What caused the demise of the 430bhp lump? Pistons, rods?

It's the cold clean air

Im so so tempted to go for around 380/390......

Davie

Hi,

Like Fredrik (Freddan72) already has written, I did manage to get 408 bhp with std internals. I run with GT3071R turbo + std internals just over 2 years, before I changed forged internals with some other modifications.

I installed first GT28RS turbo already on 2004, milage at that point was app. 34 000 miles. Since that moment I have had +340 bhp /+335 lb-ft 70 000 miles with std internals.

Now I have ran some 12 000 miles with forged internals.

In my mind the fuelling/detonation are the most important things to avoid blown engine.
Also I think that the power won't be the issue, torque yes.

- Jari-

That is quite simply not true, with a hybrid turbo you can push over 400 flywheel power on the stock internals, and 320 flywheel power with breathing mods is easy.

The internals are good for 450 bhp, BUT for that you will need a thicker headgasket, mapping, injectors etc.

You can blow ANY engine if it is tuned wrongly.

It is perfectly possible to melt forged pistons if fueling is wrong.

Running lean will produce big in cylinder temps, but so can having a poor exhaust manifold as gasses can't escape well enough.

There are lots of factors to consider but here are the absolutes:

1. Over 350 lbs ft or torque will bend stock rods.

2. Standard internals on the 20vt running over 350 bhp will not last, however you may get away with it for 20,000 miles give or take depending on how hard the engine is pushed.

3. More than 1.4 bar on the standard pistons is too much for the rings to take reliably for a lot of miles - again it depends on how much the car is pushed hard on boost.

Why not use Wizard Flea's skills; to map multilevel boost.

I have 1.3bar up to sub 5000rpm, then 1.45bar - works great!
It saves a bit of torque from the pistons and still makes great power.