Thread: gpopshop.com Big T28 Upgrade

I received a PM from an Audi guy who bought this turbo from ATP:

Audi A4, 2.0T B7 Mild Turbo Conversion (350HP) K03 to Garrett (modified stock manifold/Turbine hsg): atpturbo.com

Apparently they use the same center section, so he found my thread doing some research. The link above even has dyno testing for the K03 upgrade. Anybody know how the K03 compares to a T25? I haven't had the opportunity to dyno yet, but my turbo seems to react much the same as the K03 upgrade. It spools a little later, hits really hard at 3k and pull really strong through the rest of the rev range. Also here's an overlay I made with the bofore and after pictures. You can see how much larger the wheels on the new center section are:

Woooo,$720 they gave you the bizzness!!!! but as long as yir happy with it

Haha, I wouldn't say they gave me the business, gpop are good people. I still would have rather had a plain old T25, but what the hell. It's a good turbo and it's brand new which is what's most important to me.

nice pics

Thats all that matters

Wow that looks pretty good .

One of the guys that lives in my area has a T25 with T28 internals. I think I personally would just get a T28 right of way though.

Somebody didn't read the thread! The car already had a T28 on it. I wanted to downgrade to the T25.

Hi, I'm that Audi guy.

From the research I have done so far the turbos that Swiss and I have are Garrett journal bearing GT28s. ATP claims 350 crank HP @ 18 psi for the 2.0T FSI, which I believe. The car @ 20psi ( On the K03 Stage II+ file) feels very similar to my 360 WHP tune (K03 with a 75 shot)

Here is exactly what I have.







They ran a 12.5 on the AWD A3, and I did a 13.5 ( Could have done better but meh no more K03) on my FWD A4 before the upgrade.

Sorry about all the parenthesis.

Nice. That looks like a pretty large compressor housing, at least a lot bigger than my T25 compressor housing. I doubt mine could push 20psi safely. I just run 10psi for now. I've been meaning to call Gpop and ask where the sweet spot is for my setup. I'd say it would do well at 15psi.

I've read this thread a few times