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Very good question!A minimum of 272 and 300 metric hp are mandatory for the 40 t respectively 44 t European weight limits, according to Directive 97/27/EC of the European Parliament and of the Council of 22 July 1997 which specify that “motor vehicles must provide an engine power output of at least 5 kW/t (6.8 hp/t) of the technically permissible maximum laden mass of the combination.”That is a step back from the German mandatory minimum that was increased from 6 hp/t to 8 hp/t (metric) in 1972 and caused the production of the first 304 hp truck engines for the then 38 t maximum gross weight. They were soon followed with 320 hp engines such as the Mercedes - MAN V10 or turbocharged 6-inline of other manufacturers for the increased 40 t limit that was coming.The 1975 Mercedes OM 403 320 hp V10Actually, 6 hp/t are adequate, 6.8 hp/t are fine. You can always have more powerful engines if you want, the drivers will appreciate it, the engine will be able to run slower and last longer, gearshifts will be less frequent. Since the maximum speed is governed to 88 - 89 km/h, insignificant transit time will be gained, except on very mountainous roads. But if the truck is overloaded, it won’t be so evidently apparent when climbing grades!The tires will wear somewhat faster with a powerful engine, the truck will be more expensive to buy and slightly heavier, losing some payload. Fuel consumption should remain roughly the same since a bigger engine will be mated to longer transmission ratios and rev slower.So, as always, it’s a matter of compromises and excess on one side or the other should better be avoided.

Musk owns 193.3 million shares of Tesla which is 20.7% of the company. In 2011 this was worth $467 million. By 2019 the value of the company had grown to $75.718 billion and Musk’s shares were worth then $15.67 billion. Today Tesla is valued by the market at $668.90 billion and that makes the shares worth $138.46 billion.Tesla has been making profits and reinvesting those profits into new products that people really want. The company has been hiring people and building factories with its profits and building more and more products at greater and greater profits.When other auto manufacturers pulled back production and were losing money, Musk pushed Tesla forward toward greater production and more money. Free of the supply chain issues related to oil, and free of the pollution of oil fired vehicles, Tesla looked like the future. When their market cap — the value of all the shares in the company — exceeded the value of Ford — which was having trouble growing its profit or sales — analysts took note and figured if Tesla beat out the big boys during this Covid 19 thing, Musk had what it takes to stay in business in thecold cruel world.Martin Eberhard and Marc Tarpenning originally started the company in 2003 after Eberhard came up with the idea for electric vehicles. Following GM pulling out of the EV market the comppany was troubled. It had a good drive train developed, but it needed money to turn it into a profitable car.In February 2006, Musk led Tesla's Series B US$13 million investment round which added Valor Equity Partners to the funding team. Musk co-led the third, US$40 million round in May 2006 along with Technology Partners. He took over vehicle development and by 2008 had the first Tesla Roadster completed built around the Lotus Elise. With the Eberhard and Tarpenning drive train combined with the Lotus derived body suspension and handling, it was an EV like no other before. It handled and performed like a true sports car, and had incredible range. A far cry from the EV-1 that cost GM $1.6 billion in losses! Musk put in $53 million got 20.7% of a company that could have gone the way of the EV-1, but worked very hard putting that money to good use by hiring the best people with the best ideas and giving them free reign to build better cars more cheaply with greater perceived value than anything that came before. Now the entire auto industry is changing gear and oil is in permanent decline.That’s how Musk Eartned over $10 bilion per month in added value this year. He took a concept and is now shipping 50,000 cars a month on a rapidly growing trend line.A company is valued based on the discounted flow of money it hopes to earn in the future.Sales 2028: $28.17 BCost of Rev: $22.22 BGross Profit: $ 5.95 BOperating Ex: $4.19 BOperating In: $1.76 BTaxes:________$0.25 BDividends:___$0.56 BThe market values the company at $668.90 bllion today.These are the return histograms for the S&P 500. There is a possibility you could make money or lose money on any investment on any day. What are the probabilities going forward day after day? This is called a Markov Chain. You apply these distributions again and again and you get these random walk charts.Now this is very simplistic. There are also fundamentals involved. But let’s look at a fund that would like to make 6.4% for their investors per year which is near the peak of the 250 day histogram, and they have a 30 year window. Say they’re a pension fund with plenty of cash looking for income in the future. So, they are looking for total dividends of $50.69 B per year of$668.90*0.064/(1–1/1.064^30) = $50.69 B/yearThis is 90.5x larger than today. That’s 4.52 million cars per month. This is the size of Toyota, Volkswagen, Hyundai, GM and Ford combined. Its also below their combined market cap. If something happens to remove all the existing auto manufacturers over the next few years and leave Musk standing, this is the only thing that makes sense to those investors. What could it be?End of the Age of OilAfter spending more on Solar Energy research and Nuclear Energy research and Fusion Energy research than we have spent on going to the moon, or building up missile defense systems, we have not yet found anything as inexpensive or as easy to use as oil.Trump wrongly tells us that we have plenty of ol. No, Trump merely tapped into known reserves that were being managed by the banking families toward their next phase. So, Trump can pump lots of oil over the next four years if he’d like, but that depletes the oil sooner. It is not bringing in new discoveries at anywhere near the rate they need to be in order to sustain growth.Now this situation has been sold as a sustainability and environmental issue. However, knowledge is power, and the powerful see no benefit in telling the whole truth all the time. So, there is confusion surrounding these issue. There is also active disinormation campaigns to discredit intelligence and counter intelligence as well as those who own the oil and the money seems right for them to d.The discovery of oil world wide peaked in 1962. Generally speaking because it takes 38 years to develop an oil reserve economically, the production rate matches the discovery rate with a lag of 38 years. However, noting that the global oil discovery peaked in 1962 all things being equal oil production would peak in 2000. There is no real alternative to oil at present, or then, so it seemed best for the oil owners to create a petro dollar, which Kissinger sold to Nixon in 1971 creating the Nixon Shock. This tied the banking system directly to oil production and allowed the US to manage distribution and deveopment by managing the value of money relative to the dollar. This kept the total volume of oil world wide over time, constant. It did cut off the natural development of Africa, South America and Asia which could have taken place had adequate energy supplies been in place. Despite shaving the peak, the area under the production curve cannot exceed the area under the consumption curve.The current pandemic adversely impacts oil sales by cutting back air travel and automotive travel and travel of all orts. The possibility of an ever evolving pandemic that might kill lots of people, provides a ready means to reduce human numbers through a variety of means and point to the pandemic overpopulation etc. as the root cause.One thing is certain, the failure of oil will lead to the end of the motorcar as we have known it. The EV will be the only thing left standing. We’re talking about farm tractors, bulldozers, long distance trucking, rail, ships, all going EV in addition to automobiles.Also, people will stay put and manufacture things with small flexible manufacturing centers. They will grow food and make things locally. Long distance travel and trade will be a thing of the past. This saves a lot of energy. It also increases demand for electrical drive units and short haul EV.In this context the only thing that will travel long distances is information. So, you can see the value of StarLink global wireless hotspot. A Rep Rap Machine receiving signals from StarLink for next seasons shoe line and the shoes are made locally from locally sourced materials — saves energy and puts a premium on the service.The primary source of power will be solar going forward. While its expensive we will make use of less of it. Musk has invested in solar energy as well, with Sun City. This hasn’t come into the spotlight yet, however its an up and comer.The transparent light trapping solar cell is most interesting.Solar cells as light as a soap bubbleThe same microscopic patterning that gives a butterfly wing or a bird feather its bright colours, can be used to selectively capture sunlight to power band gap matched photocells. I patented several innovations in this area decades ago.Energy in sunlight spreads all the way from Ultraviolet to Infrared. We can only see part of that. However, by saying we can see things in this band OVERSTATES OUR ABILITY. The brightly coloured images we watch on our computer screens and HDTV, are made with only three or four phosphors. By creating a cut out at four well defined frequencies, 430 nm, 500 nm, 530 nm and 560 nm, we can absorb and make use of 85% of the solar energy falling on a solar cell, and see what is behind it. In fact, by tuning what gets absorbed and what gets reflected in these very narrow bands, lets us paint the car any colour. In fact, an ultra thin coating on the car, not only powers it, but also allows the owner to change the car colour.This would free the Tesla from charging stations. Auto drive frees the it from licensing requirements. StarLink provides global communications, entertainment, service update, navigation services, use allocation, many many features.Microrobots desiged for the cabin of of the SpaceX Starhip, turning those cabins into 5 star wonders, are adapted to keep the car interior tidy and neat and fresh smelling and assist users who may have dropped an item or left an item in the vehicle.By culling the population of less productive and more troubling elements here on Earth, but perfectly productive and happy off world, the planners hope to reduce human numbers by half over the next 30 years. This could easily be done by making humanity multi-planetary which is another SpaceX tie in.Robert Heinlein wrote a book many years ago, The Moon is a Harsh Mistress. Where he describes a penal colony on the Moon. They ended up getting their independence its a great story. The point is, all types of people will be attracted to space. It will be a wild place, and a natural place to ship malcontents - and remove them from the biosphere in a way that doesn’t cause much push back as warfare bioweapons and terrorism do.So, you can see what’s going on here. At least in the minds of some investors.While many engineers and dreamers like myself have spent their life pursuing answers to these problems along the lines here, Musk has managed to get the capital and have the focus of attention and executive skill to make it market with highly profitable and desireable products. That makes all the difference.Telecom is about to go through a major change as well and there are synergies here as well.You can see that new companies using new technology like China Mobile make far more money on far fewer sales than old line companies like AT&T and Verizon. This will really go badly for them when Musk figures out how to increase broadband to match and then surpass the legacy systems.The cable, and towers and service trucks all require oil, and manpower, and 20,000 satellites flying over head do not.StarLink is projected to Earn $35 billion per year in three years. It could earn far more, and generate far more profits.Advanced Autopilot also plays a role. People could buy their cars on time shares, and this reduces traffic congestion and does little to harm convenience.Chrysler GM and Ford developed self-driving turbine cars in 1958. This was in response to Shell’s Hubbert predicting in 1956 that by 1970 the USA would run out of oil. The man was demonised in the press and his logistic calculations were called theories haha but 1970 came with an oil crisis and Kissinger sold the petodollar to Nixon.The highly efficient turbine car with self driving features was considered a retrofuture excess by the 1970s.However, turbines properly advanced are nearly as fuel efficient as electrics and they can burn anything. In a world where there was a shortage of conventional fuels, its nice to have a car that burns unconventional fuels. That’s why GM touted the act they went to Mexico and burned Tequila in the car no problem.Further, when you didn’t have to deal with a driver, and the car could drive itself, and you didn’t have to go look for a parking spot and let the car do it for you, and if you had a trusted group of users that could use the car while its looking for a place to park, and that cuts the cost to you of running the car… you can see that only about 1/10th the number of cars get sold. Each person pays 1/4 to 1/5, and a service company makes the difference.So enter auto drive and Tesla Electric.Global wireless hotspot will provide telecom service to 60% of humanity that has never had access before. Autodrive will do the same for the automobile.There are 264 million motorvehicles in the USA today for 329 milion people. 0.8 cars per person. World wide there are 1.3 billion motorvehicles for 7.7 billion people. 0.168 cars per person.So, it will take a few years for space travel to move people off world. Population will likely rise to 8.1 billions by 2030. At that time we will start to see dramatic declines in human numbers as 5% of us leave Earth permanently each year. This has to do with the logistic function of adopting innovation. This is a product of human psychology. 2.5% of us are innovators. 13.5% of us are early adopters. Once a new trend develops, 5% of us will leave where we are, and go somewhere else. Since population grows at 1.1% per year generally, this is why populations move around. Opening new frontiers beyond Earth, will depopulate the Earth for this reason.Rockets will be adopted over time just as motorcars and airplanes were. The interesting thing is that rockets despite their massive power, has better fuel economy than bicycles, since travelling through the vacuum of space provides no resistance. Earth to Earth travel by rocket uses less fuel than travel by subsonic airplane. So, this fits within this picture as well.To replace the 1.3 billion gas guzzlers with 0.8 billion electrics between now and 2028 with 2/3 of them going to places that never had cars. The longevity of the cars are 15 years as opposed to 7 years for cars today. They use half the raw materials as cars today, and none of the fuel. Tesla will dominate in this world just as Microsoft dominates in the world of computing. Tesla will get their 4.6 million vehicles per month. 55.2 million per year — and unbelievable number by today’s standards. However, going to smaller distributed factories that source things locally, will help with this. This returns to the vision of Henry Ford. The only difference is, Ford didn’t have StarLink or the Sun.Production Rate per year.Total Cars in Circulation (14.7 years longevity)About 1/3 of the cars needed. So, they could in fact do more. Recall if the other car companies go idle, it makes sense for Tesla to make use of surplus capacity where appropriate. However, over this period new manufacturing technology is likely the better approach, because new maerials and processes will be used throughout. Still there should be opportunities for some synergies over this period.

Feb 13, 2018 - ... BMW, General Motors, Mercedes Benz, Volkswagen, Honda and Toyota set higher ... Top tier octane levels are the same as regular fuel. ... high levels of these products have the potential to damage catalytic converters. ... The detergents bind to injectors and valves, protecting against further build-up too.Here is 449 pages scientific report on premium gas versus regular gas ; please read …!https://www.iav.com/sites/default/files/veranstaltung/25/publications/34242_iav_ottomotorisches_klopfen_ans.pdfI see some German BMW, Benz, Audi, Porshe with the 87 octane gas using them since over a year. The catalysors are not made for this type of fuel and incomplete combustion will develop condensation in the catalysors. `The temperature recorded at the exhaust is -20C + versus octane 91 fuel. We have to replace all the spart plugs, the Oil , filter and clean when possible the catalysors. If not the catalysors will require to be replaced. The Turbo Charger when present does not function correctly and the consequences are devastating as the temperature of the exhaust may be lower something not recommendable. Also the engine Oil is not as clean as using octane 91 gasoline.The high compression is one of the factors but cars made for octane 91 cannot over a long period function correctly with the octane 87 gas.The combustion is not perfect and the catalysor is the one picking up the bad combustion overflow. If you have to spend over $500 plus plus to fix the car how much did you save as the engine is with combustion deposits in many places you never see present with the octane 91 fuel.You can sometimes use octane 87 but not all the time to keep the combustion chamber clean without any deposits; this is extremely important to keep the engine head area as clean as possible around the valve exhaust area port; valves do go bad when deposits accumulate around the exhaust area seat. You will have to do a overhead valve job at low miles something un warranted and quite expensive. Mercedes have tried and tried using octane 87 in high compression engine and overhead engine failure was present as the exhaust valves are the first to be damaged ;The advantage of octane 91 combustion is way better and hotter for a clean combustion that translate with a cleaner head port area and many more areas.The advantages far outweight many times the octane 87 consequences.Also the EGR Valve will clog sooner or later.Is it different to premium fuel?Yes. Top tier fuel is different from high performance premium fuel, which has higher octane levels. Top tier octane levels are the same as regular fuel.Why would I use top tier fuel?What regular gas does inside your engine.How top tier gas helps your engine.There is some controversy within the auto industry about whether top tier gas is worth the extra money, with some critics labelling it as a marketing ploy to make more money for fuel suppliers. However, numerous automotive experts suggest using top tier fuel, even if not for every tank. The main reasons they recommend it is to help avoid:Increased deposits on fuel injectors and intake valvesConsequent misfiring spark plugs and reduced performanceReduced emission efficiencyRepair bills of up to $1000 for a cylinder-head rebuildIf you have a fuel injection vehicle that needs repairs as a result of excess deposits, this could affect the resale value of your car. Some people prefer to use fuel-system cleaning products as they can be cheaper than buying top tier gas regularly, but high levels of these products have the potential to damage catalytic converters. You don’t need to use top tier gas in every tank to get the benefits either, as its unique formulation means that one tank can remove the residue from several tanks of regular fuel. The detergents bind to injectors and valves, protecting against further build-up too.Differences Between Premium and Regular GasPremium gas is similar to regular unleaded fuel. Both are made from crude oil and are highly combustible. One of the most notable differences, though, is that premium has a higher-octane rating. Most premium fuel has a rating of 90 octane or higher. Octane is important when it comes to powering vehicles while preventing knocking. When gasoline and air ignite before they should, it causes an explosion known as pre-ignition, which causes a knocking sound. Octane refers to how well the fuel can resist pre-ignition. With an octane of 90 or higher, premium gasoline is less prone to pre-ignition or knocking. Premium fuel also contains detergents and additives that help engines run cleaner. The additives and detergents result in less pollution as well.The Bottom LineThe computers that manage modern engines are able to adjust the ignition system to accommodate lower-octane gasoline — to a point. With regular gas, fuel economy and acceleration will likely deteriorate at least slightly. Because regular has lower octane, it is more prone to detonation. Burning regular in an engine designed for premium on a long-term basis or under heavy loads can cause engine knock, and that in turn can damage the pistons, valves or spark plugs. Due to the presence of knock sensors and the car's ability to retard the spark timing, you might not hear knocking, but that doesn't mean premium is unnecessary.Regular can be used at least occasionally without repercussions in most vehicles designed for premium, but it's a bad idea to make a habit of it. Bottom line: Check the owner's manual. If the vehicle manufacturer says the engine requires premium, believe it. Don't try to save a few cents per gallon by buying regular gasoline. Doing so could lead to much larger expenses in the future.http://Cars.com's Editorial department is your source for automotive news and reviews. In line with http://Cars.com's long-standing ethics policy, editors and reviewers don't accept gifts or free trips from automakers.Premium fuel is not “better” fuel, but rather different fuel. It is a shame that some marketer came up with the idea of calling it “Premium” as if it was by nature “better.” All premium means is that it will burn slower in the engine. Some engines will work better with premium and will say so in the car’s owner’s manual Some engines NEED Premium to prevent engine damage (see owner’s manual and if it says USE premium do so.)Using regular when the owner’s manuals indicates that premium is “required” can damage the engine and may reduce mileage.Engine “octane” rating is quite simply a measure of a particular fuel’s resistance to self-ignition under pressure. Quite simply, if your engine’s compression ratio is 10.5 or less to 1 and naturally aspirated, you do not need to run anything over 87 octane, or 85 octane above 4000 ft above seal level.The addition of turbochargers or fancy ram induction intakes changes things. Now you’re jamming MORE air (and thus more oxygen) into the cylinder to be compressed in a hot container with a highly volatile and flammable chemical. Even if you have one of these whiz-bang high-compression engines or turbocharged engines, the knock sensor (basically just a microphone) will feed back to the ECM to retard ignition timing in the event of a knock until the knock goes away.Corrosion and moisture concerns aside, ethanol does improve octane rating of fuel. Running pure alcohol allows for INSANELY high compression ratios like the methanol racers back in the days of open-cockpit Ducattis, Alfa Romeos, and Dusenbergs. Methanol will take some pretty severe compression before it auto ignites, hence the stupid power figures alcohol race engines can put out.There’s more to knock tendency than compression ratio.Anything that increases the flame path (bigger bore, spark plug to one side, less turbulence/swirl) needs higher octane because of increased combustion time.Modern engines generally use a compact shape combustion chamber with a centrally located spark plug.This paper talks about some of the things done to reduce knock tendancy in a Toyota engine:http://www.spyderchat.com/1zzfe.pdfThe dude who I saw throwing a fit in the service dept at the Ford dealership where I worked at one time when his warranty claim roundly rejected because he chose to run 87 octane in his Lightning pickup instead of the required 91 octane would probably disagree with you.Also when I worked at Nissan, we had alot of people complained that they were getting lousy fuel mileage in their V6 Altimas and Maximas and 350z’s. Turns out the VQ engines from around 2003-2006 really don’t like 87 octane (premium is recommended, but not required for those years) The ECU’s software is such that when it detects knocking (via the knock sensors) that it reduces the timing to such a degree that power is and fuel economy is reduced by about 15% (general consensus), that’s significant. We told the customers that 91 octane or better is recommended for optimum performance and fuel economy, and to try a couple tankfuls to and see if the fuel mileage increases, that fixed the problem every single time. The later VQ’s have some design and ECU changes that make them more tolerant to octane levels though.You have to remember that today’s cars with electronic controls are able to be to tuned much more precisely that cars of 70’s and even the 80’s. There’s less wiggle room, cars can be tuned to get the very most out of any given fuel, which means that when the fuel is less than what the car is designed for, you have to rely on the failsafe (knock sensors) which aren’t 100% reliable. When those fail, you’re engine can be damaged even if the fuel you’re using is 5 points lower than what’s spec’d for the car.But that’s in all gasoline, so what makes premium gas different? At its root, it’s an increase in octane. Octane is one of those hydrocarbons in gasoline, and it increases the resistance of gasoline to detonate prematurely in your engine. The higher the octane content in your fuel, the more resistant it is to predetonation that causes spark knock or pinging.In some premium gasolines, there are increased levels of detergents and other additives, but the basis of premium gasoline is its octane rating. At the pump, regular gasoline is usually rated around 87 octane while premium is anywhere from 91 to 93 octane.Premium Gas HelpsAs mentioned, premium gas prevents fuel predetonation under compression. To help clarify, think of it like a diesel engine. Diesel engines don’t have spark plugs to cause the fuel to ignite. It’s all done by high compression inside the engine cylinders. All the extra kinetic energy when the fuel is compressed causes it to explode and push the piston down in the cylinder.In high-compression gasoline engines, the same principle occurs with regular gasoline. The problem is that the explosion occurs too soon in the cycle and it can cause a “pinging” or knocking noise in the engine. Over time, the predetonation causes abnormal wear in the cylinders, excessive carbon deposits because the fuel isn’t burned cleanly, and can cause damage that requires expensive repairs if left for a long time.In high-compression engines, premium gas waits to ignite until the spark plug fires. That’s how your engine produces the best power and operates at its cleanest and most efficient.Who Requires Premium GasKnowing if you require premium gas is as easy as looking for a label behind your fuel door.Premium gasoline is necessary only for those vehicles whose vehicles say “Premium Fuel Required” behind the fuel door. That means that your vehicle’s manufacturer has tested its vehicles and determined that the octane contained in premium gasoline is necessary to prevent early detonation in the engine. If you were to use regular gasoline, you’d experience a reduction in power, worse fuel economy, probably engine pinging, and possibly the Check Engine light illuminated as well.That doesn’t mean there is no benefit to other users, just that it’s not required in others. If, behind your fuel door, it says “Premium Fuel Recommended”, you’re likely to experience slightly better performance with premium gasoline than regular.Gas panic has luxury car owners on edge as premium fuel runs dryThe organization used six vehicles in its testing: a rear-wheel drive 2017 Ford F-150 with the 3.5-liter EcoBoost and 10-speed automatic, a Cadillac Escalade equipped with its fabulous 6.2-liter V8 and eight-speed auto, a stickshift 2015 Mazda Miata, a non-quattro Audi A3 with the six-speed dual clutch autobox, a 5.0-liter Ford Mustang automatic, and a row-your-own MultiAir-equipped Jeep Renegade.The full report, all 68 pages of it, can be found here.[Graph: AAA]Won’t Get Fueled Again: AAA Testing Suggests Premium Gas, for the Most Part, Isn't Worth Your Cash - The Truth About CarsBy Rye Druzin and Dawn Kopecki September 7, 2017Cars with turbochargers (high-performance engines) or older, heavier cars may require premium gasoline and should be used to prevent knocking. According to an article in Scientific American, these cars have higher compression ratios and will knock without the premium fuel.1) If your car requires premium gas, using premium will allow you to optimize your car’s power. You will not achieve the advertised horsepower on a vehicle that requires premium unless you use premium, although most consumers will not even notice the change in power when switching from premium to regular.2) The octane rating of premium and regular gasoline varies from state to state. One state may require a minimum rating of 92 to be considered premium, while another may require only 90. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane) and premium (usually 91 or 93). Consult the yellow stickers on each gasoline pump that are mandatory and indicate the octane rating,3-And, something else to consider: Six automakers, BMW, General Motors, Honda, Toyota,Volkswagen and Audi, believe using Top Tier Gasoline that contains a higher-percentage of detergent additive from that required by the EPA standard, provides optimal engine performance. They claim that lower concentrations of detergent additive lowers the quality of gasoline and can leave deposits on engine parts, such as fuel injectors and intake valves, which can lower engine performance, vehicle responsiveness and increase emissions. BMW, General Motors, Honda and Toyota developed the Top Tier standards under which gas retailers must meet in order to qualify as a Top Tier gasoline retailer.(1) If your engine makes an annoying knocking, pinging or rattling sound when you accelerate or work your engine hard with a load – like driving uphill, passing a slowpoke or towing a trailer – then you’re probably experiencing engine spark knock. It’s not necessarily a problem with your fuel delivery system, but it does mean that your fuel is detonating, or exploding erratically rather than burning smoothly as it should. Eventually, this could lead to a failed head gasket, broken rings, cracked piston lands and/or flatten your rod bearings.When the engine is accelerating or lugging under load the EGR valve should open. This allows intake vacuum to suck some exhaust in through the EGR valve to dilute the air/fuel mixture slightly. This lowers combustion temperatures and prevents knock. Inspect the operation of the EGR valve, and check for a buildup of carbon deposits on the valve pintle or valve port that may be blocking the flow of exhaust back into the engine. Clean off the carbon deposits with a wire brush and carburetor cleaner, or replace the EGR valve if it is defective.(2) A bad knock sensor.Your engine has a knock sensor that should detect detonation and tell the computer to retard the ignition timing. If your engine requires premium grade fuel, but you are using regular or mid-grade fuel, the knock sensor should detect any detonation that may occur when the engine is working hard under a load and cause the PCM to retard timing. This reduces power a bit but protects your engine against detonation. However, if the knock sensor is not working, spark timing will not retard when it should. Consequently, you may hear a pinging or rattling sound (engine spark knock) when accelerating, driving up a hill, or when the engine is lugging under a heavy load.By tapping on the engine near the sensor is one way to test it. Next watch spark timing and/or knock sensor input on a scan tool to see if it sends a timing retard signal.NOTE: Over advanced ignition timing can also cause the same thing (engine spark knock). The engine computer controls ignition timing is not adjustable on today’s engines. The only way to change the timing advance would be to flash reprogram the PCM.(3) Excessive carbon buildup in the combustion chambers and on the tops of the pistons.Carbon build upOlder high mileage engines. Vehicles that never fully warm. Only driven short distances. Treating the engine with a dose of top cleaner or a fuel system additive that also removes carbon from the combustion chamber can usually clears this up. Some repair shops use a machine called a MotorVac to perform an engine carbon cleaning procedure. The machine uses a concentrated detergent to flush out the fuel injection system and combustion chambers.(4) Compression ratio too high.If an engine has been rebuilt and the cylinders have been bored to oversize. This can increase the engine’s static compression ratio. If the cylinder head has been resurfaced to restore flatness. This will reduce the volume of the combustion chamber and also increase the engine’s static compression ratio. These changes will increase engine power, but also the risk of detonation on regular 87 octane fuel. Such modifications may require using higher octane 89 or 93 octane premium fuel and/or retarding spark timing. Engines that are supercharged or turbocharged are also at much higher risk of detonation. This is because the forced air induction system increases compression. This usually requires using premium fuel.Engine Spark Knock(5) Cheap gas.Regular grade gasoline is supposed to have an octane rating of 87. If the gas station or their refiner is cutting corners and the fuel is not 87, it may knock. The fix for this is to try a tank of mid-range or premium gasoline. Some gas stations cheat on this too, and don’t always give you the octane rating claimed on the pump. Premium costs more, but may be required to reduce the knocking. Or, if you always buy gas at the same gas station, try a different gas station. Don’t buy the cheapest gas you can find. BP, Shell and Mobil are all good brands.(6) Engine overheating.If the engine is running too hot because of low coolant, a cooling fan that isn’t working, a plugged radiator, bad water pump, sticking thermostat, etc., it may cause the fuel to detonate. This could cause engine spark knock.Intake vacuum in the intake manifold sucks exhaust back into the engine. The amount of recirculation has to be closely controlled otherwise it can have an adverse effect on idle quality, engine performance and drive ability as a huge vacuum leak. Soot forms where the exhaust passes into the intake, and even within the valve itself, causing various problems. Fuel injectors, which are delicate and expensive components of the engine, may become partially clogged. As for the EGRvalve, soot and grime may prevent it from properly opening and closing. If it becomes stuck in the closed position, it will lose all function.The vehicle will continue to run properly, however it will emit nitrogen oxides at levels beyond the threshold of what is legally tolerated according to area regulations. On the other hand, if the EGR valve becomes stuck in an open position, the engine will become saturated at an even faster rate. Over time, the vehicle will lose acceleration power and certain symptoms will manifest, such as persistent stalling.COMMON EGR PROBLEMSPinging (spark knock or detonation) because the EGR system is not working, the exhaust port is plugged up with carbon, or the EGR valve has been disabled.Rough idle or misfiring because the EGR valve is not closing and is leaking exhaust into the intake manifold. You may also find a P0300 random misfire code on OBD II vehicles.Hard starting because the EGR valve is not closing and is creating a vacuum leak into the intake manifold.An EGR valve that is stuck open:When the EGR is stuck open, it will lead to a vacuum leak which in turn causes inefficient combustion, hesitation, rough idling and even stalling. The reason for this is that the car cannot combust on the carbon dioxide emitted from the tailpipe. An open EGR valve causes exhaust emissions to flood the combustion chamber, hence preventing it from functioning as it should. To check for a stuck open EGR valve, idle a parked car with the brake on and have someone examine the plunger shaft to see if it is stick open.An EGR valve that is stuck closed:This causes nitrogen oxide emissions to rise and the car might start to knock. A sharp knock occurs when the fuel in the combustion chamber ignites before the explosion in the cylinder reaches it. This leads to a disruption in engine timing. When this happens, warm up your engine and rev it, then check if the EGR valve will move.EGR valves have changed design many times over the years.EGR ValveMost older EGR systems use a vacuum regulated EGR valve while newer vehicles tend to have an electronic EGR valve to control exhaust gas recirculation. At idel speed the EGR valve should look closed. There is no EGR flow into the manifold. The EGR valve remains closed until the engine is warm and is operating under load. As the load increases and combustion temperatures start to rise, the EGR valve opens and starts to leak exhaust back into the intake manifold. This has a quenching effect that lowers combustion temperatures and reduces the formation of NOx.Here are some of the changes:Ported EGR valves (1973 to 1980s).Positive backpressure EGR valves (1973 & up).Negative backpressure EGR valves (1973 & up).Pulse-width modulated electronic EGR valves (early 1980s & up).Digital electronic EGR valves (late 1980s to 1990s).Linear electronic EGR valves (early 1990s & up).NOT ALL ENGINES HAVE A EGR VALVEOn many late model engines with Variable Valve Timing-(VVT), there is NO EGR valve because the VVT system varies the timing of the exhaust valves to provide the same effect as EGR. By changing the point at which the exhaust valves close when the engine is working hard under load, a small amount of exhaust gas can be retained in the cylinders for the next combustion cycle. This has the same effect on reducing combustion temperatures and NOx as recirculating exhaust gas from an exhaust port back into the intake manifold through an EGR valve. The big difference is that the VVT system can react to changing engine loads much more quickly and precisely than a traditional EGR valve. Using VVT for EGR also eliminates many of the problems associated with EGR valves such as carbon buildup and valve sticking or failure.EGR TESTINGFind out what kind of EGR valve is on the vehicle so you can use the appropriate test procedure. Examine the valve or refer to a service manual. On some vehicles, you may find this information on the underhood emissions decal. Also, find out what kind of vacuum controls are used in the vacuum plumbing. Does it have a ported vacuum switch or a solenoid? Follow the vacuum connections from the valve, refer to a service manual or the underhood emissions decal for vacuum hose routing information.There are several ways to troubleshoot an EGR system. You can follow the EGR troubleshooting procedure that’s listed in a service manual for the engine. On late model computer controlled engines, there may be trouble codes that relate to the EGR system. On such an application, the first step would be to read out the code or codes using a scan tool or code reader. You would then refer to the specific diagnostic charts in a service manual that tell you what to do next.check engineEGR Trouble Codes:On pre-OBD II GM applications, a code 32 indicates an EGR problem. The logic by which the onboard diagnostics detects trouble follows one of two routes. On some applications, a code 32 is set when the computer detects a richer fuel mixture off idle (indicating no EGR). On others, a code is set if the computer energizes the EGR vacuum solenoid but does not detect a corresponding drop in intake vacuum.EGR TROUBLESHOOTING PROCEDURE1. Does the engine have a detonation (spark knock) problem when accelerating under load? Refer to the timing specs for the engine and check ignition timing. You may find the timing could be over advanced. If the timing is within specs, check the engine’s operating temperature. A cooling problem may be causing the engine to detonate. If the temperature is within its normal range and there are no apparent cooling problems, other possibilities to investigate include spark plugs that are too hot for the engine application, a lean air/fuel mixture, low octane fuel or too much compression (due to a buildup of carbon in the combustion chambers or because of pistons or heads that have too much compression for the fuel you’re using). Be sure you have ruled out all the other possibilities before focusing on the EGR system.2. Use a vacuum gauge to check the EGR valve vacuum supply hose for vacuum at 2000-2500 rpm. There should be vacuum if the engine is at normal operating temperature. No vacuum would indicate a problem such as a loose or misrouted hose, a blocked or inoperative ported vacuum switch or solenoid, or a faulty vacuum amplifier (or vacuum pump in the case of a diesel engine).Sometimes loss of EGR can be caused by a failed vacuum solenoid in the EGR‘s vacuum supply line. Refer to a vacuum hose routing diagram in a service manual or the hose routing information on the vehicle’s emission decal for the location of the solenoid. If the solenoid fails to open when energized, jams shut or open, or fails to function because of a corroded electrical connection, loose wire, bad ground, or other electrical problem, it will obviously affect the operation of the EGR valve.Depending on the nature of the problem, the engine may have no EGR, EGR all the time, or insufficient EGR. If bypassing the suspicious solenoid with a section of vacuum tubing causes the EGR valve to operate, find out why the solenoid isn’t responding before you replace it. The problem may be nothing more than a loose or corroded wiring connector.3. Inspect the EGR valve itself. Because of the valve’s location, it may be difficult to see whether or not the valve stem moves when the engine speed is increased to 1500 to 2000 rpm by slowing opening and closing the throttle. The EGR valve stem should move if the valve is functioning correctly. A hand mirror may make it easier to watch the valve stem. Be careful not to touch the valve because it will be hot! If the valve stem doesn’t move when the engine speed is increased, there’s probably something wrong with the EGR valve.Another way to “test” the EGR valve on some engines is to apply vacuum directly to the EGR valve. Note; This only works on ported vacuum EGR valves, not back pressure EGR valves or electronic EGR valves. Vacuum should pull the valve open creating the equivalent of a large vacuum leak. This should cause a momentary drop in idle speed and a noticeable increase in idle roughness.Back pressure type EGR valves are more difficult to check. There must be sufficient back pressure in the exhaust before the valve will open when vacuum is applied. One trick that’s sometimes used is to create an artificial restriction by inserting a large socket into the tailpipe, then applying vacuum to the valve to see if it opens. Don’t forget to remove the restriction afterwards.4. Remove and inspect the EGR valve if you suspect a problem. Most failures are caused by a rupture or leak in the valve diaphragm. If the valve is not a back pressure type, it should hold vacuum when vacuum is applied with a hand-help pump. If it can’t hold vacuum, it needs to be replaced. Note: This test does not work on back pressure EGR valves.Back pressure EGR valves sometimes fail if the hollow valve stem becomes clogged with carbon or debris. This you can see for yourself. It’s almost impossible to remove such a clog, so replace the EGR valve.Carbon accumulation around the base of the EGR valve can sometimes interfere with the opening or closing of the valve. Do not soak the entire valve in solvent or allow solvent to get anywhere near the diaphragm. The solvent will attack and ruin the diaphragm.5. Inspect the EGR passageway in the manifold for clogging. Use a pipe cleaner or small piece of wire to explore the opening for a blockage. Sometimes you can dislodge material that’s clogging the opening by carefully poking at it. Other times, it may be necessary to remove the manifold and have it professionally cleaned. Also recommended is to clean the throttle body and intake manifold at the same time to remove varnish and carbon deposits.EGR Valve BlockageHOW TO CLEAN YOUR EGR VALVEIf your car is running poorly, it might be a sign that your EGR valve has a problem. Here’s how to go about EGR valve cleaning that you can do it by yourself.Remove the vacuum line connected to the EGRvalve. If the vacuum line looks, brittle, frayed or broken, replace it.If the EGR valve has an electrical connection, disconnect the harness carefully.Unbolt the EGR valve from the engine. Give it a slight tap if it doesn’t come right off. You can use a tiny hammer or a block of wood to do this.Remove your gasket if it looks frayed, torn or disintegrated. You can reuse it if it’s in good condition.Soak your EGR valve in a bowl of carb cleaner. Avoid submerging the electrical portion if it has one. You should soak it overnight if possible.After soaking the valve in the cleaner, you should clean the openings, passages and surfaces by using a small brush. You can also use a toothbrush or a pipe cleaner for this. Make sure to have eye protection and chemical resistant gloves because the carb cleaner is harsh.The final step is to reinstall the EGR valve. Remember to reattach the vacuum hose and electrical connections if you had any.Soon we will see all the new challenges with NO EGR in all the late model engines with Variable Valve Timing-(VVT)1-http://dannysengineportal.com/what-is-engine-spark-knock/2-http://dannysengineportal.com/exhaust-gas-recirculation-valve-egr-faq/3-https://www.cars.com/articles/if-premium-gas-is-recommended-for-my-car-will-using-regular-void-the-warranty-ruin-the-engine-1420684149253/4-Premium Vs. Regular for Older Cars5-Five Facts of Using Premium vs. Regular Gas - TrueCar Blog6-Do You Really Need Premium Gas? | YourMechanic Advice7-Top Tier Gas - Medicine for Your Engine8-http://www.thetruthaboutcars.com/2017/12/wont-get-fueled-aaa-testing-suggests-premium-not-worth-cash-cases/9-https://www.mbusa.com/vcm/MB/DigitalAssets/pdfmb/serviceandparts/service_warranty_information_booklet.pdf10-https://www.chevron.com/-/media/chevron/operations/documents/motor-gas-tech-review.pdf11-http://exclusivebenzlex.com/blog/?cat=712-Using regular instead of premium by mistake [Archive]13-Fuel For Thought: A Study On The Causes Of Foul Fuel14-https://www.iav.com/sites/default/files/veranstaltung/25/publications/34242_iav_ottomotorisches_klopfen_ans.pdf15-Fuel For Thought – Issues That Pertain To "Bad Gas" In Today's Market -16-Detonation - What Causes It And How To Prevent It