Maximum rpm for std bottom end

OAKMERE

As the title says

If I stick with normally aspirated is it worth upgrading the bottom end? Will the bottom end take 7500 rpm to match an upgraded valvetrain or would steel rods be required? If not would 7200 as some tuners go to be OK.

Cheers Oakmere

JohnnyN

I would say for what the rods cost it makes absolute sense or as my boss would say, 'Its a no brainer!'

OAKMERE

JohnnyN said:
I would say for what the rods cost it makes absolute sense or as my boss would say, 'Its a no brainer!'

I know this is probably the correct answer but I hate wasting money. I know the rods will take 250 bhp but there is no mention anywhere about rpm. Power loads the rods and rpm stretches the rod? Anyone know what they can take?

Cheers Oakmere

JohnnyN

As we have just learn't, an SC producing 270bhp with a limit of 7000rpm has just gone bang. After a long discussion with Jon yesterday, he explained the importance of the combination of revs and power. Give Jon a call. ;-)

ace-media

Standard rod's should take those sort of revs easily....!!! 7500 is fuck all in the grand scheme of things.

Any pictures of this recent engine failure?

MikeS

they say this engine's weakness is the bottom end

i wouldnt rev her over 7000 anyway unless she is mapped to give power and torque, no point in upping the rev limit as most of these engines power die above 6000, the 2.4 manifold extends the torque but loses it at the lower range

even still if your confident a map will give you 170+ bhp at 6500 then i would start think about dropping the bottom end out and replacing the rods and pistons and fitting arp bolts along with a new oil pump

the older vxhall 20xe engines had rock solid bottom ends, forged pistons, rock solid cranks and rods, the bolts were the only weakness and if u fitted arp bolts then it was good for 8250 revs standard 250 bhp

cast iron blocks 😛

JohnnyN

Please refer to Supercharger section and look at The Golden Rules-break at your peril thread.

winstar

there is a TMS TB car with schrick cams that has a 7500 rpm red line with a std bottom end, I think it could be timmyp, it is only running about 180-190 bhp.

at high revs its the big end bolts that snap not the rods.

vocky

steel rods are a good idea as they are a weak point on the z22se, especially if you run low on oil

but they are not really needed unless you want to rev to 7500rpm and go beyond 200 bhp

I expect it's the torque which kills the rods rather than the bhp.

OAKMERE

Thanks for the comments lads

Oakmere