CP-E Intercooler Upgrade Ups Power and Torque

We installed a CP-E intercooler upgrade.  The CP-E core has a volume that's around double the volume of the stock core, and is more efficient as well.  Cast end tanks make for smooth flow in and out of the core.  The kit also comes with an additional oil cooler, which is invaluable if you're going to run the car at the road course.

We followed the instructions CP-E includes with the kit, and everything fit together nicely.  Note that plumbing clearance is very tight on a car equipped with an automatic transmission (like ours is), since there's an extra water-to-oil transmission cooler that's not present on the manual-trans cars.

You've probably noticed the CP-E logo on the intercooler core.  I wasn't super excited about the logo -- not that we don't love the guys at CP-E! -- but decided to fit the core up and see how it looked before doing anything drastic like removing the logo or spraying the core black.  It turns out that you can hardly see the core OR the logo when everything is back on the car.  If you are REALLY looking closely -- like crouching down and putting your face right at the bumper -- you can see the logo.  Otherwise, you'd never know it's there.  So it'll stay.  If anything, it's kind of nice because it's an indicator the intercooler core is not stock, if someone does end up peering in there.

We did some minor trimming of the plastic vanes on the inner bumper plastic to make installing the oil cooler easier, but we didn't have to cut or trim any of the outer bumper skin.

Once done, we strapped the car back on to the dyno and ran it.  We gained another 15 hp and 21 ft-lbs of torque.

We're very happy with the results from the intercooler upgrade, and with the fit and finish of the kit.


The massive power gains we've achieved at each stage of this project are addicting.  We're now considering a full turbo-back exhaust, despite our earlier vow to keep it stock...

In other news, the AccessPort now works on all 335i models, including 2007 model years.  We expect to hear soon about the latest maps, which will include Stage 2 maps for cars with full exhaust systems.  We also expect the release of the Cobb ProTuner software, which will allow us to develop custom maps here at Mach V Motorsports.

Wavetrac LSD: 100% More Driven Wheels!

We installed a Wavetrac limited-slip rear differential in the shop 335i, and it really changes the way the car drives.  By no means does it eliminate tire spin or slip -- it can't perform miracles -- but when the rear end does give way, both wheels are spinning, not just one.  Those annoying one-wheel burnouts, which seemed to happen every time I drove the car, have been replaced my much-less-frequent small episodes of rear-end-hip wiggling as the tires struggle a little before hooking up together.  Another benefit is the elimination of the strange left-right-left jerkiness that was the result of the stock "e-diff" braking action attempting to get control of the one-wheel tire spinning.

By now we're getting pretty good at the differential swaps on these cars.  Give us a call and we can put one in for you. It takes about a day.

Note that there are two types of differentials on these cars.  Most of the automatic-equipped cars have bolt-in differentials, and some of the early manual-transmission cars do, too.  Replacing the differential on those cars is a straightforward affair.  Other cars have weld-in diffs, and that requires a bit more work and cost, since we have to have ring gear machined off the old differential.


In my next post, I'll talk about a CP-E front-mounted intercooler upgrade.  Check back in a few days.