Chris S

i no alot of it depends on how cool u can keep the piston, how much oils been squirted at it. how high the EGT temps are, CR ect and how high u rev it, but whats a rough estimate at what a standard mahle piston will take?

its a vauxhall engine, 86.5mm mahle pistons, oil sprays,

what is the standard RS cosworth piston made from??
what do people push them to before changing to forged pistons?

*Bri.4.b.Cos*

Aint got a clue but this could be a really interesting topic as i have often wondered the same.

Bri.

bud-weis

i would say 500bhp would be fine, above that i'd go forged

standard are cast

rapidcossie

yeah close to 500 bhp would prob bo OK...

but why would you want ot take the chance of scraping an engine...

get a proper set of forged pistons

Jim Green

Mines fine on Modified Standard Mahle Pistons with a modified piston top to give 7.5:1 cr along with Valve Cut Outs.....

So....Definately 428bhp No Problem......I'm guessing up to around 500bhp providing the engine is properly mapped and it don't run lean causing overheating and piston meltdown. Alot of it is down to having the engine mapped properly to avoid the engien running weak

rapidcossie

a forged piston will last slightly longer under heavy det situations but not that much longer.

Anonymous

500 sounds a reasonable ballpark if you run a fuel that allows you to get away with the highish CR

Stu @ M Developments

iTrader: (12)

At least 600.

Mike Rainbird

iTrader: (3)

It's all down to matching cylinder pressures to the spec of the pistons, so I'm with Stu, if the c/r was low enough and the turbo capable of flowing the air, 600bhp would be achievable. I did 20,000+ miles on 515bhp and standard machined Mahles. As you know, by engine was probably the most abused 500 engine on the planet . The car lived at massive high speeds at least three times every tank full (when I was a petulant youf ) for it's entire life . It would have gone on to do another 5-10k before needing a freshen up...

Chris S

the engine will ony be used at weekend and odd week nite.
if it does 10k i'll be happy.


it will be running autronic, with prob mark mapping it if hes not that busy.

i was going to run a 1.9mm cometic Standard is 1.3IIRC)

but were can i get the pistons machined?? can Norris do it??

i got a set of the Mahles allready.

Gt30 turbo, good head work, steel valves, ect



so where do all u guys get the pistons machined??
wont it make the crown any weaker?

Fiecos Dan

mines run machine'd mahles, and done fine.
at thats 450+bhp on 8.0:1cr, running 890-925oC egt's most the time, on a gt30

Chris S

where did u get yours machined mate, do u take it off just the crown or all over?

Mike Rainbird

iTrader: (3)

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