HomemadeTurbo - DIY Turbo Forum

I am also on the process of finding info for turboing H series.

As far as H22 concern, I've known 3 people. One of which he ran 298whp stock daily for almost a year without problem. That is with proper tunning. One blew his motor, and one running 280whp for 1.5 years. So, your millages may vary according to proper setup and tunning.

However, in order to get the maximum benefit from boosting and to be on the safe side, a lot of work must be done to the engine.

H series with stock internals are generally not good for FI, hence, it has FRM sleeves and high compression. However, with proper rebuild, it'll be the beast. A friend I know running 487whp on a turboed H22 EK and he spent 10,000 into the car, that is without most of the labor (he did all installation and most of rebuild himselves) beside machining: Resleeves, port, polish, bored, etc. He's running 9 daily. But it's not streetable anymore.

So on the safeside, stock H22a (earlier closed deck version, not the A4 - 97+) are safe for low boost, ~ 275whp max.

For more power, you speaking of at least 3000 into the block.

I did a lot of research, and reading (arg how much I hate it) in order to find what I need to do. Still, I'm asking a lot of people to share their experiences with problems so that I can avoid when building the block. I started a thread in the Hybrid forum of this site hoping to see some H series FI people.