k03 > k04 upgrade. What all is needed?

[ChUt26]

First I apologize if there is a detailed discussion, but I can't find an A > Z guide on exactly what is needed to upgrade my b8.5 from its factory k03 to a k04. Does anyone have a link to some info that can help me out? I plan on doing the install myself, and tow the car to a tuner to install the APR stage 3 k04 tune.

So far my parts lists consist of....

CTS K04 Turbo $1400
APR Stage 3 k04 tune $900
IE Intercooler $800
NGK colder plugs w/coils #131
ECS downpipe w/HFC $442

That's about $3700 worth of parts on an otherwise bone stock b8.5 a4. Am I missing something? I'm sure there will be misc bolts, gaskets, etc. Is there anything else I should replace while I have the turbo out? I currently have 70k miles on the engine.

[mortimersnerd]

Upgraded intercooler isn't mandatory. Nice, but not required. Also, you might consider going stage 1 or 2 first. I'm pretty happy with my stage 2 and don't see a need for KO4 given the cost. APR has an upgrade program that gives a hefty discount if you felt the need to go that route in the future.

[NitroViper]

All I bought was a high flow cat, plugs/coils, the k04 turbo and the k04 tune from IE...

All of my stuff came to just under $2000... but I used the ebay turbo in the ebay turbo thread.
You are going to spend almost $2000 more for nearly the same set up and have near same performance. But I guess if you have alot of money it doesnt matter? lol

[ChUt26]

Upgraded intercooler isn't mandatory. Nice, but not required. Also, you might consider going stage 1 or 2 first. I'm pretty happy with my stage 2 and don't see a need for KO4 given the cost. APR has an upgrade program that gives a hefty discount if you felt the need to go that route in the future.

I'm having issues with my current stock turbo. I'm trying to price what the cost difference would be if I need to replace the stock one anyways. If I'm replacing it I might as well just go k04 if it isn't too costly.

All I bought was a high flow cat, plugs/coils, the k04 turbo and the k04 tune from IE...

All of my stuff came to just under $2000... but I used the ebay turbo in the ebay turbo thread.

Thanks for the heads up! I wanted to go APR because their tune supports e85 which is readily available to me. Sadly, IE only supports pump gas. I'll look into the ebay turbos though. Might find some great cost savings there.

[Grouch]

Whichever company you go with will tell you what is required. Example, IE says you need these to upgrade to K04:

-Borg Warner K04 Turbo Upgrade Kit (required)
-IE Performance Downpipe (required)
-IE Cold Air Intake (recommended)
-IE Intercooler (highly recommended)

Intake is not necessary. Intercooler isn't mandatory but it's HIGHLY recommended. And looks like you're already planning colder plugs with the coil packs.

[mortimersnerd]

I replaced my dead turbo (143k miles) with a used K03 I got on this forum for $250 shipped. No regrets. I like the more immediate spool of the smaller turbo.

[Grouch]

I replaced my dead turbo (143k miles) with a used K03 I got on this forum for $250 shipped. No regrets. I like the more immediate spool of the smaller turbo.

I do miss the instant torque from my stage 2. Something to consider OP, you will lose some of your low end torque when you swap over to K04.

[Nano909]

Intercooler should be at the TOP of your list. No point in installing power mods if you're going to keep using the same tiny intercooler that heatsoaks too easily.

- - - Updated - - -

I do miss the instant torque from my stage 2. Something to consider OP, you will lose some of your low end torque when you swap over to K04.

I'll take a tiny loss in low end for a huge gain in top end. Car feels like a rocket with K04 compared to K03.

[J.kaseno]

This thread is exactly what I was about to post and ask. Ive got all the supporting hardware but want to figure out where the best place to buy my K04 is. Like you, my K03 is shitting the bed. Wastegate design on these turbos was awful.

After I figure out best place for the turbo, then comes time convincing the girlfriend i need to get one. She thinks I dont need a turbo at all on the car. Wish me luck on this up hill battle lol

[Grouch]

I'll take a tiny loss in low end for a huge gain in top end. Car feels like a rocket with K04 compared to K03.

Honestly, I can't say I love one more than the other. I miss the instant torque from stage 2, but the top end power with K04 is exhilarating.

[bb-tt]

Upgraded intercooler isn't mandatory. Nice, but not required. Also, you might consider going stage 1 or 2 first. I'm pretty happy with my stage 2 and don't see a need for KO4 given the cost. APR has an upgrade program that gives a hefty discount if you felt the need to go that route in the future.

I have the logs to prove not even the 3.0 tdi IC could keep up with the heat generated by the k04. Why would you spend the money on a k04 and then leave in an IC that is going to significantly reduce the amount of power you can make with it?

[Nano909]

Honestly, I can't say I love one more than the other. I miss the instant torque from stage 2, but the top end power with K04 is exhilarating.

That torque at launch is great, but when you're getting caught up by a Camry, you'd wish you had that K04 horsepower. Haha. I do not miss hitting 5k and making no power with the K03. I drive a lot on the freeway and thats where the K04 shines.

[Mars2]

That torque at launch is great, but when you're getting caught up by a Camry, you'd wish you had that K04 horsepower. Haha. I do not miss hitting 5k and making no power with the K03. I drive a lot on the freeway and thats where the K04 shines.

Exactly opposite for me the K04 a like shine on twisty B road where you rev each gear from 2nd to 4th to 7000rpm before the next curve and then again and so on......
On High way I cruise at 100mph with rev at 2800rpm Their stage 2 was more responsive. Even if I cruise on highway at 130mph i'm only at 3600 Rpm.mine start to make more power than K04 only after 3500rpm.
Maybe it's because I don't leave in US that I don't have same view. Here you can get 4 point out of your 12 point driving license if you stay on the left lane and not passing any car. You are supposed to go back to full right lane any time you don't pass. So left lane is kind of empty for those who pass. I can set the cruise control at 100Mph on highway and not touch the brake for miles and miles. That is why anytime I have the option I would take B twisty road. Highway is so boring and on highway a 100hp car is plenty enough to cruise at 100mph.

[Nano909]

Exactly opposite for me the K04 a like shine on twisty B road where you rev each gear from 2nd to 4th to 7000rpm before the next curve and then again and so on......
On High way I cruise at 100mph with rev at 2800rpm Their stage 2 was more responsive. Even if I cruise on highway at 130mph i'm only at 3600 Rpm.mine start to make more power than K04 only after 3500rpm.
Maybe it's because I don't leave in US that I don't have same view. Here you can get 4 point out of your 12 point driving license if you stay on the left lane and not passing any car. You are supposed to go back to full right lane any time you don't pass. So left lane is kind of empty for those who pass. I can set the cruise control at 100Mph on highway and not touch the brake for miles and miles. That is why anytime I have the option I would take B twisty road. Highway is so boring and on highway a 100hp car is plenty enough to cruise at 100mph.

Well yeah what I mean is K03 is cool for stop and go racing. But that's about it. I hated K03 when I'd drive through the mountains, and I hated it on the freeway. Our speed limit is mostly 65mph (everyone usually drives 80) and if a car lined up next to you, that's K04 territory, the K03 would fall flat.

[mortimersnerd]

I'm in Denver and do a ton of mountain driving. Seems like the extra lag would stick in the twisted, and it still pulls hard at 80.

[Nano909]

I'm in Denver and do a ton of mountain driving. Seems like the extra lag would stick in the twisted, and it still pulls hard at 80.

You haven't been in a K04 car. K03 pull is nothing compared to the K04. And there's no "lag", just a small loss in torque, so small you barely notice it.

[mortimersnerd]

No doubt. Just not willing to drop $3k for the experience.

[Nano909]

No doubt. Just not willing to drop $3k for the experience.

Yeah I hear you. There's cheaper options now but I'd rather drop the $3k on a BOSS kit if I were going to upgrade the turbo if I were still K03.