best cosworth pistons? wossner/wiseco/arias etc etc

[M K]

looking to buy some pistons for my engine build and may attempt the build myself with a bit of careful research and triple checking etc but not sure what pistons to go for?

looking for some that are good quality light and have low silicon content so minimal shrinking when cold reducing piston slap on start up etc,

will i want ones with valve cut outs? i am on fms high torque profile cams but don't know exact lift etc right now, but surely valve cut outs wont be a bad thing?

i will be aiming for around 450bhp or there about when finished, i dont want to scrimp on these but dont want to pay a middle man for supplying something that is available direct if buying direct or from the states is an option

thanks Marc

[steven mc kay]

i think mark from chat the cp pistons are good.

thanks steven..

[Arne]

Im using Wössner and are happy with them so far. They are pocketed and you want piston with pockets.

[mark shead]

looking to buy some pistons for my engine build and may attempt the build myself with a bit of careful research and triple checking etc but not sure what pistons to go for?

looking for some that are good quality light and have low silicon content so minimal shrinking when cold reducing piston slap on start up etc,

will i want ones with valve cut outs? i am on fms high torque profile cams but don't know exact lift etc right now, but surely valve cut outs wont be a bad thing?

i will be aiming for around 450bhp or there about when finished, i dont want to scrimp on these but dont want to pay a middle man for supplying something that is available direct if buying direct or from the states is an option

thanks Marc

Use mahle pistons and get valve pockets done.

Mark

[Tore_TJ]

I've got Wössner as well. They are coated and have valve cut outs. Have proved themselves quite strong as we had some serious fuelling issues at the dyno

[COZZFATHER]

mahle and cosworth were owned by vickers who originally started out with a steel foundry back in the 18 hundreds then who built ships and subs with weapons of mass distruction and loads of stuff,now mahle bought cosworth technology group.
so by buying mahle your buying cosworth it seems and mahle even have a head office in Northampton,not bad for a pair of german brothers

[RWD_cossie_wil]

Mahle, oe for a very good reason!

[Cozzie Bhoy]

Had Wossners in my new build initially and had to take them out cause of piston slap. Just didn't sound right in a new motor. Put in Mahle and not a bother with em..

[M K]

Where is best for mahles with cut outs then? And are they a set cr or is there various options?
Head head has only had one skim but I haven't cc'd it yet so no idea what comp ratio to go for,

thanks marc

[Nash]

Where is best for mahles with cut outs then? And are they a set cr or is there various options?
Head head has only had one skim but I haven't cc'd it yet so no idea what comp ratio to go for,

thanks marc

Just get them machined for the comp ratio you require and have the cut outs done at the same time.

[SCS j1mbo]

Where is best for mahles with cut outs then? And are they a set cr or is there various options?
Head head has only had one skim but I haven't cc'd it yet so no idea what comp ratio to go for,

thanks marc

are you going to be getting a proper live map ?

if not go with the compression ratio your chosen tuner would use on one of their chips

piston wise, for up to 520 odd bhp mahles machined with pockets and bowled to suit head and c/r you want

[Mike Rainbird]

I agree with Mark - sub 500bhp Mahle, above that CP .

They come as 8.0:1 and have to be sent away to be bowled and pocketed to achieve lower c/r. I always use Harvey for this .

I would prefer a CP piston if you're staying standard c/r.....

[SCS j1mbo]

I agree with Mark - sub 500bhp Mahle, above that CP .

They come as 8.0:1 and have to be sent away to be bowled and pocketed to achieve lower c/r. I always use Harvey for this .

I would prefer a CP piston if you're staying standard c/r.....

also come as 7.2:1 cr mike, and normally are out the top of the block too much so its possible to acheive low to mid 7's

[cozzylee]

sorry to steal the post but what cr ratio is safe for holding 25psi

[Mike Rainbird]

sorry to steal the post but what cr ratio is safe for holding 25psi

Depends what turbo. You can get away with higher c/r with a larger turbine which reduces back pressure.