Just wondering how you go about modifying the stock piston to use with forged rods ? I know Hiboost uses this combo but no one has ever mentioned how its done. With forged piston, I just don't want to deal with piston slap on cold morning startup and excessive oil usage. Thanks !
Forged Rods + stock piston !
- Thread starter turboboy
- Start date
Just send the piston to a machine shop with the piston pins you going to use. They will machine then down to the pin clearance.
Not all forged pistons sound loud. CP pistons are ok. You will know its forged but its not loud and sounds healthy, not like something that could be confused for a problem.
Not all forged pistons sound loud. CP pistons are ok. You will know its forged but its not loud and sounds healthy, not like something that could be confused for a problem.
Last edited:
Metallic36
Member
- :
- 2003 Mazda6 3.0L Speed Yellow
Bumping up.. so does it defeat the purpose of forged if you only get the rods? Can the pistons (if machined correctly) hold up to higher boost? Just killed a rod bearing, so looking into forged instead of just repairing it and keeping it stock.
Metallic36 said:
Well, pistons will hold good for 300whp and even more. You usually keep your stock pistons if you are going to push the limits with little expense. But dont expect them to hold 400whp.
And...in a event of ping/knock stock pistons will miserably fail in less time than the forged. But if you are not familiar with the ping sound, forged will go bye bye in just a blink when pushing high HP numbers.
Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by turboboy
Just wondering how you go about modifying the stock piston to use with forged rods ? I know Hiboost uses this combo but no one has ever mentioned how its done. With forged piston, I just don't want to deal with piston slap on cold morning startup and excessive oil usage. Thanks !
</TD></TR></TBODY></TABLE>
could someone explain piston slap?
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by turboboy
Just wondering how you go about modifying the stock piston to use with forged rods ? I know Hiboost uses this combo but no one has ever mentioned how its done. With forged piston, I just don't want to deal with piston slap on cold morning startup and excessive oil usage. Thanks !
</TD></TR></TBODY></TABLE>
could someone explain piston slap?
While you're waiting for a better answer, my understanding is the forged pistons expand more as they heat up. So for a good fit at operating temps they are made a bit smaller than stock, allowing them to have some sideways movement until warmed up, causing the noise?
Maxx Mazda
Contributor
- :
- Stock P5
Sleepy said:
Bigwoofer had like 10.5:1 and 8psi I think... Lasted 2 years before he blew.
http://www.pistonslap.com/whatisit.htm
piston slap, basically piston is to small for cylender when cold, makeing a slapping noise from side to side.. piston warms up, expands fits cylinder wall fine.. no more slap
piston slap, basically piston is to small for cylender when cold, makeing a slapping noise from side to side.. piston warms up, expands fits cylinder wall fine.. no more slap
kyle's protege5
Member
- :
- 2002 MP5-T
what compression do you guys think you should go with then? i would like to keep it at least the 9.0 to keep some low end.
I'll be using a t3/t4 and running water/methanol injection. Boost will be in the 15-20psi range, depending on fuel supply.
I'll be using a t3/t4 and running water/methanol injection. Boost will be in the 15-20psi range, depending on fuel supply.
Maxx Mazda
Contributor
- :
- Stock P5
kyle's protege5 said:
I have 8.5:1 and my low end is just fine. I think I'm running the thicker Cometic head gasket too. I'm not sure what I put in. Some guys run straight 8:1 and still have a bit of bottom end, but running that much boost on 9:1 might be pushing it. Lower compression lowers your risk of detonation, which provides a bit of "cushion" whil you're tuning.
