Boost Question

[nolafishr]

How much boost can the first gen 12 valve engines handle before any mods have to be made to the engine/head?

[Tacoclaw]

Before any mods? Probably around 25-30 depending on your timing. After a simple retorque to 125 ft/lbs you should be good to 40-50 depending on your timing.

Wastegating and exhaust back pressure tie into this somewhat as well, but not until around 50 or so with a tight housing.

[cougar]

Most say anything over 40. I would also throw EGTs into that. The higher your peak EGT, the more I'd lower that number. But that's just me.

[oldestof11]

Boost:drive pressure ratio is the key. Also, head bolts torqued to 125lbs or new ones to 130 can hold quite a bit.