How to build M42 Turbo for 250HP

[Hsiao]

Hi i come form Taiwan, i want to build turbo m42 for 250HP,i already have the turbo Kit(TD04 turbo),  but i don't know what's engine parts i can use. SO i need everybody help.

with 250HP m42 engine i have some question

I need to use forging piston or original?

what gasket thickness i can choose?

How many turbo pressure can boost the M42 engine up to 250HP?

thanks

[Aka-e30]

from research ive gathered it seems that the rods and crank are forged and can handle over 300hp .the pistons on the other hand i heard are the weaker point. on a good tune tho maybe they will hold up but not 100% sure on that. Ive also heard that the stock head bolts start to stretch at about
10psi if your boosting at 10psi for an extended period of time and 10 psi should net you at around the 200hp range. What im planning on doing is going with the stock head gasket thickness and mls. ARP head bolts ARP rod bolts and ARP main bolts if available and then going with some race bearings or stock would probably be fine too. CP pistons from VAC motorsports at either stock 10:1 compresston of slightly lower at 9.5:1 compression.
With the ARP hardware and forged pistons, ml gasket the high compression with about 10 to 15 psi shoulndt be a problem with a good tune and youll get nice low end (out of boost) response and it should boost up nice but that also can be changed depending on the size of your turbo. on this set up i
think you could be close to the 300 mark if tuned properly at round 15 psi.

[ChrisPino]

Here is my Google page and my Youtube channel for the E30 318is Turbo lovers.

https://plus.google.com/+ChrisPhares/posts

https://www.youtube.com/channel/UCLEu7uRERoZOnpMyy0x4enA

Cheers.