After 2 different bolts snapped on my Kraftwerks SC kit, even after replacing with ARP hardware and following all the LHT tips, I decided I needed to go with a different mounting option.
The TTS Supercharger kit uses the same Rotrex blower as the Kraftwerks kit, and has a much more solid mounting solution, so I thought I'd document the process of converting for anyone else with a KW kit looking to improve reliability.
The main difference between the kits is the use of a ribbed belt instead of a cogged belt, and more mounting points are used, which should result in less stress on components overall.

Reference material:
The car is a 2004 AP2 model.
TTS kit mounting instructions: https://7e66e993-39f5-4499-87f8-e617...58266e65c3.pdf
Full TTS kit: https://www.tts-performance.co.uk/si...ACE-All-Models
Rotrex pulley replacement instructions: https://www.rotrexshop.com/wp-conten...dbook_V1.5.pdf
All images mirrored here: https://imgur.com/a/0GYvNcr

To do the mounting conversion, I used the following parts:
From TTS:
S2KFMB1 - Honda S2000 Front Mount Supercharger Bracket Set
135mm crank pulley was included.
With Shipping to USA: £1500 / $1980 USD

From other vendors:
R50-99-0095 - Rotrex Supercharger Pulley 95mm 8 Rib
Machining of OEM crankshaft pulley - 1 hour labor / $75 at my local shop
(Optional, but recommended) Rotrex Pulley Removal Tool
(Optional) 13810-PCX-003 - Spare Honda Crankshaft Pulley

For piping connections (existing piping only BARELY fits with some stretching / bending):
- 2.5" ID 90 degree Silicone Elbow
- 2.5" ID 45 degree Silicone Elbow (I might go with a 4-ply hose if I was doing this again)
- 2.5" OD Aluminum Joiner Tube
- 3" OD 30 degree Aluminum Elbow (For air filter)

Existing parts (from Kraftwerks kit):
C38-81 Rotrex Supercharger (Any C38 should fit, expect C38r)
Rotrex oil reservoir / filter / cooler.
Fuel injectors and pump
MAP sensor
Intercooler + piping
Blow-off / recirculation valve
AEM V2 EMS





The TTS kit uses a different crankshaft pulley design that requires some modifications be done to the OEM crankshaft pulley. I ordered a second pulley from Honda so I could have this done while I was still driving the car.
I had this done at a local machine shop, and you can see what it looks like after:




This is what I started with (car running naturally aspirated without the belt on):


I did this conversion without disconnecting the Rotrex oil lines so I wouldn't have to re-prime the system. I unbolted the filter and reservoir to make moving the blower around easier:



After that I removed the 3 bolts holding the Kraftwerks assembly on, and set it on some towels to prevent any scratches:


Replacing the pulley on the Rotrex is probably the trickiest part of this whole process, and I had to try a few things to get it swapped.
I'd recommend just buying or making something equivalent to the Rotrex pulley removal tool to make things easier, but I managed without it.
The 6 bolts holding the pulley to the hub are easy enough to remove, but the main bolt holding the hub on also needs to be removed, and requires a huge amount of force.
I did this by drilling a hole in the Kraftwerks pulley so I could bolt it back on and use the belt to stop the blower spinning.

With the assembly loose in the engine bay, I wasn't able to get it removed, so I bolted it all back together with the belt installed and used 6th gear + the parking brake to hold the belt.
With an allen wrench and the end of my floor jack handle, I finally got the pulley hub removed:





Learn from my mistakes, and don't put bolts too far into the pulley hub, it might damage the bearing seal underneath:


I chose a 95mm pulley based on my tune's 8400rpm redline. With the 135mm crank pulley I received, the 95mm won't overspin the Rotrex blower until 8450rpm.
Since I didn't have the pulley removal / install tool, my method for torquing the pulley down was sketchy at best.
Using some spare bolts, I held the pulley with a wrench, and torqued the bolt down to Rotrex spec of 70Nm.



Next was removing the Kraftwerks crankshaft pulley. This is a little tricky, since the Honda tool won't work with the Kraftwerks pulley in place.
I removed the pulley from its hub to give a little more space, and once again held the crankshaft with 6th gear + the parking brake.



To get the modified pulley + TTS pulley on, I had to place my floor jack under the engine with a block of wood to jack it up. The steering rack gets in the way otherwise.
The TTS pulley uses the OEM Honda crankshaft bolt, so you'll need to find that instead of using the Kraftwerks pulley bolt.
I followed the Honda instructions for installing the bolt, which matches the TTS instructions 245 Nm.




From here on out, things are pretty straightforward, and I more or less followed the TTS instructions directly.
One item of note:
I didn't have an M12 bolt a reasonable length for pressing the idler pulley onto the new bracket, like the instructions recommend.
I was able to use a socket to fit over the provided bolt, and was able to press the pulley into place:





The TTS kit provides an OEM vtec solenoid gasket, which fits very well into the groove on their bracket. Since the debris filter fits in place, I ended up leaving it in along with the existing one on the solenoid.




The coolant hose on the intake side of the engine has to be rotated so it clears the new bracket assembly. I rotated it too much at first, and it was covering the back of a pulley mounting hole. It should be rotated just enough so it clears the bracket, but not so far that it will contact the pulley bolt when everything is bolted together.



Next I bolted the Rotrex unit to the new mounting plate, and got ready to fit it into place.
The lowest mounting point bolts into the timing cover, and its a bit annoying to fit the bolt in due to the steering rack. I jacked the engine up again to make this a little easier.




Make sure you pay attention to the belt routing when you fit the mounting plate in place. Everything is fitted except for 1 pulley, which needs to be installed after everything's bolted down.
This was a bit of a pain, since the tensioner spring is really stiff, and I didn't have room to get a very long wrench in to pull it back. I also had to temporarily loosen a couple bolts so I had room to fit the spacer in between the pulley and the bracket.



In this picture you can see where the coolant hose should be to clear the end of the bolt (which sticks out the back a little bit when torqued down)


Next is to adjust the tensioner to take up any slack. With my pulleys, I didn't have to tighten it very much, but I expect I'll have to check it again once the belt wears in a bit.



After the TTS pulley system is all installed, the oil reservoir and filter can be put back in place, and the last step is to get the charge piping installed.
The Rotrex unit sits in a slightly different spot from the Kraftwerks kit, so the original piping doesn't really work here.
I was able to just barely fit the Kraftwerks piping on with some bending/stretching, but I wouldn't trust it to stay on very long. It was enough for a test drive though.




My solution for the charge piping was to buy a 45 degree and 90 degree silicone elbow and join them together. I started with pieces with some extra length so I could trim them down for a better fit:



My previous intake pipe (that wasn't part of the Kraftwerks kit) doesn't quite fit anymore due to how much was cut off, but I've purchased another piece, and it worked perfectly after trimming off one end.




==========

First impressions from driving are very good, and it's nice to have the car back on boost. The TTS pulley system is much quieter, meaning you get a lot more of the real induction noise from the blower.
I'll have to get my car tuned again to compare efficiency, but under load the AFR didn't seem too different from when I had the Kraftwerks kit on. At low loads / cruising / idle the AFR was a bit off, so I tweaked some of the map to clean up the idle for now.
I'll be posting some videos soon of the kit running, and will be booking another dyno session to get a before and after comparison.

Hopefully this is useful to the other Kraftwerks owners out there. So far I'd say it's a great option to improve on the KW kit without going for a full replacement.

 

Well it doesn't seem like it's much of a KW kit anymore, awesome post man!

 

Thank god for that, lol.




I can't wait to start working on my TTS kit. I sold my BNIB KW kit at exactly around this time last year and opted to not go boost for another year while I upgraded my setup across the board. At this point I'm just waiting for my TTS kit to arrive. I'm going the more custom route and having my IC, piping, oil cooler etc fabbed for me vs modifying the TTS bits, which was great because it gave me the freedom to spec a lot of the stuff out myself and make it how I wanted it. Good luck with the TTS kit, you won't be having any more issues I'm thinking.

 

Excellent writeup! Seems very thorough and easy to follow.

One caution, the hub on the Rotrex that the kw pulley bolts onto is factory installed by Rotrex. Its a standard hub they use for any application that can't use one of the standard Rotrex ribbed pulleys.

TTS uses standard Rotrex pulleys, so doesn't need that hub.

In the Rotrex documentation it very specifically warns to never remove that center bolt that holds on the hub. You void any warranty you might have. It also warns to never spin the Rotrex backwards, even by hand, as that can cause severe damage.

I don't know what the reservation is about removing that center bolt. But Rotrex is pretty adamant that even Rotrex vendors shouldn't touch it. Buy blower with hub, or buy blower with standard Rotrex pulley.

So a suggestion for anyone following this tutorial, instead of buying pulley from TTS, have one made to meet Rotrex standard hub, with correct number of ribs, etc. Then its just unbolt kw pulley from hub, bolt on new pulley to hub, never touch center bolt that mounts hub to blower. Much easier, and much safer pulley install.

Rotrex technical manual has detailed specs on pulley dimensions. Maybe someone can turn those into a file for a 3d printer, someone can print it out and mount it up, make sure all dimensions are correct in real world, belt ribs line up with other pulleys, etc. A mockup.

Then send file out to be machined from billet. Make file available to others, or maybe someone can make batches and sell to others wanting to make this conversion.

Maybe all this is just concern over nothing. If the op doesn't have any long term issues after removing hub to mount pulley from tts, maybe its not a real issue.

 

In the technical manual I referenced (https://www.rotrexshop.com/wp-conten...dbook_V1.5.pdf) it says the center bolt can be removed and warranty is not void as long as you follow their proceedure (I did not, but my warranty is up anyway, and I did not spin the blower). The only note about the hub and center bolt I see is basically saying don't stop the blower from spinning by using the center bolt (at least that's my interpretation).

A properly machined pulley that uses the existing hub would definitely make everything easier. The TTS kit only uses 7 of the 8 pulley ribs, so it's possible the KW 7-rib pulley w/ hub would work, but I can't be sure of dimensions without buying one and testing.

Several people have had their center bolt snap on the KW kit, and still recovered the blower, so I think I'm reasonably safe with this swap. I'll keep this updated if I run into issues though.

 

That is indeed the Rotrex document I was thinking of. On page 28, note !B in red, it says not to remove the bolt. I will have to look again for any other places it mentions center bolt. Its been a while.

The only threads I recall where kw center bolt snapped, owner was required to send their unit back to get the bolt fixed. Perhaps there were other threads where this happened that I missed.

The 7 rib kw pulley (that is designed to use standard Rotrex hub mount) would be perfect, if they offer diameter needed, and if, as you point out, everything aligns (the pulley aligns with the rest of tts pulleys). Hopefully someone tries that out, as it would make, as you called it, the hardest part of the conversion, soooooo much easier.

I think the chances of alignment are quite good. There isn't a lot of room for design variations in Rotrex pulley specs, especially related to how far out pulley can be from blower, which is the critical spec for alignment.

Come to think of it, even if the kw 7 rib pulley isn't a perfect alignment, sending the pulley out to machine off a few thousands or whatever at the same time you send out the crank pulley,should be pretty easy. Or to make a spacer if it needs alignment the other direction.

Mount kw 7 rib pulley. Mount tts bracket to car. Using tts initial belt tension adjustment (final tension is via spring loaded belt tensioner), get a bit of slack,so you can see where belt wants to lay on blower pulley. Note how far off it is. Measure carefully. Measure twice.

Determine of spacer needed or material machined off back of pulley. Send crank pulley and kw 7 rib pulley to machine shop.

Once someone pioneers this, and figures out what needs to be done to kw 7 rib pulley (if anything), everyone can follow.

The more I think about this the better your idea of using the kw 7 rib pulley sounds.

 

I'm wondering if TTS will design a new kit in a much more simplified form like the SOS now that Rotrex offers a CCW rotation C38; no more need for an elaborate pulley arrangement or double-sided belt. If we could also get Rotrex to make a volute that points in the opposite direction like the Paxton the kit could be run with a heat exchanger vs intercooler.

 

Wait, what now? Really? A new ccw c38?

I have been working on a design idea for a simplified Rotrex bracket for our cars. But a Rotrex that spins in the opposite direction could make that a whole lot easier!

Off to research that...

 

Okay, kinda….The C38R I believe is the only one that goes CCW, and it DOES have the opposing volute.

Only issue is the C38R will put out SERIOUS juice; that's getting you more into built motor territory, and also uses a 10 rib pulley. It's a pretty serious piece that supposedly takes more grunt to run. I discussed a C38R build with Richard @ TTS before the CCW version was even released, and he told me it could be done (obviously) but it's gonna be costly, lol. Getting clearance w/ a 10 rib pulley to the crank is going to be tough....even completely shaving off the ear of the power steering unit won't be enough I don't think.

At this point I believe they can (and should) release a C38R setup for the S2000 with a much simpler mounting setup like SOS uses, as well as hopefully incorporating anti-vibration isolators.

 

Ok, yeah, that's getting into serious territory that few will want to tread. Impractical for most.