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| # | Post Title | Result Info | Date | User | Forum |
| Article: Turbocharged Engines | 183Relevance | 6 years ago | Razmig Bartassian | Submit Your Question HERE | |
| Turbocharged Engines Almost all auto manufacturers are moving towards direct-injected turbocharged engines. This is because turbocharged engines are more efficient compared to naturally aspirated engines, in terms of fuel efficiency and power. Turbochargers allow smaller displacement engines to have more power compared to their naturally aspirated counterparts. I have created this article for those who are considering a vehicle with a turbocharged engine, as well as those who already own one and willing to learn how they operate and perhaps troubleshoot any issues. As you read this article, you will get an idea on how complicated turbocharged engines really are, but learning how a turbocharged engine works will at least give you the necessary knowledge on how to approach any issues should they arise. So my goal with this article is to help those who have any sort of issues with their turbocharged engine, or those who just want to learn about them! How it Works: A turbocharger is simply an air compressor that forces air into the engine to increase its volumetric efficiency, and therefore, power. The turbocharger itself has two main components, the impeller and the turbine. The impeller is found on the cold side (or compressor side) of the turbo, and it's responsible for sucking in air to force into the engine. The turbine is found on the hot side (or exhaust side) of the turbo, and it's connected to the impeller by a shaft and center bearings. The exhaust gases from the exhaust manifold are used to spin this turbine, and therefore, powers the turbo by spinning the impeller. Now that we know how a turbocharger works, let's look at the turbocharged system as a whole: We just saw that the turbocharger compresses the air it sucks in, but when the air is compressed it generates heat, which increases the temperature of the air and lowers its density. You might be wondering...what's the point of a turbo if it forces in hot air into the engine? Hotter air doesn't make more power, does it? Well, the compressed air needs to get cooled down before it's forced into the engine. This is where the intercooler comes into play. The intercooler is a heat exchanger (usually air-to-air, but can also be coolant-to-air) that is responsible for cooling down the compressed air before it is forced into the engine, and this cooled air is known as charged-air, and the extra air pressure created by this charged-air is known as boost. This is why turbocharged engines use additional MAP sensors (manifold absolute pressure) along with a MAF sensor to meter the air entering the engine. This is the air that provides the engine with more power. Cooler air is more dense, and denser air has more oxygen molecules in a fixed volume. The more oxygen an engine can get, the more fuel it can inject, and therefore, the more power it can make. Remember that this air is being forced into the engine, and this ultimately increases the volumetric efficiency of the engine. Volumetric efficiency is exactly what it sounds like: the engine's efficiency of sucking in the proper amount of air to fill up the cylinders' volume. Naturally aspirated engines typically have a volumetric efficiency of around 80% (80% of the cylinder's volume) to a maximum of 100% (full volume of the cylinder), and this is because naturally aspirated engines use vacuum to intake air into each cylinder. The piston traveling downwards during the intake stroke acts like a "syringe" that sucks in air, but most of the time this effect doesn't completely fill the cylinder's volume with air (i.e. 80% of the volume is filled with air), especially at higher engine speeds when the valves and pistons are moving faster. Now in the case of turbocharged engines, the air is being forced into the cylinder rather than being sucked in by the piston, and this basically allows 100% of its volume to be filled with air and perhaps even more air than the given volume as the turbo builds boost (more than 100%). This is why turbocharged engines are known to have a volumetric efficiency of 100% or more. It is the increased volumetric efficiency that makes the engine more powerful. Now let's talk about the two other components that are used in a turbocharged system: the bypass/blow-off valve and the wastegate. The bypass/blow-off valve is used to release excess boost out of the pipes found between the turbo outlet and throttle body. When you let off the accelerator pedal, the throttle plate closes, leaving the pressurized air inside the pipes with no where else to escape other than back out the turbo impeller. boosted air escaping out of the turbo impeller is known as compressor surge, and it is detrimental to the turbo's health because it puts stress on the impeller and bearings. So the bypass/blow-off valve that is found either on the turbo housing or charged-air pipe releases the excess boost when the throttle plate closes to prevent compressor surge. This valve operates off a vacuum line connected to the intake manifold, so when the throttle plate closes, the manifold pressure drops relative to the pressure of the charged-air pipe, which causes a pressure imbalance that allows the piston to open up to release the excess boost. The wastegate is responsible for regulating the amount of exhaust gases used to spin the turbine on the exhaust side, which regulates the amount of boost a turbocharger can generate. It is a physical "gate" that opens and closes an alternate exhaust path that bypasses the turbine side of the turbo. Again, it uses a vacuum line connected to the intake manifold to monitor boost, so when the intake manifold reaches maximum boost (determined/set by the pneumatic wastegate's spring force), the wastegate opens so that the turbo doesn't over-boost the engine (safety feature). *Note: Modern turbocharged engines now use electronically-controlled bypass valves and wastegates instead of pneumatically-operated ones. So the ECU uses various MAP sensors instead of vacuum lines to monitor boost, which helps the ECU determine when to open/close the bypass valve and wastegate. Misconceptions: The biggest misconception about turbochargers is that they wear out the engine faster due to the the extra power and pressure associated with them. Well, this isn't exactly true because engines are built specifically for a turbocharged application. Auto engineers are not taking naturally aspirated engines and just slapping turbos on them. The engine itself has to be built with stronger internals in order to handle the turbocharger's boost. When a person turbocharges a naturally aspirated engine, does it blow up most of the time? Yes, because that engine wasn't built to handle boost from a turbocharger. When you buy a turbocharged engine, does it blow up most of the time? No, because it was specifically designed and built to handle boost. Now I am NOT saying that turbocharged engines are trouble free. In fact, turbocharged engines have a bigger potential for issues compared to a naturally aspirated engine, and this is because of the complexity (which we just observed). For example, if you get a code for running rich on your naturally aspirated engine, then either it's getting too much fuel or not enough air or sometimes both. In terms of diagnosing air restrictions, you just have to deal with the air box, intake pipe, or the MAF sensor depending on the issue. But if you get a code for running rich on your turbocharged engine, then you have a whole turbocharger to deal with because it's part of the air intake system. It could be the bypass valve stuck open, it could be the wastegate stuck open, it could be the physical turbine/impeller that is stuck. In other words, there are a lot more components to check when you have an issue relating to the turbo. In my opinion, if you know exactly how a turbocharged engine works, you'll have a significantly better time diagnosing and fixing the issues. When I first bought my BMW 428i, I learned the ins and outs of how the turbocharged system works specifically on my car (and in general), so if an issue ever comes up, I will be better prepared to deal with it. And it will also give you a better idea on how to take care of it to prevent issues. Turbocharged engines don't like slow engine speeds, they like to be driven hard to get the turbocharged system working to its full potential. Carbon build-up is the main killer for turbocharged engines, and so you want to get the turbo nice and hot to burn off any carbon before it builds up and causes problems with the wastegate, turbine, or impeller. The PCV system on these modern turbocharged engines vent the crankcase pressure into the intake before the turbo, leading to potential carbon build-up on the impeller itself. Direct injection paired with turbochargers only exacerbates the carbon build-up issue. Direct injection is well-known for causing carbon-build up on the intake valves because gasoline doesn't "wash" over them like it would in port injection. This is why carbon cleaning is a MUST on turbocharged engines every 60-80k miles or so. Troubleshooting Tips: When it comes to turbocharger issues, you NEED to data-log to see how the engine is operating while driving. Turbocharged engines operate completely different at idle and under acceleration. Data-logging is necessary in order to see how the turbo is functioning in terms of the boost it is making. Do some research to find out how much peak boost your turbo is supposed to provide and at what engine speed. Then compare and see if your turbo is providing peak boost, under-boosting, or over-boosting. Some example trouble codes relating to turbocharger issues: P0299 -- Turbocharger Under-boost condition P0234 -- Turbocharger Over-boost condition P0045 -- Turbocharger boost control solenoid circuit/open P0047 -- Turbocharger boost control solenoid circuit low P0172 -- Engine rich running condition P0171 -- Engine lean running condition Things to check: Induction piping and Intercooler: You want to make sure all the clamps/C-clips from the turbo all the way to the throttle body are sealing the pipes and intercooler tightly. Turbocharged engines operate with a pressurized system, so loose piping/clamps WILL cause boost leaks. There are many ways to test for boost leaks, and you can search up some potential ways on YouTube and Google. Vacuum lines/Electrical connections: Vacuum lines are VERY important on turbos that are pneumatically operated (depends on your application...refer to the note stated earlier). If any vacuum lines are cracked or disconnected, it will cause issues with how the turbo operates. Now if your engine uses an electronically-controlled bypass valve and wastegate, then check the condition of the wires and harnesses to make sure they are not corroded. Wastegate: The wastegate determines how much exhaust gas is diverted to the turbo to spool it, and therefore determines how much boost the turbo makes. You want to make sure the wastegate is operating properly. You can have someone rev the car while you look at the wastegate. You should see the wastegate arm "push" or "pull" as the person revs the engine. If you don't, then the wastegate may be your problem. But of course, you can search up other ways to test your wastegate for your specific engine on YouTube and Google. You should check the wastegate for an under-boost or over-boost condition. Turbo Bypass Valve/blow-off valve: You want to make sure the bypass valve is working as it should. This valve controls when to relief excess boost pressure when you let off the throttle. If it is stuck open, then the system won't build any boost in the first place. Check the vacuum lines (or electrical connections if electronically-controlled) associated with it. You should check this valve for an under-boost condition. MAP sensor(s): You want to make sure your MAP sensors are giving correct data to the ECU on how much boost the turbo is producing. Maybe give it a cleaning as it may be super dirty. As a final note, I highly recommend using an API SN+ rated oil in ANY turbocharged engine to prevent LSPI (Low Speed Pre-ignition). SN+ rated oils use a different formulation (the phrase "calcium down, magnesium up") to reduce the risk of LSPI. It was determined through various experiments that the calcium content in oil increased its ability to ignite under high pressure and heat, which therefore, causes LSPI. You can learn more about SN+ oils here and LSPI here. I hope this article was useful to those who are considering or already own a turbocharged engine. - Razmig Bartassian (@razmig) | |||||
| Answer to: Premium Gas | 105Relevance | 6 years ago | Razmig Bartassian | Submit Your Question HERE | |
| Premium gas is not a waste of money depending on what your engine takes. People are misunderstanding the word "premium" for gas. There are three tiers of gas: regular, mid-grade, and premium. It has nothing to do with the QUALITY of the gas. It's all about the octane rating. Regular is 87 octane, mid-grade is 89 octane, and premium is 91/93 octane depending on where you live. If your engine knocks like crazy with 87 octane, then try a higher octane. After all, octane rating is the measurement of gasoline's anti-knock index. The higher the octane, the more re ... | |||||
| Answer to: Distance to empty on Ford Escape 2014 | 85Relevance | 4 years ago | Benjilafouine | Submit Your Question HERE | |
| I’ll forget your last comment. I’ve been driving my very same Focus 2003 since 19 years. Bought it new. I know it inside out. I’ve been testing for three months with different levels of octane under all kinds of circumstances (Focus and Escape). I considered weather, humidity, rain, level of gasoline in the tank, etc. It is always possible that I purchased octane 94 gas that was not as advertised (although I only buy from the best outlets). Battery is new BTW from May. I am also checking it from time to time with a trickle charger to see if it’s fully charg ... | |||||
| Answer to: P0299 with P0420. How to fix? | 72Relevance | 6 years ago | Razmig Bartassian | Submit Your Question HERE | |
| When it comes to turbo issues, you NEED to data-log to see how the engine is operating while driving. Turbocharged engines operate completely differently at idle and under acceleration. You need to data-log how much boost your turbo is making and at what engine speed. Do some research to see how much peak boost your turbo is supposed to provide and at what engine speed. Then compare and see if the turbo is providing peak boost or lacking boost. Things to check: Induction piping and Intercooler: You want to make sure all the hose clamps from the turbo all the way to the throttle body are nice and tight. Turbocharged engines operate off a pressurized system, so loose clamps WILL cause pressure loss and boost leaks. There are many ways to test for boost leaks on YouTube and Google. Vacuum lines: Vacuum lines are VERY important on turbos that are pneumatically operated. Your engine has a pneumatically actuated wastegate and bypass valve that uses vacuum lines to operate it. Wastegate: The wastegate determines how much exhaust gas is diverted to the turbo to spool it, and therefore determines how much boost the turbo makes. You want to make sure the wastegate is operating properly too. When you first start the car up, have someone rev the car while you look at the wastegate. You should see the wastegate arm move back and forth as the person revs the engine. If you don't, then that's a problem and it may be stuck. Turbo Bypass Valve (or "blow off valve" some call it): You want to make sure the bypass valve is working as it should. This valve controls when to relief excess boost pressure when you let off the throttle. If it is stuck open, then the system won't build any boost in the first place. Check the vacuum lines (or electrical connections if electronically controlled) associated with it. MAP sensor(s): You want to make sure your MAP sensor is giving correct data to the ECU on how much boost the turbo is producing. Maybe give it a cleaning as it may be super dirty. As for the low efficiency catalyst code, I would check to see if the downstream O2 sensor is working properly (and of course check the upstream O2 sensor as well). The downstream O2 sensor is what determines whether the catalyst is working properly. Voltage should be around a steady 0.45 volts for the downstream O2 sensor. But before trying anything, you need to data-log to see what exactly is happening with the boost and the voltages for the O2 sensors. | |||||
| Octane 88 not good for octane 87 engines? | 57Relevance | 3 years ago | Kaizen | Submit Your Question HERE | |
| This article is suggesting that 88-octane is not good for 87-octane engines. I was of the understanding that you can always go higher octane, without ill effects, but you can’t go lower octane, because of potential knocking. The article also states that the 88-octane oil is 15% ethanol. So maybe it is the ethanol rating and not the octane rating that is problematic? | |||||
| Octane boost vs premium gas | 45Relevance | 5 years ago | RonnyR | Submit Your Question HERE | |
| Ok I just bought a used 2018 Lincoln MKZ black label. Its a 3.0 turbo charged engine. It states it take the premium gas 93 octane i believe. I filled up and it cost me $68 for a full tank. If I put regular gas 89 octane I believe and add a bottle of octane boost from say Walmart for $1-2 it would save me almost $15 per tank. It it safe to do this? | |||||
| RE: '06 Mazdaspeed 6 Power Loss, Sputtery feel in Acceleration | 85Relevance | 6 years ago | Razmig Bartassian | Submit Your Question HERE | |
| @joshhuck I have never experienced an issue like this on a mazdaspeed (at least with the mazdaspeeds my friends have owned). The only things I have experienced with those engines are the fuel pump, running rich, and running lean. I will say that your issue seems to be cylinder-specific, where cylinder 3 is having either an air, fuel, spark, or compression issue. But when I looked at the data the other time, I did find a few concerning things like the spark advance and the low boost under load. These definitely may be causing the hesitation under acceleration because the engine is expecting higher boost (more air) under heavy load and injecting the fuel necessary for it, but it's actually not getting the right amount of air. And we saw this with the negative STFT. Technically it should throw a code for low boost if it is a lack of air, but I don't think it actually has a code for that (never seen an "underboost" code on those first gen mazdaspeeds even when it really was underboosting). But my 2016 BMW would definitely throw an underboost code when it's off by a few psi because the turbo is managed through "load-based" calculations. This basically means the ECU moderates the engine's peak power using a combination of intake air temps and boost pressure. When it's colder outside, my turbo hardly makes any boost (like 10 psi max) because cooler air has more oxygen and therefore don't need as much boost pressure to make peak power. But when it's hot outside, the turbo spools like crazy (up to 19 psi) to compensate for the lack of oxygen in hotter air and make the same peak power. So you can see why a slight psi difference in this sophisticated setup would matter (the ECU controls the boost depending on air temp, so if it sees uncontrolled boost it will freak out lol). Your engine doesn't have "load-based boost" so to speak...it can make however much boost it can until it reaches a set maximum psi by the ECU (controlled by the boost solenoid mainly to protect the turbo and engine) regardless of intake air temperatures. Now I'm not claiming that your ECU can't tell whether the engine is underboosting or overboosting with a fault code, I'm just saying that I have never seen that code before on a mazdaspeed. They just generally throw rich/lean codes when it comes to lack of boost or too much boost. Anyways, I feel like that's your problem in terms of your overall hesitation, but for the misfire, it needs some more diagnosing such as with a compression test. How often does the misfire occur? You say you have to drive it for a while to get the code. Is there any other history you know about the car like previous repairs or whether it was modified? At 162,000 miles there could be a TON of carbon build-up on the intake valves, causing them to stick intermittently, which would cause a lack of air in the cylinder and a potential misfire. My friend's mazdaspeed3 has 110,000 miles and it had a serious amount of carbon build-up when I checked, so that's another "what if" to add to the list. The best thing to do is to continue doing the more simpler things (like checking the coils) and then work your way up the ladder. If you come across anything else, continue to add it here. | |||||
| Answer to: High octane gas probably did some damage to my car | 55Relevance | 5 years ago | spijet | Submit Your Question HERE | |
| Hello fellow Russian! 🙂 I'm not sure that this problem could be caused by a high-octane gas. If anything, higher octane reduces the risk of premature detonation and generally has a lower burning temperature (or so I heard), reducing the risk of blowing your engine's head off. Most likely it's been caused by some problem in your cooling system. Also, since you have squeaking noises, check if your engine gets enough lubrication (i.e. you're not low on oil and use the proper viscosity). To all Americans wondering about weird octane nubmers the OP is refer ... | |||||
| Answer to: lexus premium fuel - is it really needed | 53Relevance | 3 years ago | AutoDIY | Submit Your Question HERE | |
| Out of curiosity, I googled the manual for your vehicle: "You must only use unleaded gasoline in your vehicle. Select premium unleaded gasoline with an octane rating of 91 (Research octane Number 96) or higher required for optimum engine performance. If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research octane Number 91). Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking and significantly reduced performance. Persistent knocking can lead to engine damage and shoul ... | |||||
| Answer to: Octane Booster Question | 42Relevance | 5 years ago | AutoDIY | Submit Your Question HERE | |
| Check out the race-gas.com calculator: Race gas original 87 base octane - desired octane 91 2 ounces of race gas added per gallon of 87 octane = boosts octane to 91 Race Gas concentrate 32oz price: $32.49 (plus your state tax rate?) = Approximately $1.02+ an ounce 20 gallons of 87 octane + 40 ounces of race gas = Not worth the price | |||||
| Answer to: Gasoline Octane Question and Question About Acura Ownership | 42Relevance | 5 years ago | Whatchamacallit | Submit Your Question HERE | |
| If you use lower octane you will have reduced engine performance as well as engine knock. On Page 29 of your owner’s manual tells you what happens if you use lower octane than 91 (which is recommended by them): “Use of a lower octane gasoline [87 or lower] can cause occasional metallic knocking noise and will result in decreased engine performance. Use of a gasoline with a pump octane less than 87 can lead to engine damage.” The engine in that particular vehicle was tuned to work optimally on 91+ octane, so I would stick to that for longevity. | |||||
| Answer to: Gas type | 40Relevance | 5 years ago | Kaizen | Submit Your Question HERE | |
| Use the required gas by the manufacturer. You'll get the best performance out of the car. Lower octane gas will increase the likelihood of engine knock in cars that require higher octane gas. Knock is when the gas combusts prematurely, and lower octane gas tends to combust prematurely versus higher octane gas. Modern cars have sensors which will adjust the engine to reduce knock, but you lose performance of your engine. But using lower octane in your case may even run horribly and potentially damage the engine. Unless absolutely necessary, use the reco ... | |||||
| Answer to: 2015 lexus gas | 53Relevance | 4 years ago | Glen_stet | Submit Your Question HERE | |
| Here's what Lexus says: "Premium unleaded gasoline with an octane rating of 91 (Research octaneNumber 96) or higher required for optimum engine performance. If 91octane cannot be obtained, you may use unleaded gasoline with an octanerating as low as 87 (Research octane Number 91). Use of unleaded gaso-line with an octane rating lower than 91 may result in engine knocking andsignificantly reduced performance. Persistent knocking can lead to enginedamage and should be corrected by refueling with higher octane unleadedgasoline" Page 571 your owner's manual ... | |||||
| Answer to: DIG vs Turbo | 53Relevance | 6 years ago | Kaizen | Submit Your Question HERE | |
| Gasoline Direct Injection, Turbo, and octane are all independent of each other. And they can also all be used together. Gasoline Direct Injection means gas is injected directly into the cylinder head, instead of the intake chamber where it normally is injected. Turbo means getting more air into the engine. A turbo does this by using exhaust gasses to turn the turbo, thus getting more air into the intake. octane refers to the gasoline ability to prevent engine knock when ignited. The higher the octane number, the more compression the fuel can withstand be ... | |||||
| Answer to: Gasoline | 53Relevance | 6 years ago | Razmig Bartassian | Submit Your Question HERE | |
| Here is a great explanation on fuel octane:"The problem is that the popular components used to make the octane of a fuel higher slows the burn rate and a fuel with a burn rate that is too slow can result in an engine power loss. Of course, that is just typically what happens and it does not hold true for all fuels. In part 2, we will explore all of the alternative fuels, how they affect your engine’s performance and reliability, and which fuel is right for you." But guess what...regularly available 91/93 octane fuel at gas stations burn slower because we ... | |||||
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