nvm

yeah who are you Trevor...I haven't seen you race nitro in...idk....FOREVER! :lol:

LMAO! I know man right! I'll be back this summer with a vengeance :lol: Gonna try one of my buddies FM x3's, they say he has built a few of these in his lifetime :nod:;):cool:

Viva la novarossi! :nod:

Just wondering for some engine tuning advice form the Nova experts.

I have a new Plus 4 BTT and have ran about half a gallon through it so far running it in.

I am having some trouble getting the idle consistent.

I have started to put a race tune on it but i am having a really low drop in idle after a full throttle burst at the end of the straight. Then the idle will pick up in rpm after about 2 seconds and will stay high for about 5 seconds and then it will drop really low again ?

I have tried leaning the low end but all that dose is cause the engine to start making lean machine gunning sounds and when i lower the idle to compensate it still has the pinging sound at idle and dropping idle at the end of the straight then picking back up again in rpm then dropping back in rpm again.


Any ideas what it might be. Its a brand new engine.

Thanks.

Assuming there is nothing wrong with your tank or fuel lines (pressure test your tank and fuel lines under water for extra assurance)....start with the idle gap. Novarossi recommends 0.6mm. Invest in a feeler gauge OR close the idle gap completely and turn idle screw out 1 turn. Adjust bottom end accordingly and try not to turn idle screw more than 3 hours either way while tuning.

.6mm ;)

Oops wrong decimal placement...thanks monty, edit..fixed.

Tested tank to 6psi and not a single air bubble came out. Also pulled engine and tested to 4psi and also not a single bubble leaked out so all is air tight and leak free. I think our engines run at 3psi so should be good.

Am going to try resetting the idle gap to .6mm and see how that goes. It was at about .8mm before.

While the engine was out i did find a clutch bearing was on the way out, not sure if that would have any thing to do with the idle going up and down though. Everything seemed to spin free in the car so i wouldn't have thought it would worry it.

Just tried it again. Still doesn't want to idle stable. Tried another Nova carb and that didn't change anything either.

I was able to stop the first initial low idle drop off at the end of the straight by leaning the high end a little. But the low end is as lean as it will go and i still have the extremely high idle at first then drops back to a very very low idle. That too me says its still too rich on the bottom but its at the point of lean bogging at the end of the tank now so i cant go any leaner ???????

No air leaks in tank or lines
No leaks in engine
Fresh clutch and clutch bearings
Different carb

?:confused:?

If a engine still has a tight pinch you will never get rid of the multi stage idle down........... Once the pinch relaxes that characteristic will go away


Whats is happening is the friction from the pinch is dragging the idle RPM down...the longer it idles, the cooler it gets and the tighter the pinch becomes.....after a high speed pass the engine has plenty of heat and the pinch relaxes, allowing a high idle...but when you pull in the engine cools and the pinch drags the RPM down...If you tune it to idle good in the pits it will high idle on the track...if you tune it to idle down clean on the track it will idle down and die in the pits....It is not till most of the mechanical pinch is gone that you will be able to get the tune your looking for...... A Plus 4 is a very tight engine and chances are that at 1/2 to 3/4 of a gallon you are still experiencing a fair amount of mechanical pinch...these engines can take 2 gallons to fully break in.......... You should find that the longer you run this engine, the more stable the tune will become...... I notice this multi stage idle with all the Nova's when they are new....But once they loosen up it goes away

Ahh yes that sounds like what it might be. It is still quite tight at TDC. Wont start cold without sticking. Had about 1 gallon through it now. Guess it needs quite a bit more.

Thanks Maximo.

Hi,

Should the stock Losi 8ight 2.0 RTR clutch fit the Novarossi plus4 BTTS?

I'm asking because I have a pretty big gap between the engine and the clutch.

Also when I screw the bell to the crankshaft, when it's screwed all the way in the bell won't move :/

I guess I'm doing something wrong...

G.

You need to use the brass cone shaped collet from your RTR engine. The one that comes on a Nova will push the flywheel too far out from the engine.

Hi,

Thank You I will try that.

Will this also help the problem with bell???

G.