XRAY - Model racing cars

Hi,
I have brand new Novarossi Toro Nero with standard plug on my XT8 (08 spec).
I finished the break in process and about 1/2 gallon of 25% fuel.
I have a problem of missing low end power since day 1 with this engine.

When the Truggy is at very low speed I have no power and very poor acceleration, Once the Truggy is gaining some speed and RPM the engine suddenly "opened" and I have plenty of power (like in turbo charge affect on sport cars).

I got a lot of help on the track to solve it, here is what was done so far:
- Installed brand new plug, Clutch system, Clutch Bell and bearings (all xray)
- Changed my fuel from 20% to 25%.
- Replaced sealing o-ring on my fuel tank.
- Refresh the oils on my Diff's.
- Replaced the pipe to Novarossi pipe.
- Checked engine internal parts by an expert, all is good and clean.
- Tuned the engine by the track expert drivers that have a lot of tuning experience.

I did had some improvement for few runs but then the engine started to behave strange again on the low end.

I now looking for new ideas, this engine should be a beast but now it is very weak

There could be binding somewhere in the drive train, try brakes first and all the bearings.

1/2 gallon is not enough. She's not going to make a ton of power yet. I use more than a half gallon on my Hudy breakin bench.


Are you useing 1.1 clutch springs? I'd gear down a little also, use a smaller clutch bell gear.


Also I'd ask again in the " Houstons engine service" thread on RC tech. He seems to be the NR expert over there. Maybe you have the wrong pipe.

here is the dyno results of this engine



and the link:
http://www.rctech.net/forum/nitro-off-r ... sults.html

hi i have the same problem with my axe rossi .25 truggy motor and never been able to get it to tune also the same problen with my go 3 ports too and this is after a gallon of fuel put though them i put it down to a air leak ie with my rossi i think its the rubber boot on the carb as i can see a small hole if you find any other info why its doin this would love to know as all my engines are like this. other people have these engines and have no porblem with them but i think its down to air leaks for me not sure

jase

Do you have a friend at the track that can put your "motor only" in his car & run his clutch,pipe,tank. 3 motors with the same kind of problem sounds like something other than a motor problem.

i may have some 1 so i can try but have also put them in my xb8 buggy and still the same but alittle better as there isnt as much weight ive always thought the engine has been leaking in air somewhere? my truggy is not binding had a new tank and fuel line tryed with and without fuel filter have the 41t overdrive in the front 10 000 oil in cent diff could it be clutch shoes i use 1.1 answer rc shoes and springs with xray 14t bell

thanx chaps any info is good

jase

ps im getting so p**** with it all lol

Thanks for your comments so far.
Additional data:
I'm using the silver (hard) springs.
Gearing is at 48/13.

Next steps:
Install the engine on other kit (XB8EC)
Check for air leaks in the engine, any idea of how to do it?

I recently changed engine brand from os to nova plus 4 and after a gallon of fuel the engine was running 120c and running extremly rich and the nova guys at my track says its because they have a tighter pinch than the os engines. Now after another 1/2 gallon the engine is really starting to come to life and the temps have dropped quite a bit.. I will be putting a good race tune onto it next time out.

you need to put more fuel through it novas need 1 to 1 1/2 gallons before it drops its nuts

do the bubble test on it put a lenght of fuel line on then brush water and washing up liquid round the front bearing carb backplate and the pinch bolt on the carb then blow though the fuel line and see if you get any bubbles and theres your leak


jase

i had the same problem with my nero tried it with various pipes it was a bearing problem on mine they sent me a new one and it had tons of bottom with the same pipe set up

Jase put some new clutch shoes in and a set of stiffer spring. With the stiffer springs your engine will be on pipe more as well, so think about what shoes you'll be using.

Few updates:
Thanks for all the comments.
I did found that my end float was out of spec, I adjust it and the performance did improved.
I still have lack of power and I found that my rear exhaust gasket is leaking (Novarossi #21000)
I hope that this is the root cause of my issue.