How much is a lot?
I am talking about 164-165 degree ( it's 5.0 mm exhaust height). There is no way you can go higher due to the limited pipe space.
It is not about exhaust duration-it is whole chain of events happened in our two cycle engines. If you just increase exst ( I never try this thing-doesn't make any sence) defenetly yu will loose torq and milage will go down, but if everything else will be broght to specs-you will gain 1 minut easy. On Novas based engines with modded timing 6 mnuts 30 second is absolutly normal run time, but if material for P/S set are changed ( AAC and BRB) you can lean much further with a lot of gaining run time and power.I am talking about use fuel as fuel, not as cooling liquid. It is totaly from my knowlodge and my expirience and it is not meaning this is ruls. So if you want to prove it your self, you need to try. But please remember-if you change one thing in chain, you will need to change everything else. If everything dne right-milage will be realy good.

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.

from what ive seen with 2 stroke engines. you will always
loose some fuel as unburned especially when running more
exhaust timing because there is a period of time where the
exhaust port is open at the same time of induction. Thats
the same reason why recreational vehicles like jet ski, atv, are
being banned from some places just because it emits alot of
unburned gases. thats with controlled ignition.

From what ive seen alot of modders don't just add timing they
also work on the case. sleeve to redirect flow to the squish band
performance goes up and does eat up more fuel than a stock
motor But from what ive seen it will always eat up more fuel
when raising up the exhaust port. I wouldn't say that the engines
are inefficient because the extra consumption is going to additional power. As long as my motors have power and makes
5 min. its all good.

This is totally consistent with my observations of motors and modded motors as well.

hurry up !!! scotty i need more power !

I just sugest you ask Jose ( don't know his name) i think you know about whom I am talking about, he run my MR12. Ask him speed and run time-that engne has 168 exhaust timing ( it is 14 more degrees then stock). As I sad before, it is depend what was done on engine, where do you have tuned resonance ( only in tuned pipe or somewhere else). It is much more complecated then it looks. Just for instance, do we realy need rump in cranckshaft ( under induction port) or may be it is one more interuption?
BTW, when you have chance, can you please help me set up 710 for Revelation, I just built it and have no clue how to start setting.

Just as a sugestion, here is link to very interesting info done in Germany ( ihave already put it in other thread before)-it is my favorit-try to study it might help to see it more deep, then simple fuel escape from exhaust. Just sugestion!
http://www.control-line-team.de/moto...echnik_en.html

Ed, just build and set the car to stock setup as recommended in the booklet. You should be good to go.

A Snake?

Oh my god, Edward went over to the dark site

BTW, when you have chance, can you please help me set up 710 for Revelation, I just built it and have no clue how to start setting. [/B][/QUOTE]


just build it per instruction and I'll help you and leo make
changes if needed.

Hello Dennis,

Just wondering how the new motor is coming along

leo v.

Dennis,

Sent you a couple of emails.

Tommy

Hey motorman! just found out you are modding them engines again. Pulled out your older moster engine from the ziplock bag and started it up a few days ago, still runs like a champ.

Its going well, I need to get an update tomorrow from Gary to see where we are at
Just waiting now as its all settled and done hopefully within the next 30 days or so the pieces for the first 500 should be starting to arrive.

The engine case has been the holdup.