Can someone shed some light on this? I have been informed that Cool New Ltd (UK) is offering pulley reductions to 25%. These have been installed on owners cars.

Does anyone here have one installed? Any first hand knowledge? Numbers? How is it made? Who makes it? Rev limit correction?

 

...If we can't keep belts on 19% pulley's, do you see a practical point to anything smaller?

As for all your questions: more boost via more s/c RPM; more heat too. Yes you're spinning the blower faster than you should, but that hasn't seemed to stop us in the past, lol.

 

I had heard of someone who installed a >19% pulley on his MINI and BAD things happened.

I think the guys at helix had heard about his (this) case. You might want to inquire with them.

 

At 19% you are already pushing it. Anything smaller will call for supercharger upgrades and perhaps more troubles = reduced engine life.

 

The 19% isn't inherently evil, but it does push the blower to 100%

It's all about state-of-tune vs. duty cycle (aka driver's right foot). If you never hit WOT and don't rev over 5k, then a 25% pulley (if even possible) might work for you. On the other hand, someone that does ALMS will not want to go smaller than 15%.

 

the smallest pulley I have made is 22% reduction; the mechanical limit as far as a bolt-together pulley and hub. As far as I know, no-one has tried it out yet and it simply is an ornament on Helix' desktop.

 

Two people on MINI2 have had contact with me stating that the install was done. One of them was a 25%, the other was a 21. I don't know how or what type...waiting for more info. The website shows a pic of a pulley identical to Minimania's steel/alum. unit in 15% only.

 

Seems to me you'd need a belt smaller than the 19% belt and a modified idler-pulley asscembly. Even then what would the benefit be? Maybe a drag race only solution? ...But everything from the transmission through to the suspension would need modification - and some BIG-*** drag radials.

 

at what point does the water pump just give up?

 

Maybe that "25%" is metric...
(edit)

 

You aren't serious are you? No emoticon so I can't be sure.:smile:

 

 

The advantage is that boost would be even earlier in the rev range. The disadvantage is that it would significantly reduce the rev limit on the supercharger. Also, I am sure the 25% is well into the 20+psi range. The drag on an Eaton at that psi is really huge.

 

I would imagine that a 25% would more than max the injectors as well...

 

Assuming a 25% reduction could keep a belt from breaking (I doubt it could), it would be great for daily driving. TONS of torque down low. But you'd need a low-rev limiter such as 6k RPMs to protect the supercharger from overspinning and to prevent the MINI from running way too lean up top. But the torque would definitely be too much to the lack of traction.

 

Everyone said the 19 was a no go, and now look at it.

Will the 20 - 25 be the next thing to have?

 

I ran my car w/ recently installed 19% at Phil Wicks' driving academy today. I was tractionally challenged (stock RS-As on S-Lites) to say the least..:smile:

 

I don't know if it would be streetable, to the point were you be able to constantly enjoy the car. I enjoy the 19% I currently have. The car feels incredible.. Now going anywhere from a 20%-25% there is just many things that can happen. Belt, over revving the supercharger, it could also push the water pump to its limit. Pros would include more torque at lower rpms , and if tuned right you could get some very decent power gains . Still not enough research out there to risk it.