Irish222222

I'm working on a custom procharger setup for my 996 c4s and need some help fixing a boost leak. See pic... any idea what this hose does? I did a boost leak test and air was pouring out of this connector. Should I add a check valve so only vacuum passes through before this connector? Thanks!

cds72911

Vacuum line for the brake booster.

AnthonyGS

So yes, it definitely needs a check valve which is what OEMs do in boosted applications. Or you can disconnect it completely and run an electric vacuum pump for the brakes.

808Bill

Do keep us posted to this set up please. Any internal upgrades to the motor?

Irish222222

Awesome thanks so much for the quick help! I was maxing out at 5 psi no matter what i did...i was hoping to see more like 8 or 9. I'll get a check valve on there and let you know how it goes.

No internal changes done...we'll see how she holds up lol.

808Bill

I do hope you don't push your luck. These motors don't do well under boost from what little I've seen.

Irish222222

Thanks. I know I'm not going to make Porsche enthusiasts happy, and I sound ridiculous, but my main goal is to see if I can prove the later gen M96 to be a little stronger than everyone thinks. If that's not true, I'm using it as an excuse to tackle the LS swap 😁. AWD Porsche chasis with 600+ all motor hp feels like almost the perfect combo...just behind a 997 turbo. However, I don't drive it a lot, so my stretch goal is to be able to afford or find a steal 997 turbo before I do any damage on the M96.

Irish222222

Finally hitting the right boost...maxing at just over 10 lbs. It was a combo of that major boost leak and a bad choice of air filter material. Thanks again to the forum for help.

Will be getting a better intake solution and dynoing this summer for some real numbers.

808Bill

Keep us up to date on this, good luck!