What's the most power you can put through stock pistons and rods

[Williamspaul]

I'm about to pull my engine back out for a new flywheel clutch gear box etc At the same time I'm going to put some arp bolts in the conrods what sort of power will this be able to handle I've heard people quoting figures of 320bhp anyone got any experience of this ?

Also what hat would I need to achive this basically I want it as powerful as possible with out forgeing the engine and ideas ?

 

[Fernandez]

You'd be pushing it at 320bhp on a 225/230/R26 engine. It's the rods that will go.

Also to get 320bhp you would need 630cc injectors and a fuel pump. My fuel pump was at 114% duty at only 293bhp.

I'm forging a motor and will be going for Shakyhandmans fuel pump along with a new inlet and throttle body.

 

[Williamspaul]

So I need arp bolts to reach your sort of power and turbo injectors etc

 

[Fernandez]

I had ARP Rod bolts and a 250 turbo. At 293bhp I was using std injectors which were at 108% duty.

You would need 630cc injectors at minimum. A fuel pump would also be a good addition as mine was at 114%

We've turned everything down but because I have more torque lower down than before you can't really tell the difference in performance.

I'll be forging an engine before I go for big power.

 

[ben_r1]

IMO 320bhp on 225 internals is far too much, you want to look under 300 to be reliable but it's the torque that should be the governing factor not power. 1.3 bar is the max I'd go, although the 250 internals are much stronger but it's not commonly taken above 320 due to turbo restrictions.

 

[Williamspaul]

320 is just what I heard I'm not chAsing a particular figure I just want it as powerful as it possibly can be without forging

 

[Fernandez]

I priced up some 250 Rods and Pistons from Renault and they came out an eye watering £2k

 

[Williamspaul]

**** that for a laugh

 

[Williamspaul]

I spoke to someone who worked for wossner at French car show and he reckoned 225s and 250s have the same rods as standard it's something to do with the variable valve timing that allows it to run a higher power figure the way her described it it seemed to make sense and he seemed to know what he was on about but he could have been talking **** lol

 

[shakey_hand_man]

Power tends to stretch the rod bolts, torque tends to bend rods.. 310bhp/300lb/ft thereabouts on dynodynamics rollers

 

[Jonesy]

its the higher BHP, higher up in the rev range that bends the rods rather than the torque, hence why the stndard maps run out of puff around the 5/5.5k mark

 

[Tree200]

Just curious but after the fuel pump upgrade, pistons and rods, what will be the next stress point on these engines (block ect)?

 

[Stephenvenning]

Just curious but after the fuel pump upgrade, pistons and rods, what will be the next stress point on these engines (block ect)?

Possibly valves and springs?

 

[Fernandez]

Not so much stress points but areas to further improve and gain power are the manifold, inlet manifold and turbo.. There's about £4k there alone

 

[litchy]

When I was researching the conversion, I joined Meganesport to find out the 250's limitations and also the tuning options. All the answers to what you can do with the 225 are on there given the Meg 225's been out since 2006.

Fueling was a big issue for me cause my worry was was fitting 630cc injectors was only masking the inadequacy of the pump. When I fitted 630's, the duty was ridiculously high considering. What I needed was less from the 630's and more from the fuel pump.

Dont forget that pump was never designed for that engine and the 225 runs 3.5 bar when the Clio runs barely at 3...... 0.5 bar is huge when it comes to fueling, especially when you consider the Meg 250 runs at 5 bar!!!!

 

[Azagedon]

300 bhp and 300 lbft is the limit I've been told by a mapper (if you don't drive like a prat).

 

[shakey_hand_man]

My bent rod from a few years back was from torque, 330lb/ft.. Bolts fail in tension ie higher rpm on exhaust stroke, you'll never get a rod bolt failure due to compression load

 

[shakey_hand_man]

Block and crank are happy with 600hp, but torque levels I'm unsure.. Throttle body and inlets are complete dog egg on the megane engines, but you can still run over 500bhp with them as stock!

 

[RemyR]

As Shakey said, it's not Power that kills rods, it's torque!! You'll find most rods fail lower down the rev range at peak torque!!

Out of Curiousity, do megane 225 or 250 pistons take a floating pin?? If so, a 'Rodjob' could be possible and would save a lot of money with machining costs to the block, price of pistons, and labour with removing engine etc

 

[Azagedon]

I'm unsure but a few have used ARP bolts for piece of mind when tickling over 300 in the 225/r26 block...