I recently purchased a 997.1tt and immediately bought a Cobb Accesport for it. I came from a tuned 996tt so was anxious for the extra power. My car already had a fabspeed exhaust and headers and IPD plenum installed when I purchased it.

Once I flashed to Cobb to the car I noticed no extra power and also was not able to go above 17psi in sport mode. I went back and forth with Mitch at Cobb who was helping to diagnose (GREAT to work with and very helpful!) and we eventually decided there was a boost leak somewhere.

Today me and a friend who has a BMW performance shop threw it on the lift to test. We removed the hoses off the turbos going to the intercooler to test. Plugged one and put the plug with air valve in the other side. Each time air kept blowing out of the turbo where we had disconnected the hose on the drivers side.

After a call to another friend who suggested BRV, we removed the vacuum line connected to the drivers BRV and squeezed it tight - pressure held firm at 20psi for a good while and no air coming out of the turbo. No other leaks were heard.

Turns out the car had EVOMS BRV's already on it. Would this confirm that I am needing to replace the BRVs?

Thanks for all the help.

 

Just a follow up. I ordered the Forge Motorsport BRVs and these fixed my issued. The EVOMS ones were bad. They had fallen apart on the inside. The Forge definitely are MUCH better quality than the EVOMS ones!

Quick, easy process to change them out. Only took about 45 minutes with a lift.

 

We do have a warranty and rebuild program on those valves. Send them in and we'll rebuild them if you wanted to resell.

Keep an eye on the Forge valves as time goes on, as they will require maintenance and periodic rebuilds like any other piston-style valve on VTG turbos.

We have since gone away from a piston style valve to a new design that uses the stock diaphragm (which has proven to be reliable as time has gone on) with a billet cap and higher preload spring. They give the best of both worlds in terms of OEM reliability and higher preload for modified applications.

Sam