megane pistons and rods capabilities

[sharkeygrim]

Just a query, I am doing a turbo build on my clio, I'm doing megane pistons and rods, I have seen lots of megane owners have them running at their max at 300-305bhp with arp rod bolts? I am jw whether they'll last in my build? As a few have said there meganes have lasted a while at 305? Obvcourse the worry is the rods bending at that point buy il wondering whether to push to 300 and run a boost control so I can pot around at 230 and 270 too!

Please give me your opinions

 

[Dan@SJM]

IMO any more than 270lb-ft and you're asking for trouble, the megane rods are no different to the likes of the 197 ones. Chip bent rods on his, and his was only doing the likes of 260/270lb-ft.

You are aware rod bolts don't increase the torque capability of the rods aren't you?

The problem with what you're saying (meganes do 300+ blah blah) is that it's all down to power delivery. Because the Megane runs a puny little turbo it spoils very quickly which means cylinder pressures are kepts relatively low. When you start bolting things like gt28's to them the spool up period is quite late (in caparison) and also quite aggressive, result is massive cylinder pressures and the rods then get scared of the dark.

 

[Gray]

I've been running my Megane r26 @ 302hp /320ft.lb for almost 40K miles with ZERO issues, but remeber the rods are no stronger on the Megane engine compared to other F4R motors and the rod bolts don't make any difference.

A few of the Megane engine failures have been down to poor maintenance and injector / fueling problems.

 

[Dan@SJM]

But, fatigue also comes into it. You could probably run 400lb-ft on a brand new set of rods. But a set of rods that's potentially done 40k at 300lb-ft? Tick tock...

 

[Richy182.]

If you're going to do a build and want those sort of figures you need forged pistons and rods.

I've always been told over spec and run at 50%-75% of what the component has been designed to. That way in theory the components should be reliable. In theory.

 

[Gray]

But, fatigue also comes into it. You could probably run 400lb-ft on a brand new set of rods. But a set of rods that's potentially done 40k at 300lb-ft? Tick tock...

Very true... I am actually surprised mine hasn't gone pop yet (I was fully expecting something to fail by now).