I think 360bhp is pushing it... But no science behind this just what I've read on various other sites. Got to watch out for clutch issues too. Would be interested to hear other peoples comments on this....
Is it not the excessive torque that kills the stock r26 internals, I think they are maxxed out at 300lbft?
Good job. Lol. Atleast we know stage one maps are well under that point of bending the rods if yours lasted up to 340 ft lb
Every engine will differ from the last but rs tuning cap the torque at 300 for the safety of bending rods..I'm sure there is engines out there that will last with 320 odd and there will be some that fail under 300.
Paul capped the torque to 300 after he started to see rods bend. Mine was mapped by rs tuning when it bent the rods.
Rods are the same , pistons are different. head is different , turbo is larger. In a nutshell it appears the low rev high increase in torque kills the rods. 300ftib appears to be a "safe" limit but I think you can push them a little harder
Interesting! Rods are definately the same? So how are 250's able to safely handle more torque and power? where did the rod information come from?
I am 99.9% sure rods are the same. Lower compression with the higher capacity head of the 197/200 and dished pistons , VVT , larger turbo delivering boost later on in a smoother curve
I wont be buying one if the rods are the same as a 172. I swear lee was going to use a set ov 250 rods in his megane becuase they are stronger
http://www.cliosport.net/forum/showthread.php?693706-stripped-megane-250-265-engine Paul says the internals are differnt and look stronger but how strong no1 knows
I just told you how. The pistons are crowned and different. The rods are the same. Cam is slightly wilder.
The rods are not the same. Paul says the pistons and rods are differnt. A crowned piston withal slightly lower compression ratio would not make a rod take 380 ft lbs. renault must have decided not to put cheese rods in the 250
The overall package of different volume head with a lower CR , a different way of making boost with a different turbo, a different crowned set of pistons does explain why it is capable.
Iv asked ads for part numbers on both sets of rods, hopefully he can help us Iv also compared my r26 stage 2 graph that went bang! Against a megane 250 stage 2 graph- the 250 is down 13bhp and 20lbft at 2500rpm on the R26, but after that the 250 has around 40-50 more lbft and bhp across the whole graph! I don't care who's right in this conversation, just curious to whats being used
But you are still filling a cylinder with a volume that has to be compressd by a connecting rod. On a stage 2 or 3 map the turbo is making more psi to get the 360 bhp so the con rod needs to be stronger. Paul has already said they are stronger but not sure what they can take.
You are not comparing apples to apples though. If the volume is different then you are getting different compression ratios.
Agreed , there is little info out there ! I think the thing that kills the rods isnt the overall power up the range , but the sudden and steep climb of torque on the R26 engine.
I agree if there engines where making the same bhp with the differnt compression ratios using the same amount of psi then the lower compression engine is underless strain. But we are talking about 360 bhp 380 Ftlbs. That mean the turbo is working very hard and making a lot more psi. More psi in a cylinder plus fuel means the pistons have a harder Job to compress the volume in the cylinder hence why r26 rods would bend but a 250 doesn't hence why paul says the rods are differnt.
Two different turbos. One is working harder than the other ( the r26 smaller turbo working harder than the larger 250 one )
To make 300 bhp on a r26 engine yes its working harder then a 250 as needs more boost but we are talking about 360bhp. Anyway this is boring as paul has already said they are differnt rods. So maybe i will buy one then
Turbos size doesn't really matter mate, in terms of working harder, its just more efficient. A larger 250 turbos spool times may differ, but after my experience of fitting a larger hybrid unit there isn't any real difference. The problem is the greater cylinder volume created by the turbo/more boost pressure because of this more fuel can be added, so once the cylinder fires the rapid expansion of the gasses within that cylinder force the piston down harder and faster and bend the rods. Lowering compression will help slightly, but were talking 80lbft and nearly 100bhp across most of the rev range, so roughly a 40% increase over standard with no issues...on same rods? This is what intrigues me and why i want to know if the rods are the same
I think there are a multitude of factors that change the characteristics of how the engine bends it rods. I cant find any details of the standard rods in the 250 engine which is frustrating !
