Supercharger Performance and Engine Performance Parts

Posts Tagged ‘Lysholm’

Technorati Tags: exhaust, header, Lysholm, Mazda, Renesis, RX8

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

Building on the beautiful high revving v8 powerplant, MTM motorsports upgrades the performance, looks, styling, and handling of the 4.2 Audi RS4.

The heart of the upgrade package is a Lysholm twin screw compressor elevating intake pressures to a modest 6 psi. This fairly low boost pressure means that the engine’s static compression ration can be left untouched and that the supercharger package can be a true ‘bolt on’ affair. Following through with this ‘bolt on’ strategy, MTM have coupled the supercharger with an integrated top mount intake manifold with integrated air to water intercooler courtesy of Laminova intercoolers. Also in the mix is an MTM bolt-on cat-back exhaust system exiting in an exotic dual dual (that’s four outlets) 3″ tips.

The car is further enhanced with suspension modifications, lowering, lightweight body parts rounding off the performance package.  The result of all of this work is shifting power up from 420 hp @ 7800 rpms to 540 hp @ 8220 rpms. Torque is amplified from an original 317 ft lb , 430 Nm @ 6000 rpm to a new 412 ft lbs, 560 Nm @ 3700 rpms.

The attention to sound engineering design in this kit (using a twin screw supercharger, coupled with an integrated manifold and integrated intercooler) resulting in short intake path lengths, means that the whole package is both still highly throttle responsive as well as having more power delivery on the top end. Not only is it impressive that the car gains over 120 hp with this modification, but more impressive is that the power band growns from 1800 rpms on the stock high-revving V8 to a very meaty 4500 rpms between peak torque and peak power. This not only makes the car faster in a straight line, but makes it much more versatile on exiting corners and carrying its hefty weight and the weight of the AWD Quattro system in the lower rev range.

See the car in action

Find out more directly from MTM motorsports

Technorati Tags: Audi, exhaust, Intercooler, Lysholm, MTM, PSI, RPM, v8, VAG

If you’re a car geek like myself, then some cars (although modestly powered) will still interest you because of the sheer amount of theory and technology jammed into them. One such car is the mid 90s to early 20s Mazda 929S (AKA the millennia, the Sentia).

The car is powered by a small but very efficient Miller Cycle 2.3 liter 60* V6. The engine utilizes the miller combustion cycle in which the horsepower losses associated with the first half of the compression stroke (when the piston is much closer to bottom dead center), by keeping the intake valve open. Obviously on a typical 4 stroke motor the open valve would allow the air from the previous stroke (the intake stroke) to escape causing a loss in power, but in the miller cycle the air stays trapped in the cylinder and is rather compressed to 2.0 atmospheres due to a roots type supercharger boosting the engine to 14.0 psi. Once the piston rises up in the cylinder bore to a more efficient location, the valve is closed and the piston completes the compression stroke on its own. The short duration of the compression stroke means that the use of high boost and higher compression ratios are possible and the final configuration with 10:1 compression ratio and 14.0 PSI of boost produces a peak of 210hp @ 5300 RPMs and 210 ft-lbs at 3500 RPMs.

The car was quite impressive for its time with a supercharged V6 capable of a 0-60 time of 8.4 seconds, a top speed of 142mph in a luxury sedan, all the while still maintaining a minimum of 20mpg in the city and as much as 28 mpg on the highway; quite impressive to say the least.

Introduction of the Lysholm/IHI supercharger

A cutout view of the Millenia Lysholm/IHI charger, notice the inlet restriction and the tiny throttle body.

Because of the space and packaging limitations on the front wheel drive V6 Mazda motor, Mazda outsourced the development of its supercharger on this car to well know Japanese turbocharger manufacturer IHI, who worked in conjunction with Lysholm Technologies – the twin screw supercharger manufacturer from Sweden to produce the unit used on the Millennia.

According to contact between enthusiasts and Lysholm engineers, the unit on the millennia is closest in specification to the Lysholm 1200AX which moves 1.2 liters of air per revolution and has a maximum operating pressure ratio of 2.2 or 17.5psi and a peak flow of 635 CFM or in other words 423 horsepower @ 17.5psi!

The main difference between the Lysholm 1200AX and the Lysholm/IHI on the Mazda is the design and compactness of the new housing, the design of the housing inlet on the Mazda looks like a significant restriction point (especially since the air passing through it is not yet compressed) and there is potentially a significant power gain to be found by upgrading the supercharger inlet to with a larger throttle body!

intercooler System

As we mentioned previously in our post on intercoolers, typical intercoolers have two main modes of operation:

1- Heat sinking, by maintaining themselves at a much lower temperature than the inlet air charge, and thus being able to extract a significant amount of heat out of the inlet air charger in a very short period of time.

2- Radiation, of the absorbed heat either by being placed in the direct path of the air stream or in a circulating coolant bath for air to water intercoolers.

An engine shot of the KJ-ZEM engine showing the small front intercooler and well as the ram air guide for the rear intercooler.

 The Mazda uses two very small intercooler cores located on top of the engine inside the engine bay, and uses plastic air ducts to try and guide some air into the intercooler to radiate excess heat. However, knowing that their intercooler cores are not that large (for the power of the engine) and knowing that the supercharger produces more heat as its revolutions increase, then Mazda rather than fitting larger intercoolers or a front mount or fender mount intercooler with access to plenty of fresh air, have fitted their car with an intercooler bypass valve. The bypass valve, bypasses the intercoolers below 4000 RPMs and at low throttle openings to try and keep the coolers from being utilized and keep them as cool as possible, to allow them to work effectively (primarily as heat sinks because of where they are located) when they are needed above 4000 RPMs. I guess this kind of design works, but it’s definitely not optimum for peak power production, and for sure, when performing long repeated full throttle pulls back to back, the bypass valve will have no opportunity to operate and the intercoolers will have no opportunity to cool down. Eventually the intercoolers will heat soak and the power figures will drop from the advertised 203 hp dramatically.

Autospeed's dyno of the motor showing the sharp torque drop off at higher rpms...

If you think this is just internet theory, check out this article by autospeed where they have dynode the KJ-ZEM and the intercoolers heat soaked after a short 10 second run.

Based on the most conservative estimates based on the torque peak on that power run, if the torque peak is held to 5300 RPMs, the car stands to make at least 235hp @ 5300 RPMs which means we have at least an easy 35hp to gain on this car with some modifications.

In autospeed’s dyno run they made 196 horsepower with an outlet temperature rise of 75*C, the car also stands to make at least an additional 7 horsepower from better intake cooling.

Exhaust system:

As mentioned in our previous post about basic supercharger performance upgrades: One of the most important parts to inspect when looking to upgrade your supercharged car is the exhaust system. For the duration of time that the engine is in overlap (where both the intake and exhaust valves are open) then any exhaust pressure will work against your supercharger on a 1:1 basis.

How so? If you are in overlap and you have say 5psi of exhaust back pressure and 15psi of supercharger boost pressure, then the resultant pressure differential between your supercharger and your cylinder is only 10psi, and so your power boost from using a supercharger at that point is reduced from 100% down to only 68%. We can see this effect clearly on the falling torque readings on the dyno graph for this engine performed by autospeed. The loss of 35  potential horsepower translates on this setup to about 6psi of losses between the intake and exhaust system …

The 2-1 exhaust mid-pipe with the 180* bendand.

The exhaust system on this car combines short runner manifolds with no use of merge collectors, feeding close coupled catalytic converters, into a two into one mid-pipe with a power robbing 180* bend incorporated and no use of a nice y transition, into a single 2” exhaust all the way back.

Recommendations and power estimates:

I think it is possible to increase the power of this car to over the 250 horsepower mark with a few simple modifications:

1-      Since I intend to add over 50 horsepower to the car, it is advisable to use 1 step colder iridium spark plugs for better heat management, and to assure proper ignition even with the denser mixture.

2-      Replacing the tiny supercharger inlet and throttle body with a larger throttle body matched to the size of the charger housing, and redoing the complete intake system in that size. For a single inlet 250hp system an ideal supercharger inlet size would be a 78mm throttle body (or three square inch inlet) with a supercharger outlet of 58mm or 2.28 square inches. (Read more about supercharger porting here)

3-      Because of packaging restrictions on this engine and how hard it would be to completely redo the intercoolers for a single front mounted intercooler with a single inlet and dual outlets (one for each of the 3 cylinder banks). I would use a proper water / methanol injection system activated at around 4000 RPMs and above 10PSI using two 1.69 gallon per hour nozzles, one for each 3 cylinder bank.

4-      I don’t think anybody makes aftermarket headers for the millennia engine and it is a tight package of an engine. I would replace the closely coupled cats with straight down-tubes (again for 250hp the ideal collector size would be 1.87”) down either into a 1.87” to a 2.92” single exhaust with appropriate smooth transitioning y-pipe) or using a 1.87” x-pipe (for even better exhaust extraction and reduced back pressure) to a true dual 1.87” exhaust.

The cats would be a single (or dual for a true dual exhaust) cat placed after the y-pipe (or the x-pipe if a true dual is possible) and then feeding back into a high flow 2.92” muffler (or dual 1.87” inlet mufflers).

Using a better transition such as a y-pipe or x-pipe has the added benefit in that the different cylinder banks on a V style engine fire 180* out of sync to balance the engine out. The advantage of smoothly merging the exhaust gasses from the two banks together is that when using a smooth merge, the high velocity exhaust gases caused by a combustion in one bank, leaves behind it a temporary vacuum (or low pressure reflection wave) of as much as negative 2 PSI at the exhaust valve of the opposing bank. As soon as the other bank fires and the exhaust valve opens, the exhaust finds vacuum (rather than back pressure) in the exhaust runner which helps evacuate the cylinder faster leaving more room for fresh air in the next cycle and improving scavenging during overlap.

The total potential gain of a properly designed exhaust, with a ported supercharger inlet, and better charger air cooling would be about 47 total horsepower gained and boost may drop from 14psi to as low as 10psi possibly.

How is that for supercharger performance? 47 more horsepower at 4 less psi!

For more information and references:

Lysholm 1200AX supercharger

IHI Corporation

The miller cycle engine explained

Autospeed article on Japanese engines

YouTube Video of intercooler bypass valve actuator

1996 Mazda Millenia S statistics at the auto channel

Technorati Tags: IHI, Intercooler, Lysholm, Mazda, water injection