Piston Slap: The Fallacy of Aftermarket Performance?

Sajeev Mehta
by Sajeev Mehta

Evan writes:

Hi Sajeev!

How do people get your name wrong when it is in your email address? But that wasn’t why I was calling. My question: are aftermarket parts for brand spanking new cars sensible?

For instance, I’m picking up an Audi SQ5 and there are these ‘x-brace’ things and mount inserts. Why would Audi not have engineered it well enough in the first place? Money savings? They didn’t think whatever attribute x-braces add was ‘for’ the SQ5 demographic?

Or are companies selling mount inserts and eXtra bracing to people with $60k sport-crossoverUVs selling snake oil?

Thanks for the insight!

Sajeev answers:

You can’t make generalizations — except about the horrible people calling me Sanjeev even though my name’s been plastered all over TTAC since March 2006…but I digress.

Vehicles are designed to a certain expectation of performance, ride quality, cost constraints, and acceptance to a wide variety of consumer preferences. Aftermarket performance modifications can do better than factory stuff.

But some are worse than other aftermarket alternatives, especially against those of a creative and grassroots racer nature. Sadly, many (either by themselves or in a package) only make a difference to the owner’s perception of vehicle performance and some parts are worse than what came from the factory (i.e. oversized throttle bodies on a naturally-aspirated motor). Take it from the guy that loves tweaking RWD Fords: every scenario above is true.

It’s like walking through a metaphorical minefield: keen research, trusted advisers with years of hands-on experience, and hours of internet forum digging are mandatory to sort fact from fiction.

So, shut up and tell us, what’s the scoop on these SQ5 bits? Well, I’ve never driven said vehicle…

However, I rather like those billet aluminum bushing inserts, even though billet and anodized finishes are often overpriced flash. Yes, many forms of motorsport require such fancypants materials, but that doesn’t apply to the SQ5. Flash doesn’t sell me; tangible improvements in performance does. To wit, these babies likely improve performance out of the hole, especially with an aftermarket computer tune bumping up performance, reducing torque management and perking up throttle response.

Yet I wonder if there’s a universal fit, solid (rubber or invasive polyurethane) bushing you can buy from a catalog (or from another VAG product) — which might be like, waaay cheaper, son.

And since a new Audi is far from the flexi-flyer chassis of my beloved Fox Ford products, I question the value of any chassis improvement on a higher dollar luxury car, much less a billet aluminum one. Does it stiffen the chassis and improve feel enough to matter? Maybe it helps NVH control. Perhaps handling is more confident with other modifications. Odds are, though, it won’t make the SQ5 any quicker on a track.

Consider, if you will, improving the factory part: adding metal (perhaps triangular sheetmetal between the weak points?) welded it up by someone familiar with roll cages. Perhaps that aftermarket part is a good template. That’s more labor and it won’t be billet aluminum pretty…but, right or wrong, it’s the other side of this coin.

Don’t forget one other important fact: modifications are worth pennies on the dollar in the vehicle resale department. Many will lower the value as stock vehicles are preferred at trade-in time. The SQ5’s bits add curb appeal for buyers motivated to get on their hands and knees to see them, which amounts to precisely nobody in the used car market.

Don’t get me wrong, I love modifying cars with cool aftermarket bits, but it boils down to two words: buyer beware.

[Image: Shutterstock user Dezay]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

Sajeev Mehta
Sajeev Mehta

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  • 0grayscale1 0grayscale1 on Aug 01, 2015

    One factor that I don't believe has been mentioned is that of crash safety. Most vehicles are now designed to absorb energy in a holistic manner. A little give here and there throughout the vehicle can add up to a lot of energy absorption during an impact. If you remove some of that give with stiffer braces and/or bushings, you might end up transferring more forces to the passengers, in the event of a crash, resulting in a greater chance of injury.

    • Rpn453 Rpn453 on Aug 01, 2015

      The scale of the changes being made compared to the strength of the related structures and components is miniscule. It's like adding a hundred pounds of piping to the underside of a structural beam supporting 100,000 pounds of equipment. No detailed engineering is necessary.

  • Ronnie Schreiber Ronnie Schreiber on Aug 01, 2015

    The stock US market Audi SQ5 handles very well, remarkably so for something so high off of the ground. The suspension is good enough that Porsche pretty much uses it as is on the Macan platform mate. I thought it handled better than the A6 that I drove back to back with it. I'm enough of a boy racer that I put sport springs on my Saturn but I see no reason to mess with the SQ5's bits that keep it on the road.

  • Teddyc73 As I asked earlier under another article, when did "segment" or "class" become "space"? Does using that term make one feel more sophisticated? If GM's products in other segments...I mean "space" is more profitable then sedans then why shouldn't they discontinue it.
  • Robert Absolutely!!! I hate SUV's , I like the better gas milage and better ride and better handling!! Can't take a SUV 55mph into a highway exit ramp! I can in my Malibu and there's more than enough room for 5 and trunk is plenty big enough for me!
  • Teddyc73 Since when did automakers or car companies become "OEM". Probably about the same time "segment" or "class" became "space". I wish there were more sedans. I would like an American sedan. However, as others have stated, if they don't sell in large enough quantities to be profitable the automakers...I mean, "OEMs" aren't going to build them. It's simple business.
  • Varezhka I have still yet to see a Malibu on the road that didn't have a rental sticker. So yeah, GM probably lost money on every one they sold but kept it to boost their CAFE numbers.I'm personally happy that I no longer have to dread being "upgraded" to a Maxima or a Malibu anymore. And thankfully Altima is also on its way out.
  • Tassos Under incompetent, affirmative action hire Mary Barra, GM has been shooting itself in the foot on a daily basis.Whether the Malibu cancellation has been one of these shootings is NOT obvious at all.GM should be run as a PROFITABLE BUSINESS and NOT as an outfit that satisfies everybody and his mother in law's pet preferences.IF the Malibu was UNPROFITABLE, it SHOULD be canceled.More generally, if its SEGMENT is Unprofitable, and HALF the makers cancel their midsize sedans, not only will it lead to the SURVIVAL OF THE FITTEST ones, but the survivors will obviously be more profitable if the LOSERS were kept being produced and the SMALL PIE of midsize sedans would yield slim pickings for every participant.SO NO, I APPROVE of the demise of the unprofitable Malibu, and hope Nissan does the same to the Altima, Hyundai with the SOnata, Mazda with the Mazda 6, and as many others as it takes to make the REMAINING players, like the Excellent, sporty Accord and the Bulletproof Reliable, cheap to maintain CAMRY, more profitable and affordable.