2.5 200 safe rpm

sean1982 · 21-06-2010, 05:05 PM

just took my p20 out with the 2.5 on, running a yam drag 24, and saw 69mph at about 6500rpm, it still has the 40amp charging system on so i backed off, if i was the put the 16amp stator and flywheel from my xr2 on what can i safely rev to as it feels its got more to give. would the flywheel from the xr2 be ok or will i need an ally one?
either way im happy with the speed and it felt stable with the drag prop.

TWIN RIG · 21-06-2010, 05:06 PM

7500

sean1982 · 21-06-2010, 05:49 PM

ok cheers, will i need the alloy flywheel or will the xr2 one i have be ok with the 16amp system?

Burty · 21-06-2010, 06:44 PM

run the xr2 one for now, have you removed the oil pump?? if not dont rev past 6k till you have!!!

sean1982 · 21-06-2010, 06:46 PM

yeah oil pump is gone, mixing the fuel, the 2.5 seems to like reving more than my xr2 did!

Jay Smith · 24-06-2010, 12:05 AM

No more than 7000 rpms with stock cast pistons... Although cast pistons "can" be made a bit tougher to safely withstand extended 7000 RPMS by Cryogenic freezing them as well as top pinning to keep the locator pin in place The Cryo treatment WILL tighten up the molecules in the parent metal and make them stronger BUT when a cast piston gives up it ain't pretty. Normally jerks the rod and wrist pin from the weak piston wrist pin boss and starts clearing out the block..
I use "300 Below" for my cryo work and "John Marles Racing" for top pinning cast pistons both are in the states..

Cheers,
Jay @ JSRE