Review: Borla Cat-Back for E46 325

In January 2004, my car was a test mule for Borla Performance Industries for fitment and installation of their soon-to-be-released E46 325/330 cat-back sport exhaust. A couple of weeks ago, I picked up my car and have since driven approximately 500 miles. Having what I feel is a sufficient amount of time behind the wheel , I would like to offer this review:

So here goes:


Sound:

Understandably, my biggest concern was sound. Would the new exhaust be too loud? Would it drone on the highway and set off car alarms as I accelerated down the street? Would it drown out the sweet song of the BMW inline-6? The answer to all these questions is, thankfully and remarkably, "no."

Its apparent that Borla went to great lengths to ensure their exhaust would compliment this car. The difference over stock is noticeable the instant you turn the key. It begins with a deep muted rumble at engine start. Between 1200-2000rpm, you are treated to a nice throaty (and somewhat loud) growl. Between 2500-3500rpm, the deep growl reveals a slightly deeper, more melodic mechanical rev-up. Once past 4500rpm, the car begins to sound surprisingly stock, all the way up to redline. Lifting off the gas reveals a slightly more pronounced "burble" that settles into a low rumble as revs drop back to idle.

At steady cruising speeds, the exhaust does not drone. Planting your right foot brings back that wonderful low growl. Around town, for the full aural assault, I like to lower all the windows. At that point, the exhaust becomes quite loud at any rpm.

Compared to the 330 (and especially the ZHP), the stock 325 sounds quite tame. The Borla essentially enhances the sound of the 2.5L engine, endowing it with at least some of the "raw" quality that makes the 330 exhaust (personally) so appealing.


Looks:

Of lesser, though not insignificant concern was aesthetics. The polished tips of the Borla unit represent a welcome improvement, both in size and appearance, over the mundane stock tips. The Borla tips are angle-cut (staggered) to match the curvature of the bumper, and seem to stick out about the same length as the original tips. Relative to other cars, the outlets are only slightly larger in diameter; from a distance it could almost pass for a stock 325 with chrome tip accessories.

Update: For those concerned about scraping, ground clearance at the tip is 22cm (~8.75 inches).


Quality:

The entire unit seems very well built and assembled. The tips are polished to a nice shine, the remaining componentry untouched as flat stainless-steel. Installation of the exhaust was performed by Borla and seems to be of equally high quality. The entire product is covered by a million-mile warranty.


Performance:

I'll get this out of the way first: I notice no appreciable increase in power. This was expected given the dyno results Borla quoted: 5-8 horsepower over stock and a 150cfm average increase in flow. I don't (yet), however, have any additional dynamometer data in front of me, so I have no idea what at what engine speed these figures were achieved, nor am I able to provide torque measurements. Given the stock exhaust is already a straight-through design, these modest power gains seem within reason.

One area in which the Borla unit outperforms the stock unit is weight. The Borla cat-back weighs in at 41 pounds, a substantial 39% lighter compared to the 67-pound stock exhaust.


Availability & Pricing:

This exhaust is identified as Borla part # 140084. For more information on pricing and availability, visit Turner Motorsport's product info page at (http://www.turnermotorsport.com/html...DUCT_ID=140084).


Recommendations:

Overall, I am very pleased with this Borla product and would certainly recommend it to any 325 owner looking for a well-crafted, refined cat-back exhaust replacement. It's throaty without being annoying, saves weight, carries a solid warranty and, in my opinion, looks much better than the stock exhaust.

Rating: A


Pictures:









Sound Clips:

This first clip was recorded with a camcorder, so the audio quality is relatively poor. It doesn't really do the Borla much justice, but I'm providing it anyway for those who are interested. You will need QuickTime (or something capable of playing MPEG-4 files) to play this file.

This clip was recorded from inside the car, behind and above the front passenger seat, all windows rolled up, climate-control system turned off. Time was ~7:30pm (Sunday, no traffic), outside temperature of 58-degrees Fahrenheit.

http://homepage.mac.com/jgrgnt/storage/borla/Borla.mov

Update: This second clip was recorded using my PowerBook G4's internal mic, from behind and to the left of the exhaust outlet, at standstill (obviously). Originally a full-quality AIFF, this file was reconverted to a 192k MP3 to save space:

http://homepage.mac.com/jgrgnt/stora...rlaOutside.mp3

- Michael

Nice write up!

I would have to agree with you that the Borla is a very well built unit. Very civilized exhaust note... more agressive, yet not obnoxiously loud. I'm a bit surprised that your tips do not stick out past the bumper. Mine do.

any price projections

I can easily say the Borla exhaust is much better than the B&B (TriFlo) exhaust.

My brother has the Borla on his 330i ZHP, and I had the TriFlo on my 330i.

The TriFlo exhaust didn't have the quality of engineering compared to the Borla. The TriFlo was louder, and had horrible resonation - unacceptable for street use (great on the track though). The Borla is bolt-on, excellent quality, and hangs perfectly straight.

The sound is a bit louder than stock, yet never "rice" or obnoxious.

If you are in the market for exhaust, the Borla deserves a solid look.

Sorry if this is a dumb question but is the exhaust for the 330/330 ZHP/325 the same part number?

Originally Posted by wingspan

Sorry if this is a dumb question but is the exhaust for the 330/330 ZHP/325 the same part number?

Actually that's a very good question... and I have no idea what the answer is to that!

Originally Posted by wingspan

Sorry if this is a dumb question but is the exhaust for the 330/330 ZHP/325 the same part number?

I don't think - but maybe.

Borla did testing on 325, 330i, and 330 ZHP models. I don't know if they created three different systems, or just different bolt-on connections.

Yes, I seem to have the idea that the exhaust pipes are different sizes in the engines. On the other hand I would imagine an after market exhaust at least ought to flow at least as well as stock, so I believe there would be one unit with different mountings...?

Originally Posted by doeboy

Nice write up!

I would have to agree with you that the Borla is a very well built unit. Very civilized exhaust note... more agressive, yet not obnoxiously loud. I'm a bit surprised that your tips do not stick out past the bumper. Mine do.

Where's the pics? Oh I forgot. No digital camera.

I imagine they are the same.. the 323/328 and 325/330 share the same exhausts.. single pipe and dual pipe.. so I would imagine it's the same way for borla.. but i could be wrong..

Originally Posted by Mdk330i

Where's the pics? Oh I forgot. No digital camera.

so when are you gonna buy me one?

I'd be interested to know how this Borla exhaust compares with the ZHP stock exhaust.

Nice review...any chance you can record the sound of the exhaust from outside the car? I'm very interested in the Borla cause it's a full cat-back and not a bolt on but if it doesn't sound better than the remus from outside the car I'll prbly stick with the remus. But, I'm hoping that the Borla exhaust sounds better so I can get the cat-back. Thanks...

It would be interesting to hear what Borla has to say about improvements on the ZHP. Since the exhaust is one of the ZHP related changes, I would assume a very slight improvement especially if there is one Borla system for the 325/330/330 ZHP. One would assume that the ZHP exhaust system was optimized by BMW for all of the engine/software changes. I’m not sure where the HP bottleneck is in the ZHP system (i.e., air in or exhaust out).

My guess is that Borla uses the same unit to cover all models.

It's been a while since I drove one, but I'm pretty sure the ZHP still sounds considerably more aggressive than my 325 with the Borla. But I suppose that's understandable since I'm down a half-liter in displacement.

I imagine pricing for this model would be similar to that of the 323/328 exhaust.

I'll try to get a sound clip from the outside.

Michael

Originally Posted by jgrgnt

My guess is that Borla uses the same unit to cover all models.

It's been a while since I drove one, but I'm pretty sure the ZHP still sounds considerably more aggressive than my 325 with the Borla. But I suppose that's understandable since I'm down a half-liter in displacement.

I imagine pricing for this model would be similar to that of the 323/328 exhaust.

I'll try to get a sound clip from the outside.

Michael

If I had a way of recording the exhaust note, I would for you guys.... I'm sure someone else will handle it though now that it has been brought up..

Originally Posted by jgrgnt

One area in which the Borla unit outperforms the stock unit is weight. The Borla cat-back weighs in at 41 pounds, a substantial 39% lighter compared to the 67-pound stock exhaust.

Would the difference in weight (26lbs) have any effect on the way the car handles? Possibly not, but then again, why put the battery in the trunk in the first place? If it will make a difference in handling, one solution would be to move the battery back up to the front, but that would be a

Originally Posted by AndDown

Would the difference in weight (26lbs) have any effect on the way the car handles? Possibly not, but then again, why put the battery in the trunk in the first place? If it will make a difference in handling, one solution would be to move the battery back up to the front, but that would be a

Weight is bad.

Weight down low is better... but the lighter exhaust probably raises the center of gravity. You can't win, you just can't win...

Originally Posted by Emission

Weight is bad.

Weight down low is better... but the lighter exhaust probably raises the center of gravity. You can't win, you just can't win...

Guess that just means I'll have to lower the car a little more to compensate for it...

Originally Posted by Emission

Weight is bad.

Weight down low is better... but the lighter exhaust probably raises the center of gravity. You can't win, you just can't win...

My silly audio upgrade probably offset the weight savings of the exhaust.

Originally Posted by doeboy

Guess that just means I'll have to lower the car a little more to compensate for it...

One upgrade sparks another? Terrible. Just terrible.

So I'm thinking of getting a CAI...

Originally Posted by jgrgnt

One upgrade sparks another? Terrible. Just terrible.

So I'm thinking of getting a CAI...

Well no.... since I have coilovers.... I can just re-adjust as necessary....

but then... I too am considering a CAI....

Originally Posted by jgrgnt

My guess is that Borla uses the same unit to cover all models.

It's been a while since I drove one, but I'm pretty sure the ZHP still sounds considerably more aggressive than my 325 with the Borla. But I suppose that's understandable since I'm down a half-liter in displacement.

I imagine pricing for this model would be similar to that of the 323/328 exhaust.

I'll try to get a sound clip from the outside.

Michael

Ok, so if I have this right:

1) I can buy a Borla for a ZHP,
2) it will be quieter than the stock ZHP exhaust,
3) will weigh less
4) and generate more power?!?

If so, I gotta get one of these!

Guys,

For the first batch of mufflers only, all Bimmerfest members will get special introductory pricing. Afterall, if it wasn't for you guys this system wouldn't even exist!

Please email us direct if you are interested in a Borla and we will contact you when the systems are available. There is no commitment, you will just be notified when the systems come in and are ready to ship. You can decide then if you want to go forward with the purchase or not.

Interested? Just email us at info@turnermotorsport.com and put "E46 325/330 Borla" in the subject line. Include your name, your car model and year and of course your contact information (phone, email or both.)

Thanks!

Doug

Originally Posted by dugmar

For the first batch of mufflers only, all Bimmerfest members will get special introductory pricing. Afterall, if it wasn't for you guys this system wouldn't even exist!

Do you know about when they'll be ready to go? I've been approached by a few people already.