Kraftwerks Rotrex Supercharger Discussion

[sw20kosh]

Originally Posted by Calum

All of these kits will be pretty close to the same peak output.

Not trying to cause an arguement but the turbo will have a pretty significantly higher output than the superchargers.

[Taber]

Originally Posted by sw20kosh

Not trying to cause an arguement but the turbo will have a pretty significantly higher output than the superchargers.

HOLY SHIT!!! REALLY??!?!?!?!

[gmsii]

Originally Posted by digital_assassin

Good call @ft_sjo. I'm curious about the pulley and belt routing too. Haven't seen that one yet.
@gmsii - can you get a picture with the throttle body intake tube off shooting down to expose belt routing?

here you go:

[digital_assassin]

Awesome. You can see right where the C38 would mount to. Thanks @gmsii!

[CSG David]

I spy double-sided cog belt or are my eyes playing tricks on me? I'm curious, do the two cog gears shown have different pitch sizes?

[pheoxs]

Originally Posted by CSG David

I spy double-sided cog belt or are my eyes playing tricks on me? I'm curious, do the two cog gears shown have different pitch sizes?

From that routing yeah it needs to be double sided.

[Taber]

I will reserve my final judgement for when this kit has officially be released and installed on some cars, but I think this may end up being the FI kit for me once winter has ended.

[Calum]

Originally Posted by sw20kosh

Not trying to cause an arguement but the turbo will have a pretty significantly higher output than the superchargers.

[Calum]

Originally Posted by CSG David

I spy double-sided cog belt or are my eyes playing tricks on me? I'm curious, do the two cog gears shown have different pitch sizes?

Yup, that was my first thought. I'm REALLY curious why they didn't use two pulleys, mounted lower then the SC drive pulley, and a single sided belt. They could have maintained the same pulley coverage, and could have mounted the tensioner assembly at a 45 deg which would have made it easier to adjust while it's mounted to the car. This way, all pulleys have to be cut with a gear pattern, they have more pulleys, and a longer & more expensive belt. I'm wondering what was in the way. ???

[nelsmar]

Originally Posted by sw20kosh

Not trying to cause an arguement but the turbo will have a pretty significantly higher output than the superchargers.

Modern superchargers aren't as inefficient as they used to be... I made 360WHP with 11.5PSI on E85 and a full stock exhaust with stock header, both cats... I am pretty close to most of the turbo guys in my pressure range. Sure the turbo guys may be slightly better, but a lot of turbo setups have 1 or 0 cats, full exhaust, high flow header, etc. Mid range power? sure, they make more psi at a lower RPM with the downside of a higher transient lag than I have. But saying that a ton of power is lost by using a supercharger isn't fully accurate. But lets not take this thread off topic in a debate about what is better.

[TrogDor the Burninator]

Originally Posted by Calum

Yup, that was my first thought. I'm REALLY curious why they didn't use two pulleys, mounted lower then the SC drive pulley, and a single sided belt. They could have maintained the same pulley coverage, and could have mounted the tensioner assembly at a 45 deg which would have made it easier to adjust while it's mounted to the car. This way, all pulleys have to be cut with a gear pattern, they have more pulleys, and a longer & more expensive belt. I'm wondering what was in the way. ???

I'm not so sure the 3 pulleys need to be cut to match the cogs ...

so long as the pulleys have a bevel of some sort on the inside edge it will collect the belt and spin accordingly provided there is proper tension in the belt system ...

As for the pulley count and placement, I seem to remember a best practice of having a pulley between each cogged wheel in a machinist environment ... not sure if that applies to engine bays ... It's been years since I had that training ...

[Calum]

Originally Posted by TrogDor the Burninator

I'm not so sure the 3 pulleys need to be cut to match the cogs ...

so long as the pulleys have a bevel of some sort on the inside edge it will collect the belt and spin accordingly provided there is proper tension in the belt system ...

As for the pulley count and placement, I seem to remember a best practice of having a pulley between each cogged wheel in a machinist environment ... not sure if that applies to engine bays ... It's been years since I had that training ...

I don't know how a cogged belt would react to the cyclical compression of the cogs caused by being under tension while running over a smooth faced pulley. My thought is that the belt wouldn't like it at all, which would either diminish the belts life, or require cogged idler pulleys.

Two pulleys would still satisfy that best practice, would it not? My thought is that there would be two pulleys on either side of the compressor, but lower instead of above the compressor pulley.

I'm not trying to argue here, I'm just trying to expand on my earlier post to ensure I wasn't misunderstood. I posted my idea expecting to be told it wouldn't work, I'm just not sure why it wouldn't work.

[TrogDor the Burninator]

Oh I'm not trying to argue either Calum ... just was cleaning some cobwebs off of some distant training I had on pulley and gear systems in production line equipment. I'm all for being 100 percent wrong and learning by my foolishness. Science and understanding require it!

[kask2_6.0]

Originally Posted by Calum

Yup, that was my first thought. I'm REALLY curious why they didn't use two pulleys, mounted lower then the SC drive pulley, and a single sided belt. They could have maintained the same pulley coverage, and could have mounted the tensioner assembly at a 45 deg which would have made it easier to adjust while it's mounted to the car. This way, all pulleys have to be cut with a gear pattern, they have more pulleys, and a longer & more expensive belt. I'm wondering what was in the way. ???

My bet is that they are using the other pulleys and the back side of the belt to spin the supercharger the opposite direction of the crank pulley due to the design of the turbine.