3 replies to this topic

[Cooper Mac]

I had my Cooper on the rolling road in May, following the rebuild of the engine. The engine had zero miles on it following rebuild before it ran on the rolling road. The engine runs well and pulls nicely, but it was a little lower on the power and torque than expected.

I’d be recommended to fit a single box Millennium RC40 exhaust with an LCB, but having now looked at Calvert’s tests with different RC40 exhausts, it looks like the single box millennium RC40 is down about 6/7 bhp and up to 10 lb/ft on the millennium twin box system!!!!

I want to get at least 1000 miles on the car before I get it back on the rolling road, as the engine should have loosened up by then, and I’m thinking of changing the mid section for one with a silencer.

Does anyone have any before and after dyno results changing from twin to single box exhaust or vice versa?

Cheers!

[Midas Mk1]

Maniflow rcm system the way forward if your chasing numbers.

[imack]

Maniflow rcm system the way forward if your chasing numbers.

The historic race rcm on my mini is pretty loud, louder than the standard bore single box rc40 I had previously. Don't know hod the road rcm compares.

[Speedymad]

Interesting as I am running a single box RC40 and had been considering adding the resonator to reduce noise.  If it will make more power then that will convince the missus its a good idea as she loves the sound of the single!