Bri Bro

The answer is also temperature related. On a hot summer day with a long run the intercooler will get HOT so you need to limit boost. On a cool day, you can turn it up. I have run 18 lb on mostly stock setup (chips, 52#injectors) for over an hour on the track with no issues, outside temp was 40-50 degrees.

Bill

WOW...such a simply put, but complex question!

Certainly I do not have the time nor the space to give a good answer, but I will take a stab at the basics. The important thing to remember here is:

If you add more air (boost) you will need to add more fuel. This is critical to understand. Learn it, Live it, Love It!

If you add air and do not add fuel, you will lean (more air than fuel) out the air/fuel ratio (AFR). A lean AFR will kill your engine. To install a AFR gauge (wideband) like suggested, will allow you to monitor if your engine is running lean, but it will NOT ADD FUEL to the air you add when you increase boost.

The modifications Tom suggest are the typical mods made to increase (boost) power output. Here again it is important to know that most of the described mods, are specific to adding air ONLY (MAF, boost controller, exhaust, wastegate, bigger turbo). Again.....time bomb modifications.

Another key fact to remember, your engine is designed (by the best engineers on the planet) to run at a certain boost level (Factory) with a margin of excess for safety. The computer controls and the size of the (stock) injectors can only deal (spit enough fuel) with a certain amount of added air (boost) before you exceed the factory design (stock safety margin) and you create a time bomb (lean AFR).

To add the items suggested above you MUST add items that add FUEL (gasoline). Chips, fuel controller, and depending on the AMOUNT of air (not just the level of boost/psi) you add.....larger Fuel Injectors become critical. The computer can see a lean mixture (oxygen sensor) and from that input, it can call for more fuel (injector dwell), but if the injectors can not physically squirt (injector size) more fuel into the combustion chambers....you have a time bomb.

Along with larger injectors, I would also add to the list, larger fuel pump (bosch 044) and a rising rate adjustable fuel pressure regulator (AFPR) to FEED more fuel to the new THIRSTY injectors.

Lastly, the balance (the way the turbo/ injectors/exhaust/fuel/boost pressure/chips/fuel controller work together) of the system (AFR) is again criticaL A good aftermarket supplier (I will withold names, for your own search) can assist you with a great performing, long lasting, balanced system.

Buy as many books on the subject as you can. And read them. Talk to knowlegeable people (be carefull here). And listen to them. Do this first (before cranking up the boost) and do it correct. With raised levels of boost in a 951, your engines life depends on it.

Welcome to Turbocharging 101.

333pg333

Nice writeup there Bill.
I would also add that if you can get access to E85 and set your car up to run that, then you can ramp your boost up as well.