I have a 2006 GTI MK4 1.8T with just under 110k miles. I was informed by my mechanic that my turbo is getting old and that it either requires a rebuild or replacement soon as it is leaking oil slightly, I do also occasionally see a little "cough" of smoke at idle, although very rare and very small, so its not something that requires immediate attention. I still get good power and can still do 140 MPH easily and average over 30 MPG highway crusing. I was wondering about a slight upgrade on the turbo. If I need to replace it, why just go stock? Now this is my daily driver and I do not own another car nor can I afford to mess it up, I work at Walmart for minimum wage. I have heard that the MK4 uses a KO3 turbo system and that a KO3-S would be a direct bolt-on replacement requiring no mods and would not cause any issues as its performance increase is minimal: 1-2 PSI; 15-20 BHP increase. That sounds perfectly reasonable to me, but I wanted to double check with you guys. I've seen this forum searching for info on GTI's several times and you guys seem extremely knowledgeable. Info about my current build: I have Eibach Nurburgring edition shocks with only verly slightly cut-down coils, Voxx Racing 18-inch rims, and an HPS cold-air intake system running a K&N Cone Filter, naturally .
2006 GTI MK4? Pretty late one! They already come fitted with a 5404 compressor and 5403 turbine or what people call K03-S. Remove the TIP and check the turbo shaft for forward and backward play ( you usually get a bit of side play in these) . Also any oil in the charge pipes? If there is no axial play or oil in the charge pipes, I would suggest your valve guides are the root cause for the smoke. Oh and welcome to the forum.
Ya well 2006 was the verly last year the MK4 was produced. In fact a VIN search revealed my car is one of the final 100 MK4 batch ever built. I wanted a MK5 or MK6, but could not find one in my area for a decent price, having hunted for well over a month. That's ok, this guy was $5000, a good price considering it had just under 100k miles when I bought it last year and had the suspension installed already, plus I've never even gotten a check engine light nor have I ever had to replace a single part. Just oil changes and now I'm getting ready to do the fuel filter. Passes emissions with flying colors. So when the mechanic showed me the turbo I did notice slight play in the inlet shaft, and a small amount of oil residue in one of the pipes, not sure which one it was. I do trust him, I'm a bit of a mechanic myself and never once has he led me astray. He did tell me exactly what I had thought: that it will need replacing soon, but not quite yet. I guess you could say that it's on the verge of dying. I'm not surprised l, its the original OEM Turbo, so its got 110k miles on it. Don't all turbo cars gotta replace the turbo once, usually in the middle of the car's life? That's what I thought. Well anyways, if it does need to be replaced, is there a turbo you can recommend that would give me a bit better boost without going crazy (I don't want to, nor can I afford a whole new system and other mods for a large aftermarket turbo, I'm looking at a budget of around $1100-$1200 for a new turbo, and of course that's with a shop instillation. I don't have an engine hoist, nor do I have a garage, or even that much skill. I could do it if the engine didn't have to be removed, but that, as you probably know, is an impossibility.
The current turbo, if it has no thrust play can last up to 150000 miles + if the engine map remains standard. Usually to wake up the car, an engine map that safely increases boost from 0.65 bar for 150ps/155lbft or 0.8 psi for 180ps/163lbft to 1.2~1.3 psi, results a marked jump in performance (200-210ps/220-240lbft). Keeping all the recirculation attachments working, i.e. found bolted on the cam cover, maintains durability even when asked to work harder.
So how\where do you get a remap? I've never done such a thing, always just bolted on newer/better parts. How is it done, and what would it cost?
