BMW Z3 Borla Exhaust

Exhaust Replacement Cost: ~$399 (incl. parts, install, tax, beer bribe) Pros: Much better sound. Added HP (according to butt dyno) - particularly with intake and ECU mods Cons: Volume (doesn't bother me, but the neighbors might have a different opinion) Body work damage possible but can be avoided. Installation Time: ~3 hours Shortly after installing the Dinan chip and Air intake, I decided it was time to replace the exhaust in Dieter Z (the last of the intake/chip/exhaust upgrade trilogy). Having heard the Baba's "HANS" exhaust at BAD III, I knew that Dieter Z needed a BORLA. On the advice of the Baba, I tried to find a hot rod shop around town here in Sandy Eggo that would do the surgery. All the shops I went to jumped at the chance to work on Dieter Z, but none of them could get a BORLA through their distribution channel. Time was growing short as I wanted the have the BORLA installed before going up for BAD IV. Then it was decided that I would simply have the installation done before BAD IV at the same shop that did "HANS" exhaust. the Baba set everything up with Muffler Tech (what a guy!). I would arrive up in Stockton a couple days before BAD IV and have the exhaust done. The BORLA exhaust is not for the feint of heart. At an idle, you can hardly notice a difference from the stock exhaust. Revving the engine at a standstill, there is a definite growl - enough to scare small children and domestic animals. At full load, running through the gears, the BORLA will bring most pro wrestlers to their knees and a tear to hard core bikers' eyes. You can download a (800K) ZIP file containing 2 WAV files...one of the BORLA at idle and revving, the other under full load through the gears (only 28 seconds before a slight mishap caused the mic to meltdown). These WAVs are OK...I may post better ones once I get a replacement mic. Caution: Start with speakers turned down low...these things could blow something...and I aint buying ya'll new speakers. (click on thumbnails for full size pics - some pics courtesy Eileen and BabyZ - other pics taken, scanned, and/or otherwise made possible by the overwhelming generosity and hospitality of the Baba)
We arrived at Muffler Tech about noon. After turning over the keys to Dieter Z (along with a small bribe to ensure the best possible work and care), JR and the guys set to work. We had a concern the days before the job that the tips might not be in when I arrived. All worries were set aside when JR informed us that the tips had arrived just that morning.
	With Dieter Z up on the rack, the work began. (I really hated to see cutting torches that close to Dieter). We first looked over the stock exhaust and went over what we were going to do.
The stock exhaust includes a resonator...this had to go
	A twisty crimped pipe...this too had to go
and ending in a big bulky muffler (the thing must weigh some 20 pounds)...this definitely had to go. The stock system is quiet, but the exhaust tone lacks much, and with the air intake and chip, the back pressure sounds as if it would blow the stock muffler right off.
	So with a little cutting (I couldn't bear to watch) and removal of a couple hangers, the old exhaust was off.
The difference in size between the stock exhaust and the BORLA is quite evident.
	It took them 3 tries to form the 2.25 inch pipe just right. They wanted just the right fit with as little bending as possible. Dieter Z lost about .5 inch in clearance so they could bend it around the same area where the stock exhaust was crimped. Once it was all staged, they welded the pieces together.
They then fabricated a Y and applied the BORLA inter-cooler tips. They attached the tips in a staggered fashion that allowed the tips to follow the curve of the rear-end better than if they were attached even. With Dieter Z's setup, the tips were set even in the cutout area, but melted a bit of the left side of the tip cutout as the exhaust got hot and shifted to the left. This melting only occurred to a small extend until the exhaust had traveled its full extent, and was easily cleaned up later. The lower pic shows Eileen's BabyZ tips which were constructed closer together and angled a bit to the right. This allowed more room for the tips to move to the left when the engine was running and the exhaust system got hot.
	Because the BORLA was so much smaller, they had to custom build new hangers. They replaced the BMW rubber mounts with Honda mounts. The Honda mounts are about the same size, but have more rubber to them making them more rigid. They then bent and welded J hooks from the mounts to the muffler. Note the right angle and braced hanger on the right rear of the muffler. This setup made the muffler setup very rigid, but allowed vibrations to be dampened by the mounting rather than traveling back to the engine or body.

Exhaust Replacement