Rotrex SC from Kraftwerks
Kraftwerks is a joint venture between what used to be known as Jackson Racing and Skunk2, and Kraftwerks currently resides within Skunk2's headquarters, which is quite an impressive place. Housed within the walls of the building are a serious collection of state of the art tooling and machinery (including a full 3-dimensional rapid prototyping system), a chassis dyno, an engine dyno, a warehouse, workshop, and of course, office space. We could easily spend a full day learning about all of the resources available to Kraftwerks at this facility, but our time was limited, and we had cars to drive.
Towards the rear of the building, we found a Laguna Blue 2007 Honda S2000 sitting on Skunk2's chassis dyno. This was the same S2000 that was on display in Honda's exhibit at the SEMA show just a few weeks ago, and the reason we made the trek out to Norco. With a quick glance underhood of this S2000, many folks would fail to notice much out of the ordinary apart from an open element air filter sitting near where the factory airbox is normally located. To someone who is intimately familiar with the underhood view of an S2000, he or she will likely take note of the additional intake plumbing that snakes through the engine bay, and further notice that the serpentine belt looks somehow "different" from the factory accessory belt. And if this person spends time tracing the belt's path, eventually he or she will probably notice the extra "accessory" that's bolted down on the lower left side of the block -- this is actually a Rotrex supercharger, but Jackson has done an excellent job masking the fact that this is not a factory component.
What the heck is a Rotrex?
Some of you may remember from our 2006 SEMA coverage that Oscar announced that he was working on a line of supercharger kits featuring Swedish-made Rotrex superchargers. Rotrex superchargers have been around a while, but they're relatively new to the US tuning scene. They are technically centrifugal superchargers, but instead of the noisy gear drives that typical centrifugal superchargers employ, Rotrex uses a traction drive system that spins the impeller at more than 3 times the rate of a traditional centrifugal supercharger. This means the compressor side is churning at roughly the same rate as that of a typical turbocharger (90000-100000 rpm), and for this reason the Rotrex uses a compressor design that is very similar to a turbocharger's. One of the upsides of the Rotrex is that it is capable of developing rather high levels of boost without suffering from the thermal transfer issues of an exhaust-driven turbocharger.
Detuning for reliability
Oscar was actually tuning the S2000 at Church Automotive Testing. With the configuration they were testing, the car put down 387whp on Church's Dynapack dynamometer. On Skunk2's SuperFlow chassis dynamometer with the test car's 18" wheels spinning the drums, this figure translated to 355.7hp and 236.6 lb-ft at the wheels. These numbers go well beyond what Oscar intends to offer in the base kit, so by the time we got our hands on the car in the afternoon, he had already pared around 30whp from those figures, which is still too much by Oscar's calculations. Oscar's intention is to sell a base kit that is reasonably safe to install on a bone stock S2000, and in prototyping this kit, he has observed that that the stock clutch can't transmit much more than 220-225 lb-ft. This translates to right around 300hp at the wheels, which conveniently coincides with the upper limits for the stock fuel injectors.
The test car we sampled was running an upgraded ACT clutch and 550cc/hr injectors. The ACT's clutch capacity wasn't discussed, but on the road it seemed to have no problem delivering the twist through the meaty 18's. This car feels almost exactly like a stock S2000, except the torque delivery is smoother and there's substantially more power. At lower rpms, there's a bit more juice than normal, not dramatically more, but as you toe the throttle, the power builds at an improbable rate, and very smoothly with no noticeable VTEC engagement point (thanks to the programmability afforded by Hondata). This smooth progression in power delivery means that there are absolutely traction issues, and not a single combustion event is lost to wheelspin. While the power and torque are impressive, perhaps even more impressive is how perfectly the motor runs. The car starts and idles with no hint that it's not stock. Unlike competing supercharger kits , there is absolutely no increase in vibration or harshness. The supercharger itself is somewhat audible, but compared to the whining, moaning and groaning of other supercharger systems, this one operates at a whisper. In between shifts, you can hear a slight chatter from the blowoff valve, but that's one of the few external clues that this car is packing a formidable forced induction punch. Launching the car is easy, but combining the AP2's short and tight gearing with the lightning-fast spool up of the supercharged F22c means that your right arm and left leg are kept plenty busy working the gearbox and clutch. We can't wait until Kraftwerks adapts this system to work with an AP1 S2000 - the 9000rpm redline and slightly taller gearing should be an even better match for the system.
Drawbacks?
For turbocharged motors, this is turbo lag, heat soak (inconsistent power), and springy throttle response. Supercharged motors generally are noisy, coarse, and have a heavy flywheel feel (because while the motor is generating a lot more power, it's also fighting a lot of drag from the supercharger itself). Could it be better? Sure,wondering aloud whether the bottom end and mid-range could be further enhanced by bumping up the boost curve (smaller pulley) and then simply bleeding boost on the top end. This would also make it easier to upgrade the car in stages without physically altering the kit itself. But make no mistake, as it is, this kit is really a win-win. You get substantially more urgency from the motor without making any sacrifices in terms of driveability, refinement, responsiveness, and hopefully, reliability. And unlike some other aftermarket power-up upgrades where the additional power completely overwhelms the chassis, the Kraftwerks set up meshes so perfectly with the S2000, it could very well have been developed by a team lead by Uehara-san himself.
Details
Unofficially, this kit should be available for around $6500 with sales starting sometime in early 2008. The good news is that Oscar has also developed a kit (using a slightly smaller Rotrex unit) for the Honda Fit. Oscar says it's very much like the S2000 kit in terms of how well it works.
http://www.kraftwerksusa.com/
Towards the rear of the building, we found a Laguna Blue 2007 Honda S2000 sitting on Skunk2's chassis dyno. This was the same S2000 that was on display in Honda's exhibit at the SEMA show just a few weeks ago, and the reason we made the trek out to Norco. With a quick glance underhood of this S2000, many folks would fail to notice much out of the ordinary apart from an open element air filter sitting near where the factory airbox is normally located. To someone who is intimately familiar with the underhood view of an S2000, he or she will likely take note of the additional intake plumbing that snakes through the engine bay, and further notice that the serpentine belt looks somehow "different" from the factory accessory belt. And if this person spends time tracing the belt's path, eventually he or she will probably notice the extra "accessory" that's bolted down on the lower left side of the block -- this is actually a Rotrex supercharger, but Jackson has done an excellent job masking the fact that this is not a factory component.
What the heck is a Rotrex?
Some of you may remember from our 2006 SEMA coverage that Oscar announced that he was working on a line of supercharger kits featuring Swedish-made Rotrex superchargers. Rotrex superchargers have been around a while, but they're relatively new to the US tuning scene. They are technically centrifugal superchargers, but instead of the noisy gear drives that typical centrifugal superchargers employ, Rotrex uses a traction drive system that spins the impeller at more than 3 times the rate of a traditional centrifugal supercharger. This means the compressor side is churning at roughly the same rate as that of a typical turbocharger (90000-100000 rpm), and for this reason the Rotrex uses a compressor design that is very similar to a turbocharger's. One of the upsides of the Rotrex is that it is capable of developing rather high levels of boost without suffering from the thermal transfer issues of an exhaust-driven turbocharger.
Detuning for reliability
Oscar was actually tuning the S2000 at Church Automotive Testing. With the configuration they were testing, the car put down 387whp on Church's Dynapack dynamometer. On Skunk2's SuperFlow chassis dynamometer with the test car's 18" wheels spinning the drums, this figure translated to 355.7hp and 236.6 lb-ft at the wheels. These numbers go well beyond what Oscar intends to offer in the base kit, so by the time we got our hands on the car in the afternoon, he had already pared around 30whp from those figures, which is still too much by Oscar's calculations. Oscar's intention is to sell a base kit that is reasonably safe to install on a bone stock S2000, and in prototyping this kit, he has observed that that the stock clutch can't transmit much more than 220-225 lb-ft. This translates to right around 300hp at the wheels, which conveniently coincides with the upper limits for the stock fuel injectors.
The test car we sampled was running an upgraded ACT clutch and 550cc/hr injectors. The ACT's clutch capacity wasn't discussed, but on the road it seemed to have no problem delivering the twist through the meaty 18's. This car feels almost exactly like a stock S2000, except the torque delivery is smoother and there's substantially more power. At lower rpms, there's a bit more juice than normal, not dramatically more, but as you toe the throttle, the power builds at an improbable rate, and very smoothly with no noticeable VTEC engagement point (thanks to the programmability afforded by Hondata). This smooth progression in power delivery means that there are absolutely traction issues, and not a single combustion event is lost to wheelspin. While the power and torque are impressive, perhaps even more impressive is how perfectly the motor runs. The car starts and idles with no hint that it's not stock. Unlike competing supercharger kits , there is absolutely no increase in vibration or harshness. The supercharger itself is somewhat audible, but compared to the whining, moaning and groaning of other supercharger systems, this one operates at a whisper. In between shifts, you can hear a slight chatter from the blowoff valve, but that's one of the few external clues that this car is packing a formidable forced induction punch. Launching the car is easy, but combining the AP2's short and tight gearing with the lightning-fast spool up of the supercharged F22c means that your right arm and left leg are kept plenty busy working the gearbox and clutch. We can't wait until Kraftwerks adapts this system to work with an AP1 S2000 - the 9000rpm redline and slightly taller gearing should be an even better match for the system.
Drawbacks?
For turbocharged motors, this is turbo lag, heat soak (inconsistent power), and springy throttle response. Supercharged motors generally are noisy, coarse, and have a heavy flywheel feel (because while the motor is generating a lot more power, it's also fighting a lot of drag from the supercharger itself). Could it be better? Sure,wondering aloud whether the bottom end and mid-range could be further enhanced by bumping up the boost curve (smaller pulley) and then simply bleeding boost on the top end. This would also make it easier to upgrade the car in stages without physically altering the kit itself. But make no mistake, as it is, this kit is really a win-win. You get substantially more urgency from the motor without making any sacrifices in terms of driveability, refinement, responsiveness, and hopefully, reliability. And unlike some other aftermarket power-up upgrades where the additional power completely overwhelms the chassis, the Kraftwerks set up meshes so perfectly with the S2000, it could very well have been developed by a team lead by Uehara-san himself.
Details
Unofficially, this kit should be available for around $6500 with sales starting sometime in early 2008. The good news is that Oscar has also developed a kit (using a slightly smaller Rotrex unit) for the Honda Fit. Oscar says it's very much like the S2000 kit in terms of how well it works.
http://www.kraftwerksusa.com/
Originally Posted by Popeye,Nov 22 2007, 05:42 PM
The good news is that Oscar has also developed a kit (using a slightly smaller Rotrex unit) for the Honda Fit. Oscar says it's very much like the S2000 kit in terms of how well it works.
Not something I'd seriously consider for the S, but the Fit could use the extra horses.
JonasM
My motor build will only cost me around $10,000 for my turbo setup. However, with that setup I will have somewhere around 500whp, and be able to get more by simply turning the boost up. I would never pay $6,500 for a bolt on SC kit that will give me somewhere around 300whp. Why not buy a Vortech or used Comptech for way cheaper and still have 300whp? If a supercharger makes too much noise for you, you might want to think about just buying a civic hybrid.
Originally Posted by toofast4yalll,Nov 25 2007, 12:21 PM
My motor build will only cost me around $10,000 for my turbo setup. However, with that setup I will have somewhere around 500whp,
Who's doing the machine work and engine build ?
What turbo kit?
What engine management system?
Who's tuning it ?
What kind of fuel pump and injector size ;plus what size fuel line?
Are you upgrading the clutch and rear diff ?
Do you have an endless supply of rear tires ?
Inquiring minds want to know.
I though you already had a turbo, and the head gasket blew. So now it is on your buddy's CRX?
[/QUOTE]Haha I figured you would say that Popeye. However, having a 500+ hp real wheel drive car with no radio or A/C and a bike isn't really practical. If it rains or snows I'm still stranded and I have 2 expensive toys to insure and maintain. The turbo stuff was sold last week to my friend Martin. He had a CRX with an F20C putting out well over 600hp, now he's getting an S2000 to do the build on. Yes part of the money from selling the turbo is going to a matching Arai helmet and Joe Rocket leather riding jacket (Repsol jacket of course). I guess I realized how much money was going towards the project, and a $12,000 bike straight off the showroom floor would still walk all over any turbo S. This bike with a lot less money in it will run low 9's and be capable of 200mph. I will be sure to post pics when I pick it up.[QUOTE]https://www.s2ki.com/forums/index.ph...ost&p=10558394
BTW, how's that bike working out for you?
Back on topic, This looks like another nice option for those of us with enough money to have something different. I'd like to see what the efficiency curves look like, and how much boost this thing could put out if the motor were correctly built from the bottom up. Would make for one hell of a launch with ZERO turbo lag.
[/QUOTE]Haha I figured you would say that Popeye. However, having a 500+ hp real wheel drive car with no radio or A/C and a bike isn't really practical. If it rains or snows I'm still stranded and I have 2 expensive toys to insure and maintain. The turbo stuff was sold last week to my friend Martin. He had a CRX with an F20C putting out well over 600hp, now he's getting an S2000 to do the build on. Yes part of the money from selling the turbo is going to a matching Arai helmet and Joe Rocket leather riding jacket (Repsol jacket of course). I guess I realized how much money was going towards the project, and a $12,000 bike straight off the showroom floor would still walk all over any turbo S. This bike with a lot less money in it will run low 9's and be capable of 200mph. I will be sure to post pics when I pick it up.[QUOTE]https://www.s2ki.com/forums/index.ph...ost&p=10558394
BTW, how's that bike working out for you?
Back on topic, This looks like another nice option for those of us with enough money to have something different. I'd like to see what the efficiency curves look like, and how much boost this thing could put out if the motor were correctly built from the bottom up. Would make for one hell of a launch with ZERO turbo lag.
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Originally Posted by JonasM,Nov 23 2007, 12:29 AM
Interesting. If I'm not mistaken, there's a guy on this board (JDMChris) who has a Fit that was the test mule for the supercharger.
Yup.. JDM Chris started a thread a while back in regards to this kit. There is a lot of info (and of course, a lot of
). $6500 though.. 
https://www.s2ki.com/forums/index.php?showtopic=525647
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