Is there any real evidence that hitting the rev limit has any effect on the bolt or the supercharger? It seems that there is some speculation that this may be a contributing factor and that this is getting repeated to the point that it is assumed to be true.

The picture of the broken bolt indicates the bolt broke due to bending forces. This bending force comes from two sources. One source is the torque required to drive the supercharger. It is the torque to drive the supercharger divided by the radius of the pulley. Bouncing off the rev limiter produces a rapid acceleration and deceleration which causes a varying torque and therefore varying bending force on this bolt.

The other source of bending force comes from the belt tension pulling on the pulley. Of course, the tighter the belt, the more the bending force. The design of the belt tensioning system makes it very easy to over tighten the belt.

Another contributing factor could be that if the bolt starts to loosen and back out, then the bending moment on the bolt at the point where it enters the supercharger increases as the bolt backs out. Bouncing off the rev limiter can cause vibrations that may cause the bolt to loosen if it is not tightened properly (lock-tight helps with this). However, I don't see a key way or splines that connect the adapter to the input shaft. If there are none, then torque is transferred from the adapter to the input shaft by friction and that friction is provided by the clamping force of the bolt. If this is true, when the bolt starts to back out, the adapter would slip and the car would loose boost.

The stock S2000 has a rev limiter that cuts fuel at the limit then keeps it off as the engine coasts down for a several hundred RPM to the "recover speed" then puts the fuel back in. This is what causes the stock engine to feel like it is "bouncing" off of the limit. The FlashPro sets the limit and the recover speed independently. Hondata recommends that they be set within 300 rpm of each other, which is less than the factory difference. I have mine both set to 8200.

 

KW emailed me that they are still looking into these failures and mentioned it could be from improper supercharger pulley torque or tightening sequence, faulty hub adapter, etc... but a super tight belt would not do this as you would damage your belt or pulleys before damaging the center bolt... but that they have not confirmed exactly why this happened.

hopefully they have a response on this one ASAP...

im curious how many -81 kits had this happen vs. -91 kits...

-Mike

 

Waiting game...

 

Hi. We sell quite a lot to the US. If you see my website you will see its quality first and price second. The KW kit will monumentally fail. They are using a tooth belt which will break the supercharger as soon as the rev limiter is hit in anger. The two 8 mm bolts they have fastened the bracket to on the cylinder head will fracture the casting. Its doomed.
Please check out thishttp://rotrex.com/Ho..._Technical_Data

These are my opinions based on 7 yrs of refining our kit and seeing other kits fail and retract from the market. This development has given you something that works, we see more boost at the engine then others and that creates power. We have now catered for the 2.2 litre motor as well with revised pulley ratio's to give the most power available. I don't know which motor you have be either make awesome power. The Supersport kit is £3900, shipping is expensive at about £250. I will do you a deal of £3600 shipped. We are looking at 21 days lead time as we have had such a run on kits since the beginning of the year. I would like 50% deposit, you pay the rest when we are ready to ship. The Race kit is £4600, same shipping. I can do you this kit for £4100. shipped. same lead time. The exchange rate is around 1.65 to the Pound so your right about your cost. Sorry you will have to have a word with Barack see what he can do for you . If you want more info its best to email me richard@tts-performance.co.uk

All the best

Richard

quote from reichard @ tts.

 

Rotrex directions specifically prohibit cog drives. I mentioned this at least a year ago. Time will prove the point.

 

omfg.
y didn't i see this before.
also i kinda felt like kraftwerks don't give a sh!t, since rotrex prohibited n they still make a kit with it.

 

Well if that's true I'm glad I went TTS

 

^^^

 

Any chance you have a link? I read through the c38 manual and don't remember coming across that. Could have missed it though.

 

I just re-read the Rotrex Technical Handbook (the document that Rotrex publishes for kit makers to tell them how to design a kit using the Rotrex supercharger). Section 4 discusses drive belt design and uses ribbed belts as the example. They say that Rotrex supplies the supercharger with various sizes of ribbed pulleys or an adapter that can be used if the kit maker chooses to use a pulley that Rotrex doesn't provide. I didn't see anything about prohibiting cog belts. Can you point to the Rotrex reference that prohibits cog drives?