Opened up my Rotrex today. Here are my thoughts.

[projek_01]

@CSG_Mike
I'm curious to know what happens if the unit is older than 3 years. Do you know what Rotrex offers to those owners? It's something I didn't look into with KW.

[projek_01]

I finally got to replacing every bearing with NSK bearings which Rotrex also uses from the factory. Luckly, all but one of the bearings I purchased locally were made in Japan. Not sure if that makes any difference (likely not) but it's JDM yo.

Rotrex made all of the bearing bores a little big to make assembly easy I assume. Unfortunately, the bearings are not seated properly and slowly enlarging the bore as time goes on. I noticed that there was some signs of wear in very bearing bore but less severe compared to bearing #2 in the previous photos.

I decided to use some Loctite 660 retention compound on all of the bearing outer races to prevent them from spinning.




Hopefully this will be the last time I see the inside of this thing.


Mated the two parts back together using Ultra Black RTV and red Loctite where needed. It feels good to have it back together

[amcp1]

Originally Posted by projek_01

@CSG_Mike
I'm curious to know what happens if the unit is older than 3 years. Do you know what Rotrex offers to those owners? It's something I didn't look into with KW.

Could tag someone from Jackson Racing as well. Would be interesting to hear what they say.

[Frantic]

Thank you for the write up, very good info.
Did you have much trouble pressing the drive unit back together?
How did you press the compressor wheel on and off without snapping the shaft or damaging the drive unit?

[HachiRokuX]

So is the JRSC not a good long term option for FI? My understanding is that it’s been a very reliable kit for most people but it seems like it has some design flaws..


Sent from my iPhone using Tapatalk

[projek_01]

Originally Posted by Frantic

Thank you for the write up, very good info.
Did you have much trouble pressing the drive unit back together?
How did you press the compressor wheel on and off without snapping the shaft or damaging the drive unit?

The theory of the inner workings is nothing revolutionary. They basically turned a planetary gear set into rollers by making the "ring gear" super tight. Effectively making everything interference fit and preventing the surfaces from slipping.



With heat, reassembly was a breeze. Heating both the "ring gear" and compressor assembly at 400F for 10min allowed them to be re-assembled with hand strength.

Originally Posted by HachiRokuX

So is the JRSC not a good long term option for FI? My understanding is that it’s been a very reliable kit for most people but it seems like it has some design flaws..


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I wouldn't say that the kit isn't reliable. My problems likely stemmed from improper belt tension due to my Kraftwerks cogged belt system. Many guys including "The Speed Academy" on youtube use their Rotrex exclusively for track at high RPMs without any issues.

The hardened and therefore brittle sunshaft is probably the Achilles heal of the Rotrex blower. It wouldn't take much for Rotrex to improve it and I hope they have already done that.

[mrg666]

Originally Posted by projek_01

@CSG_Mike
I'm curious to know what happens if the unit is older than 3 years. Do you know what Rotrex offers to those owners? It's something I didn't look into with KW.

Rotrex offers them to buy a new unit. My C30 is still working just fine after 25K miles (2 years). A new C30 is $2200 and I would just order another unit when/if there is a problem after 3 years. Simple, right?

Whatever you are trying to prove here, my experience is that Rotrex compressor is a good and reliable product. And by the way, I really doubt that compressor you are trying to fix will ever work or be reliable again. Thanks for the pictures though.

[CSG Mike]

The JRSC is very reliable, both on the track and for street use.

[projek_01]

Wow, what makes you so sure that my unit will never work or be reliable again? Do you have a mechanical or engineering background to explain why it wouldn't?

I'm glad your unit is good and reliable. I'm not trying to prove anything. I have nothing to gain from showing the flaws in my Rotrex C30. I spent my hard earned money to buy this supercharger just like everyone else but mine was starting to fail. It's not like I'm trying to sell people turbo kits and steering them away from a Rotrex.

Just like the FA20 engine, the Rotrex is a decent unit. Many people have put lots of miles and track time on it without a single issue. However, I'm just merely pointing out it's flaws and showing places where it can be improved in my opinion. This is equivalent to someone doing a FA20 teardown/rebuild from a spin bearing or thrown rod. I feel like some people are getting a little offended when I jab at some design flaws.

The blower is fairly reliable for most people but we also can't ignore the fact that a fair amount of people have experienced failures with the KW AND JRSC (less often). We are lucky that our FA20 doesn't rev to the moon like the F20C or K20 in the Honda world. Type in Rotrex failure in a Honda forum and you will see what I mean. Either way, my opinion IS biased because I own a failed unit. I admit that for sure. As a retailer of the JRSC or owner of a working unit, you are entitled to your own opinion.

Originally Posted by mrg666

Rotrex offers them to buy a new unit. My C30 is still working just fine after 25K miles (2 years). A new C30 is $2200 and I would just order another unit when/if there is a problem after 3 years. Simple, right?

Whatever you are trying to prove here, my experience is that Rotrex compressor is a good and reliable product. And by the way, I really doubt that compressor you are trying to fix will ever work or be reliable again. Thanks for the pictures though.

[mrg666]

That unit is sealed and not serviceable for a reason. Engineering tolerances get pretty tight to function reliably at 100K rpm. You have no idea about those tolerances and material specs. And, yes, I am an engineer and wise enough not to share credentials on public forums.

Thank you again for the teardown; that was interesting. But I don't take your design criticism too seriously. If you want to risk more of your "hard-earned" money by installing that unit again Sure that is my opinion and it is your car. Good luck.

Originally Posted by projek_01

Wow, what makes you so sure that my unit will never work or be reliable again? Do you have a mechanical or engineering background to explain why it wouldn't?

I'm glad your unit is good and reliable. I'm not trying to prove anything. I have nothing to gain from showing the flaws in my Rotrex C30. I spent my hard earned money to buy this supercharger just like everyone else but mine was starting to fail. It's not like I'm trying to sell people turbo kits and steering them away from a Rotrex.

Just like the FA20 engine, the Rotrex is a decent unit. Many people have put lots of miles and track time on it without a single issue. However, I'm just merely pointing out it's flaws and showing places where it can be improved in my opinion. This is equivalent to someone doing a FA20 teardown/rebuild from a spin bearing or thrown rod. I feel like some people are getting a little offended when I jab at some design flaws.

The blower is fairly reliable for most people but we also can't ignore the fact that a fair amount of people have experienced failures with the KW AND JRSC (less often). We are lucky that our FA20 doesn't rev to the moon like the F20C or K20 in the Honda world. Type in Rotrex failure in a Honda forum and you will see what I mean. Either way, my opinion IS biased because I own a failed unit. I admit that for sure. As a retailer of the JRSC or owner of a working unit, you are entitled to your own opinion.

[CSG Mike]

Originally Posted by projek_01

Wow, what makes you so sure that my unit will never work or be reliable again? Do you have a mechanical or engineering background to explain why it wouldn't?

I'm glad your unit is good and reliable. I'm not trying to prove anything. I have nothing to gain from showing the flaws in my Rotrex C30. I spent my hard earned money to buy this supercharger just like everyone else but mine was starting to fail. It's not like I'm trying to sell people turbo kits and steering them away from a Rotrex.

Just like the FA20 engine, the Rotrex is a decent unit. Many people have put lots of miles and track time on it without a single issue. However, I'm just merely pointing out it's flaws and showing places where it can be improved in my opinion. This is equivalent to someone doing a FA20 teardown/rebuild from a spin bearing or thrown rod. I feel like some people are getting a little offended when I jab at some design flaws.

The blower is fairly reliable for most people but we also can't ignore the fact that a fair amount of people have experienced failures with the KW AND JRSC (less often). We are lucky that our FA20 doesn't rev to the moon like the F20C or K20 in the Honda world. Type in Rotrex failure in a Honda forum and you will see what I mean. Either way, my opinion IS biased because I own a failed unit. I admit that for sure. As a retailer of the JRSC or owner of a working unit, you are entitled to your own opinion.

How high the engine revs has nothing to do with high how the Rotrex is revved. The pulleys used determine the ratio, and a rotrex geared to rev to 90,000 (for example), will rev to 90,000 at redline, whether the driving engine is doign 6000, 8000, or 10,000 rpm.

In other words, the engine's RPM + gearing determines rotrex RPM, not just the engine RPM.

[projek_01]

Originally Posted by mrg666

That unit is sealed and not serviceable for a reason. Engineering tolerances get pretty tight to function reliably at 100K rpm. You have no idea about those tolerances and material specs. And, yes, I am an engineer and wise enough not to share credentials on public forums.

Thank you again for the teardown; that was interesting. But I don't take your design criticism too seriously. If you want to risk more of your "hard-earned" money by installing that unit again Sure that is my opinion and it is your car. Good luck.

Fair enough, you have a stronger educational background (engineering) in this stuff than I do. Saying I have no idea about the tolerances and material specs however is incorrect and is very naive. Rockwell hardness measurements and micrometers were used to check the specs before reassembly. I also checked the alloy that Rotrex used with instrumentation I have access to just for my information.

Originally Posted by CSG Mike

How high the engine revs has nothing to do with high how the Rotrex is revved. The pulleys used determine the ratio, and a rotrex geared to rev to 90,000 (for example), will rev to 90,000 at redline, whether the driving engine is doign 6000, 8000, or 10,000 rpm.

In other words, the engine's RPM + gearing determines rotrex RPM, not just the engine RPM.

I realized that I wasn't thinking right when I wrote that on my drive home today. What I meant to say is that those engines change RPMs very rapidly especially when people dump their clutches to launch into VTEC. The rapid change in RPM is rumored to be snapping the brittle hardened sun shafts. We know that hardened steel = brittle. Just a theory though and not a proven fact.

Either way, what's done is done and I am confident enough to run this blower. I will run some nylon filters on the hot side pipes before the intercooler for some added protection. Best of luck to me!

No more arguing on my end - what's done is done. I wrote this thread to help people understand what is potentially happening inside their blowers.

[Frantic]

I hope the little rotrex goes for years to come.

[toast]

Thanks for this thread projek_01. Always nice when someone tries to help out the community by showing what is going on inside a unit.

Here's hoping your unit outlasts the one belonging to the Simpsons character from upstate NY.