My 2010 Volkswagen GTI is my personal testbed for stuff I haven’t done before. I’ve never agonized over optimizing any of my previous eleven cars as much as I have with this one, usually preferring to keep it simple. I’ve also owned a total of three turbo cars: my 2007 BMW 335i, a 2008 Subaru Legacy Spec.B, and my current 2010 GTI. I’ve never gotten a modern turbo car tuned, until now. I’m a big fan.
I didn’t tune my previous machinery because I didn’t want to deal with the potential of reduced reliability on cars that were already notoriously unreliable. On the 335i, the spark plug and ignition coil intervals became an eighth of their original life. On the Subaru, I thought the coils might explode if I so much as talked about a tune while sitting near the car. With the GTI, I have the privilege of many great choices and excellent products that take full advantage of the car’s surprisingly advanced ECU.
After some research, I settled on a company called APR. This is a well-known outfit specializing in VAG cars, and have race-proven its tunes in Grand-Am. APR has campaigned its own products in motorsport, which speaks volumes to its capabilities. The company also has a great website that shows you dyno graphs for every tune it sells, and the GTI stage 1+ tune is advertised as a +78 lb-ft over stock torque peak, and +61 HP at a decent amount of the rev range, tapering down to +30ish horsepower closer to redline.
Finding a good tune for your particular car can be tough. Some cars will require a professional dyno tune via Cobb Accessport like Subarus, and some cars (mostly European) will have really good off-the-shelf tunes. The forums can be hard to trust because most people don’t really drive their cars hard or they drive them too hard. My rule for finding a good off-the-shelf tune or good tuner: Have they tested the tune on a race car or actually developed the tune on a chassis dyno? If not, I’d avoid the tune. Also, this is a situation where it’s best to go with a bigger, reputable brand.
I ruminated on the tune for a long time. The $600 install cost wasn’t deterring me, that’s actually a bargain for reliable, developed horsepower. I agonized over how it would make the engine feel and rev. I was worried that the GTI would no longer be satisfying to rev out like the stock tune.
The stock tune purposely leaves a lot on the table in the mid-range. You can even see it on the APR charts, the gains to be had exist primarily in the meat of the 2,500-4,500 RPM mid-range. It seems like VW holds the stock turbo back aggressively so that the power is more manageable, more linear, placebo’ing a sense of high-RPM power. If you weaken the engine at the mid-range, you can make the top-end feel stronger by comparison.
Again, the stock tune revved out very nicely. I always wanted to wind it out, to get that little bit extra out of the car. The APR power curve, while impressive, suggested a less rev-happy engine, if a more effective one. Deciding that if I ended being dissatisfied with the feel of the tune I’d just dump money into a bigger turbo, I pulled the trigger and made an appointment to get tuned.
There is zero magic to getting an APR off-the-shelf tune. You show up, pick whether you want the high-torque or low-torque tune, settle in for an hour, and bam your car is tuned, no dyno. APR already did all of the work on the dyno, while maintaining all of the factory safety strategies and advanced math, so all that gets done to the car is a simple re-flash.
The random Sun Valley shop I chose for its proximity to my home did a fine job and even sold me some useful parts I needed to fix my bad battery ground. The bonus to this location was that I could take Little Tujunga Canyon Road to-and-from the shop for a back-to-back comparison. I chose the low-torque tune (to save my clutch and hopefully preserve some revviness) and settled in for an hour. Not long after, I had a newly stage 1+ tuned GTI! I chose stage 1+ because I do have a Unitronic intake already installed in my car, and could benefit from a more aggressive engine map.
I installed a boost gauge a few months before the tune to get an idea of baseline boost numbers. On the stock tune, the GTI generally targeted 10-12 psi at its peak boost around 3,000 RPM, and tapered to about 6-7 psi at 6,000 RPM.
I pulled out of the alleyway where the shop was located, let the car warm up a bit on the way to a main road, and dove into the deep end of the throttle pedal. My new peak boost? 20 psi at 3,000rpm, tapering down to 12 psi at 6,000 RPM. The difference in power is fucking nuts.
The stock tune felt benign, non-threatening, like a friend that never sets a boundary and says “OK I’ll drive you home.” The APR tune felt like an explosion, an event that took a second to process, like the friend that is the life of the party and repeatedly yells “One more shot bro! No balls! You won’t, wimp!” The APR tune robbed me blind, and took my shoes for good measure.
Any notion of worry about a “powerband” flew out of the window with the thrust I felt from the TSI engine. Sure, it didn’t rev out as well, but it didn’t rev out badly. It still was pretty good, and usable everywhere. The big difference is that I know had to manage my throttle in the canyons where I could be a little more lead-footed with it. This is the mod that has made me close to pulling the trigger on a limited-slip diff. I now had The Mod Bug.
A good tune is worth every last penny. You know what was the best part for me?
My car was tuned in the past, so I got an APR warranty transfer. Instead of $600, I got the tune for a goddamn song: $150. It doesn’t get better than that folks. That has to be the cheapest horsepower of all time. Even for $600, go get a tune, curated engine feel and powerband be damned. We all need more power, more torque, more boost. It will make you froth from the mouth.