MKV GTI - returning to stock ecu

[xristo]

Hi all - Within a few weeks of taking ownership of my mkv gti 2 years ago, I went and got the giac ecu. So I don't have a lot of experience with the car stock.

Although babying my car, I only get 450 kms out of a tank, or 12l per 100 kms. I'm thinking It's due to the giac flash, and returning to stock may alleviate the problem.

has anyone removed their aftermarket ecu flash and later regretted it?

[Corey_R]

There's a big difference in performance, especially torque in low revs, between the stock ECU and the aftermarket ECU's on the K03 based GTI's. Whilst I don't know anyone who has removed their aftermarket ecu flash, I know a lot of people who have regretted waiting so long to get one... so I presume you would also regret removing it.

Having said that, whilst I'm not an expert on the GIAC T&C's, I'm sure that you could get a GIAC dealer to return your car to stock so that you can do some problem determination and figure out whether the fuel consumption issue is related to the tune or not, and then later have them reflash it. I'm sure that the only charges, if any, would be the for the labour involved in doing the two flashes.

So give them a call and have a chat

[TomC]

What sort of driving do you do? If it's mainly stop start then I wouldn't have thought 12L/100km was all that unusual for a tuned car. Even if you baby it, the constant excellerating and stopping drinks the juice, especially as the boost on a chipped car comes on much earlier than stock.

As a point of reference, during the week when I do a mainly straight line constant speed commute I get down to 7L/100km but during the weekend when I'm doing stop/start runabouting (not sure if that's a real word ) it goes up to around 11L/100km.

[DNA Tuning]

I don't think the GIAC dealer would mind returning it to stock for you temporarily as long as you are not expecting a refund of course.

As for fuel economy, you have to try and stay off boost. As Tom has advised above, the ECU tunes will allow the turbo to spool quite significantly even at low engine speeds so if you keep your foot off the throttle you should be fine.

A lower and upper range of fuel economy ranging between 7 to 11L/100km depending on the nature of your commute as about as good as it can get though. With most tunes you do get some benefits when driving at low loads around town though; for instance our tune leans the desired lambda slightly during idle/low load scenarios and advances ignition timing quite significantly as well - two factors that contribute to improved fuel economy.