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!
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.
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.
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.
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 🙂
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
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.
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.
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.
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.
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
Well you guys need to know these Superchargers have the highest failure rate of any forced system... Sadly it’s what’s on our Tacoma. I should have done more research before buying the URD Rotrex kit. My .02 cents is it’s a POS‼️
@@gabeh7373 No warranty on mine as I let it set in the box for two years because I had a few surgeries & while healing I read a LOT of bad reviews on these! They can’t be rebuilt and they are about $2k and up from the prices I have seen. You have to buy a totally new SC‼️ The Internet is full of negative feedback on this SC. Yes it’s a neat design but they break all the time...Ours is on a Tacoma the system is by URD / You R Dumb for buying this system. 👎
That sucks! I was considering one for my Lexus but I have to do my research. I'm curious of Rotrex has changed any of the design elements within the supercharger if they've been getting a high failure rate?
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.
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‼️
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.
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.
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...
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
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?
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.
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.
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
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.
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.
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.
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.
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.
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
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..
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
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.
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
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?
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
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 !!!!
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.
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
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.
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
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.
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
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.
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.
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)
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 👍🏽
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
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
@@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?
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?
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
@@LHTPerformance so it only has 5000 on it. It made a loud clang noise when I was driving it. Then it started running like it had a miss or air fule mixer is wrong. I started it last night and it sounds like the shaft is spinning up fast. But their is not very much air pulling in. And the muffler just sounds like bad. It has no power. And to much throttle will kill it.
the tolerances probably became so bad that all those smooth surfaces no longer have any traction. pretty shitty design, you could do the same with actual gears and it would never wear out if you have the same fluid system.
Mahir Fredericks actually the surfaces don’t really touch when in normal operation. The fluid fills the gap and under compression turns very viscous. That’s what actually transfers the power. On the bench it spins because the clearances are off due to disassembly. That’s why Rotrex doesn’t recoils these units and they are essentially destroyed in the tear down process.
@@wantapgt yeah ima call BS on that explanation, grated that even if we talking machine ground metal surfaces we still cant actually say they are ever "touching" but we close as can be, generally we have a very low metal to metal friction coefficient, the fluid has the effect of improving the coefficient exactly as you say and lubricating at the same time. However Under load this super charger will get hot, really hot, and it's definitely not the Fluid that imparts spin from the Ring to the Planetarys and so forth, if that were the case you would start producing less boost as the part becomes heat soaked due the the fluid expansion and therefore less density, thus less spin on the final drive shaft. But the homies at LHT have already confirmed that after the part becomes hot it produces more boost. This is because tolerances are becoming tighter and therefore more friction between the surfaces... thus less slip. Also, it spins on the bench because humans have much less torque then cars. LHT said that the unit is defective before they opened it, i suspect under an actual engine load the surfaces just cannot impart enough spin to the compressor, this is because traction flud is a lubricant first with a traction additive . Using your fluid imparting power logic this unit would never be able to fail if the correct tolerances are met. they most likely have decreased in diameter by a thou or 2 Most importantly you cant compress a fluid, *fucking sigh* so logically speaking, using your fluid transfers the power idea, where there is compression there is high pressure and as such also, the inverse will have to exist in the same system, aka a very low pressure... a low pressure on parts with tolerances like these would suffer from massive cavitation bubbles which would absolutely destroy the surface of the rollers. lastly, The planetarys are in sitting in a carrier housing with the ring gear around and the sun in the center, the clearances are just fine on a bench as long as all the parts are concentric, every surface in this unit has been turned and then ground to be a friction fit and should provide a gear increase as such. But all i was trying to say above is that you can get this same effect if you used actual gears, which will be much less likely to fail, and essentially could be a quarter of the size in thickness, i would consider this manufactured failure, even thought the kit is awesome, they know that forces are quire low and can get away with gear train which only uses friction. over time they know there would be slip in the system causing wear and thus the unit slowly becomes less effective.
@@mahirfredericks4013 We both were partially correct... but me more so.. The fluid is what transfers the torque, like I said. Under pressure, or compression, whichever word you want to apply in this case, the fluid becomes viscous, like I said before and transmits the torque. The illustration you can find in the technical handbook shows the fluid going between the rollers and doing the work. There is no way the tiny contact patch between two smoothly machined surfaces can transmit torque on their own for any useful amount of time. Likely that blower failed because there became a gap too large for the traction fluid to work its magic across. From the rotrex technical handbook that came with my S2000 kit: The Rotrex patented traction drive uses a steel annulus with a small pre-span to secure contact between the roller planets and the sun shaft with a reasonable force. The ramp or wedge effect increases efficiency and reliability in the transmission by regulating the torque transfer capability on demand through self-adjusting planet geometry. This is a key operational feature since friction is highly dependent on surface pressure, slip and temperature conditions in the traction fluid. Developed specially for its use in Rotrex superchargers, the special traction fluid momentarily increases viscosity under high surface pressure, enhancing the traction drive performance by securing the optimum friction between rolling elements while cooling and protecting the system My interpretation is that "reasonable" force means almost none at all. Also included is an illustration that demonstrated the principle I was trying to explain. Google "rotrex technical handbook" and go to page 9 to see the illustration on the right. Clearly showing its the fluid that does all the work.
@@wantapgt k im going to give you some physics advice here... read "Fluid Mechanics and Thermodynamics" you will take notice that, a fluid cannot exert an axial force in the direction of a tangent which it acts upon only SLIP. ill leave that for you to interpret... but its up to you to believe the marketing wank.
