INSIDE A KRAFTWERKS SUPERCHARGER - Rotrex

This was a broken supercharger a customer sent to us. We've installed these but never really seen how they work.
We take this apart and explore.

[@tireflipper8000]

Once the 38R is out, pull it apart and see where the changes occurred . They are supposed to be addressing the failures associated to rev limiter /shaft issues. I would think they would make the barrel and shaft out of one billet piece rather than the current 3 piece situation and beef up the pins on the oil pump mechanism. Thanks for the breakdown!

[@WezleyB]

It's 6am here.. morning coffee and LHT is a perfect match..

[@AntonBabiy]

So simple yet works wonders! Before the cover was off I thought it would be a multistage plantery gearbox but nope, all smooth components for low noise and high efficiency. Thanks for the teardown 🙂

[@michaelovitch]

It's an epicycloidal system. The same is used on excavators and bulldozers drive trains ,but backwards,to reduce speed ,increase torque,reduce load per moving part. It's a really old design,and this one is just working on simple friction,with no teeth. If you get loose bearings,looser tolerances and no more friction,so no more spinning.

[@TheMick26]

Welcome to How Stuff Works - LHT edition.😊 Thanks for the sneak peek inside the supercharger, John and George. That was very interesting.👍 Have a great weekend, guys.

[@GazornanDSR]

Just an FYI in response to the couple of nay-sayers. I've run a c30-74 on my track-built Miata for about 8 years. 70-80k miles. Often over-spinning it in competition, 200+ dyno runs in car development. Car makes more than double the stock horspower, even with the current engine with stock internals, (unit outlasted the built race engine) Issues with mounts and tensioners (KW and TDR), but never with the unit. I'll be upgrading to a c30-94 without reservation.

[@socleanmx6]

God I love these videos!!! The attention to detail and the willingness to take risk .

[@TommyBlanton]

My Kraftwerks C30-94 failed today. Looks like the shaft that mates to the pulley failed. Can’t take it apart until I get it shipped home next month.

[@bjornmuskus634]

Inquiring minds were well fed today! Thanks for the educational upload.

[@rickschmidt210]

It's basically a Paxton SN series that uses 3 cylinders instead of 5 balls. And while the rotrext pulley turns the drum, the paxton SN pulls turns the ball carrier (piece in the rotrex that the 3 cylinders ride in). I bet it's a precise fit ,because the paxton had big springs that squeeze th barrel portion against the balls to get th traction

[@robertjordan9075]

Thanks for sharing that, I love learning about cars.👍🏽👍🏽👍🏽

[@TommyMccoyMedia]

Man I butchered my c30-94 unit on my channel lol. I took mine apart but was no where near as professional as this.Thanks for the educational upload!

[@LHTPerformance]

Tommy Mccoy lol.

[@bgh187s2k]

Specifically, what was the issue with this unit? It seemed to be in ok condition.

[@HalferLandPerformance]

Seems like the shaft that was floating (sat into) the pulley side was slipping. Watch and he says he thinks they should have pinned it or welded it. If that shaft freely spins then only it will spin and comp will not. Could be wrong but that seemed to be the one weak link

[@PhilipChafin]

I'm working on something very similar to this, but reduction. Friction/interference planetary, genius. So, the fluid lubricates, cools and provides static fluid friction...

[@mattm840]

great video. would disagree that you need a large turbo to make 350whp. that is really a drop in the bucket for most turbo honda setups. i know you guys are pretty conservative with your hp numbers/goal. keep up the great videos, would love to see more technical, in depth stuff like this.

[@T3KN0iD]

Thanx for this one...! Knowledge received.

[@hectorherbert6585]

I think what you mentioned regarding maybe a pin (or two) through the shaft is a great idea and could be done if you have the proper tools..

[@HalferLandPerformance]

That’s why I love you guys, though we have disagreed on the past. You dive in, wanting know more about what you’re doing, not just bolt stuff on and calling yourself “Car Builders”...you truly can do it all....and if you can you’ll figure it out.

[@danxta1353]

Would the barrels be able to hold enough torque to break the press fit "key"? Would there be slippage on the barrels before any breaks?

[@TreadTalk247]

Just ordered a Rotrex CCW Supercharger kit for my Gen 2 (2008) Suzuki Hayabusa!! Cait wait to run down the track w 350-400 HP at the rear wheel!!!!

[@DeathStar5]

On my old Rotrex unit. It was the impeller shaft that snapped under load.

[@johnchristopher3032]

Subscribed. Never used one of these. Looks cool.

[@SnowAmbassodors]

Ive had the sunshaft break like 3 times on my supercharger. I run 12psi on a little yamaha apex snowmobile just to get 240-245 hp

[@TommyWook]

So they work on viscous coupling of the planetary set. Interesting.

[@julianlewis632]

Thanks great information, I want to fit one on my 2012 NC Mazda

[@ricepony33]

Could internal parts be made in titanium? I can see the advantage of the weight in terms of a heavier Flywheel effect if it had a clutched free wheel design, but since it’s always connected lower internal weight would be beneficial. HKS makes a similar unit, not sure if it’s more reliable though. The issues I’ve read about seem to involve the larger compressors and rev limiter hits. I’d guess the shock sent through all those multipliers also multiples internal torque and thus damage.

[@nezabytes]

Good question.

[@gyffjogofl7676]

Best thing i have seen on youtube

[@Gadget0343]

The input shaft threads into the power transfer bar. When it is operated the input shaft tightens into the bar. This is why you never turn the pulley backwards. Doing so can damage the pump and can unscrew the input shaft from the power transfer bar. Never turn the pulley backwards.

[@Trading-Freedom11]

I have one of those in my camaro Ss , can’t wait to get 38r to come out

[@2013DArt]

thanks man I was wondering how it works I'll try to make it the unit myself

[@naturafibre7905]

I was wondering whether rotrex use planetary gear. And if they do, i considered that they have a break through, because as i remember gears have angular speed limitation. When i do my research for my thesis long time ago, i can only up to 70000 rpm impeler speed with a pair of spur gear.

[@IronmanG74]

I am looking at putting a rotrex on a classic mini as they are very neatly packaged. But as you say no one has much to say about them. Regarding the 'pressed' weak point. Maybe it's designed for that to be the weak point. If it wasn't what would break and what would the effect of that breakage be

[@MiniMattTV]

Graham Boyle keep an eye on classic mini DIY 👌🏻

[@LimitedGunnerGM]

The lack of gears and reliance on the friction modifier fluid for driving the turbine suggests that something as simple as wear in the planetary set of 0.001” would have a significant difference on the driving force.

[@Time-Trvlr]

I would describe it as a planetary without gears. Zero clearance keeps it from slipping, maintained tolerances determine its life expectancy.

[@amcluesent]

Needs EE's whiteboard to explain!

[@902Boots]

Interesting video!

[@juggsauce]

Seems bound to fail through wear. Everything is fixed diameter and over time the tolerances will fall out of spec and slip will occur. Seems like if the barrels, shaft, and ring were slightly conical and there was a spring to hold them against each other the whole assemble would hold itself in spec over time and wear.

[@n.prince2458]

👍 Impressive! Subscribed!

[@drewmorg.]

What is the downside to Rotrex, other than cost, compared to the Vortech's or more commonplace Centrifugal systems?

[@harman1967]

Maybe a splined impellor drive shaft would have cured the potential weakness within the unit, however this would have surely resulted in slightly higher manufacturing costs and been passed on to the customer.

[@danielarmenta2220]

Lo que mas me sorprendio fue los "engranajes planetarios" si asi se le pueden llamar por que no vi ningun engrene ahi pero es casi de cero ruido por lo que pude notar !!!!

[@Brunofssky]

Thanks!

[@1YouTube_you]

Fantastic supercharger! I run one on my Polaris Slingshot and I beat that thang

[@Petriilove]

En mi humilde comentario, creo yo que esos rodillos que estan dentro, funcionan como unos balanciadores y tambien gias para el eje para darle mas estabilidad al eje central y de peso para que guire constante.

[@mitreswell]

Great video demystifying what's inside them. I'm not an engineer but you'd think there'd be some cooling fins on the unit, or does it need some heat to make the oil inside function properly. I don't understand what the oil pump inside does. Is it circulating the oil through a cooler maybe, hence no need for cooling fins? It reminds me a bit of a viscous coupling, which is a dubious device in my opinion. These things seem ludicrously expensive too, compared to a turbocharger. Hard to believe D-motor use them on their aircraft engines, as they don't appear to be particularly reliable. Seems a good concept though, just needs some further refinement and development to be totally bulletproof.

[@brassmonkeegaming8583]

Rotrex use a traction fluid which also has its own resorvior, filter and cooler.

[@ViewThis.]

1:41 That red stuff is blood of the last employee who underperformed at his duties.

[@shimasaliminaeeni7793]

Thanx a lot for your good movie. Would you please inform us also about oil pump, canister and oil circuit? What type of oil pump used in ROTREX? Have a good day

[@rexdrabble4988]

I can see why they fail and I can also see the perfect solution. So simple you you will say,thats just too easy

[@R1k0_SM]

I think I'm going this route over turbo on my nc! ty!'

[@barneyruckus]

I wanna see an exhaust driven centrifugal turbocharger. Then you’re not limited by the rev limit of the pulley and you’re not robbing the engine of any power. I imagine you could make the turbo much smaller as well

[@blown06tc]

You guys can rebuild these at LHT???

[@markmccawley2526]

What does the traction oil do? I always thought that they operated on a slip principle like a torque converter. Thanks for opening one up, very cool.

[@wantapgt]

Mark McCawley traction oil fills the tiny clearances between the barrels and the center shaft and turns viscous under the high pressure it encounters when being squeezed. The fluid is what actually transfers the power. Under normal operation there is no metal to metal contact.

[@TTSPerformance]

OK. The issue is not with the supercharger its with the belt drive. Kraftwerks uses a tooth belt on these S2000 conversions. Rotrex say categorically to use a poly vee belt. If your not going to follow the rules you're going to break it. The input shaft is not pressed in, it is screwed in. Follow the rules and it won't break. The shock loads when hitting the rev limiter or launch control are nasty and the tooth belt transmits the shock and the shaft strips the thread of the input shaft. TTS Performance do an S2000 kit with vee belt and auto tensioner, they don't have any trouble.

[@randy6350]

That’s the BIGGEST BUNCH OF CRAP I’VE EVER HEARD‼️ This supercharger has the highest failure rate of any & ALL FI systems. The system I have uses the proper belt and they STILL FAIL ALL THE TIME‼️ Neat design but a POS‼️

[@nezabytes]

​@@randy6350I'm going to have to agree based on all the failures I've seen.

[@alexgrossman1074]

Im not very familar with these rotrex superchargers but if i spin the turbine does it build pressure? it feels the turbine gets tightly and releases as i spin it. Is that normal? i just had it rebuilt

[@WhyAreYouMakingMeSad]

Спасибо мужики, что показали как это чудо работает

[@matthewmohri9990]

What if any advantages would you say The Rotrex designed Centrifugal Super Charger has over Vortex? You answered my question at the end of the vid. Thank you.

[@LHTPerformance]

Matthew Mohri It’s more efficient for one, it takes less power to run and produces very good HP. It is a little more fragile than the Paxton, Vortech etc

[@HaveFunEatingIt]

Really interested in the Rotrex system. If I do opt for the KW kit I’ll be coming to you guys for the install. Do you have any longterm experience with the longevity of these units? I’ve watched essentially every s2000 video you guys have posted, so I’m aware you’ve been installing these for years. I’ve just been hearing that these tend to grenade after 20k miles stemming from input shaft bearing failure. Do you have any customers with lots of miles logged on this kit?

[@Bmxvtec23]

HaveFunEatingIt would like to know this myself

[@wantapgt]

HaveFunEatingIt the forums have many cars with 30,40,50k miles on their kits. But some have early failure too. Many variables

[@mrschwifty5564]

head units wear out like everything else my P1 Procharger needed new bearings and seals after 15k hard miles.

[@houdini8o8]

appears to be a simple planetary gearset....sun...ring...carrier....

[@robevans3980]

houdini8o8 except they’re not geared together. The friction that turns them seems to be coming from an interference fit or from a very tight tolerance and the viscous fluid used taking up that tolerance and allowing friction to increase.

[@fredosan4299]

Just curious, how did you guys press back the sleeve in? Bench press or using torch to warm it and press? By the way these type of supercharger usually fail on the roller bearing, which i suspect of the compress tight fit to drive the shaft result a heavy stress and may due to dirt in the oil to cause it fall into the bearing which fail during operation

[@ozman1975]

Awesome!

[@ryry1251]

Most of the time the shaft brakes first from the head were it's bolt on to the compressor wheel.

[@3nginuur]

Interesting design. I assume the compressor wheel continues to spin when not under load like a turbo does due to the tri bearing setup? What failures are you having? No boost or leakage? Or lost of boost etc from 10 psi to 5 psi? I think I can probably figure it out, it is such a simple design. Oh, I am a mech. engineer so thank you for sharing the innards.

[@MrRacingJake]

The impeller shaft breaks and bearing goes bad. There's lot's of video's out there.

[@patonbike]

Are these actually better than Vortech, ATI, etc. with regular old gears inside? It sounds like you are saying they are significantly more efficient??? I've got a Vortech V3 Si on a Subaru EJ253 and I'd like to get more power out of it. I'm maxed out the Vortech at 52k impeller speed. We only make about 320whp at 15.5psi @ 6200rpm. I'm thinking about putting a Rotrex C38-71 on it and spinning it to Rotrex redline of 90k with a 70mm pulley (crank puley is small: 5.22" so 70mm Rotrex with 7.5 step up ratio will get us around 90k impeller @ 6300rpm). I am wondering if you can offer any insight? The C38-71 should put us right in the middle of their compressor map... unless of course the Rotrex is so much more efficient that I should size up the Rotrex, expecting to make more power at a given Pressure ratio. Even on the C38-81 we'd still likely be inside of the white "island" on the compressor map. My goal is basically to make as much power as possible without having to rev out the engine much more or more at all (i.e. I don't want to rev it out to 7k) I've also looked at ATI's procharger CS-1 which has an 8.3:1 step up ratio. If I am going through the effort of starting my build over from scratch I want a significant increase over 320whp we're getting now.

[@heathfox573]

shaft screws into driver , M16 fine thread

[@bigbuddhacustomsllc8001]

Who do you recommend to rebuild them I know kraftwerks doesn't, they don't even offer a rebuild kit. I have a c30-94 needs to be rebuilt

[@UrboyNK]

@LHT Performance Did you find the problem? I have the same issue with the same S.C.

[@straight_intro]

All that stuff works by a force of traction? I’m wondering how the hell is doesn’t slip inside?!

[@caycebennett8667]

How do you monitor oil pressure and temp? Mine has an independant oil cooler than the engine oil.

[@diegoortiz301]

Have you guys tried rebuilding these units...i have a spare one that took a dump on me a few weeks ago and wondering if anyone repairs or rebuilds these units?

[@fernandohood5542]

How much power is required to drive a rotrex? How did you get the outter cylinder back on?

[@tysonfaulk2719]

I can't get the impreller off of my c15 did u guys have trouble with this one?

[@GPx1]

you guys have any interest in rebuilding mine? its a c30-64 rotrex. just got it off the car and the impeller side has play.. looking around for rebuild options as im out of any sort of warranty options..

[@CCMCJONESEK]

How did u guys get the barrel pressed back in?

[@koukislides9109]

Do you guys offer a rebuild for an older C30 Kit?

[@billreeves7128]

I installed one on my 2013 MX5 about two years ago, and found the wine a bit loud. Two years later it sounds like a jet engine, to the point where it hurts your ears if the hood is open, any suggestions on how to make it quieter

[@LHTPerformance]

I would recommend a fluid and filter change if it’s been a while. Keep an eye on the fluid color. As it darkens it get a charcoal color and needs to be flushed.

[@Dadon2424]

Y does the rotrex always break in 06 si 😳

[@TireBurner85]

Do you have a lot of damaged rotrex units?

[@jasonhass9845]

Thanks for the look inside! Was there an issue with this unit, and were you you able to fix it? Keep up the great work!

[@wantapgt]

Jason Hass Rotrex blowers are non serviceable. Simply disassembling them throws the clearances off enough to render the unit completely useless. I know this due to experience with a Rotrex engineer

[@JupiterxBlues]

@@wantapgt question: I hear these types of superchargers are reliable. Is the unit being non-serviceable a major issue? Or do these supercharhers generally rarely break for it to matter?

[@brxmr]

minuto 3:50, como sacas la parte negra de su posicion en el cubo? yo tengo 2 unidades c30-94 roto en casa y estoy desmontando una de ellas, busco alguien que pueda reparar mi unidad y aprender bien su funcionamiento, yo soy de españa

[@jeffreygoss8109]

Who said there was an issue? And what was issue-besides broken.

[@pursk8erboy]

Curious as to what you guys determined was wrong with the unit and if you were able to fix it. I have a C38-91 that died on me and is sitting in my garage because Kraftwerks won’t get back to me, and if you guys have a solution I wouldn’t mind shipping it out to Florida 👍🏽

[@TTSPerformance]

HORSEPOWER4321 1 second ago OK. The issue is not with the supercharger its with the belt drive. Kraftwerks uses a tooth belt on these S2000 conversions. Rotrex say categorically to use a poly vee belt. If your not going to follow the rules you're going to break it. The input shaft is not pressed in, it is screwed in. Follow the rules and it won't break. The shock loads when hitting the rev limiter or launch control are nasty and the tooth belt transmits the shock and the shaft strips the thread of the input shaft. TTS Performance do an S2000 kit with vee belt and auto tensioner, they don't have any trouble

[@lcq4blackstar]

@@TTSPerformance thank you for sharing your knowledge on these units! much appreciated 🙌

[@reallife4598]

Did anyone happen to notice the size of the turbin wheel

[@F0BBYLEE]

The "special" traction fluid smells like ATF.. no? is it the same fluid?

[@LHTPerformance]

Abe Linkin no. Only use Rotrex fluid.

[@mikejones9]

What k20 would the kraftwerk supercharged work best in?

[@LHTPerformance]

I like the kit in the 8th and 9th gen civics. The k motor in another chassis require removing the AC which I’m not a fan of. The blower sits in the place of the AC compressor

[@foreyfriend145]

Subj: Weak link. The black plate connecting the "driver shaft" to the cage is my main suspect. Why? that poor single piece of metal has to suffer the whole impact of reprated violent inertia variations..alone, I think the link between the driver shaft and the cage should look rather like a spokef wheel a gruyere cheese full holed disc in order to have the necessary rigidity/flexibility.

[@chippydc5]

Im seriously looking at this type of supercharger for my DC5R but iv seen so much about these snapping the shafts and failing. do you get any of these fail out of the amount of kits you have done?

[@LHTPerformance]

K20TBH We have very few issues at all. Most of the issues are related to the belt having too much tension.

[@chippydc5]

Ok that makes sence. Would a rotrex be the better option for me on track or potentially look at a turbo?

[@LHTPerformance]

K20TBH If it’s just weekend track use either will work. If it’s serious road course I would recommend a build NA motor.

[@stevenbroughton9264]

Can they be repaired? Mine just went out

[@LHTPerformance]

There is a place in England but I don’t have any experience with them.

[@petemiller5813]

Great video. Very insightful to see the inner workings. The use of the speed multiplier is very interesting. Is the Rotrex oil used primarily for cooling? What was wrong with this unit?

[@wantapgt]

Pete Miller Besides cooking, traction oil fills the tiny clearances between the barrels and the center shaft and turns viscous under the high pressure it encounters when being squeezed. The fluid is what actually transfers the power. Under normal operation there is no metal to metal contact.

[@misterbulger]

Anybody see an ebay centrifugal super charger? Some of their turbos work great... I figure they have to make a Chinese one that's not thousands of dollars... all I've found so far tho is a mini roots for a dinky little engine.

[@deetesmin]

Torotrak transmission system

[@paulkhelley2123]

I got a kraftwerks on my 2020 GT Mustang. It only makes 5.5lb of boost, no leaks. Quite disappointing

[@rocsti5402]

Any update. What head unit? Sounds like something is off

[@paulkhelley2123]

I ended up getting rid of it and fitting a Roush. Terrible customer service

[@D20shortz]

Do yall rebuild?

[@LHTPerformance]

We don’t. Sorry.

[@BMfins]

Why would you use this over say a Paxton or vortech?

[@A_Bad_Driver]

Simplicity and power delivery most likely. Low to almost no extra load on the motor at low revs but gives a very linear power delivery like the other superchargers. Has its own lubing/traction fluid separate from the oil and coolant going to your motor. Very compact accessories (fluid filter, cooler, reservior)

[@hazimiqbal4636]

1:7 ratio i think

[@scotttufts]

You guys should add a hot side to the rotrex and see what kinda power you can make

[@jameshoneyc]

There so secret because it's named after a man centuries ago. An Archimedes drive.. basically a planetary gear system with a twist......the gears have no teeth.

[@UpShiftTrackdayVideos]

You mention that you keep the shaft rpm below 90000rpm, How much under would you say to be safe?

[@PiterStreak]

I've seen people run them to 100k rpm for an extended period of times without issue (3+ years). the only thing they don't do it rev bang. rev banging kills these units.

[@UpShiftTrackdayVideos]

@@PiterStreak Yea, I killed a C30-94, in just over 2 years. It was spinning to a hair off 99k, thankfully Rotrex replaced it and I upgraded to a C38-61. I believe my new setup will spin the C38-61 to 88k.

[@224rebels]

You skipped half of the disassembly...

[@bighomieJ5X]

Doesn't really look all complicated to me ..

[@phantom2488]

still dont get why we cant spin it backwords

[@TTSPerformance]

HORSEPOWER4321 1 second ago OK. The issue is not with the supercharger its with the belt drive. Kraftwerks uses a tooth belt on these S2000 conversions. Rotrex say categorically to use a poly vee belt. If your not going to follow the rules you're going to break it. The input shaft is not pressed in, it is screwed in.THIS IS WHY YOU CANT SPIN IT BACKWARDS. Follow the rules and it won't break. The shock loads when hitting the rev limiter or launch control are nasty and the tooth belt transmits the shock and the shaft strips the thread of the input shaft. TTS Performance do an S2000 kit with vee belt and auto tensioner, they don't have any trouble

[@TTSPerformance]

U undo the threaded input shaft