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Would someone please explain to me how you can get more power without using more fuel? If it's this simple to do, why aren't the manufacturers themselves doing it? Surely given the price of fuel now, manufacturers would be falling over themselves to quote better fuel economy figures.
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I have had my wife's car re-mapped and can confirm it has improved the mpg as well as the torque and brake horse power. It's made a noticeable difference.
2 litre Ford diesel engine in Jag X Type, 130 bhp standard and roughly 330Nm torque.
Now 165-170 bhp and 390 ish Nm. Fuel economy improved by about 3 -3.5 mpg. It also allows it to rev a bit more.
The way it was explained to me was that the manufacturers juggle the govt fuel figures, which are lab based and unrealistic for road use. Also they have to take in to consideration different markets e.g. very cold, very hot, poor fuel supplies etc...then there's the potential for warranty claims, so they'll de-tune to be safe...and..a re-map (not a chip) is pertiment to that particular vehicle only, whereas a manufacturer, through economy of scale, builds a load in one hit.
Best £325 i've ever spent on a car.
Have a look at 'CNL re-mapping' via google, would have no hesitation in recommending them.
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Thanks very much for the info westpig your summary is exactly how I thought these things are supposed to work. I'll check out that website you mention.
Cheers.
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I would be very carefull regarding any modification to a engine which isn't from the manufacturer and which will give you no guarantee to the long live of a car which is chipped or tuned.Modern cars have very complex software.
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I would be ver
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Generally a remap is better than any plug-in device for the reason Westpig stated - it is suited to the individual car whereas a plug-in has generic data.
Before you do anything, have a good think about whether the Tino is:
1. running a well looked after/serviced engine that is showing no excessive oil use/rattling/etc.
2. capable of being driven with an extra 40bhp at the top end and still manage to handle/brake adequately.
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>>>> 2. capable of being driven with an extra 40bhp at the top end and still manage to handle/brake adequately.
Really good point - I had a Fabia vRS remapped from 130 to 170 bhp with similar levels of torque increase and to be honest if it was used to the max it was a bit too much for the chassis and brakes - evidenced by the number of owners who upgrade the suspension and brakes after a remap. Swapped it for an Octavia MK 2 TFSi remapped from 200 to 250 bhp and it handled it easily with no issues.
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If you want a fast car buy one ,if you have to upgrade brakes and chassis to acommedate the remapping I would leave it alone.
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I would be very wary of stressing what must be (at least) a 5 year old people carrier with any more power/torque - it wasn't designed for it, the components are getting more fragile & you'll need to upgrade/revise your insurance policy. I doubt also, that claims for decreased fuel consumption, in practice, give any real overall saving.
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QUOTE:...""Would someone please explain to me how you can get more power without using more fuel?""
With a diesel engine, I imagine only by getting more complete combustion/expansion in the cylinder during the power stroke and ensuring that the combustion doesn't continue beyond bottom dead centre and into the start of the exhaust stroke. But it shouldn't do that anyway, I'd have thought !!
In a petrol engine that would be less likely to happen as combustion is more or less instantaneous.
QUOTE:...""If you want a fast car buy one ,if you have to upgrade brakes and chassis to acommedate the remapping I would leave it alone.""
It's like these boy racers who spend £20,000 upgrading a Vauxhall Corsa. I wonder if these owners have a moment of realisation, like waking up from a bad dream!
Edited by Sofa Spud on 20/01/2011 at 10:34
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Had our Discovery 3 remapped and it transformed the car. Feels like a Range Rover Sport now, and the economy is much better. A run down to SW France on the autoroute showed 8-10 mpg better fuel economy, so I'm chuffed and wish I'd taken the plunge when we bought it.
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The claims of tuning companies are dubious. It's hardware that 'makes' the horsepower, not electronics. It is impossible to make more horsepower without increasing the mechanical and thermal stresses on the engine, clutch and gearbox. Tuning companies rely on carmakers leaving a wide saftey margin on ALL of the major components. This is a dangerous assumption. Manufacturers compete with other manufacturers and they have every incentive to push their components as hard as they can. Over engineered parts are heavier, generally have more friction (worse fuel economy) and cost more than parts that are just strong enough.
Because a diesel runs lean, it's utterly trivial to get more power from it, simply by stuffing more fuel in. Upping the turbo boost pressure will keeps smoke at bay. But getting an engine to survive at higher outputs is hard, very hard. But with a diesel you have no way of knowing when you've pushed the engine too hard. A petrol will start detonating when the boost gets too high. This is easily detectable, and the ECU can pull spark or fuelling before damage is done. A diesel will just keep going until something major breaks.
The other side effect is emissions, particularly NOx. Better economy through advanced injection timing always comes at the expense of a huge increase in NOx. Diesels have become much cleaner than they used to be. Chips send the emissions back 20 years or more. Currently the MOT test for diesels is a joke. Quick check for visible smoke at maximum governed speed (no load). I believe that a more stringent test is coming in this year, and I woud be surprisd if the chipped engines will pass.
OEMs spend a fortune developing engines, with the best engineers and test facilities in the world. They are not going to leave easy pain-free gains on the table.
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But some engines come in multiple outputs, VW and Mazda spring to mind straight away. Agreed there is a limit to what can be achieved, but as I've said before, the ultimate engine protection device is the right foot. It is unlikely that the engine will be driven in such a way that it is developing max HP and torque all of the time.
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Waht's the difference between a Mark1 BMW Mini and a Mark 1 Mini Cooper?
The ECU. Tuning chip costs £350 vs £1500...
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What's the difference between a VW 1.9Pd 90, Pd110, Pd130, PD150? After all, they're all VW 1.9 turbo diesels, right?
Well, intercooler, pistons, injectors, camshaft, turbo all vary amongst that range of engines that superficially appear identical. Of course the 90 hp engine was conservatively fuelled, but whilst it shares perhaps 95% of it's components with the 150, those parts that are changed, are changed for good reason.
Intended application is important. Yes, a short burst of acceleration won't heat soak parts like a prolonged hill climb, but will the driver be dilligent enough? OEMs are already offering overboost features that take advantage of this fact, they really are pushing parts harder than you think. Look at car engines that are used in light commercial vehicles. What do the manufacturers do? Derate them. Why? Because the high output offerings offer poor durability when driven hard.
The average driver is simply too ignorant to change the oil, let alone live with an engine operating outside factory specs. The argument goes that after rechipping, you can drive around at lower revs and save fuel. Since EVERYONE likes low end torque there is no reason not to maximise this from the factory. But there is plenty of reason to limit torque at the bottom end, if bearings and lubrication are marginal at low engine speed.
Why do chipping companies never mention physical quantities such loads on bearings, Exhaust temperatures, peak cylinder pressures, piston crown temperatures, valve temperatures, valvetrain stability NOx/particulate trade-off etc etc. Funnily enough, these are the topics with which real diesel engineers are focussed upon. Instead they mumble some c**p about the fuel quality in Turkey (irrelevant), hot summers in Spain (modern diesels are mapped on intake air temperature), and commonality for different emissions regulations round the world (must be why VW and MB had to completely re-engineer their diesel engines sold in the US).
Up the output, and use it and the engine/drivetrain WILL have a shorter life. 20,000 mile test is hardly conclusive on an engine designed to last 250,00 miles. But please take responsibility, accept that you are your own warranty and tell prospective purchasers that the car is outside factory settings.
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I bought a belgian 1.9 DCI scenic new out of the showroom. This was a 115 hp model.
Till 5000 km it was bog standard with only Shell V diesel to help against poor low rev pickup. At 5000 km it was rechipped plus a K&N air filter was fitted by Renault sport in Brussels.
This transformed the scenic into a very quick car. It is now a joy to drive. Gone are the response problems. Shell V diesel is still standard as we here have very strict annual smoke tests. This is the third year without any problems.
The DCI is rated at 173 bhp and 400 nm @ 2000 rpm. Average feul consumption over 50,000 km is 5.8 litre per 100 KM.
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Diesels engines operate in an excess of air - the intake tract is not throttled.
Fancy air filters and/or induction kits do not (and cannot) make a difference.
Buying one sort of diesel over another won't affect performance or smoke test results.
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Buying one sort of diesel over another won't affect performance or smoke test results.
Really? What happens if using one fuel with lower additives results in a carbonned up engine and the other fuel leaves a carbon free engine?
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What are these additives that Shell Vpower use (that apparently help low RPM pick up), that other brands don't. Why don't they advertise these additives instead of boasting about cetane rating?
As I've said elsewhere, Cetane is a double edged sword. For a given molecular weight of fuel, higher cetane tends to result in higher in cylinder soot production (hardly helpful for 'carbonned up' engines). High cetane wil tend to reduce diesel clatter (although a lot of the noise is injectors rather than knock), which will make the engine sound smoother, but it won't yield more power or efficiency
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It doesn't. It's all marketing. Additives are snake oil.
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Cynic! And don't forget cold air induction-it's well known that OEMs purposely heat the intake air to reduce the performance (and NOx emissions).
You can usually gain 30% power with a performance exhaust kit too. The huge pressure drop across the rear silencer chokes the performance and economy right down. What will those darstardly engineers think of next to spoil our fun? They should have gone to K and N.
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My DCI on Shell V diesel and rechipped. I live and drive in Holland. The number one government enemy is not drugs,drink or smoking it is the Diesel driven car !!!!!. Most diesels with 30,000 Km do not get through the very strict smoke controls.One of the reasons why VW/Audi have stepped over to common rail.
If England steps over to the same smoke control standard as here then you will learn very quickly over clean and dirty fuels.
As to Fancy induction system the less restriction of clean,cool air will always be better than a standard paper one. You only have to have it cleaned per 50,000Km not replaced per 20,000 km for the price as if it was gold plated.
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I forgot to add I still have an extended Renault warranty of 4 years, I have had no drive line problems of any kind,no diesel knock only super smooth tubine power. Starting at -15+ is always smokeless and within seconds.
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Air going into a diesel engine is not restricted in any way. There is no throttling of the intake tract. More air is circulating in the intake and around the valves than could ever possibly be burnt in each 'breath' the engine takes.
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Do you really believe an airfilter does not restrict ?
Try breathing through one.
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You miss the point. Yes the filter restricts, but even downstream of the filter there is more air available as each valve opens than a diesel engine could ever possibly suck in.
The same is not true for petrol engines, where the amount of air reaching the valves is restricted (throttled) by the throttle butterfly(ies).
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Down line are the turbo vanes and how faster and better the air flow the less resistance and better response(turbo Lag) also do not forget the airflow sensor on a common rail diesel
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Yes, that's why the pressure drop in OEM exhaust systems downstream of the particulate filter is tiny-really. All of the easy gains have been thoroughly exploited. If you want to successfully modify your engine, it will require costly hardware upgrades/and or nasty side effects. There are no free lunches.
You're claiming a 50% increase in power with stock injectors and a stock turbo. For this to be true, Renault must have grossly oversized key parts. Turbos and injectors have very limited flow ranges. No engineer would oversize them-ever. You also claim 5.8l/100km. Well, at 48 mpg you're clearly not making use of that '173hp'-so are in no way able to substantiate its long term durability.
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We are talking about a belgium market renault converted by renault sport Belgium also constant use of Shell V diesel. The ride style is continental there is always somebody trying to climb into your boot so it is quick enough to teach them others.The fuel consumption can be confirmed by the dealer and the onbourd computer. My previous renault had 170,000 Km on the clock no oil, no leaks no problems.
I always had Golf TDs from 1984 on untill they got so expensive then Peuguot td`s to Renaults All had more than 180,000 on the clocks the VW`s in there lives under 5 ltre per 100km the France group all around the 5.6 to 5.8 litre per 100. I have never added oil to any of these cars, they cost me only service with tyres on the average 40,000 KM.
All I can say that this last car is the the most civilised and smoothest of them all
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As to Fancy induction system the less restriction of clean,cool air will always be better than a standard paper one
The first clause is right-that's why every modern engine ttakes in cold air from the front of the engine bay.
The pressure drop across a clean paper filter is very small, certainly not enough to effect performance by more than 1 or 2%. This is why no OEM wastes time researching alternatives.
Some pressure drop is necessary in order for filtering to be effective. Paper filters are much more effective than oilled mesh at filtering. If you don't think that matters, think again. Detroit 2 stroke diesels were famous for their oil control problems-oil ended up in the scavenge space instead of on the liners. Certain bright sparks thought it a good idea to reroute this oil back to the sump. Engines with this modification died very quickly. Why? The oil in the air box was contaminated with particles from the intake air. Your common rail diesel operates at much higher pressures and tolerences than a detroit...
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OEM paper filter is for the after service to make money and not what is better for you or the engine.
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No, it's because no other sort of filter offers any tangible gain. For the millionth time, diesel engines operate in an excess of air and the 'flow' through the intake tract is immaterial.
Paper filters aren't exactly expensive to replace.
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Explain why a paper filter costs 67 euro`s to replace per 20,000 KM. If that is not a ripoff what is well?.
Also when we got the first Golf diesels in the 70`s they got such a thrashing that the paper was filthy after the first 2 to 3,000 kms thus you got a screwdriver and made holes in the paper folds to get it to 15,000 Km replacement.
So as so the 1500 VW diesel was lucky if it lasted 100,000 kms due to the to soft piston rings. VW vision was it was cheaper to replace the rings as a rebore.
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30% gain with a performance exhaust? Yeah, right. Been reading the marketing material from tuning brands like K&N or Janspeed?
Tell me, what would be the manufacturer's incentive to fit such an inefficient system if that were the case? Fuel economy is a major selling point these days, and you can bet your bottom dollar that manufacturers will be doing everything they can to maximise it.
I don't think they purposely heat the intake tract. Feeding cold air direct to the valves in a modern car requires intricate design in a tight space, as well as expensive materials. For the very small gain in performance that a cold air feed gives, it just isn't worth it.
Old cars had lots of underbonnet space, so choosing the 'best' route (few sharp bends, constant bore, away from hot areas) for the intake tract was easy. Modern cars have no space at all, so the intake tract just goes wherever there is room. It is more a case that they don't bother to try and cool it, rather than than purposely heating it.
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gfewster-I was being Sarcastic-I thought the tone was obvious!
Back in the days of carburettor engines, the intake manifold was heated and the air filter drew air from the exhaust manifold. It was necessary to prevent carb icing and fuel puddling in the manifold at low load. Hot rodders realised that WOT performance was hampered and a market of cold air kits (optmistically called ramair-like total pressure is going to be different from static pressure at road speed) emerged. Enthusiasts conveniently ignored the awful low load and transient response side effect. With multi point/direct injection, these concerns are moot. All modern engines are cold air induction, but the 'performance' market doesn't like to lose it's easy money spinners.
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Some common sense:
www.pumaracing.co.uk/gentune.htm
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Not too relevant for turbo-engine tuning.
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An afterthought over the airfilter. I am in our group of old idiots a flying instructor,between we three we own five planes.All fitted with standard wiremesh K & N filters.At the local airfield all 70+ planes all fitted as standard K & N wiremesh filters. If you what to be accused of murder or suicide try to suggest paper filters.
True you can say that is not a car engine and has to perform in an other way but it is well that your life hangs on the line and paper is still paper.
At this airfield a self builder\owner has converted a Nissan micra TD diesel engine as his power source(chipped and K&N filter) He has more than 200 hours up, flys very cheaply through europe and laughs us out with his (to us) cheap shell V diesel fuel.
Again you can say that is not a car but that are the facts and cynics cannot in anyway dispute that.
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Opahale-if you're going to tell lies, at least say things that are unfalsifiable, so you look less of an idiot.
Gosh how clever! Lycoming and Continental build those heavy, polluting, inefficient, low compression air cooled engines running on 100LL. If only someone would think of installing modern common rail diesel engine instead. Private air travel would be revolutionalised!
It's never that simple. The shortcomings of aircraft engines are endured because of their simplicity and failsafe operation.
There are very few diesel engines certified for light aircraft. Experimental aircraft (to which you must be referring) can of course use an engine of the designer's choosing. Diesel still isn't popular. The complexity is one thing. Torque fluctuations are another. The torque fluctuations are dependent on the number of cylinders, and the compression ratio. Proprellers do not like torque fluctuations...
That's why delta Hawk went down the 2 stroke alley...
Now, stop boasting and grow up.
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Boasting ? we are only doing what the yanks are doing and why are Renault busy with a flat 2 cylinder 4 piston DCI diesel motor and why are we using 6 blade composite props.
The current motor here is the flat 4 from Rotax if you think that is simple look it up in google.
Of course we need to grow up and we we are idiots because we just do it and prove it
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Where does the 'we' come into it-were you involved in its development?
Can't wait to see superchips "up to 30%" stage 1, phase 2 chip for the carby.
I wish Renault luck with the opposed piston scavenged motor-they'll need it. Plenty of engineering consultancies have lost a fortune on researching 2 strokes in general, and the opposed piston system in particular. The need for two rotating assemblies is a massive disadvantage, and the recipricating mass is still 4 pistons, 4 con rods. For 2 power strokes/rev. No better than a 4 cylinder 4 stroke. Absence of a valve train is a plus, but more than offset by the need for an external scavenge pump. Ricardo are also trying hard with a 2 stroke, variable compression design-I'm somewhat doubtful. Detroit Diesel threw everything at trying to sort out their 2 stroke diesels, and have spent the last 25 years desparately trying to get out of the 2 stroke business. It's a funny old world. le plus ca change...
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we is a long story and not that interesting. Aero diesel engines are another topic than chip tuning a car. However look up WWW.Zoche.de, very nice yet to a concrete delivery date and price.Also Freedom motors,w***el ag,centurion 2.0,SMA LE SR-305 E, and WAM.
All these sites will give you an insight into the future of Aero Diesel engines plus there are many gifted self builders busy only for their own use.
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You've been censored opahale! HJ thinks your contributions are offensive.
Aero diesel engines are not new-they have been used since the 1930s. Seldom will you find a genuinely 'new idea' in engine technology. Sometimes improvements in materials or electronic control will make an old concept viable-but the concept is almost never new. Wikipedia still cites claims of Bob Crower's amazing 6 stroke engine-the idea of which was patented in 1915. Poor old Crower may be able to grind a camshaft but his understanding of thermodynamics is woeful.
whilst the aviation industry continues to believe that mechanical simplicity is the key to safety in small planes (notice that virtually all certified aero engines still use carburettors) the diesel engine hasn't a chance.
Self builders don't have any of the inconvenience of convincing a sceptical FAA that their engines should be certified airworthy. Shoehorning an automotive Turbo diesel into an engine bay hardly merits theterm 'gifted'.
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SMA is Renault and the LE SR.305 E has a full european certification. Your reaction is the reason why you never hear what we are doing. If you think for one minute the FAA is dificult try the RLD.
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Back to OEM paper filter explain why that costs 67 euro`s per 20,000 km`s. K&N costs me nothing however I still have to pay for the pollen filter, 46 euro`s per 20,000 KM. Is that clever after marketing of a ripoff ?
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It doesn't cost 67 eur per 20,000km. If you pay that for it, you're an idiot. Buy it elsewhere and fit it yourself.
FOR THE LAST TIME, DIESEL ENGINES OPERATE IN AN EXCESS OF AIR - THE INTAKE IS NOT THROTTLED, NO AIR FILTER (other than a clean one) CAN POSSIBLY IMPROVE PERFORMANCE.
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Sorry - didn't see the sarcasm! Doofus I am....
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>>Do they work as promised?
If you believe in free (fuel) lunches & that the only important component of a high(er) performance vehicle is the raw output from burning the fuel - then yes.
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Of course they work brilliantly, their purpose being to correct the elementary mistakes made by the teams of idiot incompetent engineers at Peugeot/VW/Toyota/etc, who have no idea how to design, optimise and manufacture a diesel engine.
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How sarcastic he (or she) is.
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Of course they work brilliantly, their purpose being to correct the elementary mistakes made by the teams of idiot incompetent engineers at Peugeot/VW/Toyota/etc, who have no idea how to design, optimise and manufacture a diesel engine.
Well how come my wife's car, which was re-mapped nearly 2 years ago, has noticeably more performance, can rev a bit more freely (diesel) AND has had an mpg improvement (approx 3-3.5 mpg)?
I'd accept that a clutch or DMF might go more quickly than it would before, but the reality is i'm not likely to do racing starts and don't ride the clutch, so that should help to minimise it.
Everything in life is a balance. We've done 20,000 miles on a re-map, with the car now showing 60,000 on the clock.
Best thing I ever did to it...and if i've just cursed the thing and the clutch goes next week, i'd still think it was worth it, i've got the performance of the 2.2 model for £325
Edited by Westpig on 31/01/2011 at 19:11
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I have had a perfomance chip for a year. Fuel consumption?
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I'have had a performance box for a year.
Fuel consumption? Unchanged.
More power? Yes
smoothness? No change.
Just more diesel rattlle when cold for mile 1 then unnoticeable...
I note the clever remarks are from people without chips. (except on shoulders:-)
Edited by madf on 31/01/2011 at 19:21
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More power same fuel the magic formula I shall put it along side my bottles of snake oil.No chips on shoulders just an common sense brain.
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I buy some snake oil from you Andy sell it here for a profit there will be buyers.
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I'have had a performance box for a year.
How much extra power and torque is there Madf ? Does this make the car nicer to drive long distance? What company supplied the box?
EDIT : I hope you can find this post !
Edited by corax on 20/03/2011 at 13:13
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"EDIT : I hope you can find this post !"
And I'm still hoping that unthrottled will find my post of Thursday 10 Feb 2011 at 21:08.
:-)
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Again, 20,000 miles is hardly conclusive bearing in mind that the engine has a design life of over quarter of a million miles...
If you religiously moniter fuel economy, you're probably not the using anywhere near the maximum torque of the car save for a few short bursts of acceleration.
Having said that, you seem to be well aware of the potential risks and have weighed them up and accept them. That's great-that's what hotrodding is all about. But there are less honourable people who would happily chip a car and if they start having problems, either remove the remap and try and claim a warranty repair, or sell it on to some unsuspecting buyer without mentioning the modification. That isn't cricket.
Finally, if you're getting better mileage it'll be at the expense of a huge increase in NOx emissions. Luckily for chippers, oil burners aren't subject to NOx tests for the annual MOT. Thanks for sending emissions improvements back 20 years. That'll warm my heart as I have to stand outside the pub to smoke so that other people don't have to breathe my pollutants.
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I think the title of this sums it up nicely:
www.torquecars.com/tuning/tuning-mpg.php
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Incredible-an honest magazine article!
I've tried the warm air intake trick-couldn't measure much difference. Partly blocking the radiator is the best easy mod i've done. Do it every winter.
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Just a few comments:
By buying them in thousands, with no individual packing or handling and no seller mark-up, the manufacturers could get these chips for half the price. Curiously they choose not to, even though a £200 option to give x% more power and torque would be a surefire sales booster.
Look at the sites of the chip sellers: they don't guarantee that their chip in your car WILL give x% more power and y% more torque. They prefer to say that their chip CAN or MAY give UP TO more power and torque. I find that strange, but perhaps I'm just cynical.
How many of the chip enthusiats here have had their vehicles independently tested before and after installing a chip? None apparently (or else they are keeping the results to themselves for some reason). They are genuinely persuaded that their car goes better after installing a chip because that's why they bought the chip. Nobody likes to look a fool or admit they are wrong, even to themselves. I could reccomend several psychology textbooks which deal with the phenomenon of rational people persuading themselves that something happens/exists even when there is no proof, or proof of the contrary.
I may be mistaken, but I seem to remember a chip seller claiming that his products could make the seats more comfortable....
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How many of the chip enthusiats here have had their vehicles independently tested before and after installing a chip? None apparently (or else they are keeping the results to themselves for some reason). They are genuinely persuaded that their car goes better after installing a chip because that's why they bought the chip. Nobody likes to look a fool or admit they are wrong, even to themselves. I could reccomend several psychology textbooks which deal with the phenomenon of rational people persuading themselves that something happens/exists even when there is no proof, or proof of the contrary.
Look. After our car was re-mapped, my wife drove it to work the next day and immediately rang me. Her comment of "What a difference, it goes like wotsit off a shovel" is quite out of character for her...and she is not really a car person. If she can notice it in a 4 mile commute, then there's a noticeable difference.
When i'm now sat on a Scottish Highland 'A' road, with the car fully laden, behind a lorry waiting for a safe overtake, I can now do it in 4th gear and have a smooth, linear surge of power, rather than as before have to bung it in 3rd and then run out of revs half way down the lorry.
When i'm in lane 3 of the m/way and someone quite slow moves out of the way, I no longer use 4th, I leave it in 5th, same principle.
I'd guess my chosen m/way cruising speed is now revving a little bit lower...so combined with the no need to change down, that'll be where i'm getting my fuel savings.
The car has been transformed. The garage that does the work on my car took if for an MOT, when I dropped into the equation i'd re-mapped it, the owner said "Oh, I thought it was a 2.2 " (instead of ther 2.0 it is)..
If you don't believe me then you'll just have to presume i'm a liar and b*******ter.
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No, you're not a liar-but the driving experience isn't the whole story. Everyone knows that the torque curve of a direct injection diesel is horrid-great at mid range and poor below ~1700 RPM and above 3000 RPM. The engine designers KNOW this, so why do they do it?
Emissions? Not really. Euro V emissions testing is conducted during the official drive cycle-which for a typical 150hp 2.0 diesel in a medium size family car is a very gentle drive. This leaves the designers with most of the torque curve to play with as they please.
So why is the torque curve horrid-especially that all important 1000-1700RPM range?
1.) insufficient lubrication is one reason. Big torque=big bearing loads. Coupled with low oil pressure, thin oils, and narrow bearing shells. Not a nice combination.
2.)High piston temperatures. The combustion bowl is in the piston crown and the piston isn't directly cooled. Diesel pistons run hot-up to ~350C, compared to ~200C for a gas engine. At 350C, aluminium alloys are really at their limits. Increase the fuelling without an increase in air flow and you push those temperatures higher. At those engine speeds, bumping up the boost is a real struggle-so you have to go richer.
Turbo charged direct injection diesels have been popular in industrial use since the 1950s. Truck drivers quickly discovered that overfuelling could cause piston overheating and seizure.
Marine users had the opposite problem. They idled their engines for days which caused the engines to run cool which could lead to bore glazing.
Direct injection diesels are quite sensitive to misuse. It is this sensitivity that kept them out of passenger car use for so long.
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Engines are designed to be run at max revs continuously and thrashed to b*****y. Margins are included to account for sub-optimal servicing, especially extended oil services.
Increasing the torque/power/heat output for brief periods may cause a slight increase in engine wear rates but since road use doesn't permit non-stop thrashing it has little bearing on engine longevity.
As for improved MPG this may be partially explained by being able to avoid downchanges in a more highly tuned engine when accelerating.
Lambasting remaps/chips as being bad for engine health is fairly moot when the pages of this and other forums are littered with unadulterated engine death stories.
On a test-track running for 24hours there may well be a significant difference in engine life after 'turning the wick up' but in normal use with a well serviced engine premature engine death may be difficult to detect.
I'd be more concerned that the basic vehicle's braking/suspension/tyres might be pushed past their safety margins when pressed hard.
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Good points.
Apart from the downshifting theorem.
A 70mph cruise on level ground requires about 35hp. At 2500RPM, that equates to 73lbf.ft of torque. A typical 2.0 Turbo diesel will develop well over 200lbf.ft Why the need to downshift?
If someone can't be bothered to shift-why buy a manual-and a diesel at that?
Lugging a laden car up a hill at 1500PRM to save a gear shift is bonkers. Shifting a 5/6 speed synchro box is easy. Truckers used to row their way through 15+ gears with no synchro hubs for assistance.
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An engine running at 2000rpm has a lower level of internal friction than the same engine at 3000rpm.
If the two engines produce the same power by virtue of increasing torque in the slower running engine, it is likely to use less fuel than the faster running engine in producing the same work.
And a car travelling at a steady 70mph is not developing over 200lbft of torque - it may well be if it is accelerating of course - it will be doing ~35hp of work as you mention, and again the slower running engine will likely lose less energy in losses and thus be more efficient (hence 5th gear usually being more efficient than 4th at the same vehicle speed).
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"And a car travelling at a steady 70mph is not developing over 200lbft of torque - it may well be if it is accelerating of course - it will be doing ~35hp of work as you mention, and again the slower running engine will likely lose less energy in losses and thus be more efficient (hence 5th gear usually being more efficient than 4th at the same vehicle speed)."
I concur. But for cruising at any semi legal speed, the stock map is perfectly adequate. The idea of holding onto low gears in case you might need to suddenly accelerate is plain silly.
But lugging a heavy vehicle up a hill at very low revs to try and cut engine friction isn't a good idea. Spark ignition tuners are terrified of detonation because of the heat loss problem. Yet diesel tuners ignore it because 'that's what diesels do'. That's why heavy duty engines always keep the AFRs above ~20-it's not smoke that's the problem-it's heat. Don't think HD diesels aren't 'tuned'-the turbos sit at 20+PSI, and chamber pressures hit 200BAR.
Heat soak is exactly why Peugeot and other manufacturers use 'overboost features' that allow higher boost/fuelling for very short durations. Getting more power out of a diesel is trivial-getting it to live with the power isn't-and requires user sympathy which frequently isn't present.
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True.
However manufacturers design engines to be used under the worst case scenarios eg. fully loaded, going uphill, while towing maximum permitted loads (plus a little extra).
If Car X is, however, not fully loaded and chugging up the Alps at 1700rpm, there is no reason increasing fuelling/boost by a modest amount will automatically predispose the car to dying, or even significantly wearing.
The suggestion that manufacturers are putting out cars that at soooooo close to the edge of performance/boost isn't perhaps quite as true as sugested earlier.
The main problem is what I believe you mention way up the thread - with turbo diesels (moreso than petrol) you just dont know how much extra rope there is to play with.
I would guesstimate there is at least 10-20% extra torque to be chugged out of most engines before one's palms would get sweaty.
Would I risk my own car on such a guesstimate ? Only after plenty other punters have before me - like trying out new drugs on patients!
Edited by Lygonos on 02/02/2011 at 22:20
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As an example, Mitsubishi produce their own brand of tuning kits for their turbodiesels - all of which up the outputs by 20% or so without losing engine warranty.
Of course, they may have tested them fully and found failures only started after 60,000 miles, so maybe it's not so safe after all !
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Ha ha! That's very true. There's a lot of guesswork involved-and plenty of people on this forum seem to be having problems with engines in (supposedly) stock trim. The problem with engines is it they aren't GCSE Physics rigid bodies problem-there's no safe threshold (ie tensile -20% safety factor).
Good of you to pull some heat out of this thread-I was going to comment about stainless cat back exhausts-but it's benign. Why worry?
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"High piston temperatures. The combustion bowl is in the piston crown and the piston isn't directly cooled"
Funny that. My Yaris diesel appears to have jet lubrication directed to the underneath of the piston crown..
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So did those old cummins 855 engines. 300HP from 14 litres. And they still had a habit of seizure. Piston undercooling is better than nothing, but it isn't the same as having the combustion in the head.
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So are you plain forgetful? Or just trying to scare us?
Because you now contradict yourself on engine cooling.....
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Yesterday I had the 60,000 Km service and to my horror every service now per 2011 includes for Diesels complusory smoke NOx test . My DCI sailed through without any problem.
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No it doesn't. The new 2011 regulations reduces smoke limit down to 1.5m-1 for cars registerd after 2008. Easy to achieve since the smoke test is done at maximium governed speed UNLOADED. Care to show me some evidence that Belgium? has different standard for annual emissions tests than the UK-bearing in mind that EuroV is the standard level accross Europe...?
And I was going to congratulate you for finding a certified diesel powered aircraft engine.
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There are downsides to having a car re-mapped and having a significant improvement in power/torque (over and above the possibility of clutch/DMF failures or similar..which probably won't affect me, as the car will have been renewed by then, hopefully).
Driving it in the snow, proved more problematic. With a noticeable increase in grunt at 1800 revs, you'd get a nice surge of power, but just at a time you were trying to do everything gently.
The other thing is, a chap I use to do paintwork, had the car to re-spray the rear bumper as yet again some clown had crunched it. When he gave it back, he complained it had a fault and was 'flat' below 1500 revs. It wasn't, is just feels like it, because the 'old' performance is so different to the 'new' performance, but you don't get the 'new' until about 1800 revs.
I couldn't possibly go back to the 'old'.
The comment above about brakes/suspension etc being up to improved performance is valid..i'm rather hoping that because my manufacturer does a 2.2 model anyway and my performance is now similar, that the components will not be that much different (2.0 diesel Jag versus 2.2 ).
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What did the remap do to your insurance?
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I have moved to holland and they hate diesels. That extra test costs me 40 euro`s more per service OUCH. Renault told me they are now testing double up particle filters and they claim a cleaner exhaust than the air they discharge into,that is what they are saying. There was in the time a lot of the discussion over who would pay any engine damage due to the max speed unloaded test. It got so bad in Belgium that you had to give full thottle yourself.
The Belgium smoke test is carried out in government controlled MOT test stations. There test parimiters are available on the internet. The Dutch are the strictest in Europe. Germany has the TUV control also to find on internet.
There are aprox 2300 planes flying with diesel engines and the robin flight trainer is offered standard with diesel. An order for 35 has been placed by a flying school in America.
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I still can't find anything pertaining to a NOx test for the Dutch APK. Soot and NOx are not the same thing. The car owner is responsible for making sure the engine is in good condition before submtting for testing. Silly test anyway, since no one drives around at red line in neutral! They should run it on a rolling road, say 2000 RPM, 300Nm wheel torque, typical of driving conditions.
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The clean fuel is LPG gas and a lot of dutch drivers started to use this .The Dutch goverment got wise to this and started to hike up the taxes making it more expensive than it should be.Goverments tend to act hyprocritical if their is money to be made from the taxpayer.LPG is a byproduct and should cost very little.
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The Dutch still use LPG nearly every filling station in Holland has a lpg pump however the rest of europe you have to hunt the pumps down.LPG had its problems round the change from carb to injection and the gas tank, takes up a lot of room in the boot of replaces the reserve wheel. OK untill you get a puncture. Plus have more than 60+ kgs in the back of the car. The car in holland is seen number one taxation object and the government exploit this to the fullest. You do not think for one second they will play fair with the motorist.
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I feel your pain but it's the same in Blighty. Cars are taxed to the hilt while every other pollution emitter gets away virtually scot free (domestic gas, coal, diesel when used for purposes other than motoring (wtf??), aviation kerosene etc.
I always think of the 'eco friendly' Guardianistas gallivanting round the globe on tax free avaiation fuel, while poor old motorist gets clobbered for driving to work. It's not fair!!
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I don't get the LPG thing either. No one would bother with it if it wasn't taxed so favourably. Why is it taxed so favourably? I suppose in the old days, it was 'cleaner' burning than petrol-but a good fuel injection system (ie any multi point) is clean burning anyway. Carbon emissions are similar to petrol.
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No chemical energy source is a 'by product'. Propane can also be used as a feedstock in the petrochemical industry. I don't see the justification for loopholes. If using crude oil is bad and emitting carbon is bad, then it's bad accross the board. I hired a boat once and the fuel bill was split 60/40. It was assumed that 60% was used for locomotion (taxed), and that 40% was used for the generator (untaxed). Same engine, same diesel, same emissions-ridiculous.
With a proper sequential FI system, I doubt that LPG emits less particulates than petroleum. CO, CO2, and, NOx, and UHC emissions should be virtually identical. If governments want to discourage inefficient vehicles, then offering an incentive to switch to a lighter fraction of crude oil is bonkers. That's the trouble with perverse incentives. The money used for converting to LPG saves tax, but not energy. Why don't they provide an incentive to save energy? Mad world!
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