I'm considering build an engine with forged piston/rods, but before I spend the money I'd like advice on what power ouput the standard internals can reliably take

around 350bhp is the max

with a circa 330flbt

and it will only take those figures with the correct supporting mods - many engines have expired at far lower levels of power & torque

What are the supporting mods

front mount intercooler a good one (pro alloy or evo 6 on ..though they will all work at those figures) jbt is selling one now in for sale..
decent filter and exhaust..stage 3 hybrid or gt 28 r or rsr even rs..hybrid will be cheapest .
most important by far a live map from fc performance though you can run a generic chip with a fuelling trace but no where near as good ort safe as the fc performance map..you may also need bigger fpr and walbro pump but thats not a given just a maybe
check out tuning section for more details 20vt the knowledge

Is there any point is using forged pistons and standard rods or do they both need changing for 350+ BHP

my thinking is to go the for both pistons and rods,then you can go for what ever power you want.without openening the engine up again to replace rods.

Agreed - I did it the expensive way - forged pistons / standard rods - six months later, I bent a rod (too much torque) and had to have the engine stripped again to have Cunningham rods fitted

OK mate,
I'm begining to think you're taking our small bet on next years AGM sprint day far too seriously.
It's only a pint of beer for gods sake !!

I have just done this with all the supporting mods, so to speak!

First and foremost..the cost is more that current value of the coop.be prepared for this.

More engine power is excellent and you will be able to run a much higher boost, but take heed you need to have good stopping power (cue: brakes) and a suspension refresh would be recommended. It doesnt end there as downpipe and exhaust may need upgrading at some stage.

Plan carefully and plan ahead..the end result can put a seriously long lasting grin thats hard to remove!!!

Is the simple answer that unless forged con-rods are used there is no point of using forged pistons ??

No - if you are going for 350bhp then stock rods are fine. They bend when you go over 350 lbs ft, and if you are going for a high rev limit then the rod bolts have been known to let go. You wont be going to 7,500 rpm+ unless you are running a big turbo that is capable of going well over 350 bhp - anything smaller than a GT28RS will drop off at the top end revving that high.

You have to set what your ultimate aim with the car is, and what needs to be done to get there. Questions like this are always going to be subjective, you can only generalise to a certain degree - there is no simple answer consisting of 'bolt these bits on, and you'll be fine mate':

1. What power / response do you want?
2. What turbo do you plan to use?
3. What boost do you want to run?
4. How much money are you prepared to spend?
5. What am I going to use the car for?

after sorting all of this out you can work out:

1. How am I going to get the fuel in
2. How am I going to keep the charge temps / water / oil temps down?
3. What exhaust will I need?
4. How is the car going to be mapped?

etc...

The answer should be, do it once, do it right.

You get a nice new shiny engine, with forged pistons and standard rods. The rods fail on you, engine out, rebuild again, maybe new pistons, going to cost a few grand again in parts and labour, or you could spend the extra £800 and get the rods fitted first time round.

If you are only building a 340 bhp engine then I dont see the need personally, but if you are nearing common limits (i.e. over 350 bhp) then it is certainly worth doing.

You can of course do everything right and nothing on a budget, and still end up with an engine that fails, which is why I asked about budget.

The 20VT engine runs very well at 300bhp on a budget, but go for over 400bhp on a budget and it'll last a few thousand miles. If you do it properly it'll last a LOT longer - but if you push the engine hard (i.e. track) I doubt you'll get over 40-50,000 miles out of it.

My mindset is with Begbie here and thats why I went the whole hog and just did everything. Yes it is prohibitively expensive, but then nothing ventured, nothing gained IMO.

Put it this way, once you open Pandora's Box, there is no going back.. and the supporting mods drain the wallet.

Both Begbie and Suba have loads of knowledge and experience..so plan and plan again