The Basics of Turbocharging and Supercharging

By popular demand: a Q&A on supercharging (and turbocharging).

Q: What’s a supercharger?
A: An internal combustion engine works by drawing a mixture of air and fuel (the intake charge) into its cylinders, compressing that mixture, and then burning it. The more air/fuel mixture that can be crammed into the cylinders to burn, the more power the engine produces. You can increase power in three basic ways: you can improve the engine’s ability to draw more air and fuel into the cylinders and expel its burned exhaust gases (its volumetric efficiency, or ‘breathing’); you can increase the swept volume of the cylinders (the engine’s displacement) so you can fit more air and fuel into each cylinder; or you can pump the intake charge into the cylinders under high pressure, squeezing more air and fuel into the available volume.

Forcing air (or air-fuel mixture) through an engine’s intake valves at higher than atmospheric pressure is called supercharging. A supercharger, therefore, is a mechanical air compressor that pressurizes the air going into the engine’s intake manifold. There are several types of compressor used for car and truck engines, the most common being Roots-type, centrifugal, and Lysholm-type compressors; each has pros and cons, but they have the same basic purpose.

Q: So, what’s a turbocharger, then?
A: As we said, a supercharger is an air compressor and it requires a source of power to operate the compressor mechanism. Most automotive superchargers are run by a drive belt (or occasionally a train of gears) operated by the engine, much like a power steering pump or air conditioning compressor. An alternative is to run the supercharger with a turbine wheel placed in the engine’s exhaust manifold, turned by the flow of burned exhaust gases rushing of the engine. An exhaust-driven supercharger is called a turbocharger. (Years ago, they were often called turbo-superchargers, but that term has fallen out of common use, although it is occasionally applied to combinations of engine-driven and exhaust-driven superchargers.)

Q: What’s the advantage of supercharging (or turbocharging)?
A: More power! The more you increase the pressure of the intake air above the local atmospheric pressure (boost), the more power the engine produces. Automotive superchargers for street use typically produce a maximum boost pressures between 5 and 15 psi (0.33 to 1.0 bars), providing a proportionate increase in power. This is particularly useful at high altitudes: A supercharger can pressurize the intake charge to something close to sea level pressure, compensating for the power lost to reduced air density at high altitude. (Superchargers are popular for high-altitude aircraft piston engines for precisely that reason.)

Q: Does adding a supercharger or turbocharger burn a lot of fuel?
A: All else being equal, yes. Engines burn air and gasoline at an ideal (stoichiometric) ratio of about 14.7:1 (depending on fuel blend and octane), which means that if you burn more air, you must also burn more fuel. Even when the supercharger isn’t producing much — or any — boost, a supercharged engine is somewhat less fuel efficient than a non-turbocharged (normally aspirated) engine of the same displacement and configuration. On the other hand, a supercharged engine tends to consume less fuel in day-to-day driving than a larger displacement, normally aspirated engine of similar power. For example, a 2.0-liter (122 cu. in.) turbocharged four-cylinder engine with 240 hp (179 kW) will generally be somewhat less thirsty than a 3.5-liter (214 cu. in.) normally aspirated V6 engine of the same output, at least in relaxed normal driving. As any owner of any powerful turbocharged car will tell you, however, if you use the boost a lot, you’ll pay the price at the pump. In other words, your actual fuel consumption will be roughly proportionate to the engine power you use (what engineers call specific fuel consumption) more than the size or configuration of the engine.

Q: Why use a supercharger instead of just using a bigger engine? Wouldn’t that be easier?
A: To some extent, it would be. A supercharger significantly increases an engine’s specific output — the amount of power generated per unit of engine displacement (usually quoted in terms of horsepower per cubic inch or horsepower per liter), but, as the old adage says, there’s no substitute for cubic inches (or, more pithily, no replacement for displacement). Increased displacement provides more power without the added cost, complexity, and sometimes nonlinear behavior of superchargers. Still, a large-displacement engine usually ends up being bigger and heavier than one of small displacement, which makes it harder to fit under the hood,and does unfavorable things to weight distribution. A smaller, supercharged engine can provide similar power with less bulk and somewhat lower average fuel consumption and carbon dioxide emissions. In addition, some countries levy prohibitive tax and licensing surcharges on cars with large-displacement engines, making a smaller displacement, supercharged engine much cheaper to buy and operate.

Furthermore, any existing engine design can only have its displacement increased so much without a major redesign, so the addition of a supercharger or turbocharger can be a useful way to pep up an existing engine that has reached the limits of its growth potential. It’s a relatively easy “bolt-on” power increase that doesn’t require a vast amount of engineering work.

Q: Why don’t superchargers produce maximum boost all the time? What’s “turbo lag?”
A: The amount of boost any supercharger produces is dependent on the size and rotational speed of its impeller(s) as well as the type of compressor it uses. (For example, centrifugal superchargers, whose output increases proportionally to the square of the rotation speed, are most efficient at high speeds, while Roots-type superchargers are most efficient at lower speeds.) The peak operating speed of a typical automotive supercharger is more than 30,000 rpm — for some turbochargers, more than 100,000 rpm. The compressor does not produce its full boost until the impeller has reached that speed.

Let’s look at a specific real-world example: the belt-driven Paxton Model SN supercharger used on Studebaker’s R2 engine and offered as an option on some GT-350 Mustangs. Described in some detail in the July 1966 issue of Car Life, the Model SN was a centrifugal supercharger with an impeller 5.8 inches (147 mm) in diameter, geared to rotated at approximately six times the speed of the engine crankshaft. It produced its maximum boost, 5.0 psi (0.35 bars), at an impeller speed of just under 30,000 rpm, corresponding to an engine speed of 5,000 rpm.

What about at lower rpm? As we mentioned above, in a centrifugal supercharger, the boost is proportional to the square of the rotation speed. If the supercharger produces 5 psi (0.35 bars) of boost at 5,000 rpm, reducing engine speed by half would reduce boost by a factor of four, which in this case would be about 1.25 psi (0.09 bars). Halving engine speed to 1,250 rpm — just off idle — would yield only about 0.31 psi (0.02 bars) of boost.

What did that mean in practical terms? When the supercharger was making full boost, it provided a significant amount of extra power, on the order of 20-30%. At very low speeds, however, boost was negligible, probably not enough to make up for the power used to run the compressor. This was borne out by contemporary road tests of the supercharged GT-350, which found the supercharged car no faster than its normally aspirated counterpart under about 40 mph (65 km/h), but noticeably quicker to 60 mph (97 km/h), with significantly higher trap speeds in the standing quarter mile (0-402 meters).

Turbochargers, which usually use centrifugal compressors, have the same limitations as other types of supercharger, further complicated both by the turbo’s higher peak speeds and the fact that the speed of the impeller is dependent on the speed of the exhaust stream rather than engine speed. Unlike an engine-driven supercharger, the turbine speed isn’t fixed; it varies with throttle position (among other things).

At steady cruising speeds, the turbine is often spinning well below its boost threshold — that is, turning too slowly to provide any boost. When you press the gas pedal the speed of the exhaust gases increases and the turbine begins to accelerate, but there’s a delay while the turbine overcomes its own inertia and accelerates (spools up) to peak speed. Since that peak speed is usually quite high, this produces a brief but annoying delay, known as turbo lag or boost lag, where not only does the turbocharger not produce any extra power, it actually reduces output slightly because of the increased back pressure the turbine creates in the exhaust stream.

The severity of turbo lag often depends on how much boost the turbocharger produces. More boost requires either a bigger compressor — which has more inertia — or a higher operating speed, either of which take longer to spool up. Engineers have developed various tricks to reduce turbo lag, including reducing the mass of the turbine blades, changing their shape to improve their acceleration, and even adding movable nozzles that change the direction at which the exhaust stream hits the turbine blades, depending on their speed. (Porsche recently introduced a “variable geometry” turbo system, claiming it to be a first, but Chrysler and Honda had conceptually similar — albeit short-lived — systems back in 1989–1990.) Some sports cars have also used two or more sequential turbochargers of different sizes, a smaller turbo offering good low-speed response and a bigger one that takes over to provide maximum boost at higher speeds. The limited-production Porsche 959 used sequential twin turbos, as did the third-generation Mazda RX-7 and fourth-generation Toyota Supra Turbo.

Reducing turbo lag is easier with turbochargers whose maximum boost is relatively low; the “light-pressure turbochargers” used by some Saab and Volvo engines, for instance, don’t produce a great deal of boost, but they have little lag and a fairly linear power curve.

A more complex alternative is a two-stage turbo-supercharger, which uses both an engine-driven supercharger and a turbocharger in sequence. The supercharger is designed to produce its maximum boost at low speeds; at higher speeds, a clutch disengages the supercharger and the turbocharger provides the boost. This was not uncommon on aircraft engines in the 1940s and Volkswagen recently reintroduced the concept with its “twincharger” engines, used on some European Polo and Golf models.

Q: Are there other disadvantages of superchargers and turbochargers?
A: Definitely. The most obvious are cost and complexity. Aside from adding a bunch of extra parts to the engine (which means more to break), the moving parts have to be precisely machined and quite strong. Turbochargers require fairly exotic materials to withstand both the high temperatures of the exhaust system and their very high operating speeds. Forced-induction engines need to be well lubricated as well, and they tend to put a big strain on the engine’s oil system, requiring good-quality oil and frequent oil changes to avoid a build-up of sludge.

Another potential problem is detonation. If you increase the pressure of the intake air, you also increase its temperature. When the mixture enters the cylinders it is compressed before it burns, raising its temperature even further. If the mixture is too hot, it may be prematurely ignited by hot spots within the combustion chamber (this is called detonation, preignition, or knock). Detonation can cause severe internal engine damage. To reduce the risk of detonation, forced-induction engines often have their compression ratios reduced so that the pistons do not compress the mixture as much prior to burning. This avoids detonation, but it means that the engine’s power output is reduced, particularly when the supercharger is not producing much boost. Many forced-induction gasoline engines require higher-octane fuel, which is less susceptible to knock, but costs significantly more.

As we’ve mentioned above, superchargers consume a certain amount of engine power even when they aren’t producing useful boost. Turbochargers increase back pressure in the exhaust, which also costs power. The compressor can also create a certain amount of internal drag at low speeds. At maximum boost, the increased power provided by the compressor far outweighs these parasitic losses, but they make the engine less efficient off-boost.

Superchargers and turbochargers also take up a little more space in the engine compartment and add a certain amount of weight. These penalties are modest compared to the benefits (bolt-on superchargers typically weigh less than 50 pounds and fit fairly easily under the hood), but they’re not negligible.

Moral of the story: there is no free lunch.

Q: What’s an intercooler?
A: As we said, increasing the pressure of the intake air raises its temperature, which is really not desirable. Not only does it increase the risk of detonation, it lowers the density of the intake charge, which starts to defeat the whole purpose of supercharging. There are several tricks that can reduce that temperature. One is to inject a little bit of liquid (such as water or alcohol) into the intake manifold; some of the thermal energy of the compressed air then goes to vaporizing the liquid, reducing the air’s temperature. Another method is to add an intercooler, which is a heat exchanger — basically a small radiator — that removes some of the heat from the pressurized air before it enters the engine’s intake manifold. A properly designed intercooler dramatically reduces the intake air temperature, avoiding detonation and, as a bonus, increasing the density of the intake charge. Intercoolers aren’t generally necessary for low levels of boost (less than about 5-6 psi/0.3-0.4 bar), but they’re virtually mandatory at very high boost pressures.

Of course, adding an intercooler further increases cost, complexity, mass, and bulk. The heat the intercooler extracts also needs somewhere to go. If it’s an air-to-air intercooler, it needs a good flow of cooling air; if it’s an air-to-water intercooler, the engine needs a bigger radiator to cope with the extra heat added to the engine’s cooling system.

Q: How long have superchargers and turbochargers been around? Did Saab invent the turbocharger?
A: The Roots-type compressor has been around a lot longer than the automobile — that type of blower was patented back in the 1860s for mine shaft ventilation and the first patent for an automotive version was filed by Gottlieb Daimler (of Daimler-Benz fame) in 1900. Rudolf Diesel patented the supercharged diesel engine in 1896 while the centrifugal supercharger was patented by Louis Renault in 1902. The turbocharger, meanwhile, was invented by Alfred Buchi and patented in 1905. Turbochargers were used on diesel engines starting in the 1920s, but the difficulty of manufacturing turbines able to reliably endure the higher exhaust temperatures of gasoline engines kept turbochargers from wide use on petrol engines until the mid-1930s. Turbochargers became common on aircraft engines shortly before and during World War II.

Every so often you’ll find someone on the web claiming that Saab offered the first production turbocharged gasoline engine, which is simply not true. Turbocharged race cars began to appear in the early 1950s, but the world’s first production car with a turbocharged gasoline engine was the 1962 Oldsmobile F-85 Jetfire, followed a few weeks later by the Chevrolet Corvair Monza Spyder. The Jetfire turbo lasted only two years, the Corvair turbo for four, but both beat Saab by more than a decade.

Turbochargers are nearly universal on modern diesel engines, but forced induction for petrol engines has fallen in and out of favor over the years. With increased political pressure for better fuel economy and reduced carbon dioxide emissions, however, turbos are again becoming common. In fact, some engineers think that light-pressure turbochargers will eventually become standard on gasoline engines, just as fuel injection has. Predicting the future of this industry is always a dicey proposition, but at least for the present, forced induction is an increasingly popular solution to the always-tricky problem of extracting big-engine power from smaller, less-thirsty engines.

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Add a Comment
  1. does either one s/c or t/c consume more gas then the other?

    1. A supercharger will usually burn more fuel overall than a turbocharger. The reason is that gear- or belt-driven supercharger consumes a substantial amount of engine power — in some applications, more than 30 hp at high rpm — all the time, whereas the turbocharger consumes less power when it’s not in boost. Naturally, there are a lot of different variables, and the turbocharger may consume more fuel when it’s in boost, but in general, the supercharger creates greater mechanical drag and frictional losses. This is why turbochargers are much more common for street cars than superchargers, although new tricks to reduce the parasitic losses of superchargers may shift the balance somewhat.

      In full-boost, flat-out driving, the turbo is less thirsty than a supercharger, but as the owner of any Subaru WRX will tell you, if you spend a lot of time on the throttle, a turbo can be very, very thirsty indeed.

  2. Is there an aftermarket turbo for the Chrysler 3.5 L engine?

    1. As far as I know, there is not, but I’d suggest asking the folks in the Allpar forums (at

      They would probably be able to tell you.

  3. Would you happen to know if there is an aftermarket turbo or supercharger for the 3.0L V6 found in a 2003 Mitsubishi GTZ? Or who I could ask? Or someplace to find a suitable super or turbo for the engine? Thanks

    1. I don’t know — sorry!

  4. Do you think supercharging be achieved effectively with bottled oxygen enhancement used at near maximum throttle for an extra boost in performance in conjunction with larger high speed jet?

    1. I’m not sure I understand the question: Do you mean, “Would bottled oxygen added at WOT create a supercharging effect?” Or, “Could bottled oxygen be added to a supercharged engine for additional power?” In both cases, the answer is “Maybe?” In the first instance, it would depend how and under what pressure the oxygen is added to the mixture. In the second instance, I suppose it would be comparable to using nitrous oxide in a supercharged engine. I’m not at all qualified to comment on how well either would actually work in practice, whether it would risk serious engine damage, or if it would present a fire hazard — you’d probably need to talk to a competent professional race builder about actually doing something like that.

  5. I have a 1999 Chevrolet Suburban 2500 with a7.4 vortex motor I use to tow a trailer with 2 cars on it, what would be the best setup, using a turbo or turbos? And what would be the best configuration?

    1. I’m really not qualified to offer technical advice on vehicle modifications — sorry!

  6. Typically, what is the temperature of the air leaving a turbo-charger and entering an inter-cooler?

    1. That isn’t a simple question. It depends on the outside air temperature and pressure, the efficiency of the compressor, how much boost it’s producing, and a number of other factors (such as how much the ambient air is being heated en route to the compressor).

      There are a number of online calculators for estimating those and other turbocharging parameters if you want to play around with the variables to see their effects.

      1. Thanks, Aaron. Yesterday I did read that the temperature can be as high as 350 F. so I see I cannot use flexible pvc like I first thought.

  7. Long time reader, first time responder. Thanks for all the well-researched articles and sharing your wealth of knowledge. One minor correction, though. The twin turbos in the VG30DETT-powered second-generation Nissan 300ZX are not sequential, they’re T25/T2 hybrids in parallel, each feeding the opposite cylinder bank’s intake. I tried to find a source more authoritative than “I’ve driven mine for 19 years and 288K miles”, but the best I came up with is [the Technical School forced induction page].

    1. Thanks for the correction — I’ve amended the text.

  8. can I twin turbo a 1.8? It’s currently in a 1998 Audi A4 and already has a turbo aswell. I only ask because I want to make one of the Quattros a little rally kinda sleeper. Thank you!

    1. I’m afraid I’m not qualified to give technical advice — sorry!

  9. Hello Aaron Severson,

    My name is sricharan, i am from India. I would like to get some suggestion about the centrifugal supercharging on small engine car, i am talking about a 800CC normally aspirated petrol engine, what parameters should i consider before selecting a supercharger which would be safe to run on such a small engine. can you suggest me some thing, if not it would be very great if you could advice a book or a website where i could find this technical information. Thank you sir

    1. Hi Sricharan,

      I’m really not qualified to offer any kind of technical advice. I understand the basic principles of supercharging, but I’m not an engineer or a mechanic and I don’t have the kind of information you would need for that. Sorry!

  10. What is responsible for the introduction of the turbo boost at a prescribed rev range
    ie the nissan standard SR 20 has the turbo affect coming in at 3000rpm. Since modifying the engine with cam upgrades,valves,pistons and exhaust upgrades the power boost now only comes in at 5000 rpm. Why?

    1. George,

      I’m not qualified to provide any specific advice on modifying or repairing engines, but speaking generally, the boost produced by a turbocharger is proportional to exhaust gas flow — not engine RPM, as is the case with a supercharged engine. Generally, altering an engine’s breathing by adding bigger valves, a more open exhaust system, a high-lift camshaft profile, and so on allows greater high-RPM airflow (and thus more power) at the cost of reduced intake and exhaust velocity at lower speeds. Since the turbocharger uses exhaust gases to spin the turbine, such changes are naturally going to alter the boost curve accordingly. Again, it’s not like a mechanically driven supercharger, where the turbine is geared to the engine’s crankshaft speed rather than being driven by exhaust gases.

      1. An engine is a vacuum pump, hence nearly all the factors that contribute to volumetric efficiency also apply to forced air induction. The CFM, PSI induction pressures, displacement, air flow friction, both intake and exhaust, exhaust pressure, cam height and duration, cam timing, low internal engine masses and weight, low internal engine friction, and throttle opening, all effect power and torque. The engine itself in design is limited by angular momentum of the crank, inertial mass of rods and pistons,and cam and factored and calculated by the metallurgy of materials used in the engine. Once an engineer calculates the destruction point based on tensile strength of the engine( Red Line RPM) a program is calculated in conjunction with the turbo chargers or superchargers to regulate internal pressures. The air and CFM going into the intake ports is regulated by Air Flow Meters going through the induction system from the outside. Internal turbo pressure is regulated by waste gates, and relief valves. Theoretically a turbo will continue producing power to the limit of the angular momentum of the turbine and compressor where a supercharged device will fall off considerably past a certain RPM, due to Crankshaft friction loss and the much larger veins of the compressor within the supercharger itself. Everything is regulated by the CPU of modern day engines, depending on the demands of the engine at the time, air flow , temperature, Vacuum, exhaust gas recirculation, load etc. So generally what is being discussed is generally true, but the chip and other engine management controls must match the size of the blower, which ever one you use so the blower can also match the demands of the engine at the time for maximum efficiency and emissions , along with durability concerns. It is very possible to produce 100 percent more power and torque of an engine, but even with better oils today, the extra top end pressures of the engine can reduce the engines ability to produce the same efficiency of power and durability over a sustained period of time.

  11. Is there a supercharger available for a Lexus ls430 v8?

    1. I know there was a TRD supercharger for the 1UZ-FE and 2UZ-FE, but I don’t know how well it’d work with the 3UZ. I believe there was a Greddy kit as well. I have no actual experience with any of these and I’m not able or qualified to tell you any more about them than that they exist. Sorry!

  12. Hey
    It would be great if u could comment about the changes that has to be made in the ignition timing for a naturally aspirated si engine which is to be supercharged… I’m well aware that it depends on individual engines.. I just need to know to what extent the ignition should be advanced or retarded(I strongly believe it shld be advanced since more fuel air mixture gets into the cylinder.. ) I’m talking about an engine that is carburated doesn’t have an onboard ecu or electronic

    1. I’m afraid that would end up sounding perilously like technical advice, which I’m not qualified to offer. It’s not a simple question, since it depends on the compression ratio, the turbocharger A/R ratio, how much boost you’re using, how aggressive the timing curve is to start with, and whether you’re using any other tricks like water injection (see 1962-1963 Oldsmobile F-85 Jetfire). Short of some complex mathematical modeling that’s certainly beyond me, about the best you can do short of trial and error is find people you trust who’ve built turbos or superchargers for similar applications and see what they recommend.

      As for advancing versus retarding, all I will say is that you might want to keep in mind that electronically controlled engines with knock sensors manage detonation (which can be a real problem with forced induction) by retarding the ignition timing as soon as the sensors detect spark knock. So…

  13. excellent Article !

  14. I am getting ready to buy a new 4Runner Limited (AWD/4Wd, 2015/2016 ?), I have the opportunity with the purchase (after purchase, but part of the after purchase package) to add a supercharger, years ago I had a turbo on a Subaru… it was fun, but I found myself being too lead footed as I liked the sound of the spooling up…. it ended up being terrible on fuel, so I am focusing on the supercharger…. I live in Phoenix which is 900 feet+ in elevation and it HOT during the summer…. aside from the obvious power increase, my in interest is better economy and power on demand…. I have noticed in the greater Phoenix area during the summer time… my various cars are kind of doggish in operation…. hot air and higher altitude, what I am trying to do is offset that by jamming more air in and end up with something that resembles reasonable fuel economy with normal driving… I have had my hot rods, now it’s time for a sleeper with some extra bells and whistles. TRD offers a nice roots blower that I am interested in….
    Thanks for your thoughts on this matter.


  15. Pls sir,what is the amount of fuel and air that goes into the chamber for combustion?

  16. Aaron,

    While the term inter cooler is loosely throw about in the vernacular an inter cooler is technically placed between super chargers. Two stage superchargers where used in some WWII aircraft engines to give added boost at high altitudes and the charge from the first stage was cooled before it entered the second stage. What most of us have, whether roots type or centrifugal as in a turbo are charge air coolers. My EcoBoost 3.5 has an air to air charge air cooler, as it is referred to by Ford. Tomtomz roots type if he indeed opted for it has an air to water charge air cooler mounted under the what in the ’50’sand ’60’s at least was commonly called a blower. Toyota’s charge air cooler for the 4.0 V-6 uses a system separate from the engine cooling system.

    Newer designs have virtually eliminated any perceptible turbo lag. Going back in time to in head exhaust manifolds has allowed turbos to be mounted directly to the head which I assume helps them spin up with less lag as they are closer to the exhaust valve, offers a shortened heat path and more receptive media for that heat ( Al vs air) for the exhaust turbine and increases exhaust velocity. Computer control of throttle valves has also played a big part as well as computer controlled blow off valves to eliminate over run where boost pressures don’t drop in direct response to throttle closure. These and other refinements of turbocharging have the motorcycle industry where turbo lag and overrun doomed the turbo bikes of the 1980’s looking at turbos again.

    1. I’m as willing to be pedantic about terminology as anyone, but in this case, I don’t think the use of the word intercooler is wrong; the definition has simply evolved since World War II. Of course, an intercooler in the modern automotive sense is certainly a charge air cooler, but I would consider that more a definition or description than a more technically correct term. It’s comparable to the word turbocharger as an alternative to “exhaust-driven supercharger.”

      Turbocharger and supercharger applications have certainly come a long way. Aside from the factors you mention, another consideration is that knock sensors, precise electronic ignition control, and particularly the adoption of direct fuel injection for gasoline engines have greatly reduced the need to sacrifice off-boost power for on-boost survival. It’s not like 35 years ago, when turbocharged engines had to use lower compression ratios and sacrifice a bunch of spark advance so they wouldn’t blow up under boost. Modern OEM turbochargers benefit greatly from being carefully integrated with the rest of the engine management system; we’re not to the point that engineers at Saab (among others) once predicted, where turbochargers are simply taken for granted on all engines, but it’s getting there.

  17. Up to what point can a Naturally Aspirated engine handle the stress of adding turbo or supercharger? Is it pretty much “time will tell?” I am in the planning stage of adding a turbo on a NA 3.7 V6 engine and i was wondering if i should be saving more money just in case things break earlier than i would expect.

    1. Joe,

      I’m not a mechanic or engine builder, so I’m not qualified to tell you how to modify your engine or how much boost it can take. The latter is always going to be a difficult question and will vary considerably depending on the engine and the application.

      Keep in mind that there are many different kinds and areas of stress, including direct mechanical strain (breaking a con rod or something like that), the adequacy (or lack thereof) of lubrication, and heat-related stress. The latter can involve water, oil, or both. One of the potential issues of forced induction is that it dumps additional heat into the oil, sometimes in areas the stock oiling system wasn’t designed to handle; if you look at the sorts of modifications manufacturers make when developing a turbocharged or supercharged version of an existing engine, you’ll notice that sometimes those involve revisions to the lubrication system, either to help cool certain parts or to improve circulation in certain areas to discourage coking in that spot.

      Manufacturers have the great advantage of being able to do extensive testing to figure out what the weak spots of an engine are likely to be, even if that means blowing up some engines — something I assume you want to avoid! The best I can suggest is to talk to others who’ve done similar installations and see what kind of issues they’ve run into.

    2. You can actually research everything you are wanting to know on the internet as I did and found that even though I have a naturally aspirated 7.3 diesel that if I add a turbo that does 10 lbs of boost or more that it would lift the heads on my engine and break the head bolts and to be honest there truly are more certified people to answer questions that this redundant person can’t answer anything

      1. This is not a forum for modification or repair advice and I have never represented it as such. Indeed, given the number of times I’ve clearly said that I can’t help with that kind of stuff, I’m puzzled that people keep asking. Even if I were qualified to advise people on repairs or modifications, which I am not, I’d shy away for legal liability reasons.

  18. On a small block Chevy is it capable to install a supercharger and still have powersterring and altinator I’m talking like a 6-71 supercharger with the big belts. If so is there a kit for them or something thanks

    1. I can’t help with parts or modifications, sorry.

  19. Any redundant person knows how a supercharger or turbocharger works and to be highly educated on them and to have a forum for them you should actually learn a few things about them like take a 1988 f250 truck with a non turbo diesel (or naturally aspirated 7.3 v8 diesel engine) I do know that if you add a turbo without doing a bunch of internal work then it can’t even produce 10 lbs of boost without lifting the heads and breaking the head bolts so please learn something more than just how they work and no I don’t need a response as I myself am not a certified mechanic but I do know how to research what I am looking for but I do have knowledge of mechanic work as to the fact that I have several race cars that I rebuild every year and I did stumble across this forum trying to find out if it is even remotely possible to add a supercharger to my diesel truck

  20. People…..REALLY? It seems that most of the people posting questions here are on the WRONG FORUM! General informational questions from people who have already done their application-specific homework and have an understanding of what they are trying to accomplish belong here. If you had a thought 10 minutes ago starting with ” I wonder…” GO DO YOUR HOMEWORK IN A VEHICLE-SPECIFIC FORUM!!!! Any additional questions may be answered here for general direction once you’ve figured out what direction you are going and what the specific limitations of your vehicle’s engine are. I have been working on a NeonSRT4 since 2004 and found the information here enlightening, but this isn’t the place for me to look for specifics on my project. Just general guidelines to make sure I’m still headed in the right direction. Please keep this in mind, and the best of luck with your current project! :-)

  21. a vsl which one is design kort nozzel system vls l 41m. b. 9m. d .4.5m.
    gearbox ratio 5.65:1 but the dockyard adviser remove the kort nozzel system fitted open propeller didnot modify neither gear ratio nor mian engine(1360BHP) like this vsl being prepared finally went to sea but failed to reach the rated rpm when the vsl in trawling mode(mid water system) engine cannot reach is rated rpm because the propeller overpeached and getting the all enigne parameters above the maxm.
    say exhaust temp mix. 500 but engine getting more than recommended 600
    rest of the other parameters like this
    So im thinking to add intake manifold centifugal blower snd check the propeller pitch wheather it is over pitched or not if like this canot perform csn i suggest to chnge the gearbox ratio 7;1 because the propeller orginally kort nozzel design thats why for open propeller 7;1 gb rstio will be up to the mark pls give me a suggestion

    1. I’m sorry, I’m really not qualified to give any kind of technical advice.

  22. plz tell me which one run first supercharger or engine…

    1. Most superchargers rely on the engine for motive power — a belt- or gear-driven mechanical supercharger is driven by the engine in the same manner as a power steering pump or air conditioning compressor while a turbocharger is driven by exhaust gases. An electric supercharger (that is, one where the compressor turbine is run by an electric motor) isn’t as directly operated by the engine, but since power for the motor still ultimately has to be supplied by the engine (if only in the sense of recharging the battery), that’s sort of hair-splitting. So, broadly speaking, the answer would be “the engine.”

  23. can i use supercharger in toyota 5a engine , which model of supercharger should be better and what other parts should be added in my car (ae91) ,,, how much horsepower can i get from it , and is it cost much fuel, can i run it in natural gas

    1. As I’ve told other posters repeatedly on this thread, I can’t advise anyone on modifications or repairs. There was a factory supercharger for the 4A-GE engine, but how well it would work for a 5A I don’t know.

  24. Can a turbo be mounted further down the exhust system to reduce heat?

    1. I suppose, but you’d also lose exhaust gas velocity that way, so it would be less efficient.

      1. Do you have to adjust the pump after turbocharging an disel engine

        1. I would presume so, but I can’t advise you on modifications or repairs, sorry! (I’m not at all qualified for that.)

  25. Hey Aaron.I have a Lexus IS250 and I install a supercharger kit I bought from USA called LMS.I m on stock exchast and the car was running great but during my summer vacations the spark plug melted and burned one of my valves.I fixed everything again but I want to ask you if the stock exchast has something to do with what happened.Does a supercharger set up need certainly an Exchast?The car is running 7psi and I use AEM water meth kit as well.I installed an AEM AFR gauge and I see 12,5 max at wot.The car was running great until summer.I m in Athens Greece and it s very hot in Summer.All I want is your opinion about the stock exchast .I don’t want noise that’s the reason I didn’t change it.Do you think that exchast caused it?Thank you in advance

    1. An engine-driven or electric supercharger doesn’t necessarily need a special exhaust manifold or exhaust system — certainly not in the way a turbocharger does — although depending on how much boost it produces, it may need some means to avoid detonation. I’m not able to offer repair or maintenance advice, sorry!

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