Supra Convert

[pwpanas]

Originally Posted by Sonyps307

2jz is good for way more then 500hp. But I heard the valve train can only take 600hp but I'm not sure. Also the stock 2jz internals are already forged

WOW. How can you be a member of this forum and be so uninformed???? Please read back through some of the other threads on this topic!

The 2jz-gTe is good for well over 1000hp, including the valve train. In fact, the record on an oem 2jz-gTe shortblock is ~1050rwhp (1,235hp at the crank). A number of race teams have used the oem pistons with aftermarket rods (Carillo) and put down over 1300rwhp.

Over 1000hp, the oem connecting rods can be the weak point (especially when using nitrous as a power adder). However, I strongly suspect that with proper tuning, a brand new 2jz-gte with oem rods & pistons, a ported head, aftermarket cams, the oem valve train, and a big (eg. 92mm) turbo (no nitrous) could hit 1200rwhp. Wish I could afford to bankroll that experiment!

The oem valve train fails at about 35psi of boost. Specifically, the intake-side oem valve springs are too weak to hold back that much boost, so they get blown open by the boost before being opened by the cams. This can lead to shims popping out (quite a bad thing). Although I don't have any hard data, most agree the oem valve train will also fail over about 8K rpm, again due to the relatively weak oem valve springs (again, shims can pop out). Stiffer valve springs (and/or dual valve springs) fixes those problems, but will likely reduce the service life of the engine. In other words, keep it under 35psi of boost and under 8k rpm, and there's no need to worry about the oem valve train.