What's the factory boost on the SC of the Cooper S? Are there any replacement pulleys available yet to up the boost on the S? All I've been able to find are basic bolt-ons (I/H/E) for the normal Cooper. Thanks. :smile:

 

0.8 bar

 

do not even consider installing an aftermarket pulley that is supposed to magically boost the power output, as the fuel delivery mapping might not be sufficient and you will end up with a lean mixture and excessive combustion chamber temperatures that would eventually lead to engine failure, the modifications required to increase the horsepower by increasing the boost pressure require comprehensive modifications so as to maitain reliability ! unfortunately there is a lot of bozo companies that advertise cheap and badly engineered products targeting the profane/misinformed consumer.

 

Thanks for the info! Wow, I didn't expect it to be that high for a factory setting. I'm not new to engine mods (tho I come from an NA background) so I'm familiar w/ the other areas that need strengthening b4 proceeding reliably. I just wasn't sure whether there were any mods out yet that upped the boost. Do you happen to know how much boost the stock bottom end is able to handle? I assume the car comes stock w/ some sort of boost dependent FPR. How reliable is that piece and up to what boost level? How much power are the stock fuel pump and injectors able to handle? Do you happen to know what duty cycle the injectors are running at at stock boost? I read in another post that you're developing a kit (not sure if it's for the S or the std model) that will make about 230bhp. Do you plan on using bandaids (e.g. fuel controllers - A'pex, Fields, Greddy E-manage, etc.) or will you provide a remapping of the fuel and ignition maps? Thanks.

 

Hey peterj, or anyone else, is it just me or does almost 12psi (0.8bar) seem really high for only a minimal 50hp gain? The base motor puts out 115bhp while the S puts out 163bhp. I know roots-type blowers are not very efficient, but that seems like extremely poor efficiency there. Is the head just not prepped well enuf to flow the added air from the sc? A JRSC on a civic or integra adds about 50-60whp at just 6psi. Anyone have an explanation for this? I know this may be too technical a topic for a car that isn't even for sale yet here, but just some thoughts that came to my head. At 12psi starting w/ the base 115bhp, I'd expect over 200bhp at the least.

 

I agree this does seem like an awfull lot of boost for only 50hp....
The only thing I can offer is that maybe this is why JCW's is pulling 200+ when chipped.......
Looks to me like there is some room to play with the S.
Only time will tell I guess.
SW

 

Sfiveten, does the JCW chip just modify fuel and ignition maps? Did they change the SC pulley to make the 200+hp?...or are they running factory boost? I couldn't find any info on their site. Thanks.

 

This is what I read....
"The aftermarket engine tuning kits sold under the newly-established brand reflect over 50 years in the front line of racing car design and construction and evoke memories of the halcyon days of Cooper racing. The engine conversion will initially be available for the MINI Cooper, developing a worthwhile increase in power from 115ps to 132ps. A replacement high-compression cylinder head, fully polished and gas-flowed, is matched to new free-flow intake and exhaust systems for maximum efficiency. Following the sales launch of the supercharged MINI Cooper 'S' in 2002, the 'Works' conversion for this car aims to deliver some 200ps. Both conversions meet all of the stringent vehicle emissions and engine regulations."

I've heard rumors elsewhere that it will be mostly due to chipping.
Superchips has already pulled 25hp out of the base cooper.... who knows... other than that not much in the way of details just that it will be.....
I just hope it won't cost my arm and one leg. :smile:
SW

_________________
Motor On!!..... Mini Me!!

 

Bear in mind that aftermarket sc kits are bolted on to engines where the compression ratio is maintained at a rather hi level 9-10.5:1, while as in the case of the cooper s the cr is reduced to 8.3:1 from 10.5:1 on the cooper , hen ce a lesser gain in HP despite the relatively high boost pressure, manufacturers are always concerned with durability and reliability + cost issues, in order to increase the cr + high sc boost they would need to have forged Crankshaft, forged connecting rods, forged pistons reinforced valve train components....... what do you think the price of the car would then be???

 

Thanks guys for the info. I just got a reply from JCW saying the conversion kit that makes 200bhp will be for sale in the US in September.

Re high CR and boost, I disagree that the raised compression requires replacement of the bottom end. I thought BMW's came w/ forged cranks already? As for forged rods and pistons, even on 10.5:1CR, as long as the fuel and ignition maps, along w/ fuel delivery system, are setup and tuned properly, an FI motor running 10.5CR wouldn't have any reliability probs (it's all in the tuning). Regardless, starting from the S's 8.3CR (no sense in debating the S w/ 10.5CR since it doesn't exist), w/ 12psi of boost, there still should be more than a 50bhp gain, especially w/ the intercooler to cool down intake charge (I'm still expecting about 200bhp at 12psi w/ IC even w/ 2-pts lower compression). Valvetrain strength shouldn't be a question as long as the lift and ramp rate of the cams aren't changed. I'm not sure if the valves are stainless, but that's not a biggy to replace if needed to handle higher boost, especially from the factory. I'm sure they built in some guardband safety into the internals, so the stock bottom end can most likely handle more than factory boost, but my questions mostly concern factory boost and low output that boost generates. Sounds like JCW is doing some headwork in their "conversion" kits, which may elude to the head and intake mani being restrictions in flow for the SC. Possibly a 2.5" collector header and exhaust would help as well.

 

too many misconceptions!

 

Please explain the misconceptions. If explained, they will no longer be misconceptions. If you're referring to inaccuracies in my statements regarding boost, rest assured I'm not a newbie to this game. A civic 1.6L sohc motor (similar to the Mini's) has only 9.5CR, yet can net 35-40whp (about 40-47bhp) at 5-6psi on a jackson racing sc, which is also a roots-type blower. Knowing that the roots-type blowing is not the most efficient, and taking into account the 1pt lower CR of the S, at DOUBLE the boost pressure, it only nets an extra 5-10bhp over a similar setup. Of course, there are tons of variations in this comparison such as head/intake/exhaust design, etc. but not enough to account for that much of a difference in gains. If you know what the restrictions/limitations are, please share. However, 1pt lower CR and almost twice the boost just doesn't make sense. Thanks.