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R1 5PW + Rotrex = worth it?
nstrug - 26/3/08 at 08:40 PM

Does anyone know if someone has used a Rotrex on an R1 5PW? I'm toying with the idea but I'm not really sure how to proceed.

My main issue is how to get drive off the end of the crankshaft. The timing cover end of the crankshaft has a nice M10 thread in it that is used by a bolt to retain the pickup coil (60Nm according to the workshop manual so probably 10.9 though the bolt is unmarked)

Would this be suitable for fitting a shaft to drive the pulley?

The timing cover has a threaded plug which provides access to the crankshaft end. The timing cover itself is cast ally and looks reasonably strong. Would it be enough to thread a roller bearing and fit it into the plug hole, or do people usually fabricate a bracket so that the drive pulley is supported on both sides?

I've never seen any supercharged bikes up close so I'm really interested to know how people get the drive out for the charger.

Cheers,
Nick


nstrug - 26/3/08 at 08:41 PM

quote:
Originally posted by nstrug
The timing cover end of the crankshaft has a nice M10 thread in it that is used by a bolt to retain the pickup coil



Of course I meant pickup rotor...


hobbsy - 26/3/08 at 10:05 PM

Interested in what you find out but I've been slightly biased towards turbocharger conversions as they seem to spool well and its cheaper to get a new Mitsi turbo thats suitable than a Rotrex.

Plus it arguably easier to make a turbo manifold sometimes than fab a reliable supercharger drive.

Plus the amount of horsepower it takes to spin the charger.


nstrug - 26/3/08 at 10:33 PM

quote:
Originally posted by hobbsy
Interested in what you find out but I've been slightly biased towards turbocharger conversions as they seem to spool well and its cheaper to get a new Mitsi turbo thats suitable than a Rotrex.

Plus it arguably easier to make a turbo manifold sometimes than fab a reliable supercharger drive.

Plus the amount of horsepower it takes to spin the charger.


I know all the above but just wanted to do something a bit different - and I like my sidepipes


hobbsy - 26/3/08 at 10:37 PM

Hey you can still keep the side pipes with a turbo, you just need to mod them a bit

Plus the rotrex is just like a turbo on the compressor side so kinda acts similar ish to one in terms of spool and boost vs rpm (well kinda...).

Its ain't rootes s/c put it that way. I'm sure you already know this know.

Check out MK (I think) who did a GSXR1000 with a Rotrex... Rizla decals if I remember?


Daimo_45 - 26/3/08 at 11:49 PM

Must be do able. TTS do a conversion kit.

Linky

[Edited on 26/3/08 by Daimo_45]


Coose - 27/3/08 at 08:29 AM

The TTS kit takes the drive off the clutch gear. They cut a hole above the clutch in the crankcase and mount the S/C there. Apparently they work very well!

After owning a Polo G40 in my youth, I'm afraid it'd be supercharger over turbo for me every time!


Coose - 27/3/08 at 08:30 AM

Hmmm... Looking at your link it seems that the kit drives off the end of the crank, so it should be even easier to fit! They must have moved away from the clutch-mounted kit.....


MikeRJ - 27/3/08 at 08:40 AM

quote:
Originally posted by hobbsy
Plus the amount of horsepower it takes to spin the charger.


It does takes some power to drive a turbo charger as well, many people seem to think it uses purely "waste" energy.


hobbsy - 27/3/08 at 10:37 AM

Not a cheap kit either. You could cobble together a turbo kit for under a grand or so. Depends if you have to pay for fabrication or you can do it yourself.

Plus you can get more than 30% power gain that way Even with a stock bottom end.

And ref G40 Polo - isn't that a positive displacement charger so will drive quite differently to these centrifugal "half a turbo" Rotrex's?


nstrug - 27/3/08 at 09:34 PM

Yes, TTS do a conversion but its very expensive and they only do 04 R1 onwards, presumably because they don't like the CV slides on the 5PW throttle bodies.

TTS only quote 30% power increase which seems low to me - plenty of people are getting 50-100% power increases, although with a need to drop compression at the higher levels of boost obviously.

What TTS do (taking drive off the crank) is what I would plan to do, just wondering what actual machining needs doing.

Nick


Schrodinger - 27/3/08 at 09:39 PM

there have been some articles in PPC over the last couple of month on using superchargers and where to source them and mount them.