hi recently brought a set of mahle 86.5 pistons for my st205 and was wondering if anyone knows max bhp there good for or what would you recommend

Potentially OK for massive HP if the ring gaps and piston bore clearances are done by someone who know how to build a high horsepower engine, and then it is mapped with supporting mods etc

detonation will kill all pistons: quickly¬!


how much bhp you want?



there is a thread on here from a Russian Tuner using modified stock ST215 pistons and support 500+ AWHP

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posted by Jon379

hi gary max im after is 450bhp ,reason i was wondering was mahle state clearance is bult into the piston, ie 86.5 bore and pistons are supposedly a drop in but doesnt state if any more clearance required if running high hp, nitrous etc je pistons normally state certain clearance for different applications so was just wondering max bhp before having to play with clearance

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JP
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Ask James at TGT - they use Mahle pistons for their engine builds.

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Yeah James will be using some in my build as not using the HKS 87mm but using the HKS stroker crank

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aren't malhe low expansion piston ?

You have to run small or big clearance on JE, CP, ... depending power goal because they are high expansion piston.

yes mate they are low expansion pistons, just curious as people say they cant run as much power as je ,cp pistons, im quite happy with boring to 86.5 and dropping in as per spec, but was just curious if any one else has run high hp with these installed and if so what hp

If the Mahle piston is 'low expansion' then I'd have thought that they are high silicon content 4032 alloy which is more brittle and therefore be more prone to ringland failure than the 2618 Al alloy used in JE and CP pistons. The TTE rally engines used Mahle pistons but they were only expected to cope with 300-350bhp.

There's no doubt that the Mahle pistons would require less clearance and hence run quieter (less piston slap) but you don't have so much of a safety margin as with 2618 pistons if you experience detonation. The TTE rally guys almost certainly ran high octane fuel e.g. >101 in their engines to reduce the chance of detonation but that isnt really an option if you are planning on using the car as a daily driver on the road.

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
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2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

What Don said.
The Mahle available are 4032 alloy low expansion.
Also there is a possibility that TTE ran alternative spec Mahle pistons made from 2618???

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JP
GT4DC Treasurer

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Yes, that wouldn't surprise me JP. Mahle currently do a very trick steel/alloy piston for the Audi R15+ diesel Sports Prototype. I'm sure you don't get those in your A4 TDI repmobile

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

what tracktoyfour said is basically what i thought about the mahles, which was why i was trying to get a max safe hp figure,will stick to 400-450 hp max basic spec of my car is going to be
86.5 mahle pistons
crower rods (pistons and rods weight matched)
balanced crank
acl race series bearings
new oil and water pump
exedy twin plate clutch (might be a bit overkill)
ported head and overhauled
hks valve springs
cams standard for now possible 264 spec
850 injectors
apexi power fc
currently got a td md260 hybrid turbo but dont think it will get the power i need but martin at td reckons with spec of build i should see min 400bhp but not convinced
engine will be built in the summer months when its warmer

Hmm I doubt a TD hybrid will get 400bhp. more like 360 ish IMHO. Either that or you will have to run megaboost

ACL race bearings heh? Don't these require regular changing due to wear rate? More suited to race applications where engine is stripped and rebuilt each season IIRC.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

yes you have raised a question i too wondered... my brothers car i 'believe' is ACL race bearings... i also heard these can not be as good as the Toyota bearings over many miles.... can anyone enlighten us to if the ACL bearings are not as reliable over mialge wise as toyota items?

Hi,

i know a company hear in austria that uses ACL often in his clients cars without problems

a friend uses power enterprise in his CS, also without problems

greetz

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street legal?.....perhaps in tschibuti

race series bearings are more heavy duty so can take more punishment supposedly heres a write up
.
ACL Race bearings are designed to withstand higher RPM conditions and featuring:
High strength overlay plate with reduced thickness
Hardened steel backs on all Conrod Bearings
Increased crush and elimination of flash plating
3/4 grooving on Main Bearings providing optimum oil supply
Tight consistent wall tolerances
Oversize chamfers where applicable
and the spec of turbo is
MD260
High flow 57 Trim T04E compressor wheel - CNC re-profiled compressor housing - 360 degree ramped thrust bearing, modified bearing housing, left hand thread inconnel shaft & wheel, staggered gap/ total seal turbine end piston ring fitted. Max recommended boost level 22-24 p.s.i after speaking to martin at td he seems to think around 400bhp the turbos at fensport are 48mm compressor wheels so i dont know am really tempted to sell this turbo and go gt3071 or 3076 but would like to see what it would do