M7H

Try a new plug first....

rcabj

iTrader: (1)

hi.. can anybody give a review or comments on the Novarossi LL3...? tq

ziggy12345

Fantastic engine... I have 4 for sale

Ghett0

Quick Question:

I am still using my old Rossi engine from `2000. It’s a MT12. It’s been running well for years. I just recently purchased the MTX-4 and dropped my old MT12 engine in and she works great. I will be racing this summer and I think its time for a new engine. I think I would like to stick with Nova Rossi. Which Rossi engine\pipe would be a good fit for racing this summer, it must be ROAR legal.

Thanks

Osiris 75

iTrader: (18)

Nova plus 12-3

tenderfoot57

O.K. here's the question for ya all. I have a NSR 12 that I have modded the crank and sleeve. The engine ran fine last season and I went to fire it up today and had a strange experience. The engine will sit there and idle, as soon as I give it any throttle it starts to run backwards, it will idle like this for a few seconds then I give it gas again and it stalls. Whats the deal? The only difference from last year to this is the type of fuel that I am running.
Thank in advance for your thoughts.
TF

Dynamite

starter box battery not connected in reverse?

blanks596

iTrader: (20)

can anyone tell me how many head shims to use for the N12LL3 with 30% fuel?

M7H

How much did you do to the crank?...
If you really changed the timing, you just might have gone to far....
and then these things can happen......

unc_tarheelz

Considering buying a 12-3SCT (HotMod) at a good price and was wondering which pipe would be the best match on a small technical track(120ft x 70ft) ? Also, what is the difference in 5/6/7 fin manifolds?

I'm a newbie to Nova motors, so any help would be appreciated.

Thanks

Dredd

Novarossi EFRA 2630 Pipe. The different manifold lengths affect the powerband you want. Shorter is more bottom end punch and longer is more top end. I'd start with the 6 fin manifold like in my sig.

SalvadoriRacing

at a very very short track you can even try the efra 2601

SalvadoriRacing

it's the opposite.............

the shorter the manifold, more power at higher rpm.........

the longer tha manifold, more power at low rpm.....

Dredd

where did you read this cause every single place I read and checked said the longer length gave more top end because the resonation takes more time to pass through.

Nitro-mech

iTrader: (102)

SalvadoriRacing is correct !!

http://www.challengers101.com/IntakeTuning.html

Copied from above: Read last paragraph !

A 2-stroke is different of course since there is only a finite amount of fresh mixture available in the crankcase to be transferred up into the cylinder. In a 2-stroke, we want to maximize the retention of that finite fuel charge. We can't afford to "waste" any of it by having it escape out the exhaust port.. This is not a concern in the 4-stroke because the intake flow of fresh mixture is unlimited, or at least limited only by the duration of the intake valve timing. The closing of the exhaust valve prevents significant escape of the incoming charge.

The exhaust tuning of a 2-stroke is designed to preserve the positive pulse going down the pipe and reflect that positive pulse back up the pipe. A racing engine exhaust system uses an expansion chamber at the end of the pipe which is basically two cones that reverse themselves prior to the end "stinger" where the spent exhaust is allowed to exit the chamber.
That sort of expansion chamber creates a very strong positive wave reflection back up the exhaust pipe, and this positive pulse will reduce the amount of fresh charge escaping out the exhaust port, and in some cases, force back into the cylinder any charge that may have escaped before the positive pulse arrives.

On 2-stroke racing engines, we will see an immense change in power delivered when the exhaust system is tuned for a particular RPM range and the engine revs into that range. It's called "coming on the pipe" and the burst of sound and power that occurs when that happens is easily witnessed.
The length of the exhaust pipe, prior to the muffler, is another important factor due to the speed of the pressure waves mentioned earlier. The length must be such that the exhaust pulse can travel to the end of the cone and be reflected back up the pipe to arrive at the exhaust port just before it closes.

Higher RPM will require a shorter pipe and lower RPM a longer pipe to produce the maximum effect at the RPM we want to use for maximum horsepower. It's not practical to vary the pipe length, so we compromise with some specific length that will deliver the best push at near top RPM.