[blaze6]

i've had look on the forums but couldn't find anything on this so apologies if this has already been covered, - is there any advantage to getting a reduced super charger pulley AND lightened/enlarged crank pulley? as a pose to one or the other? presumably the same performance gains and power delivery through the rev range can be achieved? with one, and there fore cheaper to get one or the other? ie: why get a 17% sc pulley with a lightened crank pulley when you can just get a 19% supercharger pulley?

[Jaw_F430]

Quote: Originally Posted by sayanthan (original)

i've had look on the forums but couldn't find anything on this so apologies if this has already been covered, - is there any advantage to getting a reduced super charger pulley AND lightened/enlarged crank pulley? as a pose to one or the other? presumably the same performance gains and power delivery through the rev range can be achieved? with one, and there fore cheaper to get one or the other? ie: why get a 17% sc pulley with a lightened crank pulley when you can just get a 19% supercharger pulley?

I would go just for S/C pulley. IMO I would avoid crank pullies

[DaFlake]

I'm in the no crank pulley camp as well as the original is a dampened and the ones on the street are not.

[BigShow]

Quote: Originally Posted by DaFlake (original)

I'm in the no crank pulley camp as well as the original is a dampened and the ones on the street are not.

What he said! The un-damped pulley's change the harmonics and have been known to cause oil pump faliure which can lead to a big bills. BMW damped them for a reason.

[captint]

I am in the other school and have already had my supercharger pulley done, but not my crank pulley done, although I have a lightened one to fit, i need a slightly different one for my new mods. I am however have my oil pump rebuilt as a precaution. I just want freer flowing revs, without the crazy expense of going down the Flywheel route

[MINIMANIAUK]

Quote: Originally Posted by BigShow300 (original)

What he said! The un-damped pulley's change the harmonics and have been known to cause oil pump faliure which can lead to a big bills. BMW damped them for a reason.

I would have said are suspected to cause oil pump failure at certain rpms and after a certain lenght of time . The smaller you go with the s/c pulley the less belt contact area you get and slipping of the belt at high rpms becomes a possibility

[MINI-Morgan]

I vote SC pulley although too small can cause belt slipping and reduced belt life. 17% seems to be the best size if you are running a bigger intercooler or its winter

[turtle343]

ive been thinking about this too. would it be worth fitting a 15% pulley to a jcw that lives in really hot weather or would that be dangerous?

[DaFlake]

Quote: Originally Posted by turtle343 (original)

ive been thinking about this too. would it be worth fitting a 15% pulley to a jcw that lives in really hot weather or would that be dangerous?

Plenty of guys down your way run 15% with no problems. I don't see an issue with it. Go above that and you need to start worrying about heat soak.

[roland2003]

..well Big Shows theory on the performance crank pulleys causing oil pump failure is completly wrong. We have had a car in running stock crank pulley and pump failed. (yep new engine) Cause? high rpm.....rev limit was set to around 7700rpm. (not a GTT conversion)
Oh this also overspeeds the SC /water in a big way too(with reduced SC pulley) ., so if you want your power to arrive at over 7K it could spell trouble.

[ScottyBoy]

Ive been running a 15% pulley an 2% crank pulley for around 10 000 miles and all seems fine and ive been thinking of re-fitting the standard crank pulley and upping the S/C pulley to 17% for the reasons that has been mentioned hear.

Im not sure which way to go so ill see what the outcome of this thread.....

[slider]

Quote: Originally Posted by roland2003 (original)

..well Big Shows theory on the performance crank pulleys causing oil pump failure is completly wrong. We have had a car in running stock crank pulley and pump failed. (yep new engine) Cause? high rpm.....rev limit was set to around 7700rpm. (not a GTT conversion)
Oh this also overspeeds the SC /water in a big way too(with reduced SC pulley) ., so if you want your power to arrive at over 7K it could spell trouble.

i have the GTT +3% crank pulley on my 210 jcw although i did have Roland fit a new oil pump , idler pulley & tensioner pulley at the same time.
I am however thinking about fitting a 15% or maybe even a 17% s/c pulley as well to further increase performance . I have recently fitted a GTT intercooler to help lower the inlet temp as i've been contemplating this mod ever since Roland fitted the crank pulley.
what are your views on this ( both Roland & other people)

[MINI-Morgan]

I did run the GTT enlarged crank for 25K miles with no problems so far but have taken it off for future projects and smoother running.

[MINIMANIAUK]

"Im not sure which way to go so ill see what the outcome of this thread....."

You will probably not get the answer , the crank /internals will have a resonant frequency ,and it is this frequency that the stock damper is designed for , this frequency has multiples at which rpms it reoccurs --- If it were below 6800 rpm ,then we would know as there would be plenty of failures already, what is not known is the rpm above this that would cause problems and how many times the engine would have to hit this frequency to cause failure.
High rpm power and running does have its limits ,including piston ring speeds ,which will no doubt be the subject of another thread

[BigShow]

Quote: Originally Posted by roland2003 (original)

We have had a car in running stock crank pulley and pump failed. (yep new engine) Cause? high rpm.....rev limit was set to around 7700rpm.

Quick question, how did you know the car's rev limit was set at 7.7k rpm? Was this measured on the dyno before the pump failed or after, or did you fix it then dyno it and then find out it was set at 7.7k rpm?

To change the rev limit to 7.7k it must have been custom remaped no? Superchips doesn't rev that high as I've seen that map taken apart. So that leaves West which runs to 7,250, Minispeed runs to 7,5k , MTH runs to 7,250... can't think who else increases their rev limit to that level so await your answer.

Are GTT crank pulleys damped then?

[Lucky Dave]

I have been running a GTT 17% with the 1% crank pulley for the last 29,000 miles with no issues. Fact.

I was hoping to see this thread to be full of real facts and the findings posted by the finder.

Not full of hearsay, possible issues and aggressive questioning.

[GRSmotorsport]

Quote: Originally Posted by BigShow300 (original)

Quick question, how did you know the car's rev limit was set at 7.7k rpm? Was this measured on the dyno before the pump failed or after, or did you fix it then dyno it and then find out it was set at 7.7k rpm?

To change the rev limit to 7.7k it must have been custom remaped no? Superchips doesn't rev that high as I've seen that map taken apart. So that leaves West which runs to 7,250, Minispeed runs to 7,5k , MTH runs to 7,250... can't think who else increases their rev limit to that level so await your answer.

Are GTT crank pulleys damped then?

My cars rev limit is set at 7250rpm as you thought, not that I rev it to that much to be honest.

No lightened crank pulley on my car, just a 17% supercharger pulley and 15.5psi of boost

[Paul Webster]

On one side of the argument you have to ask why did the engineers re-design the pulley when they already had a Cooper one (even if the snoots are a different size)

Then you have to ask yourself does the supercharger cause a vibration from the pulley through the belt.

Then you have to ask yourself with all the money they had why did BMW have dampers that failed and were replaced under warranty.

If your car had one replaced under warranty could this already harmed the oil pump?

Then you come into the aftermarket world where really there are no tests on engine rigs at 6000rpm for a 1000hrs or 200,000 miles simulated because no one can afford the R&D for what little profit there is in said item.

So basically the consumers are the ones who conduct the durability tests, we know off a few which have had problems with oil pumps but we dont know the documented history of there engines.

It might also be down to a particular brand that has a problem only time will tell.

Would I run one? dumb question really when you consider the original engineers didn't calculate me running 100hp of nitrous through a stock engine.

[BigShow]

Quote: Originally Posted by Lucky Dave (original)

I have been running a GTT 17% with the 1% crank pulley for the last 29,000 miles with no issues. Fact.

I was hoping to see this thread to be full of real facts and the findings posted by the finder.

Not full of hearsay, possible issues and aggressive questioning.

Exactly my point Dave so here are the facts that are available....

What I have found out is that the stock crank pulley used on the Mini engine has an elastomeric vibration damper to keep the pulley from creating harmonic vibrations in the crankshaft. Harmonic waves can travel through the drive train and through the crank. If there is nothing at the end of the crank to absorb the wave, it will travel back in the opposite direction to meet the next wave. This causes the unfavourable harmonic vibration. The first thing to take the abuse is the oil pump gear and we know what happens when that breaks. So why are we changing the stock part for an un-damped lightweight version? BHP gains? I’d love to see the data showing the gains.

But if you still see the benefits of a lightweight crank pulley and you have a pre-facelift car*, use one that's been designed using many thousand hours of research, use the face lift MCS crank pulley that is lighter than the original but still has its damping capabilities.

There are however a number of people considering changing oil pumps because recently one oil pump on Mini2 has failed resulting in a new engine! What research went into confirming that the pump failed because of high RPM, in fact what research went into finding out why it failed at all? Was the oil sent off for analysis? Were the failed parts tested for weaknesses that could have been inherent in their manufacture??...the answer is no.

I've run my engine to 7.2k rpm pretty much everyday and on track and on the dyno for 30k miles (out of 44k miles) and my oil pump hasn't gone bang and neither has my engine. I've trawled through the Neon forums too and as yet haven't found high RPM's causing oil pump failure there either and some of those engines have now run past the 150k mile mark.

So why are we taking off a perfectly good oil pump and replacing it with another. Just taking the thing apart to fit a new part comes with risks in itself as the old part will have been fitted at the factory and been nicely bedded in along with everything else it comes into contact with.

So we’re happy to change oil pumps due to high RPM’s over a period of time even though it’s not proven to be the cause of failure, yet no-one has considered if there are other contributing factors such as the un-damped lightweight crank pulley which we know causes harmonic issues as above.

That’s why I mentioned it and that’s why I personally wouldn’t recommend sayanthan using one. At the end of the day when we chose to upgrade parts for reasons of performance, we must accept that things can go wrong. As a buyer of performance parts I really want to see the resarch that shows: A) proven performance gains and B) the affect of fitting this part on other parts in the engine. I know this might be asking too much but we are quickly learning what makes power on a Mini and what can actually lose power and potentially shorten the life of the engine. I'll start a new thread on that subject though to ensure I don't drag this one off topic.

*The '05 cars after January build dates have a different crank pulley. That crank pulley weighs in a 5.5 lbs, whereas the earlier cars all the way back to '02 have the same 7.2 lb crank pulley. The Alta pulley weighs 0.9 lbs.

P.S Could the change from a stock crank pulley to a lightweight one the week before the oil pump failed caused the changed harmonics to find a weak link in the oil pump that had been there since day 1? Mmmm food for thought.

[MINIMANIAUK]

Leaders for Manufacturing (LFM) PROGRAM AT MIT - LFM BONINI01

Not quite the prefered design process!!!! it was never going to be perfect ,but has proved robust
It highlights just how important cost was and why somethings are not quite up to the jap engined cars and subsequently caused problems . I dont think the thousands of hours R&D we would like To think was put in actually was put in due deadlines to be met