Originally Posted by
gortan
dear all,
i'm in need of advice. I've got myself an ofna jl3 engine. I've done the break-in without issues.. comfortable running temperature.. good smoke trail, nice sound while accelerating, etc. After the break-in I was happy with the performance although I knew the motor could be pushed further. So far I was using 20% nitro.
After I changed to 16% I've started seeing some issues. To get the same performance and get the car to shift at same spot on the track, I had to lean a bit the hsn. Now the temperature runs higher...260F with less performance then I've had with 20%. any leaner and the engines gets too hot. Also when gradually accelerating the car off the ground, it starts fine but at a point in time, the revs start dropping rather than increasing, but there's still alot of smoke coming out...
I've read somewhere that this engine is shimed already for 30% nitro. Should I remove a shim and see if it helps?
I may blame the pipe as well. I'm running a copy of an efra 2017 pipe.
I ordered a picco 2607 now but it's still a month away to get it. Would the tuned pipe make the difference I'm looking for?
thanks.. sorry for the long post.
g
In your case, I would remove one of the copper shims and richen the HSN out from the leaner settings you tried above. Then I would retune the motor. If you have to much head clearance with low percentage nitro............the fuel mixture is not being compressed enough for optimal burn. The motor will produce lots of smoke, create lots of heat as a result of over leaning... ...........and not make alot of power. Don't blame the pipe......maybe it's not the optimal pipe........but if the motor ran good with the 20% ...it will do fine with the 16% ....if it's shimmed properly. I would have removed a shim with even the 20%.