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« Last post by ZoliWorks on March 26, 2024, 10:34:35 pm »
Yeah I've used the same calculator. 215 to 225 is what I'd say it feels like. I can definitely feel that low end instant torque surge of the K03 but due to it being faulty, it dies off quite fast and proceeds to pull slightly better than a stock GTI. My money is on the wastegate actuator but we'll see when I pull it off and inspect it.
Now as far as options go, I've been thinking about them for the past few weeks and it's very hard to decide.
K03 - €1100
CHRA is most likely faulty as I and my mechanic both think there's too much oil in the intake, and the exhaust manifold appears to be cracked but could just be a streak of rust cause if that crack was real, it would already be in 2 pieces. Repairing the turbo would cost no less than 400 euros. Turbo repair/refurbish shops here only provide 1 year warranty and their reviews are evenly split between either 1* and 5*, I dont really want to take a chance. Getting a turbo from another car costs aprox 240 euros and nobody guarantees that it works, it isnt cracked internally, it isnt eating oil or that it'll last, so that's also out of the question. Getting a replacement turbo is pretty much the same deal as getting a refurbished one. Opinions are very split between mechanics but the general consensus is that you either go OEM or you go home. And they cost around 500 to 700 euros. OEM turbos cost upwards of 1k euros.
K04 - €1300
What I said about the K03 also applies here, however, I'm much more confident about a 2nd hand K04 than I am about the K03. Problem is, people know how much potential these turbos have and they are so rare that you can barely ever find them at any reseller. After searching for a week, I only found a single yard selling one for 500 euros. Now I did find brand new Borg Warner K04's for sale locally but they cost anywhere between 1200 and 1500 euros.
Downpipe - €300
Now as far as running the K04 will go, I'll be getting a downpipe with a 200 cell cat anyway to help turbo longevity since OEM I have 2 cat's and they are quite restrictive, but I wont be getting a full performance exhaust because I want my car to stay relatively quiet. Sports downpipe is imo the perfect middle ground between keeping the sound relatively stock, no drone, and providing room for power. Found an Aliexpress kit for 300 euros incl shipping which I'm fine it. At the end of the day it's just a pipe and if the cat lasts 2 years, I'm happy, given that just a sports cat is half the price of that downpipe here and they dont last any long either.
Intake - €200
Found an Aliexpress intake but dont quite like that due to the way it mounts so I'll be going with a German one, Ta-Technix, for 200 euros. It secures onto the vacuum pump so it doesnt bend in the middle like the Chinese ones do, has a heat shield and a filter. What more do I need?
DV relocation kit - €50
Aliexpress, 50 euros for the whole thing incl shipping.
Injectors - €400
With just the turbo, I can get tuned for 305-315hp. No injectors, no fuel pump, no pressure valve, or sensor. however, I will look into this when the time comes and get them all fitted. In all fairness, I don't estimate these to cost more than 400 euros, brand new (excluding the pump).
Upgraded fuel pump internals - €600
If I go down the K04 line, I'll get this. Didnt really research brands and prices cause it aint a priority right now. Between 500 and 800 euros.
Forged piston rods - €900
Arguably the second most expensive part of the whole process right after the turbo. If I'm serious enough about the K04, this will have to be done in order to safely reach 350HP. I'll probably slap in cams and pistons too.
TLDR
So in the end I really only have 3 options
K03 - €1100
Get my turbo replaced with an OEM one and know that I'll be set for life and that the car will have great low rpm torque and acceleration but will lack past 100kph and wont have any room for more power
K04 basic - €1200
Get a used OEM K04, downpipe, intake, DV relocation kit and remapped, making 310 or so HP with room for improvement. Car will probably lack low-down, wont have the same kick, but middle and top end should feel vastly different. Should be quite good when accelerating past 100 and I'll also have a much more reliable and better built turbo.
K04 all out €3000 to €4000 ontop of K04 basic
Gonna cost a lot but would max out the car. 350 to 360hp and over 500nm torque before hybridizing the turbo. Will get everything from above plus boost pipes and a twincooler setup with an S3 intercooler. Should be quite fun honestly and a pretty decent sleeper build. Not quite sure if worth it tho so I'll continue to think about my options for a while longer.
As things are right now, I'm split between K03 or K04 basic. Even if I stay K03, I'll be getting the downpipe, intake, S3 cooler and likely boost pipes too cause those were leaking. I've fixed them temporarily but I want a proper setup. So all in all my K03 plans might as well turn into a K04 job since I'll be running 70% of the required mods anyway.
This brings me to my original post and why I made this thread. K03 or K04? 03 pulls stronger down low and it's great for city driving that I do a lot but 04 provides more middle and top that comes in handy when I go on longer roads. Not quite sure about the low end but I dont think it'll be as punchy as the 03.