Enthusiasts have been tuning vehicles since the first car coughed into life. Back in the day, performance-minded pistonheads could enhance their car’s fun factor by putting stiffer springs on the distributor advance, or changing the top dead center degrees. In fact, there were hundreds of relatively simple ways a clever wrench could wring more performance out of his [formerly] humble four-wheeled steed. Today’s cars are too heavily computer-dependent for such simple tricks. Enthusiast-oriented entrepreneurs have created a whole new market of electronic modifications to fill in the void.
The ECU (electronic control unit) regulates various elements of the modern car’s activities: fuel delivery, spark plug detonation, etc. Manufacturers program the ECU’s software to balance the car’s performance with fuel economy, emissions, safety and reliability. In almost all cases, carmakers leave a large margin of performance on the table. If nothing else (cough warranty costs cough), the extra oomph would sacrifice some of the car’s commercial appeal.
Third party tuners download and disassemble the ECU’s source code (i.e. hack), and then recode portions of the software to unleash unused performance. Some chip tuners can dramatically increase horsepower and torque. In other cases, where power increases are limited, chip tuners improve the overall power delivery, remove top speed limiters and raise the car’s redline.
GEEK ALERT! OPTIONAL SKIP GRAPH
Until recently, ECU tuning required a hardwire modification. If the ECU software was socketed, a user could remove the factory programmed ROM and replace same with a new chip from the tuner. If the ECU software was soldered, then the pistonhead usually sent the ECU to the tuner for modification. Thanks to OBD-II access (now required by federal law) and the use of flashable ROMs (which allow for reprogramming by the manufacturer), tuners now can simply reflash the ECU without hardware modification.
APR offers several ECU options for Audi, Porsche and VW enthusiasts seeking extra oomph for their German-made, well-designed whips. In addition to modifications that remap the power delivery, customers can pay for the ability to switch between stock and “enhanced” modes, a valet mode (to reduce power below stock), and a 100 octane mode to accommodate race track gas. I tested APR’s competitively-priced 93 octane program upgrade ($599), with one mode ($100), on a 2006 Audi A4 2.0T.
Our local APR dealer performed the installation in about 1.5 hours. Once the software was installed, he showed me how to switch between no-go and go modes using the cruise control set button. Liberating the hidden horses was a bit tricky, and not always successful. In one case, I couldn’t start the car for a few minutes after activation.
APR promises a 41hp increase and a whopping eighty-five pound-feet more torque. The change in the car’s performance was dramatic. In real world testing, I dropped over a second from my normal zero to 60mph sprint time. Equally beguiling: acceleration was notably stronger throughout the entire power band.
APR improves performance in the Audi [in part] by increasing the turbo’s boost pressure. From the factory, turbo pressure at maximum acceleration is about twelve psi. APR ups this pressure by five psi. APR insists that the Audi engine can easily handle twenty psi. As long as you use 93 octane fuel (hence the product’s name), APR claims their upgrade remains safely within this margin. Long-term effects are unknown, but I noticed no engine issues over a ten-thousand-mile test.
This brings us to the thorny side of these mods: their effect on your warranty. Some owners worry that an APR or similar upgrade will void their factory coverage. While some dealers are quick to use modifications to deny a warranty claim, the Magnuson Moss federal warranty act specifically prohibits denial of coverage unless the modification actually causes the claim. But do you really want a protracted court battle with your car dealer?
The chip tuners offer no guaranties– which is worrying. The ability to turn off APR’s modifications and “hide” them from the factory technicians (“valet mode”) offers some peace of mind. HOWEVER, should the factory update your car’s software, the APR software will be overwritten. And this is occasionally done as a matter of “routine” during scheduled maintenance.
Now, some more good news…
The APR upgrade didn’t reduce the Audi’s fuel economy; in fact, I measured a slight increase in fuel efficiency. The ECU upgrade also works well with other engine modifications, such as cold air intakes, headers and larger diverter valves.
Overall, the APR ECU modification is an impressive effort. It greatly improves engine performance with only a slight, ongoing financial penalty (due to its need for premium dino-juice). Outside forced induction, no other modification gives as much bang for the buck as an ECU upgrade. For those looking to increase performance on their Porsche, Audi or VW, the APR program should be on the short list.
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Nice to see a chip/software review, thank you TTAC! I used to own a 1.8T GTI 7 years ago… until an unlicensed, uninsured illegal immigrant totaled it… grrr. I only had the chance to drive a friend’s impressive chipped 1.8T and was going to “chip” mine too… before it was destroyed.
You might consider comparing this with some of the other flash upgrades on the market as well (one of them even offers a “free trial period” of a few hours of drive time) and rank the driveability of each.
Chip tuning is the bread and butter of many “brand name” tuning houses – it’s extremely low-cost to overwrite your ECU ROM image. The process itself takes seconds. APR will make something like $1000/hr doing flashes vs $100/hr for hardware intake/exhaust work. IMO, they earn every penny for the time and effort it takes to develop their flashes.
That being said (or maybe due to the fact), there is a grassroots movement to allow the owner to do exactly what APR does at home, in their garages, and on open stretches of road. Open-source and/or free-software solutions like EcuFlash (Evo/DSM) or Enginuity (Subaru) give the home-wrench the ability to reflash their ECUs thousands of times. What you save in initial costs (a couple hundred dollars), you have to make up in testing time, fuel, and the invariable risk that you will damage something in the process. It definitely is not for everyone, but for the OCD guy who likes to muck about with *everything* in your car, it’s definitely the most involving solution. I’ve learned more about turbo-charged applications as they relate to combustion engines than I ever thought I would, and I honestly thought it was a blast. Case in point, it’s common knowledge that a freer flowing exhaust will increase horsepower on a turbo-charged car. Most anyone that spends time in an enthusiasts’ forum will glean that it “reduces backpressure” allowing “quicker spool”, etc. When you’re the guy tuning your car, you get an almost visceral sense of the drop in back pressure. You can watch the boost spike hit earlier and more predictably, and then you can really tune for some serious high-end HP or try to flatten that torque curve out with changes to ignition timing. I think I have something 40mb of logs from the stock-to-exhaust tune process. More when I installed my home-fab cold-air intake. It was just fun. Period.
On the other hand, if you can afford a 911 turbo, the opportunity cost of self-tuning is way too high to justify spending dozens, maybe hundreds of hours fine-tuning VANOS and fuel maps. If you make $150/hr (what I calculate to be the baseline income to afford to run a $150k sports car), and you spend 50-100 hours to tune your ride, you end up costing yourself $7500-$15000 to get it “just right.” Probably not worth it unless the experience itself is what you’re seeking ;).
I like how some tuners are releasing software that comes in a separate module which plugs into the ecu and can be removed when going to the dealer to avoid said warranty issues. I was always afraid to do this to my 1.8T Audi, due to it being a lease and all the noises and issues it had, but now I really wish I did.
Apologies for the newbie q., I get that the APR dealer has to install it but is the software transfered to you in a form that allows one to reinstall it if a factory tech overwrites it? Do you have to return to the APR dealer for a refresh & pay for another 1.5hrs labor?
curisu :
Regarding DIY chip tuning like EcuFlash or Enginuity, VW AG’s Motronic engine management programming may be far more complex, fickle and sensitive compared to the EVO and Subaru’s EMS systems.
Motronic is deeply integrated into the car and controls nearly everything. For example, APR has the option to let you switch between octane maps, boost maps and valet mode through the cruise control stalk. I’d be afraid to mess with it myself…
i know on alot of japanese turbo model cars the best bang for your buck is just get an after market air intake,and then go buy if you need more power some high flow cats and bigger diameter pipes and then a boost controller and air-fuel meter,or a programmable ecu with down loadable maps specific to the car. i just put a kit in my non turbo 6 cyl that included an air intake and piggy back air fuel computer for 500 dollars and claims 11-27 horse power over the rpm range. i did notice that it spins the tires now with the traction control on and sounds a lot better but im not sure its too good on the autox 6 speed tranny.—dont you already have to run premium in that audi? i thought most turbo/gasoline engines you had too to run premium gas to stop detonation.maybe thats why your mileage is better because a lot of turbo cars will retard the timing if you dont run premium.sounds like the engineers really detuned that motor for emissions or reliability purposes if premium wasn’t recommended to start with.
Federal EPA regulations will probably be amended to prevent this in the future. Despite evidence that pollution is either unchanged or reduced with these mods the prevaling wisdom in D.C. is that manufacturer knows best. It’s illegal to even take an air cleaner off the engine if it is preceived to affect emmissions.
im sure the billion dollar after market industry will have a couple of lobbyist hired to explain to the gov. that unless you remove the cats on the exhaust or have a bad o2 sensor that these mods wont effect emissions.
@Areitu
I admittedly have zero experience with VW/Audi/Porsche tuning.
That being said, I wouldn’t describe ECU tuning in the Evo/Subaru world “simpler” by any stretch of the imagination. For instance, the most recent customized ECU images coming from the community (well, okay, a *very* small subset) provides some pretty nifty features like a knock/detonation indicator that blinks your CEL, a quickly switchable “valet” mode that reduces the rev-limit to something you preset (2200 rpm out-of-the-box), and the more application specific modifications to control how the 3 diffs work in conjunction with each other. One current release has software-based NLTS (no-lift-to-shift) available; folks in the forums are bragging about getting 0.3 secs off their ETs.
There is an amazing depth still to be found in the stock ECUs. “Finicky and sensitive” is more an aspect of how early an adopter you want to be. My Evo is a daily-driver that I hand-tuned. I’ve learned to wait a couple weeks for bugs to be worked out of the newer releases before flashing my ECU. 99% of the time, after the growing pains are dealt with, the ECU is as stable as if Mitsubishi engineers wrote and tested the software themselves.
I do agree with you to the extent that the average car enthusiast is not likely to want to get deep into the guts of ECU tuning. The ROI for that time spent is, well, not profitable. Given that the VW/Audi/Porsche markets aren’t likely to be filled with penny-pinching, garage-based tuners like the Japanese import markets, I’m not surprised that OSS/FOSS projects aren’t available to tune those marks. And I’m equally unsurprised that big tuning houses turn to well-known (and expensive) 3rd party ECU’s to do finely-grained tuning. Those ECUs are beautifully documented and allow such a breadth of custom code to be run that it would be a joy to work with something like a Motronic, and consequently, fun things like switching AFR maps on the fly for power vs efficiency is very straightforward with them. Getting it integrated with the CC stalk or other stock instrumentation is probably a quick thing for them; the hardest part was probably the UI/UE decisions (i.e., how long to hold the Set/Accel before entering map-change mode, etc.).
@stuntnun
dont you already have to run premium in that audi? i thought most turbo/gasoline engines you had too to run premium gas to stop detonation.maybe thats why your mileage is better because a lot of turbo cars will retard the timing if you dont run premium.sounds like the engineers really detuned that motor for emissions or reliability purposes if premium wasn’t recommended to start with.
I thought so too – I think the european engineers think all American drivers are idiotic and purposefully detune their high-compression/forced-induction cars to run on 87. My wife’s mother’s Volvo C70 has a turbo 5cyl that *recommends* using 87 octane. Blew my mind when I read it on the fuel cap.
I believe that the bulk of the fuel savings come from properly scaled injectors vs voltage latency (so the ECU better knows how much fuel is squirting), a properly leaned-out map that makes safe power (tending towards the magic 12.5-13.3 AFR), and more efficient end-to-end setup (intake/exhaust). A healthy respect for the new-found power is also a boon as you probably won’t stomp it at every light. ;)
stuntnun
Premium gas as required by the manufacturers is 91 octane. 93 octance is not available in all states, so APR for instance has a 93 program and a 91 program. I assume Michael has 93 available.
Also it does not take another hour and a half for a reflash. That’s just for the original install of the modified ECU.
curisu
There are plenty of penny pinching VW/Audi folks.:) However, there are so many established chip tuners with prices as low as $300 that it never seems worthwhile.
Nuespeed and APR have always put out quality parts for the VAG cars, good review. But chip tuning is old hack. PnP is the new way to go.
i was reading on audi motors,maybe that one has direct injection so maybe it burns gas cool enough to stop detonation,but i know mazda uses that and still recomends premium–im glad we have 93 octane here,im wondering what is the motive in states that disallow 93 octane?
Its only some states that don’t have 93. We have it in Texas.
Had a 1.8t 04 Audi Avant 6spd.Sport APR’D and was amazed at the transformation and the lack of articles on the inexpensive and totally reliable performance boost. Leased the car for four years and when I turned it in I put the upgrade to slept (valet mode). I also had an ECU upgrade done once when I went in for service and when I got the car back I went to my APR installer and they told me the upgrade was invisable to the Audi Dealers. Amazing product. I miss my Audi. I’m a Lexus salesperson and my wife made me get an automatic IS250. No more sticks for me. What a shame…