Product Review ALTA Performance "Stealth" Cat-back Exhaust System for R56 Cooper S

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I have yet to drive a car that was absolutely brilliant and completely perfect in every sense. No, of course I haven’t. Perfection is just an...
  1. Ryephile
    ALTA Performance "Stealth" Cat-back Exhaust System for R56 Cooper S

    Product Review by Ryan Malcolm
    Photos by the Author​


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    The Review MINI

    INTRODUCTION

    I have yet to drive a car that was absolutely brilliant and completely perfect in every sense. No, of course I haven’t. Perfection is just an ideal, not a possibility. There are, however, a select few cars that come pleasantly close to driving perfection. Moving down the ladder, there is a good selection that has fantastic potential, and a whole crop of pure crap. The 2007+ MINI Cooper S hatchback is scratching on the door to that first category of automotive pin-up models. There are a few minor niggles that keep it from that coveted category however; the front control arm bushings, the rally-cross ride height, and the standard exhaust system. While the first two can be addressed with mathematics and physics, the quest for melodic yet powerful exhaust tone is something that will always be haunted by the human ear’s subjective analysis.

    The factory Cooper S exhaust system is no technical slouch; it has two compact catalytic converters, a center resonator and a large muffler out back terminated with two large chrome exhaust finishers all connected with nice stainless steel tubing. It’s a well made and well designed system. Even the tone sounds quite good…from the curb! Once you’ve fastened your seatbelt in the R56 Cooper S, the factory exhaust does little to tantalize the senses. It gags the acoustics of the fantastic direct injection turbo Prince engine so resolutely, it is almost impossible to drive with the windows down and have any sense the engine is running, let alone what RPM it’s running at. This makes sensual, enjoyable driving a much muted experience. It practically sucks the life and fun out of the MINI compared to its hugely visceral predecessor, the R53.

    I’m not alone in this analysis. As a result, there has been a near-instant reaction from the aftermarket community in putting into production a flood of exhaust systems on the market for the R56 Cooper S. These exhaust systems have a breadth of features from value-oriented to exotic unobtainium vaporware. ALTA Performance was not the first to market with their exhaust systems; however, their offerings appear top-shelf in both design and manufacture. ALTA offers four exhausts to choose from to match your aesthetic needs. They offer dual slash tips and a large oval tip, both available in either highly-polished stainless or black-ceramic-coated stainless. All of their systems use the same basic formula; large diameter 304 stainless tubing, V-band clamps, and straight-through perforated core mufflers for minimum backpressure and maximum power with the R56’s turbo-power plant. These ingredients sound tantalizing, however in an automotive world where so often the whole is less than the sum of its parts, will the ALTA provide a home run to nudge the R56 Cooper S into the automotive Hall-of-Fame?

    Shipment, Packaging & Parts
    SHIPMENT, PACKAGING & PARTS

    It all starts innocently enough. A big, plain, brown box arrives at my doorstep. The nicely printed lettering “ALTA MINI PERFORMANCE 'The Finest MINI Cooper Components in the World'” instills a warm fuzzy feeling in a potential owner’s wallet and lets them know they’ve just purchased something special. Oh, but wait a second. Just below that silk-screening is an orifice that doesn’t appear intended. Let’s investigate.

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    Opening up the box of goodies I see why; the rear muffler section’s hangar couldn’t wait to get out of the box and has poked its head out into the real world. No damage was done, however ALTA could improve the packaging tightness to add a layer of rough-shipping-company repellent. Looking further, it does appear ALTA has taken a moment to package up the exhaust. The main box is separated into two sections; the upper section houses the rear muffler and tip, while the lower section nestles the hardware box, cardboard-wrapped mid-pipe, and front muffler section. It’s all very nice looking, and they even spent the money on putting each exhaust section in heavy PVC bags to protect the finish. Only that slight lack of packaging material with the rear muffler section is keeping me from drooling all over the place in awe.

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    This exhaust looks impressive. There, I said it. Of all the exhausts I’ve played with [and fabricated myself] over the years, I must admit the construction and finish quality appears top-shelf. The V-band flanges are formed from small sections of tubing and welded to the main tubing pieces, which keeps the whole thing lighter than billet flanges with minimal loss in seal quality. For a street exhaust, these V-bands are all you need, and far superior to any 2 or 3 bolt flange which are basically guaranteed to leak. The black ceramic coating is also very well applied, with smooth uniformity over the entire exterior of the exhaust. The finish is a sexy satin black, and should not only provide years of maintenance-free good looks, but will also help keep the exhaust heat energy within the exhaust and not radiating into your floorboards or engine compartment. It’s a superior finish, one that I use on my street rods and personal projects.

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    An interesting bit of the system is the adapter to connect the factory front exhaust section to the ALTA cat-back exhaust. It is a three piece fabrication that starts off as a slip-fi t joint to the stock 2.2” [56mm] exhaust tubing, which expands smoothly with a two-piece fl are section that ends up at the 3” diameter V-band flange. It’s a compact adapter that I would expect to have good flow characteristics. The only thing ALTA could have done is used a less complex single section of tubing that has been expanded from 2.2” to 3.0”, however I have a hunch the very strange 2.2” tubing may have contributed to their decision to go with a three-piece design. The front muffler section uses a huge 6” diameter muffler that you can easily see right through. ALTA appears to have custom mufflers built using 3” perforated core stainless steel as the basis, and uses stainless steel wool for sound attenuation material. The front-section terminates with a V-band flange following a slight bend to follow the MINI’s exhaust tunnel. The mid-section is simply a section of tubing with V-band flanges on either end. It does have a slight bend in it to align the system to the shape of the underside of the MINI. The rear muffler section has a large perforated core muffler using similar construction as the front resonator muffler, however it’s larger internal volume and longer length collaborate to give wide-band frequency attenuation. The rear-section comes with the exhaust tip finisher pre-installed. This is a good starting point, but be prepared to tweak its fitment slightly to your tastes.

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    The rest of the hardware is within a neat white box. It contains the front adapter flange with t-bolt clamp, three V-band clamps, a piece of heat shield, an ALTA license plate frame, warranty info, installation instructions, and two 3/8” aluminum lock collar clamps that allow you to center the rear muffler section within the rear bumper exhaust opening. Of particular note are the V-band clamps themselves; they are of very high quality, using all stainless construction and castle nuts. I’m a big fan of castle nuts. They are self-locking; withstand very high temperatures and vibration without backing out. I give kudos to ALTA for not overlooking the little things that impact reliability. What I wasn’t so crazy about however is the V-band clamps appear to be a size too large. The clamps must be tightened down almost all the way before making solid clamping force on the flanges. At that point there are several inches of thread sticking out from the clamp. Not only does this create an installation concern, but an under-car snagging concern too.

    Instructions & Installation

    INSTRUCTIONS & INSTALLATION

    If you’ve installed one exhaust, you’ve installed them all. Or have you? The ALTA system is one of the few that actually include instructions. Not only that, but they’re printed in full living color! As with all instructions, I will admit I actually sit down and read them before throwing the car up on jack stands and slipping on my Kevlar head sleeves and mechanics gloves. The ALTA instructions, however, left me a bit confused. The Special notes, Bill of Materials, and Installation by numbers were surely well meant; however, nowhere in them do they ever mention or show the orientation of any of the three sections of the exhaust. Ok, we can probably deduce the exhaust tip is in the rear of the car, and one of the pictures shows the stock front section mated with ALTA’s special adapter and ALTA front section, but I honestly had to trial-and-error how to mount up the center section. In the end, the slight kink in the middle-section points forward and up.
    [See pictures for the approximate orientation]

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    ALTA’s instructions did give me a chuckle. There is a spot for the packaging technician to initial they’ve checked the contents before sealing, however that spot was totally blank in my set of instructions. Why have it included if you’re not going to use it? Speaking of not going to use it, I have no idea what the section of heat shield ALTA included is used for. The factory heat shield works fantastic and there’s no need to reinvent the proverbial wheel, so what’s it for? There is no mention in the instructions what to do with the heat-shield, and to that there’s no line item on the Bill of Materials for a piece of heat-shield either. What is there, however, is a line item for “(1) Polish packet.” I’m assuming they’re not speaking of sauerkraut and kielbasa, but a metal polishing kit. I turned the shipping box upside down and searched my workbench, but alas, I couldn’t find the Polish packet. In all fairness, neither of these items makes an important difference in the real world when you’re actually installing or enjoying the exhaust, but it is my duty to point out the inconsistencies.

    The tools needed for the installation are straightforward, if not typical for exhaust work. Unless you haven’t lowered your MINI [bit of a joke there], you’ll need a set of jack stands to prop up the car to access the exhaust. The basic game plan is you have to remove the center tunnel brace, then remove the factory main exhaust, cut it in half, and assemble it to the ALTA cat-back exhaust. We start under the engine oil pan where the exhaust downpipe meets the main exhaust. To knock the factory ball-joint V-band clamp loose you will probably need a rubber mallet or a carpenters hammer. Even after removing the fastener, the factory clamp likes to stick, so a tap with a mallet will loosen it. The test MINI had a tough Michigan winter under its belt, so the factory clamp needed the more persuasive action of the carpenter hammer. Using a set of Chan-nel-lock piers helps to un-preload the clamp so you can remove it from the exhaust. Slipping off the rubber exhaust hangars has always been a bit of a challenge for me. I’m not sure if I do it the hard way, or others feel the same, but they are a bit of a pain to pull over the nubs on the exhaust hanger rods. I take my trusty PB Blaster and squirt some between the hanger and the rod. I then use a thin and long flathead screwdriver to lever and slide off the rubber hanger. Sometimes using two screwdrivers helps to pry off the hangers.

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    The tools used for the install:
    • 10mm and 13mm deep well sockets
    • 3/8” ratchet
    • Hammer
    • Chan-nel-lock pliers
    • PB Blaster, WD-40, or equivalent
    • Two small slotted screwdrivers
    • Tape measure
    • Sharpie marker
    • Earplugs!
    • Cutting tool [I used an angle grinder with cutoff wheel]

    The factory exhaust is very rear-heavy, so it helps to have a second set of hands to help remove the exhaust from the car. Once it’s on the ground, first admire how the exhaust appears to be longer than the MINI itself! At 10 feet 10 inches, the factory exhaust certainly is scary long. I can’t imagine the shipping expense of getting it to the Oxford factory. ALTA definitely thought out the shipping end of the situation by sectioning their exhaust into three neat sections. Since the ALTA cat-back does rely on using part of the factory exhaust, it's important the factory exhaust be removed from the car in pristine condition. Accidentally pole-vaulting it over the neighbors’ fence in anti-stock rebellion will probably result in a large tab at the local pub along with an angry neighbor. The ALTA instructions are a bit fuzzy on the next step. The stock exhaust must be cut between the center resonator and the secondary catalytic converter. In other words, it has to be cut between the two 4” round can thingies near the front of the stock exhaust. Get out your 12 foot tape measure. Have a friend hook the end over the exhaust tips and stretch it out until you see 89.0 inches. Grab your Sharpie and make a circumferential line exactly at 89.0 inches from the tips. This is where I cut the stock exhaust. ALTA’s instructions say to cut “roughly here.” I don’t like making approximate cuts, so I did a bit of comparison measuring between stock and ALTA exhausts before coming up with 89” as a solid figure. It’s worth noting the test car has the JCW body kit, so tip alignment with standard or factory aero bumpers may need a different cutting length. It would be beneficial for ALTA to either disclose or discover a recommended cut length of their own to boost installation confidence and keep people from being confused or indecisive.

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    The next steps are easy. In no particular order, you put the adapter, clamps, and all exhaust sections together and hang it on the car. Keep all the clamps snug [not too loose, bias on the tight side] to get a feel for how it all fits. The V-band connections let you rotate the bits to achieve maximum clearance and perfect tip alignment. This is where your friend’s pair of eyes will be handy in helping align the exhaust. Remember the tip itself is adjustable for extension and rotation. Be sure you have at least a fingerwidth of clearance between every inch of the exhaust and the heat shielding, and don’t forget the heat shielding is very flexible in creating more space where you need it. A good piece of advice to remember is to orient the V-band clamps so the nuts are easy to access yet the extra threads are not protruding so they could accidentally snag road debris. When the system is all hung so it looks fantastic and the tip is centered within the bumper opening, finish torquing the V-band clamps and the rear muffler hanger lock collars. One facet of the design I’m dissatisfied with is the center tunnel brace. The instructions give a loose template on how much needs to be trimmed to clear the center resonator. In my opinion, there’s no good reason for the center resonator to be positioned to necessitate this interference fit. ALTA could have pushed the center resonator and adapter two inches forward and there would’ve been no issue. Cutting the center tunnel brace may have a subtle effect on NVH, as it is altering the usefulness of the brace. The test driver found no difference in NVH or body stiffness during his test period, however I object to this cutting strictly on principle and the fact it could have been easily avoided. I will chalk this up to one detail ALTA did overlook.

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    Behind the Wheel
    BEHIND THE WHEEL: SUBJECTIVE IMPRESSIONS & OBJECTIVE DATA

    Beyond the installation, there is little to say that isn’t gushingly positive. Upon starting the car for the first time after the installation was complete I found no exhaust leaks, no rattles, and a subtle yet exquisite exhaust tone. If a Subaru WRX went to Italian boarding school, attended several social gatherings with Ferrari and Lamborghini friends, and returned home with an Italian accent, this is how the MINI was transformed with the ALTA cat-back exhaust. The exhaust sounds one part supermodel sexy, one part show-off muscular, and one part no-frills race-car performance. The amplitude and tonal quality inside the car is eerily similar to the JCW exhaust included in the JCW Tuning Kit; however, the ALTA retains a shade of that Italian overtone that makes it so intoxicating. It’s distinctly present, never overbearing, and adds a slice of mature sports car to this hot-hatch. The test driver has reported the exhaust tone as “amazing” and feels it’s a genuine addition to his Cooper S. He also feels that its amplitude is totally appropriate for the character of the car. It’s worth noting the test driver commutes with his rear seats folded down, which does noticeably add to the overall exhaust amplitude level. Nevertheless, the volume of the exhaust remains sporty but not overbearing. The test driver has reported that during his lengthy daily commute, the ALTA cat-back exhaust adds a distinct improvement in torque across the RPM band, and also a slight reduction in turbo-lag when transitioning from deceleration to acceleration. During the two-week test duration, no change in fuel economy was realized [calculated gallons into trip odometer].

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    LIKES:
    • Luscious Italian-accent exhaust tone without being too loud
    • Excellent fi t and finish: flawless black ceramic coating and quality welds
    • Highly tunable installation fitment with high grade V-band clamps and lock collars

    DISLIKES:
    • Instructions need additional info to help order and align exhaust sections
    • V-band clamps are a size too large
    • Revision needed to fully clear the center tunnel brace

    RECOMMENDATIONS:

    I confidently recommend this exhaust to anyone, yes anyone, looking to add significant character to their daily-driven MINI without going “over the top.” This exhaust sounds fantastic, adds seat-of-the-pants performance gains, is very well made, and despite my minor installation quibbles, is not a tough install for an R56 exhaust that keeps both catalytic converters. The price may seem a bit steep to some at first, however once the level of quality is realized [the stainless V-band clamps, the 3” 304 stainless tubing, and custom stainless mufflers], it is clear the ALTA cat-back exhaust is honestly a solid value.

    ALTA Performance Response

    ALTA Performance Response

    Thank you for taking the time to review our exhaust system. Please allow us a moment to explain our position on a few things that concerned you about our product.

    V –Band Clamps

    Unfortunately, V-band clamps must have a long stud in order to fit around the flanges. The length of the stud is derived by the size of the flange the clamp has to get over. You can trim the stud after installation but if you ever have to take apart and reassemble the joint it will be more difficult.

    Packaging

    The heat shield you received is actually for the R53 Exhaust. Totally our goof as to why that was in the box. On your car there is no use so it can be discarded. As for the missing polish packet. Perhaps it should not have been on the included parts list. The obvious reason you did not receive a polish packet is because you did not purchase the polished exhaust system. We provide a polish packet to polished system owners so they can keep their system in tiptop shape! We have actually completely changed the way things are packaged and checked now. A separate inventory sheet will come in the box showing that everything has been checked by the person who packaged it. There will also be a check off list on the instructions so the consumer can make sure they received everything they need to complete the installation.

    Recommended Cut Length

    The cut length differs slightly for everyone. (As you noted that your vehicle has a body kit compared to stock MINIs). We do disclose that you need to cut the exhaust just behind the rear catalytic converter and show a 1/3-page image on the instructions clearly illustrating where to cut the system with a large arrow and a note that says “cut OEM exhaust roughly here. You do have a margin of about 9” (roughly anywhere in between the factory catalytic converter and the factory resonator) that the system could be cut. Remember the joint we provide to the factory system is a slip fit and will slide up and down stock exhaust tube. We applaud your efforts to make an exacting cut but you could have cut the system several inches longer and simply slid our joint over the stock system further, netting the same result.

    Cutting the Center Tunnel Brace

    Trimming or spacing of the center tunnel brace is not mandatory for the exhaust system. The instructions have a special notes section, which says “IF you would like to make adjustments to your tips, some cutting of the center black brace may be necessary”. In your case, your vehicle has a body kit, which moves the exhaust tips back, also pulling the center resonator back and regrettably into the center brace. Unfortunately you would be one of those people who have to “make adjustments”. The resonator is as far forward as possible. We could use a smaller center canister but feel it would change the sound of the system. (The sound you liked) For some customers like yourself, having to remove a 1” piece of sheet metal is an acceptable sacrifice to get the sound and performance your car deserves. The car you performed the installation on is unique. Most vehicles do not require and modification of the center tunnel.

    In his personal PDF “how to” (see attachment) Adam noted that he cut the brace on his car but there was no need to cut the brace on our test mule. Each car and user is different though the overwhelming majorities do not require any cutting.

    We appreciate your honest evaluation and hope that you will look at our comments as explanations and not excuses. We were please to see that you enjoyed the sound, look and quality of our system and we look forward to submitting other products for review.

    ALTA Performance
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    Original Source

    Written by: Ryan Malcolm, Jun 1, 2009,

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