One of the facets of BRR, is that we strive to be a complete “one stop shop” for our customers. We had one of our customers come to us with a “custom” request….he wanted full headers, upgraded exhaust, improved performance and HP, but still wanted the car to be fully “smogable”. This particular car also has an automatic transmission.
So, the project included the following –
Evosport underdrive pulley kit
Dinan software upgrade
High flow CATS
Here was the standard fabrication issue. The eBay headers, have an exit point that is farther to the rear of the car…and obviously, since they are headers, they have no CATS. Then, w the auto tranny, there is very little room in the transmission tunnel to locate the CATS at the exit of the headers, and if we were to move them to the area behind the auto tranny, then, they would have fit, but another problem would rear its head….
CATS require a threshold temperature to be reached to be active, and to perform their function. If we moved them too far to the rear of the car, then the threshold temperature would not be reached. We could have done the fabrication, the soluton would have worked….until it came time to be “smogged”. So, what to do?
BRR decided to custom fab the header collector area, and in doing so, we could fit the new high flow CATs back up into the engine bay, where they need to be, and maintain the clearance from the lower control arm, the transmission tunnel, and to be far enough away to also not create heat “soak” w the auto tranny.
This would also require movement of the O2 sensors, and re-wiring of the rear O2 sensors to extend the length. We also wanted to ensure there was no obstruction of the flow of the exhaust for performance.
We did all this within 2 days…all the parts, all the custom fabrication, all the new wiring, all the other parts on the car, and tested, and produced an AWESOME solution….so, be on the lookout for one quick and amazing sounding E46 330i.
Here is pic of the header and mating of the CAT, also noting that we have different metal types – we ended up w 1/8″ clearance on all sides, and away from the control arm, away from the tranny, away from the tranny tunnel, so that we wouldn’t have any rattles or connections or noises or wear –