A couple of months ago I reinstalled an IS20 turbo in my Mk7 GTI to collect data on some products when matched up with the stock turbocharger.
Deciding upon which tune to use was an immediate decision I faced, which took me back to the subject of the Stage 2 tune list that I started about three years ago.
Along with that list, I posed the question about what the “best” tune was and offered a $500 reward to the person who could prove what was best.
Although I was serious about paying the reward I also knew that it was an impossible task given the different goals and priorities people have, it was meant as a rebuttal to people who claim one tune is the best.
Although identifying a single best tune is unrealistic, collecting a comprehensive body of data on several popular tunes is not.
I decided I would do this with a few popular Cobb-based tunes, namely Sneeky Tuned, EQT, and Stratified. To establish a baseline to make a comparison with the stock GTI IS20 tune would also be evaluated.
Cobb offers a much-maligned tune with the Accessport which was another candidate to add to the lineup.
Off-the-shelf tunes would be the product used since results from custom tunes would be relevant only to my car.
More details about the planning are provided on this page. Mk7 GTI Cobb OTS Tune Comparison Plan
Data was collected on the street, the results of which are found on this page. Mk7 GTI Cobb Tune Street Data Collection
A trip was also made to a DynoJet dynamometer to log similar information. Mk7 GTI Cobb Tune Dyno Data Collection
Finally, it was time to sift through the data logs and develop summary data for comparing trends between the various tunes.
The street data summaries are available on this page. Mk7 GTI Cobb OTS Tune Street Summary
The summary of dyno results is located on this page. Mk7 GTI Cobb OTS Tune Dyno Summary
As the data shows, each of the tunes functions differently from the others and what is the “best” fit for one person is likely not the “best” for other people.
The benefit of having comparison data is that allows individuals to weigh their priorities against the attributes of the different products to decide what fits their needs the best.
The data I was able to record does not support the poor reputation that the Cobb OTS tune has. The tune appears to strictly follow the OEM Knock prevention strategy and the lower boost and timing that it operates at would provide additional safe operation. The tradeoff is in power production, but with a bump of roughly 40 whp and 50 wtq over the stock GTI tune, it’s a decent step up for no additional cost.
For my part, I prefer the Stratified tune on account of the negligible difference it has from the OEM Knock prevention strategy – a topic discussed in detail on the Noise & Knock page. The tune delivers solid power and good overall acceleration. At $100 it’s also quite a bargain if you already own a Cobb Accessport.