Posts Tagged ‘twincharging’

The Nissan GT-R is designed to be a Porsche killer. Being the flagship of all Nissan (and currently all Japanese Supercars), it has claimed that it runs a Nurgurg Lap faster than a standard porsche 911.

To add insult to this injury, tuning camp “Power Enterprise” has embraced this new beast and twincharged it. Wait! I stand corrected … They have successfuly QUAD CHARGED it.

I really feel like i’m no longer talking about cars, maybe I’m really writing about Intel quad core xeon processors.

The core of the twincharger kit is a pair of Rotrex C30-94 Superchargers which are EACH rated for 44 psi peak and a peak of 600cfm (400hp) when injesting ‘free air’. The thing is, these chargers here are installed inline, with the factory IHI turbochargers feeding the inlets of the Rotrex Superchargers.

To do this, the kit comes with a new intake plumbing kit including proper T-bolt clamps to make sure everything is secure in the engine bay under pressure. New high flow air filters feed uncompressed air to the factory IHI turbochargers, then the air is routed out to the 2.40″ inducer of the Rotrex C30-94 where it is compressed even more. The highly volatile and doubly -- compressed mixture is then routed to a pair of front V-mounted intercoolers and then directed to the intake manifold.

The whole setup also utilizes a power enterprise Kevlar accessory belt to prevent belt slip and belt stretch at higher rpms, which maintains full boost and full efficiency from the Rotrex Superchargers.

Keeping the entire mix under control is a new piggy back style ECU called the P-Map which over-rides factory ignition timing and fuel delivery, but also has the capability for more advanced features such as nitrous additional injection maps, and launch control settings.

Once the mixture is consumed by the monsterous engine, it is expelled through a 100% Titanium with an 89mm (3.5″) mid section feeding into dual 70mm (2.75″) outlets.

The result of this mix is a power hike from around ~500 crank hp to a dyno proven 640+ WHEEL hp which is a healthy gain of over 200 hp on an already insanely fast car.

Technorati Tags: exhaust, GTR, Nissan, Power Enterprise, Rotrex, Tuners, twincharging

The whipple 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 whipple screw clearly showing how the lobe from the three lobe screw tightly fits between two lobes from the 5 lobe screw to compress the air for inter-screw compression.

The secret to this style of ‘hybrid’ blower is the two intermeshed rotors of different lobe numbers (see illustration). 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. 

So how is the whipple best used. Some people are interested in SIGNFICANTLY boosting their small displacement motor to make it not only have better low rpm torque but also unrestricted peak RPM power. In two of our articles (one, two) we have talked about how you can combine a typical roots style charger for low rpm instant boost, with a high rpm solution of turbocharger or even a centifugal supercharger that is sized proparly to elevate your motor to the required peak psi -- that above which your typical roots style supercharger may not be able to provide effeciently.

Well here’s the whipple solution. If you use a whipple charger, then you have the best of both worlds, you have a positive displacement charger that has no spool up lag, as well as internal compression allowing you to achieve high PSI levels without the need to for overspeeding your blower to do so. 

So, with the use of a whipple charger you can have a fairly flat torque curve from zero to redline giving you very predictable traction and launch control (which is why whipples and other screw type chargers are popular in drag racing or coming out of corners in road coarses). A predictable and linear torque curve also is more forgiving to overgeared cars and more forgiving with different driving styles. 

A video of a whipple-charged GT-500 mustang and dyno showing the infamous flat torque curve…

Here is an overview of whipples available chargers:

For more Information please visit:

Whipple

Technorati Tags: CFM, effeciency, Rotor, twincharging, Whipple

Our last articles about combining supercharger performance with turbocharger top end seems to have found some online appreciation. So, I’ve decided to write up a step by step on how to do the math for twin-charging your own car.

I’m going to start with a typical compact car engine, such as the Toyota Celica 2.2 liter 5sfe engine. The engine makes 135 hp at 5200 RPMs with a 6200 RPM redline.

For starters, every horsepower requires about 1.5 CFM of air (depending on the air density).

So 135 naturally aspirated hp requires a flow of 202 CFM at pressure ratio of 1.

The pressure ratio is the ratio of turbocharger or supercharger boost pressure divided by atmospheric pressure. Each 1 atmosphere is equal to 14.7psi of pressure… thus:

PR = (14.7 + Boost pressure)/14.7

So for a normally aspirated car: PR = (14.7 + 0) / 14.7 = 1.

Supercharger calculations:

Using 14psi as our target boost (and the maximum safe boost we’d want to extract out of a roots style supercharger) we get the following pressure ratio:

PR = (14.7+14)/14.7 = 1.95

New expected horsepower level: old HP * pressure ratio

New HP = 135 * 1.95 = 263 HP

New CFM = 227 * 1.5 = 395 CFM.

So now, we have our supercharger flow requirements, we need a supercharger able flow 395 CFM at a pressure ration of 1.95 (or 10psi).

Going through different Eaton supercharger maps I had available I find one available option:

1-      The third generation M62 or the fourth generation MP62 are capable of producing 395 CFM @ 1.95 PR @ 13,000 RPMs.

My final expected hp is going to be less than the original estimate263 for two reasons:

1-      The supercharger requires 35 hp to drive it at 13,000 rpms.

2-      The outlet temperature (if not managed through a proper intercooler) is going to be 88*C higher than the inlet temperature, and with every 13*C by rule of thumb costing us 1 hp of power, then 88*C would equate to a power loss of 7 hp.

Our final supercharged power figure (with no intercooler and no other bolt-ons) is

Final hp = (original hp * pressure ratio) – supercharger drive power – (delta T (Centigrade) / 13)

Final hp = 263 – 35 – 7 = 221 HP

Supercharger Dynograph:

14psi Eaton M62 on a Toyota 5sfe

More power can be made between 5000 and 7000 RPMs with bolt on modifications designed to shift the power peak to the right, mainly cams with longer duration, and properly designed headers.

With this graph it is clear that the power of superchargers is mimicking a 95% larger motor by providing linear boost across the entire RPM range. This makes the engine feel like a much larger engine which is great for OEM applications.

Turbocharger:

As we’ve seen in our previous calculations, it takes 35 horsepower to drive our M62 to maintain 14psi of boost on our motor. Because of this horsepower requirement, we find that with superchargers there is a point of diminishing returns when talking about higher boost and flow levels.

Now if my ultimate horsepower goal is 320 horsepower for this motor, then let’s do the math:

Pressure ratio = 320 hp / 135 hp = 2.37

Solving for boost: 2.37 = (14.7 + boost)/ 14.7

Boost = (2.37*14.7)-14.7 = 20 PSI

CFM requirement = target hp * 1.5 = 320*1.5 = 480 CFM ~= 33 lbs/min

(Some turbocharger compressor maps are graphed in CFM vs PR, some are in lbs/min vs PR, 14.47 CFM = 1 lbs/min depending on air temperature and density).

So to find a turbocharger that will give me my target HP goal, I need to find a turbocharger that has the point 480 CFM of flow at a 2.4 pressure ratio on its map.

Now I’ve done this search before so I know that the best turbo for this engine is a T3/TO4E 46 trim…

VERY IMPORTANT: Other trims of this compressor such as a 50 trim a 54 trim a 60 trim or a 60-1 trim, although they do have more CFM flow capacity, they cannot produce those CFM’s at the pressure ratio that I’m looking for. This is why you REALLY need to check your engine demand and flow requirements on your turbocharger compressor map. If your engine needs cannot be plotted on your compressor map then it’s not a proper turbo for your motor and it may never spool or create boost. A smaller turbo with a taller map (rather than a wider map) that produces less peak CFM, but at a higher pressure ratio, may be more adequate for your sized motor. Bigger is not better you really have to choose the right turbo for your application.

By starting with 2.4 PR and plotting my flow requirements at that pressure ratio on my compressor map I find that this motor is a good match for my engine, it will be fully spooled to 20 PSI by 3000 RPMs! It is also capable of supporting my peak power requirement of 480 CFM @ 2.4 pressure ratio at its peak efficiency of 76%. This means that the turbocharger outlet temperatures will be acceptable, since it is working within its peak efficiency and thus should be most power friendly.

Note: Again, I already knew this was a good turbo for this motor because I’ve been through this process before, if you’re doing this for the first time you want to plot your engine demand requirements on several different compressor maps, and compare both spool (the minimum RPM that the engine will make your peak boost at) and your compressor efficiency at peak demand to make sure that the turbo you choose will spool early and give you good power efficiently at higher rpms.

Now for the three rpm points that are not on my compressor map, I iteratively reduce my pressure ratio, recalculate my CFM flow requirement at that pressure ratio, and look to see if I can plot that point on the compressor map. Essencially I am trying to find the maximum boost that chosen turbocharger can support at that engine RPM.

Here are my results:

One thing to note here, my turbocharger can no way produce any boost for this motor below 2000 RPMs. At those lower RPMs the turbo is more a drag on the engine trying to spin itself up to its operating RPM to produce enough CFM to pressurize the engine. In a typical turbocharged application it is good to use a bi-directional bypass valve (rather than a unidirectional blow off valve) because the valve will bypass the turbocharger at lower RPMs feeding the motor directly from the intake system. This will prevent the unspooled turbo from choking the motor, and also help the motor produce more horsepower at lower RPMs which will help spool the turbocharger faster by providing more exhaust gasses to the turbines side of the turbocharger to spin it up.

As you can see the major difference between our supercharger and turbocharger is that our supercharger was able to produce boost at any rpm, but did not shine at higher RPMs where it’s efficiency and required drive power increased. On the other hand, our turbocharger is unable to produce any power boost (but rather a power drag) at lower RPM’s trying to spool up, but it shines at higher RPM reaching its peak efficiency at our power peak.

Once the turbocharger is fully spooled, the wastegate begins to open bypass the turbine restriction on the exhaust, which means there is virtually no horsepower loss driving the turbocharger at this point. As far as thermal losses are concerned, I went and factored in the turbocharger efficiency and outlet temperatures, and if the system is un-intercooled, the turbocharger is only costing us 9hp at peak power due to its outlet temperatures.

So the final HP figure = original hp * pressure ratio – temperature loss

Final HP = 135 * 2.4 – 9 = 315 hp.

Turbocharger Dyno Graph:

TO4E 46 trim @ 20psi on a 5sfe motor

As you can see the turbocharger produces a non linear power graph that is heavily weighted towards higher RPMs providing us with no power advantage at lower RPMs.

The thing to note here is that I started with a car with a low redline of 6500 RPMs and a great turbo for it. As the engine’s peak rpm gets higher and as our peak power target gets higher into 400 and 500 hp range, the choice of turbo to support those power figures will be larger, and naturally the power graph as well as the first RPM that the turbocharger will spool at will all shift to the right another couple of thousand RPMs.

The higher your HP goals, the more need there will be for twin-charging, because you will be using a larger turbocharger that takes more RPM and more exhaust gas to be able to spool and create positive boost for the motor.

Twin-charged:

Now if I overlay the two charts on top of each other we can see the potential benefit of twin-charging:

Twincharged 2.2 litre engine

As you can see, until the turbocharger has spooled, the supercharger provides us with 15 more horsepower and possibly more if the engine were not completely stock, or we had higher power aspirations and used an even larger and later spooling turbocharger.

The other advantage will not show up on a dyno chart, if you’re doing 50mph in top gear (5^th or 6^th gear) then the amount of time you spend going from 1500 to 2500 RPMs may be a very long time at such a long gear, even though it seems like a small part of the dynochart posted above compared to the 3000 RPM’s of turbo goodness above 3500, it will be a significant disadvantage during a quick passing attempt where you are left without any boost. Now being twincharged, no matter what the RPM and what the situation, when you stop the gas you will get a power boost to help you pass. If you stay in the gas (to go from a pass to a full on drag race) then the RPMs will rise, the turbocharger will come online and carry you through impressively to your redline in a flash… This is also a huge advantage on the track coming out of corners in the wrong exit gear.

Now do this for your own cars… if you need help with it leave me a comment.

You can easily find compressor maps for your chargers using google image search…

Other twin-charger articles:

The Twin-Charged Hyper Car

Twin-charged Performance

Technorati Tags: boost, compressor map, pressure ratio, Supercharger, turbocharger, twincharging

If you’re interested in turbocharger and supercharger cars, then look no more!

The Spanish have a saying about the world cup:

“In the world cup, everybody plays, but Germany always wins”.

This theme of Jealousy from the “German Machine” extends to other countries in Europe as Germany is an uncontested leader in EU manufacturing. One such example is a small Danish design and engineering firm that just released their first super car!

Introducing the ZENVO ST1:

I’m not sure what the brand name Zenvo stands for? Does come from a state of Zen that you reach being one with your machine? Does it come from novas or newness and innovation ? Or does it come from ENVY!

I think it must be the latter for sure as why should Bughatti be the only European manufacturer delivering a road going supercar delivering over 1000bhp! Now Bughatti is an Italian brand but it is no secret that Bughatti is now managed by VAG (Volkswagen Audi Group) who are the visionaries of the Veyron and it’s 400kph jaw dropping performance.

The ZENVO ST1 leaves the supercar market behind and enters the market as a Hyper Car, the term until 2009 that was exclusively reserved for the quad turbocharged 0-60 in 2.8 seconds Bughatti Veyron. The ZENVO does rely on boost to make a mind boggling amount of power, but rather than a 16 cylinder engine and four turbochargers, the ZENVO relies on a unique combination of a good old V8. The 7.0 liter eight cylinder engine draws its support from two battalions, one is a supercharger to boost low end power performance (as if the torque of a 7.0 liter V8 was not enough), and a turbocharger to carry the car the car all the way through the rpm range and with a healthy dosage of boost up to its peak of 6900 RPM.

The result of all this mayhem is 1104 hp @ 6900 RPMs and a terra shattering 1054 ft.lbs of torque @ 4500 RPMs!

Beyond being a hyper-car the ZENVO is also a street worthy car coming in complete with navigation, xenon headlights, adjustable racing seats, adjustable ground clearance between 105 and 150mm to help navigate speed bumps, and a Heads Up Display with an integrated G-Meter.

The car although it has all the amenities you could want in a  road car, is also very aware of its race car nature and is fitted as standard with exotic parts like CARBON WHEELS, in addition to the typical racing gear such as the built in roll cage with 4pt safety harness, racing style light steel structure, & Carbon-fiber panels.

Find out more about these Hyper Cars here:

ZENVO ST1

Bughatti Veyron

Technorati Tags: Bughatti, carbon fiber, OEM, Supercharger, twincharging, VAG, Zenvo

The first time I ever heard of twin charging (using both a turbocharger and a supercharger on the same motor) was probably back in year 2000. At that time I was very interested in performance for the Toyota Celica and naturally I also read a lot about its sister cars (that shared some of the engines) such as the Camry and the MR2.

One of the most interesting aftermarket parts I ran across at the time was the HKS turbo kit for the 4AGZE powered 1^st generation mr2. The 4agze (for those that are not familiar with Toyota engines) is a peppy 170 horsepower 1.6 liter engine powered by the Toyota SC-12 roots type supercharger. On this car Toyota used an electromagnetically clutched supercharger that could be disabled during low power requirements such as cruising, and engaged when the user demands it.

One of the most important parts of the HKS kit is the bypass valve. This valve was used to direct air from the supercharger to the engine at lower rpm/flow points. Once the rpm’s rise, and the engine starts to demand more air, and the turbocharger is fully spooled, the valve switches over gradually till the turbocharger alone is feeding the engine while the supercharger is completely bypassed.

The theory behind this kind of system is to use a small positive displacement (roots style) supercharger. Supercharger performance efficiency is typically its highest at lower engine and supercharger rpms (for example from idle to 4000 rpms). Above 4000 rpms the supercharger’s performance and efficiency starts to drop, the horsepower required to drive it starts to rise exponentially, and the air temperature coming out of the supercharger starts to rise dramatically limiting performance.

On the other hand, using a generously sized turbocharger will allow us to feed the engine efficiently with cooler air (than that from an overworked supercharger) and maintain high rpm performance. The problem with using a larger turbocharger is that a generously sized turbocharger typically doesn’t spool before 3000 to 4000 rpms giving us a limited power band and thus providing no performance boost at lower rpms.

The idea of twin charging is to use both a supercharger and a turbocharger to have each one do what it does best, have the supercharger boost the motor for low end torque, and as it runs out of steam, the turbocharger comes online to carry us through to redline.

There are three aspects to these types of systems that make them prohibitive to most tuners:

1. Cost and complexity: Having a complete supercharger system as well as a complete turbocharger system on the same time is a lot of money to spend and a lot of parts to deal with and diagnose in case something goes wrong.
2. The bypass valve used to bypass the supercharger (and yet hold in all the air pressure coming from the turbocharger) as well as being able to control this valve electrically or mechanically requires a custom made one off valve that isn’t quite available off the shelf.
3. Since we are using two different types of chargers with two different efficiency maps, it can get very complicated to figure out how to tune the motor (especially with much simpler fuel injection systems that were used at the time) because the air density can vary dramatically at the same rpm point and pressure level depending on which charger is feeding air to the motor and at what proportion. This is also where the HKS turbo kit for the 4agze was at its weakest, namely at smoothing the transition point fueling between the supercharger to turbocharger switchover.

However, what is interesting to me, is that even with the advent of more efficient superchargers (such as the 4^th generation eaton chargers with coated rotors, higher tolerances, and lower friction drives capable of extending their working rpm range from 12000 rpms up to 16000 rpms), and with the availability of faster spooling turbochargers such as dual ball bearing turbochargers, or VTN (variable turbine nozzle) turbochargers that some people still attempt to turn twin-charger theory into practice.

Here are three examples:

Alta’s Turbo System for the 2002 to 2006 Mini Cooper S

“The Alta Mini Performance Twin-Charged Turbo kit for the Mini Cooper S features a Garrett GT3071R turbo capable of producing up to 400 horsepower! “

“Alta includes a 5% larger supercharger pulley in the kit to reduce the supercharger boost output. By pushing more boost through the turbo and less through the supercharger, the kit increases in efficiency and produces more power reliably.”

As I mentioned earlier, one the main things to understand about these systems is how the different chargers have different efficiency ranges, and based on that, require precise tuning especially at higher boost levels. But unlike 10 years ago, the technology is now available where you could very easily purchase install and tune from scratch a standalone engine management system within a week.

“A fuel computer such as the Turbo XS D-Tec or the Apexi SAFC are both simple options for fine-tuning your fueling. For those looking to take things further, Hydra EMS and Alta have developed a Standalone Engine Management system designed for use with this kit.”

The Twincharged 350z

“An ORC supercharger takes care of the low rpm boosting while a large Blitz/KKK K5 turbine comes into play at higher revolutions. The result? Power all the time with an impressively immediate throttle control. The engine remains completely standard, but even the low boost setting that is currently being used now is enough to develop an impressive 550 PS and a very full torque curve that peaks at 60 kgm.”

With these kinds of systems, the driving feel and engagement from the noise of the engine by is something that can’t be explained or debated over the internet like the ongoing debates of ‘fast spooling turbocharger vs twin-charger vs highflow ported superchagers’:

“The immediate acceleration and lack of lag are what first surprises; there is no trail off of low-down torque or high-end power, and the boosted V6 seems to pull all the time in any gear. It’s almost electric in character. There are all sort of noises being made: supercharger whine, large turbo spool up, an exquisite exhaust note and external wastegate chatter when you lift off the throttle.”

ford Mustang Turbo Kit – The Hell Raiser !

Like I stated earlier, one of the complexities of twin-charging is sourcing a reliable bypass valve and controlling it for a smooth transition between supercharged and turbocharged power delivery.

One solution to this problem is sequential-charging where the supercharger outlet feeds the inlet of the turbocharger or vice versa. The advantage of this type of system is that low boost settings (for example a boost setting of 7psi for the supercharger which is a pressure ratio of 1.5) and a boost setting of 7psi for the turbocharger waste gate which again is a pressure ratio of 1.5) results in more than 14psi as the resultant pressure ratio is 1.5*1.5 = 2.25 which is around 18psi so that neither the supercharger nor the turbocharger has to carry the full load of boosting the engine up to a pressure ratio of 2.25. For the mustang for example, combining a factory set 6.5psi of superchager boost with turbochargers set for 13psi we get a combined 24.4psi of boost.

“The secret is compound boost and water/methanol injection. The Hellraiser kit uses two 61mm Turbonetics turbos that blow into the stock Cobra supercharger. The turbos send 13 psi of boost through an air-to-air intercooler and then to the blower, which compounds the boost to 24.4 psi and pushes it through the stock intercooler (which is mounted directly under the blower) and into the engine.”

The disadvantage of a this kind of a system is that if the turbocharger has outlet temperatures 60 degrees above ambient, and the supercharger has outlet temperatures 80 degrees above ambient, then the combination of two chargers in series (rather than having them in parallel with a switchover bypass valve) results in that the air entering the engine can be as high as 140* above ambient temperatures which is horrible for performance unless you have extremely high octane gasoline or a really low compression ratio boost friendly motor.

In addition to using TWO intercoolers to cool the charge down, the hell raiser kit also uses water injection to further reduce the air temperatures and increase the effective octane rating of the motor’s fueling:

“To allow that kind of boost and power safely on pump gas requires a Snow Performance water/methanol injection system, which Hellion set up with six nozzles firing into the induction tube just before the blower, and they are fed by three pumps and an 8-gallon fuel cell mounted in the trunk. Without the methanol injection, the system can still make nearly 1,000 hp, but the engine is on the ragged edge of destruction.”

This may seem like a lot of work and complexity, but if you think about what it takes to buy a 1000hp car then you’re looking at one of either a Bughatti Veyron, or a Hennessey Venom-1000 SRT-10 Viper, or an extremely modified car (such as a Toyota Supra, Skyline GT-R, Turbocharged M5, or Turbocharged corvette). To be able to buy this kind of power in Kit form is truly a feat of engineering and goes to show the time and effort that Hellion Power Systems has put into developing this kit.

Find the complete articles here:

Alta Turbocharger Kit for the Mini Cooper (discontinued)

Twincharged 350z – Turbo Magazine

Hellraiser by Hellion Power Systems

Technorati Tags: mustang, tuner, twincharging, water injection