[TallAndy]

December 04

[venox22]

2003 and approaching 40k miles

I have the common belt squek(even after new belt) and cold start rattle from the belt/tensioner too, so thinking as preventitive maintenance change the tensioner/crank pulley all in one go

[roland2003]

Hi Robbo, the variations are in the cars not in the parts we fit. The variation in Rolling Road accuracy is such that you could get a 'reading' of anywhere between 190 and 250bhp I think its Dave on here got over 250bhp IIRC
Andy the LSD only helps if the wheels are spinning and you are not pointing straight. My R5 we used for alot of drag racing in the late nineties only had standard diff but always spun both wheels as was pointing dead ahead,so nothing could be gained using LSD. On road legal tyres I could get a 2.1 sec 60 foot time. Not bad for a road going FWD car.
Best regards Roland GT Tuning

[duncanbanana]

my guess the 170 bhp and the 225 bhp arnt giving out the bhp you say they are , i bet the 170 is more and the 225 is less
Also driving styles will have a play in it to
Redun mini was faster than mine ,even though we had the same mods done to them, mine was an 03 and is a 05 , the gearbox was the difference his being a little faster due to the gearing

[BlueMax]

Interesting thread! Some comments:

1. I agree that the revised gear ratios make quite a difference in driveability of the MCS, especially standing start acceleration in 1st. Not sure if it is a 'massive' difference, BMW official 0-100km/h figures are 7.4sec 163hp previous gearbox vs 7.2 sec 170hp new gearbox, so only 0.2 sec. I own an April 04 MCS (now with JCW 210 hp). There used to be quite a bit of hesitation, lag in 1st gear pullaway before the JCW, with JCW it is smooth but still does not 'feel' as snappy as a stock 06 MCS which I drove recently. BMW quoted figures 0-100 for the 200hp JCW old gearbox was 6.7 or 6.8 sec if I remember correctly and is now 6.5 or 6.6 for the current 210hp models. An 04 model like mine with 210hp should slot in somewhere between current stock MCS and current 210 JCW MCS, should be closer to the latter. I do not know what it would do head to head with a new stock MCS, keeping in mind that initial pull-off may be a fraction slower with the tall 1st gear but you can then hang on much longer before shifting to 2nd, short shifting earlier must take away some of the initial advantage?
2 Given the above, it is apparant that 0-100 times are still pretty close and on pure straight line accelaration an JCW MCS should not be giving a stock MCS (even with same gearboxes) a thrashing. Life is not all about straight line performance. Point of my reply being - do some in gear overtaking type acceleration and you should see the converted models blow away the stock ones. Certainly the JCW conversion in my instance did not change the straight line acceleration hugely but once the engine is on the boil above 4000 rpm, the performance difference pre and post conversion is like night and day. I same some video footage of an 05 JCW MCS against a JCW MCS racer used in our local production racing class (significantly lighter, optimally tuned etc), both driven by professional racers from standing start over 400m - the racing version pulled ahead but not by nearly as big a margin as I would have expected. Pit them against each other on track and there will be no contest.
Just my 2 cents

[St00ge]

venox, the jcw pulley is over 14% in reduction size....

also, the LSD can help in straight line standing starts, if one tyre has for some reason, more grip than the other....

[venox22]

well the one i have and measured isnt or one that Roland came across either!!

[T-bone S]

This size thing needs to be cleared up. - I have always read that JCW pulley is 14.4-14.6% reduction.

Seems funny how there can be such big difference in readings 11% or 14-nearly-15%

[St00ge]

Quote: Originally Posted by venox22 (original)

well the one i have and measured isnt or one that Roland came across either!!

Really? Yours too? I read about the one roland measured, but wasn't aware of yours...

Maybe you were unlucky Just goes to show JCW tolerances not being brilliant. The head work on the JCW is also meant to be rubbish. I like the exhaust though. And the injectors

[roland2003]

Hi Guys,
STOCK CRANK PULLEY DIAMETER is 138.5mm +/- 0.1mm . This is what I have very accuratly measured to the 'top of the V groove form' on 2 early types and 2 later types. So no differece in drive ratios between early and late,just weight.
BTW we do a stock size, a +3% and a 'new' +1% GTT lightweight 2pc Alloy Crank Pulley. The latter is not on the website - they are all the same price.
JCW SC PULLEY DIAMETER tbh I havnt measured many of these as they need to be off the car to get an accurate measurement and usually we give them back to the customer. Of the ones I did measure one was around -11.5% the other 14%. I'd like to measure more before I can conclude anything on this
Best Regards Roland GT Tuning.

[T-bone S]

we eagerly await!

[St00ge]

hey roland how come you never advertised the SC inlet plenum mod on your site? I always thought that was an awesome idea.

[T-bone S]

Agreed - I think its looks good too. - along the lines of the M7 AGS.

[St00ge]

Quote: Originally Posted by T-bone S (original)

Agreed - I think its looks good too. - along the lines of the M7 AGS.

apparently roland got 20psi with a 17% pulley and his big intercooler. That's 19psi for me, with a stock IC and 17%. That's significant. And its free (i.e. the SC isn't working any harder, not money-wise)

[Matblack]

Quote: Originally Posted by BlueMax (original)

Interesting thread! Some comments:

1. I agree that the revised gear ratios make quite a difference in driveability of the MCS, especially standing start acceleration in 1st. Not sure if it is a 'massive' difference, BMW official 0-100km/h figures are 7.4sec 163hp previous gearbox vs 7.2 sec 170hp new gearbox, so only 0.2 sec. I own an April 04 MCS (now with JCW 210 hp). There used to be quite a bit of hesitation, lag in 1st gear pullaway before the JCW, with JCW it is smooth but still does not 'feel' as snappy as a stock 06 MCS which I drove recently. BMW quoted figures 0-100 for the 200hp JCW old gearbox was 6.7 or 6.8 sec if I remember correctly and is now 6.5 or 6.6 for the current 210hp models. An 04 model like mine with 210hp should slot in somewhere between current stock MCS and current 210 JCW MCS, should be closer to the latter. I do not know what it would do head to head with a new stock MCS, keeping in mind that initial pull-off may be a fraction slower with the tall 1st gear but you can then hang on much longer before shifting to 2nd, short shifting earlier must take away some of the initial advantage?
2 Given the above, it is apparant that 0-100 times are still pretty close and on pure straight line accelaration an JCW MCS should not be giving a stock MCS (even with same gearboxes) a thrashing. Life is not all about straight line performance. Point of my reply being - do some in gear overtaking type acceleration and you should see the converted models blow away the stock ones. Certainly the JCW conversion in my instance did not change the straight line acceleration hugely but once the engine is on the boil above 4000 rpm, the performance difference pre and post conversion is like night and day. I same some video footage of an 05 JCW MCS against a JCW MCS racer used in our local production racing class (significantly lighter, optimally tuned etc), both driven by professional racers from standing start over 400m - the racing version pulled ahead but not by nearly as big a margin as I would have expected. Pit them against each other on track and there will be no contest.
Just my 2 cents

I would have writen something very like that, it strikes me that a lot of the extra power in the JCW is delivered well after 4,500RPM and as cars racing in a striaght line aren't going to be in this power band for a lot of the time you're not going to see a big difference. Put the same cars on a track and keep them on the boil (over 4,500RPM) and you'll see the increase performance in the higher BHP cars shine through. Currently running in my JCW and it doesn't feel that fast , about the same as the test MCS I drive, but the few times I have crept over 5000RPM it really gets excitable

I need to be spending more time in this power band roll on 1250!

MB

[T-bone S]

Quote: Originally Posted by St00ge (original)

apparently roland got 20psi with a 17% pulley and his big intercooler. That's 19psi for me, with a stock IC and 17%. That's significant. And its free (i.e. the SC isn't working any harder, not money-wise)

I read his little write up reference this mod - but then all a bit quiet. - definately should be marketed

[BlueMax]

MB - JCW wonderful to operate in the upper rpm ranges, fuel companies also agree!

[Matblack]

Quote: Originally Posted by BlueMax (original)

MB - JCW wonderful to operate in the upper rpm ranges, fuel companies also agree!

Fuel prices have gone down about 10% in the last two weeks over here, which means I can press the loud pedal 10% further

MB

[venox22]

So do you know the weight difference Roland??

Miniac qouted this in another thread ''The crank pulley weighs in a 5.5 lb versus the earlier 7.2 lb version.''

How much lighter are your GTT ones versus the Stock ones??

Quote: Originally Posted by roland2003 (original)

Hi Guys,
STOCK CRANK PULLEY DIAMETER is 138.5mm +/- 0.1mm . This is what I have very accuratly measured to the 'top of the V groove form' on 2 early types and 2 later types. So no differece in drive ratios between early and late,just weight.
BTW we do a stock size, a +3% and a 'new' +1% GTT lightweight 2pc Alloy Crank Pulley. The latter is not on the website - they are all the same price.
JCW SC PULLEY DIAMETER tbh I havnt measured many of these as they need to be off the car to get an accurate measurement and usually we give them back to the customer. Of the ones I did measure one was around -11.5% the other 14%. I'd like to measure more before I can conclude anything on this
Best Regards Roland GT Tuning.

[roland2003]

Hi venox, the GTT crank pulleys weigh in at around 1 pound (1/2 Kilo). BTW we also do a '+1% ' aswell as 'stock 'and '+3% 'diameters.
Best Regards Roland GTT