I recently installed the Green Diesel Engineering tune on my 2006 Jetta TDi DSG, now with 120,000+ miles, simply looking for a change as it looks like I will be keeping the car till the wheels fall. I thought I would share my experience with the group. What I was specifically looking for was an improvement in everyday drivability along with improvement in mileage. In the drivability area I was specifically looking for more immediate response in throttle and decrease in turbo lag in those rare situations where I need to "floor it" to avoid accidents, etc. (In the few cases where I have done that in the past 120,000 miles, there is always a noticeable lag, black smoke, then just enough power to get by. -- No accidents so far). I have now put about 2000 miles on the car since the installation of the ECO version of the tune, and have tried to maintain my normal driving style to get a good comparison between the stock tune and the new (ECO) tune. Here is what I have found:
MPG -- Historical averages with the stock tune: city driving 32-33mpg, mixed ~38mpg, pure highway max mpg ever noted by me 44.22mpg(this last mpg was with no additives). Since the tune I have not really done any truly mixed driving, but in pure city driving where I measured it (1 tank) the mpg was 35.56. There have been 2 tanks I have driven with the ECO tune that have been 95+% highway driving: First was on highways with speed limit of 70mph (max speed by GPS 78mph), with small amount of driving downtown Chicago. That measured 45.68mpg. The second was predominantly on 65mph highways, with some 55mph stretches (max speed 74.6), and a wee bit of driving in a small town. That resulted in 48.78mpg.
A couple of things to note:
-- I did not realize till this morning that the tire inflation dropped 6psi below recommended since I last measured it about 4000 miles ago in warmer weather.
-- All the recent tanks of fuel (~last 4000) miles have had Opti-Lupe XPD in them. (this resulted in a 1-2mpg increase on the highway c/w no additive for the stock (original tune). The best mpg with the additive prior to the GDE tune was 43.6mpg if my memory serves well -- I try not to be too obscessive-compulsive about these things.
-- Driving style: Old guy, tired of tickets (typically within 5 mph of speed limit on lonely highways, o/w moving with traffic flow, whatever the speed), maximal use of cruise control. Typically assertive driving, can be aggressive as needed (Grew up in Washington, DC area). Have raced and rallied in the past.
Drivability:
-- I have only had to step on it a few times in traffic since the change. The most noticeable differences: little to no turbo lag, no smoke.
--There is now a quite noticeable low pitched sound ??100-200Hz when I come off the accelerator at slows speeds (coasting up to a light or corner). The same sound occurs when I shut off the engine and lasts for 2-3 seconds after the engine stops.
-- The soot accumulation on the bumper is now gone.
-- Warm-up time in cold weather is unchanged (i.e. still slow). How it does at below zero F is yet to be seen.
-- It may just be me, but the glow plug light cycle seems to last a wee bit longer.
GDE Service -- Very rapid response to my order, and problem with installation (problem centered on incomplete instructions at website referenced in the papers with the device to rewrite the flash drive -- This may simply have been a website thing, as I could only get the first page of the instructions. The people at GDE responded rapidly by sending me the instructions. I also found full instructions via a Google search online.)
Overall impression -- The tune does what it says it does (I cannot comment on the "HOT" tune. Both the drivability and the mpg are noticeably improved, at least for me, with my driving style.) And the GDE service was good.
$600 is about what I paid for my last car