Dan wrote:
I'd be very interested!
Just started to translate
bit later i'll post here.
Diceman wrote:
Without detonation, and with correct piston to bore and ring end gap clearance I see no reason why the std piston will not survive high BHP.
Domspun wrote:
Usually, reliability depends a lot on the tuning. A good programmable ECU with a lot of dyno and track tuning will give great result with stock engines.
exactly. Piston-cylinder gap _must_ be increased. Stock rings are holding well. My 3sgte generates only 553hp (but already for 2 years and 8500km of
frequent full throttle)
but this lancer evo with st205 STOCK pistons w/ increased combustion chamber....generates
667hp@1.9 bar
Other one car 460hp. Celica ST185, stock st205 pistons w/ increased chamber, later they made dyno on 100 octane and reach 510hp, unfortunately i don't
have graph.
dale wrote:
....especially as 90% of st205's running only 1.2 bar or more suffer ringland failure... not a good percentage ratio of success to fail in the grand
scheme.
but i would love to hear more indeed!
1.2bar+stock injectors and pump also with really high temp in intake due to poor stock intercooling - that's the limit, and then say hello to
detonation.
TrackToyFour wrote:
Have to agree with Dales comments. The practical experience of many people running 3S-GTE's over 350bhp with the stock hypereutectic pistons is that
eventually the ringlands will fail. The more brittle nature of these stock pistons mean they are more susceptible to damage from detonation. The forged
2618 alloy pistons are the least prone to detonation damage.
if engine is planned for high output, it is necessary to use bigger piston-cylinder gap and reconcile low CR if running on usual petrol.
TrackToyFour wrote:
Running such a low 7.6CR and high boost of 2.4 bar does that not mean the engine is more suited to drag racing? The lack of power/torque off boost
inherent in such a spec would make it really difficult on circuit. Particularly tight and twisty tracks.
If you've managed to solve that problem I'd be fascinated to hear how its done.
i'm not professional racer not even high-class....driving for fun only and really like winter events - just keep the engine above 4000rpm where turbo
starts to generate the boost, but i know guys who really likes asphalt racing, and precisely preparing their cars, but nobody was confused with lower CR
- choose right type of camshafts and turbo and get spool where you want and according to gear ratios.
Regarding toyota pistons
Photo of drawing for new chamber. Final thickness is 6mm, like on 2.2ltr 3sgte HKS strocker pistons.
Side view of st185/205/215 ans 2jzgte pistons, as you can see pistons are different - chambers, thickness.
Thikness of pistons top.
Height from pistons top to back side.
all together
Finally....i was chasing for lower CR, and found out that best deal for that is using 2jzgte pistons and came to 7.5:1 CR, but there comes 3 problems:
1 - exhaust valve spotfacers must be increased due to mirror position of intake and exhaust 2jz vs 3s
2 - piston skirt must be cutted 3mm because it meets with crank balance weights
3 - new cutout for oil nozzle
If these problems are to deifficult to be sorted out, just choose st205 pistons as they have highest thickness and distance from top of piston bo back side (see pictures).
Guarantee for long and happy life of pistons and rings is correctly programmed ECU, balance of boost, CR and fuel...and of course driver of the car
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Great to see a Caldina side feed TB and plenum. on the red car. Is this an ST185 fitted with a Gen 3 or Gen4 3S-GTE? Very similar setup to my track project. Looks like coil on plug ignition. It would be good to hear the details on the electrical system mods too