Supercharger Performance and Engine Performance Parts

Posts Tagged ‘Displacement’

Here are two interesting articles on updating your already supercharged ride:

1- This article looks at replacing the older generation 1.7L Kenne Bell twin-screw with a larger 2.1L charger. The articles goes inside the charger to show you the differences and similarities between the older and newer supercharger head units. The icing on the cake is the final dyno run showing the differences between the 2.1L and the 1.7L chargers.

MMFF – Supersize Me

Read the rest of this entry »

Technorati Tags: Displacement, eaton, Kenn Bell, mustang, snout pulley

The Lysholm / Autorotor Supercharger is a unique and very practical chager. The unit is a great compromize between a positive displacement supercharger (that creates boost pressure by over pumping and over feeding the engine with air) and a compressor (similar to a turbocharger) that compresses the air inside the supercharger housing before sending it out to the charger piping.

The unique three-five design of the twin screw chargers relies on a 3 lobe and a 5 lobe rotor intermeshed to capture the air flowing into the supercharger for inter-screw compression. The combination of an intermeshed 3 lobe and 5 lobe rotor means that the rotors inside the housing are operating at different rpms with a ratio of 5:3 to keep the rotation of the lobes (3 lobes to 5) in synchronsim. This complex design allows the rotors to capture air (in its natural volume) from the back of the blower housing, and push it foward as the screws rotate. As the air is moved forward it is captured and compressed between the intermeshed rotors as well as being pumped (in positive displacement) from the inlet port at the back of the charger housing to the outlet port near the front.

Because of this unique design, screw style chargers are able to outperform simpler rotor based chargers in two aspects:

1- The blower is able to acheive a higher pressure ratios because the compression is combined between positive displacement (overfeeding) and between direct compression of the air (inter-screw compression).

2- Since the air is compressed inside the housing, the housing is able to ingest and move more air (higher CFM ratings) for a similarly sized roots style blower.

These kinds of superchargers boast great adiabatic efficiency of up to 68% while at the same time being able to deliver that high efficiency at high boost levels of up to 18 psi. With such a high potential peak boost level, these chargers are capable of matching the top end delivered by a typical turbo system, without the lag and throttle delay disadvantages of spooling a turbo. Because of the positive displacement nature of this charger, the charger will always be able to make boost at any rpm so long as they bypass valve is closed.

Some applications for this unit include the OEM install of 1.1Liter Lysholm / IHI hybrid in the Mazda Millenia motor.

Other kits include the BBM upgrade kit for the Volkswagen Corrado. The kit replaces the G20 centrifugal supercharger with the lysholm twin screw system. As you can see in the dyno below, the twin-screw outshines the smaller centrifugal unit both in the lower rpms and in the top end and this exactly the result of the inter-rotor compression keeping flow and efficiency up to par at higher rpms while positive displacement fills out the low rpm torque.

Here is an overview of Lysholms available chargers:

Lyshom	pressure ratio	Boost	CFM	HP	effeciency	displacement (liters)
1200 AX	2.2	18	636	424	64	1.2
1600 AX	2.2	18	848	565	66	1.6
2300 AX	2.1	16	1059	706	65	2.3
2300 R	2.2	18	989	659	68	2.3
3300 AX	2.2	18	1236	824	66	3.3
3300 R	2.2	18	1236	824	66	3.3

For more Information please visit:

Lysholm

BBM

Technorati Tags: Autorotor, boost, CFM, Displacement, Lysholm, pressure ratio, Rotor, supercharger performance, VAG

This is the triple distilled guide on engine performance parts to help you make the most power with the least effort. There’s an abundance of bolt on and custom application engine performance parts available for any vehicle, and the internet is full of advice, trials, and feedback from enthusiasts, brand promoters, magazine editors, and even racers about which performance parts are best for your car. 

Engine performance hinges on one of THREE general factors:

1-      raw power factors

2-      efficiency factors

3-      Power boosters

3-      Power Boosters:

Typically called forced induction, power boosters include serious modifications to your engine that can result in a 30 to 400% power increase while maintaining the same raw power and efficiency figures (i.e. at the same peak rpm and with the same displacement).

Because of this serious increase in power, power boosters are the great equalizer that allows smaller engines to simulate and exceed the performance of a much larger engine. Originally these technologies were developed for conditions where more power was needed with a limitation on the physical dimensions of the engine. A prime example for this would be requiring more horsepower for a plane that would see most of its usage in high altitude thin air. The engine for this type of aircraft faces the difficulty of having to carry its weight and still maneuver with high performance and accuracy, which places maximum weight and size requirements on the engine and complete aircraft. Furthermore, the engine would have to operate efficiently and produce power in thin air which is less dense and thus less oxygen rich making it have less power potential.

After time these technologies moved into automotive racing and from there into aftermarket modifications and finally into production automobiles.

There are three types of Power boosters I want to mention here:

Engine Compression ratios:

Some may argue that this is an efficiency modification, but since this modification actually ADDS more horsepower rather than freeing up system inefficiencies I have chosen to set it apart here.

The addition of 1 compression point typically results in a 4% power increase and reduced fuel consumption. Bumping up a car’s compression ratio from a typical 9:1 compression ratio to a more performance oriented 15:1 for example is a potential power increase of 24%. I don’t think this kind of power increase can be considered an ‘efficiency’ upgrade but rather a legit power boost.

Let me disclaim here that increasing the motor’s compression ratio , as well as using all the other power booster modifications in this section, significantly increases the final combustion pressure produced inside the motor (especially when using more than one power booster in tandem), and thus there is definitely a need for:

1-      Higher octane fuel requirements to prevent preigntion detonation and reduce the speed of the flame front for normal ignition events.

2-      Heat management, through increased head cooling, using aluminum heads, colder spark plugs, and upgraded cooling system capacity to be able to cope with a significant increase in power (and its co product which is heat).

3-      A more conservative retune to a richer air fuel ratio that helps maintain stable exhaust gas temperatures that indicate a sustainable combustion process rather than an explosion occurring inside the engine

4-      A more conservative retune to for ignition timing and cam overlap that helps maintain stable exhaust gas temperatures that indicate a sustainable combustion process rather than an explosion occurring inside the engine.

Chargers (weather they are turbochargers or superchargers)

Turbochargers and superchargers intercept air in the intake system before it reaches the engine and compress it making it denser leaving more oxygen per volume of air. If the air is compressed to half its size for example then we will be able to fill a 2.0 Liter engine with 4.0 Liters of air per revolution. If we also make available double the fuel injection coupled with proper tuning, then we can successfully produce double the horsepower because there is literally twice as big a combustion occurring inside the engine.

Of course under normal conditions the engine would never breathe 4.0 Liters of air on its own, and thus charger works as a pump that keeps the engine pressurized by overfeeding or force feeding it with more air than it would have ingested under normal conditions.

The term boost or ‘psi’ (pounds per square inch) is a measure of how much pressure is placed on the motor and thus boost is highly related to how much more air is ingested into the motor. Every 1psi of boost is equivalent to a power increase of 7% over what the engine would make without a turbocharger, so increasing the pressure of an engine by just a few psi can show a significant increase in power and torque.

With 93 octane gasoline and proper tuning, boosting an engine to 15 to 18psi is pretty safe and thus increasing an engine’s power by 120% is not uncommon with a ‘street’ friendly turbo system. More power increases can be seen with race setups and higher octane availability.

One of the advantages of turbochargers and superchargers is that since the air is compressed (for example to half its original size at 14psi) then  a conservatively sized 45mm throttle body looks to like a 63mm throttle body from the point of view of the compressed air. In this way, turbochargers and superchargers can overcome inefficiencies in the design of the engine’s intake path because compressing the air makes it occupy a smaller volume (for the same oxygen content) which makes the intake system seem like less of a flow restriction.

This also makes some of the efficiency modifications (namely those between the charger and the intake valve) less in need of being modified as they are less of a power restriction.

Nitrous Oxide Injection

Nitrous oxide injection is similar to turbochargers and superchargers in that it delivers more oxygen to the fire in the same volume of air and thus in the same engine displacement. Nitrous oxide does this in two ways:

1-      Rather than compressing air to a smaller volume to increase oxygen density, nitrous oxide is composed of two nitrogen molecules and 1 oxygen molecule. This composition makes nitrous oxide 33% oxygen rich by volume compared with normal air which is around 16% oxygen by volume. What this means quite literally is that if we had an engine breathing pure nitrous oxide flowing at room temperatures and atmospheric pressure then the horsepower output would simply be doubled.

2-      However nitrous oxide is delivered to the engine in compressed form (as it is compressed to 1000psi when it is packaged into the bottle). Using the same formula for pressure and volume that we used for turbochargers, a 1000 psi pressurized bottle is compressed 70 times or to 1/70^th its original volume. This  means that feeding an engine purely with nitrous oxide at the temperature and pressure at which it comes out of the nitrous bottle, we could potentially produce 140 times more horsepower from that engine than we could having it breathe normal air! How is that for a replacement for displacement?

Practically speaking, nitrous oxide is usually used for a power boost of 50 to 100% depending on how prepared the engine (and the user is) for the power boost, and depending on the style of nitrous delivery (for example progressive direct port nitrous injection is the most reliable type of injection for 100% or more nitrous power boosts).

So in summary of the whole article…. Here’s what I recommend:

1-      Figure out how much horsepower you want to achieve

2-      As stated in part 1, figure out the engine combination with the highest potential that is allowable for you in the rule books.

3-      Look at how much boost you will need if any with that engine combination to reach your power goals

4-      Depending on weather you need a 20% power boost or a 200% power boost, pick your power adder (from a small compression increase, to a small nitrous shot, to a larger supercharger or turbocharger setup, to a combination of power boosters) that will allow you to reach your goals.

5-      Last (and not first), plan out the supporting and efficiency modifications that are required for that engine and power adder combination (from part two of this article). Basically you want to install the efficiency parts that will allow you to flow the amount of exhaust gas that you need at your peak power level, and optimize your entire engine package around your target peak PRM, anything else would be a waste of money.

6-      Understanding that upgrading engine efficiency is limited to a 10-20% power increase over stock as well as performing modifications planning in the sequence that I have just described, may save you TENS of THOUSANDS of dollars from being wasted upgrading a motor that just frankly doesn’t have the raw power potential (in terms of displacement, RPM or stroke) to meet your power requirements, or requires an unrealistic power boost combination (such as a 400% power hike using an exotic turbo setup) to reach the power goal requirements that you have.

I know that most of the advertising and development in performance modifications spent on things like intakes and exhausts (covered in part two of this article), but that is easily explainable:

1-      Those parts although they don’t add much horsepower to your car, are exactly what 80% of the people are willing to install on their cars because they sound cool, are cheap, may require no tuning at all, and are fairly easy to install.

2-      Those parts are also a gateway modification to more power modifications in the future, and so come at a smaller entry price and smaller install complication to get you willing to work on your car and purchase parts (basically a marketing ploy). If everyone were chucking their stock engines for a larger big block grabbed from the junkyard then all the shallow aftermarket performance companies (producing only efficiency parts) would go out of business leaving only the companies that have the depth of experience and science to build crate engines and power adder kits. So for these companies to stay profitable they need to keep you invested in your stock engine which allows them to secure their place in the industry, weather that wins you races or not.

However if you are serious about modifications, you will use my 3 piece guide to start your modifications plan with the end in mind. If you really want 700hp then you are much better off with a 500hp engine running a measly 6psi of boost than you are trying to boost a 150hp 4 cylinder to 54psi or trying to feed it 550 horsepower worth of nitrous.

Technorati Tags: compression ratio, Displacement, engine performance parts, exhaust, intake, N2O, Supercharger, turbocharger

There’s an abundance of bolt on and custom application engine performance parts available for any vehicle, and the internet is full of advice, trials, and feedback from enthusiasts, brand promoters, magazine editors, and even racers about which performance parts are best for your car. This is the triple distilled guide on engine performance parts to help you make the most power with the least effort…..

Engine performance hinges on one of THREE general factors:

1-      Raw power factors

2-      efficiency factors

3-      Power boosters

1-      Raw power factors:

There are three raw power factors that decided whether you have a good ‘platform’ to build power on or not: Displacement, RPM, Stroke. Confused? I will explain:

                A: Displacement:  The old adage: “There is no replacement for displacement”.

Displacement is the size of your engine and thus the size of your cylinders, as your engine and cylinders get larger (by swapping to a larger engine, using overbore pistons, and increasing the stroke of your cylinder) or by any other engine design (wedge or rotary or other) that gives you a larger volume engine. As you increase the volume of your engine, you have more room to fill with nice combustible air / fuel mixture, and the bigger the volume, the bigger the potential bang, the bigger your potential horsepower.

It goes without saying that if I take a 6.0 liter V8 and a 3.0 litre boxster 4 with similar design from the same manufacturer that the 6.0 liter V8 probably makes about double the horsepower of the 3.0 liter boxster 4, and so one of the oldest and most effective tricks in hotrodding (and in Reliable OEM performance packaged cars) is to stuff a BIGGER motor , in a smaller chassis.

If you’re familiar with bottom end kits including overbore pistons, stroker cranks, stroker kits, and cylinder sleeves, then all these kits work on increasing performance essencially by increasing displacement and giving you more bang (quite literally) for your block.

B: RPM (revolutions per minute):

Every time an engine fires and ignites the air fuel mixture in the cylinders, the expanding gasses of the combustion process create a force pushing back down on the piston, exerting torque on the crankshaft, and rotating the crank, the transmission and eventually the wheels giving us acceleration. Depending on weather you have a 2 stroke, or a 4 stroke (or other) the engine will fire once every 2 or 4 revolutions. So say you have a 4 stroke motor at 1000 revolutions per minute, that means that within one minute you have 250 combustion events in your motor, which delivers torque to your crank (and eventually to your wheels for acceleration) 250 times in that minute. If we go up to 2000 RPMS, the revolutions double, and so also the rate of engine firing doubles to 500 combustion events, giving you essentially double the horsepower.

So, in terms of RAW power potential, the maximum RPM that your engine can operate at, is linearly related t how much raw power you can produce.

Formula one cars (and motor cycle engines as well) have in their quest to produce the lightest yet most powerful engines they can, used engines that are smaller in size (less volume/displacement) but more than made up for the loss of displacement by revving those engines up to 18000 revolutions.

So if you’re looking at an engine swap, and you have two engines to work with of the same volume, always take the engine that has a higher safe redline, as with that car, you have more revolutions to work with and ultimately more opportunity to make power.

cams, headwork, and other such modifications work on this principal of power production by trying to shift your peak power rpm up as high as possible giving you a higher peak horsepower figure.

C- Stroke:

What I mean by stroke is not the distance travel of the piston inside the cylinder, but rather, I mean weather we are talking two stroke, or 4 stroke, or other stroke.

A 2 stroke engine fires once every 2 revolutions. A 4 stroke engine fires once every 4 revolutions. If I had two engines of similar efficiency, the same peak rpm, and the same displacement, where one was a 2 stroke, and one was a 4 stroke, the two stroke motor would produce double the horsepower of the 4 stroke motor at every rpm point, because quite literally the 2 stroke engine has double the combustion events and delivers torque to the crank (and eventually to the wheels) twice as often as a 4 stroke motor.

Now in most situations we will not be able to convert our 4 stroke engine to a 2 stroke… but If for example I had the option to use a 2.0 liter 4 stroke in my race car vs. using a 2.0 liter twin rotor rotary engine which essentially fires one time for every revolution, then using the rotary engine of the same displacement will produce FOUR times the power output (holding all else constant : displacement, peak rpm, stroke, efficiency…etc).

To summarize section 1 of this series:

If I had to choose a motor for my race car, I would open up the rule book for my racing series and look for what is allowable in terms of maximum displacement, rpm, and stroke. And I would then choose the engine where the following calculation produces the largest result:

Raw power potential = DISPLACEMENT * MAX RPM / STROKE

This simplifies comparing for example two engines that are cheaply available at a junkyard if I wanted for example to build a low buck racer:

A)     4.6 Liter ford crown Victoria V8, 4 stroke, with 6000 RPM redline.

Raw Power potential = 4.6 * 6000 / 4  = 6,900

B) 2.3 Liter Honda CRV Inline 4, 4 stroke, with 8000 RPM redline.

Raw Power potential = 2.2 * 8000 / 4  = 4,400

C) 1.3 Liter Mazda dual roter, 1 stroke , 9500 RPM redline

Raw Power potential = 1.3 * 9500 / 1 = 12,300

D ) 1.3 Liter Hyabusa Boxster 4, 2 stroke , with 13000 RPM redline.

Raw Power potential = 1.3 * 13000 / 2 = 8,450

As you can see it’s very easy to see that if allowable in the rule books, and so ranking these engines according to my preference (from highest to lowest):

Mazda Rotary >> Hayabusa Boxster >> Ford V8 >> Honda I4

Of course the gearing, gear ratios, and final drive ratios for each engine would be different to make it work for my application… but when focusing on raw power potential this is how you pick them…

Technorati Tags: Displacement, Rotary, RPM, Stroke