What is the max boost you can put into the I4 engine before you need uprated pistons?

I4 being twin cam 8 valve Sierra
16V RS2000
16V 2.3 Scorpio
16V 2.3 Galaxy

This question is really aimed a Stu but anybody with any experience is welcome to help

Thank in advance for any advice.

Mark

 

Never tried, so have no accurate answer, sorry.

But i will say dont forget the rods

 

Are they the weakest link?
I rev my 2.3 to 7000 rpm on a regular basis on stock rods

Mark

 

Is it the RPM or BMEP that kills the rods? do they snap or bend?

Thanks

Mark

 

Anyhow, I would remember that teh RS200 already has proper forged pistons, so that would not be a concern.

 

RS200 !

I wish

Just manky old cast pistons on the RS2000 though.

Mark

 

It has been known to bend the buggers.... but certainly not at the spec your at currently, so thrash her to death

 

Thanks Stu
But "IF" I were to go forced induction with a max of 6psi do you think a 10.3:1 CR I4 bottom end is up to the job?
I'm just too damn tight and lazy to rip it all out again for new pistons and rods.

Mark

 

Its impossible to say with me having not tried that particular setup...

"Rake it till ya break it" Let me know

 

I'm getting a bit bored with the performance as it is, so once I've fixed my motorbike I might give it a go. The 4x4 cossie intercooler kicking around my garage looks like it will squeeze in down the front.

Another quick question Stu if you have the time

I've fitted a 2mm decomp plate under the barrels on my bike and this has thrown out the cam timing, do I set the timing to standard settings or is there a 'rule of thumb' for LCAs on a turbo engine?

Thanks again.

Mark

 

Well,
The wheel centres are the same, its the belt thats now too short. Personally id try standard, and then retard her a bit for more top end if required.

Lobe centres are actually quite similar on a turbo setup, just a little more overlap and less lift as a rule, but it doesnt make the difference some think, dont believe some of the hype

Do they do a vernier for the model you have? that would make life extremely easy

 

I don't think they do verniers for my bike but the accepted way of doing it in the biking world is to diamond file the bolt holes to elongate them and when you are happy locktite it all in place.
Thanks for the advice, I'll try standard timings and see how I get on.

Mark