[Dougal]

That is kind of a blanket statement about chipped diesels. I don't know if they all are blowing black smoke. I do know that quite a few chips are sold here, as BD Power is based here and sells all over the world. We have annual aircare inspections here and also mobile inspection units on the road which do and can pull over any vehicle pushing out lots of black smoke. That is the only contaminant they check for - opacity. Personally, I have seen many more TDIs bellowing out clouds of black diesel smoke than any of the likely chipped North American diesel trucks.

It depends on a lot of factors. The average tdi car has a lot less head-room in the turbocharger than the likes of a cummins dodge and is a lot more difficult (or expensive) to upgrade. So getting more power clean costs a lot more $$.
Comparitively it's easier and cheaper to up the boost on a cummins or other pickup, you've got more space and plenty of options on the market. So if you want more power and clean it's not as difficult. But off-boost they can smoke something terrible.

The air/fuel ratios stock can be around 20-22:1. You can tune a bit hotter and richer to 18:1 and still have clean and safe tune for towing and altitude work. At 16:1 you'll hit scary EGT's and be blowing smoke no matter how good your injection system is.
14.55:1 is stoich for a diesel.
A mild chip can give a 20% increase and still stay within safe limits for sensible use.

Some muppets in europe have paid for tunes giving 13:1 AFR's on a diesel. It's not performance, it's engine destroying pollution. The only reason those guys haven't melted pistons is because they can't stay on the power long enough.

 

[hedydd]

With my limited knowledge, I believe chipping gets rid of the settings which reduces pollutants, so in a way it turns it back into a more "old school" diesel, no?

The chippers would like you to believe that their products are rather sophisticated. In truth there are three main types used on diesel engines engines. One that raises injection pressure. One that increases the amount of fuel. These two could be combined. Then there is a true re-map of the existing engine management ECU which is the one that can alter more sohisticated parameters. This needs to be loaded into the ECU to overwrite the original engine management fuel map.
The engine might or might not meet original specification emission regulations after 'chipping'. But it will not be far out unless overdone.

 

[crushers]

the unit that i use that overwrites the map also has a setting for resetting to stock parameters...

 

[hedydd]

the unit that i use that overwrites the map also has a setting for resetting to stock parameters...

If you have an unit that sits between the engine ECU and the injector pump, or an unit that plugs into the pressure sensor at the end of the common-rail, consider how it might overwrite anything in the ECU map.

 

[Dougal]

Flashing maps is not for the faint of heart. One glitch and your vehicle becomes an ornament that's quite expensive to get moving again.

I have remapped my work car. It wasn't a flashable ECU so I had to unsolder chips and re-write new ones. It's a serious investment in time and mental effort, but the results are perfectly controllable and all the ECU's safety features are there and working.

Interface boxes, they just intercept the signals and increase them by a fixed percentage, taking all the ECU's safety features and bypassing them. But they're still better than the common-rail pressure sensor kludges that are all over ebay.

 

[hedydd]

I know how much effort goes in. They're spending billions and have some of the smartest engineers in the world.

In that article you see they managed to gain only 2% improvement on the test cycle. This is where engines are at in the development curve, all the big improvements are long gone, they are chipping away at 0.1% improvements and stacking them up to get overall single digit increases in engine efficiency.

While the whole vehicle gets 11% better fuel economy than previously (22% for the other mentioned), that's vehicle and accessory savings, they made only 2% in the engine.

They actually managed 2% better economy from just two of the improved engine features, that is before the higher injection pressure and other changes. The S class has not been modified as far as I know, apart from the engine, yet they still gain 11% on the combined official cycle for the vehicle. A substantial proportion of this must be down to the cooling system modifications which splits the cooling and indeed disengages parts of it when the engine is started and until it has warmed. A stop-start system would, or possibly does, improve economy further. Every little helps. And yes, of course the design of the whole vehicle is very infuential to the economy, which is how they improve the economy by a massive 20+% on already good [seen in a historical perspective] economy for some models where the engine is fitted while also substantially reducing all emissions from the exhaust.

For all this they still manage to improve the driveability and the actual acceleration to 60 by 10%.

 

[floridan surfer]

You can chip a Landcruiser? What happened to this thread?

 

[hedydd]

You can chip a Landcruiser? What happened to this thread?

Yes, the D4D in the 90/120/150 is commonly chipped and the 100 and 200 series diesels can also be chipped. Not sure if the 200 diesel ECU is tamperproof like many latest versions but if it is, it could be flashed. Not sure if anyone has done a V8 diesel Toyota yet but the 1HD-FTE is chipable. Thought about it myself. A friend has a 90 D4D with a tunit chip
Diesel Performance Vehicles supported by Tunit Performance

Yes, the V8 is listed there.
It makes a huge difference in performance and I am surprised that it has not thrown a rod in its 125,000 miles. It has been perfectly reliable.

 

[Dougal]

Yes, the D4D in the 90/120/150 is commonly chipped and the 100 and 200 series diesels can also be chipped. Not sure if the 200 diesel ECU is tamperproof like many latest versions but if it is, it could be flashed. Not sure if anyone has done a V8 diesel Toyota yet but the 1HD-FTE is chipable. Thought about it myself. A friend has a 90 D4D with a tunit chip
Diesel Performance Vehicles supported by Tunit Performance

Yes, the V8 is listed there.
It makes a huge difference in performance and I am surprised that it has not thrown a rod in its 125,000 miles. It has been perfectly reliable.

The tunits on that page are interface boxes. Word is around the campfire that toyotas commonrail diesel ECU's haven't been cracked yet so can't be remapped internally.

Graeme has a chip (unsolder, resolder) for a 1HD-FTE. Hopefully he can give me a crack at the original chip when it's off the board.