Hi all,
I have been doing some research into turbos etc and i think I have finally decided what I am going to do.
My original plan was a big turbo conversion using a GT250r turbo (as Coopman has), then I saw the ATP turbo kit using a GT28rs, but after speaking to the guy who will be doing the software for whichever option I choose, he has advised me that a hybrid turbo may be the best route...
This involves taking apart the stock Mini Cooper S turbo, upgrading the internals such as the thrust bearings and the shaft, and placing larger turbine and compressor wheels onto it. A common upgrade is the K04 wheels which are upto 5mm larger and thus are able to flow quite a bit more air. (bear in mind a turbo spins at upto 90,000rpm so 5mm makes a lot of diffference!!)
I have been quoted 725$ to do this and it
will run on the stock map, although I will be getting my map altered to suit it. According to my tuner, he has done one before and achieved 292bhp (BHP not WHP) and this was using a Cooper S with only a Milltek Downpipe (no other mods). It was running around the 20psi mark on a hybrid K03 turbo and had a slightly raised redline of 7150rpm.
He was able to safely get it to hold 20psi from 1500rpm till 5850rpm, and then it held 18psi until the redline.
With doing a hybrid, you retain the quick spool up of the characteristc K03 turbo as the compressor wheel can either be left stock (so quick spool up) or made slightly larger so that it will flow more, but have a slightly slower spool.... this is upto the size of wheel you decide upon. Apparently most K03 and K04 turbos have the same size compressor wheel, although there are some "powerful" K04 units which have a slightly larger compressor wheel.
He reckoned this was safe and within the turbo's new limits, and well in the limits of the car. He linked his software upto to the knock sensors and said that the finished map was still within the safe margins, and there was no knock anywhere in the rpm band.
He said the stock injectors have been rated upto 330bhp but they were running at 100% duty cycle and thus werent safe to be run at that everyday.
I will hopefully be getting this done in the coming months, so with myself and Coopmans large GT28R turbo we should see some exciting results from these R56 motors
