rotrex chargers
Turbo Mini Forums

morning..

im doing a bit of research for next year when ive got space/money/life to start a new project.

im trying to find out info on using rotrex on an a-series. ive had a search about on here and havent found much useful info.

rumour has it there has been a mini using a rotrex, does anyone know any more info?

i dont want to start off a turbos vs supercharger thing.. but i figured if anyone knew about this you lot would..

cheers

There was indeed a mini with a Rotrex. Guy was in Scotland or somet. I think Evo knew who it was....

I seen a red one in a minimag yonks ago. Ill dig it out if you want.

Back once again like a renegade master

jordan - please, thatd be great

That is the same one.

I used to have a rotrex on my old golf - great little chargers. Loads of boost.

Rotrex Scs are rubbish IMO, a crosss between a turbo and a supercharger, but the worst parts of both. i.e a high boost threshold using lots of power.

They have a use in that they can be bolted on to stock (read high CR) engines because they only make useful boost at high RPM where the dynamic CR is lower (I think that's right).

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I was running 1.6bar on mine.. over 1bar from 2000 and up..

hi will,

didnt see you guys at gurston last weekend, you still sprinting the 998?

im interested in your comments, rotrex claim their chargers are around 96% drive efficient.

i'll come clean i used to be a saxo owner (i can hear you all muttering under your breath now) and these guys use the rotrex extremely well getting 200bunnies upwards out of the 1.6 16v 120bunny lump.

im interested in all comments/opinions/facts..

cheers

hang on when did we move from Banana's to Bunny's?
:)

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

sorry.. habbit. or should that be rabbit lol

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

not a huge fan of the eaton to be honest (i can feel more people hating me by the minute).

the C15 is only 158mm diameter at its largest part so its not exactly huge. i know theyre like hens teeth second hand although i think id buy new anyway just for peace of mind.

roight.. not wanting to start a cross forum flaming session, i want to iron out any flaws in my thoughts about this... ive put some of the above concerns to some guys that run rotrex (not a-series) and this is what they can back with in response.

1 - they do have high boost threshold compared to most tubo's and positive displacement s/c's, and they may sap more power than a turbo, but they're definitely more efficient than any of the positive displacement superchargers.

Saying they combine worst parts of both simply isn't true, the worst part of a turbo is lag and the amount of heat they put into the charge. The worst part of positive displacement s/c's is they are terribly inefficient.

2 - True the compressor is only efficient over a certain range, but thats true for all turbos and S/C's. The advantage of the Rotrex is that the relationship between the input speed and the turbine speed isn't linear so as the input speed increases the turbine speed doesn't increase as quickly so the tubine can remainig spinning within its efficient region across a wider rpm range.

the Rotrex works differently from conventional S/C's, which people who have not used one dont understand.

3 - if those comments are true they have soething drastically wrong with the set-up.
there has been one guy using a c30/64 he could not run the compressor at full rpm even without an intercooler as it just kept destroying gearboxs + head gaskets--with only 8psi it gave more power than either sprintex or eaton ,was also more fuel efficent and quieter and reliable.

I'd be interested in how they claim 96%, when the highjest figure you see on any Garrett is less than 80%... 96% for any compressor is frankly, well, unbelievable....

taken off rotrex website..

So, how do they achieve 96% system efficiency?
Take a compressor at (say) 85% (optimistic, sure, but let's try it), multiplied by a planetary gear-train of 95% (wildly optimistic, even for a floating plantet planetary, which is nothing new), and that it 80.8%.


80.8% is not 96%.
Maybe it's the engineer in me, but something smells of BS.

honestly i dont know dave, this is all fairly new to me technically wise. i'll try and find out but in the meantime.. http://www.rotrex.com/

Edited by alpa on 24th Apr, 2008.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

dave - my fault, i mis-quoted rotrex. the drive unit is 96% efficient.

I think this was the one at the IMM in scotland, some years ago...







Regards,
Andreas

http://www.minifreunde.at

Edited by turbodave16v on 24th Apr, 2008.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

they are about the same price as a K1100 conversion and a turbo combined.. which is of course a different kettle O' clams.

given the choice i would probably want a Lysholm i think. (also quite dear but also very compact)

Edited by Sir Yun on 24th Apr, 2008.

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/