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The most hard-hitting tune causes flames to shoot out the tailpipe.Lou Trottier/The Globe and Mail

Coming up with engaging family outings is a challenge for most parents, especially as our children get older and we can no longer simply order them around. So when my eldest daughter and her boyfriend suggested that I, my vintage Porsche and her mother should all attend a car show together, we had to respect the initiative shown and consider it. After assurances were made that there was going to be more than just teenagers in attendance, we decided that an evening car cruise was a good idea. I was pleasantly surprised to see several high-end exotics mixed in with a couple hundred vehicles in various states of modifications. My 1966 Porsche 912 was without a doubt, the oldest vehicle at the show. Hilariously, the other half dozen people at the show that were the same age as yours truly seemed to really get a kick out of seeing my lonely, classic car sitting amongst a sea of newer vehicles.

The hundreds of younger onlookers seemed to be mostly interested in pyrotechnics. Throngs of young people wandered from car to car looking for the ideal photo-op. Vehicle owners took turns revving their car’s engine to its RPM limits, setting off pops and backfires. Those who managed to get flames firing out of their tailpipes became the gold medallists of the evening. I couldn’t help but think about all the damage being done to those poor engines as I walked around.

I can only guess that the current trend to modify vehicles so that they burble and pop on deceleration was originally inspired by the Italian exotics of yesteryear, like my old Weber-carbureted-equipped Ferrari. It was these incredibly inefficient, yet musical sounding Weber carburetors that influenced the soundscape of classic race scenes in almost every vintage James Bond-era style movie. These carburetors, when tuned properly, produced the sweetest pops and cracks when decelerating, and throaty roars when accelerating.

Now, a new generation of car enthusiasts is achieving these burbling sounds by altering their onboard computers. This modification is called tuning and vehicle owners can buy tunes online, where they are referred to as pop and crackle, big bang and burble and flames. These tunes overwrite parameters, modifying the factory-set fuel injector timing. Essentially, when the driver revs their engine to its maximum RPM and then releases the throttle, the now-modified computer commands the fuel injectors to inject a tiny amount of fuel just before the engine’s exhaust valves fully close.

This tiny bit of unburnt fuel makes its way into the vehicle exhaust system where the hot exhaust pipes and/or muffler will ignite the fuel, causing it to pop and backfire. These tunes are sold in stages, with more aggressive tunes resulting in even further amounts of fuel being injected into the engine, causing louder pops and backfires. The most hard-hitting tune causes flames to shoot out the tailpipe.

As I was researching this piece, I chatted with a colleague at an Audi dealership that saw a newer Audi R8 V10 towed into the dealership in a no-start condition. After hours of diagnosis, the dealer technicians eventually discovered that the engine’s exhaust valves were burnt, causing a lack of engine compression. Additional diagnosis led them to the car’s onboard computer, which had remnants of aftermarket tampering. Despite the owners attempt to remove traces of the tune, Audi was able to detect it and deduced that a previous unauthorized tune had caused the engine damage. The constant exhaust popping and backfiring caused excessive exhaust back pressure, which in turn prevented the exhaust valves from seating and closing properly. When exhaust valves do not close and seat properly, they are unable to transfer heat into the cylinder head, causing them to overheat and eventually burn out.

While third-hand information is never perfectly accurate, my understanding is that this R8 owner was denied any warranty coverage and is now dealing with an engine repair bill similar in cost to that of a brand-new Toyota Camry.

While my advanced age may prevent me from comprehending this fad, I do understand one universal, age-old thing. If you want to play, you eventually have to pay.


Your automotive questions, answered

I have a 2016 BMW X5 diesel at 75,000 kms. It currently runs well, but I have a question about future maintenance that I should be prepared to do as a preventive measure. Also, at what point is it better to consider a trade in? Thanks for your column.

John F

Diligent maintenance/servicing and attentive record keeping of your vehicle’s service history undoubtedly helps retain its value. Obviously, its trade-in value is at its highest right now, especially in this crazy used car market. If you are debating trading it in against a new vehicle now versus a year from now, I would say do it promptly to take advantage of the higher trade-in values.

From my experience, if you are looking at this solely from a long-term, cost-of-ownership perspective, the vehicle will be reasonably easy on the pocketbook for its first 10 years. Once it starts giving you problems however, you will quickly realize that life with any diesel vehicle is front-end loaded. What I mean by this is that the first owner reaps the benefits of the fuel savings, etcetera, while later owners bear the brunt of the costly repairs. That being said, and to answer your first question, there is no real future maintenance that can be done as preventive now to alleviate this situation.


I’ve been researching the concept of vehicle “tuning” more and more and see claims of HP and TQ boosts of 30+ from either $650 software downloads that get uploaded to the car via the OBD2 port or gadgets that plug into specific wires in the engine. Wondering if you could share any thoughts into this? Interested in primarily if they’re legal (emissions?), and how they may impact the long-term reliability of the engine. Does boosting the turbo psi by a few points really cause potential for engine damage?

Gregory C, Toronto

As with any performance modification, horsepower is never free. It comes at the expense of fuel economy, elevated emissions and general wear and tear. The two questions for anybody about to modify their car is: can you afford the upgrade? Can you afford the repercussions?

The tune you are referring to will not affect your fuel economy drastically when driving normally. It’s when you put your foot into it that you will feel it in your wallet. The extra power achieved from a 30hp tune is immediately noticeable and addictive. Yes, the car will burn more fuel, mostly because you will be more tempted to pass that slow-moving car or enter the highway on-ramp a little bit faster, simply because you can.

As with any internal combustion engine, your catalyst and emissions systems are designed to handle the quantity of unburnt fuel as it was originally specified. When you add more horsepower via a tune, all the systems work a bit harder. While not immediately noticeable, I’m sure the catalytic converter will live a shorter life, but it’s hard to quantify when we are discussing an interval of that length of time.

The main issue for you as the owner of the vehicle is always going to be elevated wear and tear. Therefore, all auto manufacturers are unforgiving on any vehicles that have been modified, even software-based modifications. They believe that premature engine and driveline failure in tuned cars is not their problem and will generally deny any relatable warranty claims. And yes, they can tell when their software has been modified. Your vehicle is likely nearing the end of its factory warranty and the temptation to tune it will be higher. Keep in mind that even though the manufacturer warranty is up, any future product warranty extensions or freebies from BMW may be voided by the tune.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing “Lou’s Garage” in the subject line.

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