Originally posted by AMGRacer
Well in my experiences with normal motors (Novarossi RS and MT series especially) once you go above 5mm your milage on any sort of large track is terrible and you lose too much bottom end even with other mods. I am certainly no expert on these things but to make power you need fuel. I have never played with special sleeves etc I am a normal guy with Nova motors and a dremel.
Mayby these new higher temps motors are changing the rules, never seen em myself. Cant say I have ever seen an easy 6.5 minutes out of any modded Novarossi I have owned unless the track is way small. Will be interesting to see if your motors change the "modding" rules.
I don't want to through rok in your yard, but PS12 has nothing to do with modding of existing engines. It is totaly different concept in nitro design.
You are right to make power we need fuel to burn and create pressure-to make power, but how much fuel is realy burning and how mach just dumped to air. On conventional design engines to do not fresh mixture goes out with exhausted gases, designers are putting extra ports to redirect mixture out of the exhaust port-this is the place where we are realy loosing power and milage, on top of it temperature issue related to gas flow etc. If just increase exhaust timing without adjusting the rest of possible varibles will defently bring power down, even on top end not only on bottom end.
My Piston and sleeves sets I wouldn't call special, it has been use in nitro engines at list last 20 years in other nitro aplications-airmodeling and boating. I have no clue why in RC cars no one so far didn't try it. I may be will say something realy creasy, but still will say-materials properties of P/S sets is about 75 % of power what we can have. It is not fun to work with this "exotic materials"-BRB is very hard to work with-like heat threated still and Aluminium to chrome plating-is realy difficult process, but to increase power brought to this, so we have to live with that
On an other note, we did experiment, when we blocked buster by peice of silicon tubing on stock engine and it doesn't change performance, but milage went up. So based on this experiments next generation of PS12 will have totaly different porting configuration.
So talking about only one event will not give us a lot of benefits.
Just for instance, induction timing on my engine is 230 degree ( most advanced engines tofday I saw no more then 220 ). If you will try to do the same on coneventional engines it won't work-tuning will be pretty hard and power will realy low. This is one of the reasons why I decided to look power in different direction-not to try redirect flows and fight with other issues, just build what I think is right.
Just can sugest you, before you make any cutting, try to do step by step way, change one thing at the time and keep your notes for reference for next time. after some time you will know exactly where to cut and how muchfor particular aplication.
BTW, on OZ in next couple days will be run 2 of PS12.2. It is little bit different version from prototypes-some minor changes was done. So you will have chance to see it there in OZ.