New Manual Transmissions Are Definitely Sucking: Part Deux

(shiny aluminum flywheel)

I got my Mini back together on Saturday. The new light weight flywheel/transmission is awesome. The engine revs so much quicker with a much faster take off. The clutch pedal feels lighter and take up is quick. It shifts smoothly but a bit touchier, just like a manual transmission from 15 years ago, I love it. I was so stoked to have successfully dissembled the front half of my mini and then put it back together with a quiet and functioning transmission on the first try. BUT THEN…

New Manual Transmissions Are Definitely Sucking: Part Deux

A new problem has arising and I would greatly appreciate your help and suggestions. Even though the car starts and runs well she doesn't want to build boost pressure. The car feels like it’s making 2-4 PSI (stock is 17-22PSI). There is no OEM boost gauge. I’ve ordered an OBDII Bluetooth plug for my phone so I can download the infamous “Torque” app so I can read the computer data and clear codes.

When driving and giving it lots of throttle I don’t get the nice compressor sucking noise or a BOV whistle like usual when I let off. I can’t hear much rushing air at all over the valve train roar. The exhaust is factory so I can’t hear the turbine whistle. The turbine housing uses an integrated waste gate so it’s also hard to hear how much air is being forced through the turbine versus the waste gate.

I have run through the following trying to figure it out:

I pulled off the intake tube into the turbo, there was a light coating of oil from the stupid PCV but nothing seemed wrong with the impeller or shaft. It spun happily by hand and on start up with exhaust pressure. The turbo is quiet at idle with no rattling or bearing noises.

I checked the hot side tubing and the hot side of the intercooler itself for or any kind of blockage. Other than a bit of oil (stupid PCV) it was clear.

I took off the tube running between the intercooler tubing and intake manifold. I used compressed air to shoot air back through the cold side pipes and intercooler, nothing came out and the air flowed nicely.

I took off the intake manifold, checking the vacuum ports , I didn’t seen anything loose or open.

I checked the OEM electronic BOV module on the compressor housing, it was plugged in. I traced the wiring back to the wire harness and into the ECM. I checked the ECM cables and pins.

I pulled off the vacuum line running to the waste gate actuator and stuck it to my tongue, it was getting vacuum from the manifold at idle.

I put it all back together and asked one of my kids to rev the motor to 5,000 RMS while I squeezed the intercooler silicone hoses, I felt some pressure build in the hoses which shows that they are building pressure. Without an engine load I don’t know who much boost pressure it would build.

I left the battery unplugged Sunday.

I hooked up the battery and drove the car to work this morning. The car drove well with that slick new clutch but again it wasn't building/holding boost. 1-3,000 RPMS it feels slightly slow, above 3,000 RPMS the torque curve falls off without boost.

A bit of back story on the 2007 Cooper S R56 Turbos, MINI failed to offer heat shielding for the oil lines at the turbo which can cause the oil to coke up the oil lines and starve the oil of turbo. The Waste Gate Actuator can get some rust build up on the actuator shaft which can keep the waste hate from opening and shutting properly.

New Manual Transmissions Are Definitely Sucking: Part Deux

My guess is that the waste gate is open slightly due to the actuator not functioning properly. BMW/MINI don’t sell a replacement actuator. So I’m probably pulling the turbo myself and sourcing a local shop to rebuild the turbo.

Do you all concur?