I need advice...PLEASE HELP!!!
 

I'm trying to setup my needle setting and i think i messed it up (i'm not really a good tuner :(). Now i can't get my engine to run right. I just went through my 8th tanks. Let 3 tanks idle and just run my car today. I'm trying to get the right setting for my NS12S5. When the engine is cold, i have no problem starting up, but after a few laps the engine start acting funny by not having consistent rpm high and low the it died. I thought it was too lean so i richened up 1/8 turn on high needle, but still doing the same thing, i changed the plug but makes no difference. I kept the temp between 200-220 but seems the engine running too lean. What's wrong? Right now i have set it up 4 turns out on high speed, 3 turns out on low needle and the fuel adjustment on the flush. I'm not really understand what's happening here and maybe you guys can help me out. Thanks


later...

If in doubt, always reset the needles on the rich side. If I were you, I'll turn out the HSN 6 or 7 turns out. Turn out the LSN needle to 4 to 5 turns out too with the brass needle flushed. The idle needle should be set so that the slide carb is less than 1 mm open at idle.

On the starter box, start the engine. Tune the HSN first slowly 1/8th of a turn at a time. To make sure that your engine idles, you may want to turn the idle screw up a little just for this moment. Tune the HSN so that the engine should be able to reach the high end RPM very nicely without hesitation. The high end should sound crips. Make sure you see smoke coming out of the pipe while you're doing this. If the engine spits out fuel from the pipe literally, the HSN is still rich. Lean it slowly untill you only see smoke. While tuning the HSN, use the temperature gauge (if you have one) as a rough guide to know if your engine is overheating.

When you got that HSN setting, now you can tune the LSN. While you lean the needle 1/8th of a turn at a time while watching the engine head temperature, the engine should be able to idle well (15 to 20 seconds) and the low end engine RPM should respond quickly without any hesitation. Look for smoke coming out from the pipe when tuning the LSN.

Once you got those settings, you can fine tune the HSN on the track on the longest straights and adjust the LSN and idle needle accordingly. Hope that helps.

Just make sure that if you are going to richen it that you don't go overboard and make it run too cold especially during the running in process!

I personally never play with the needles cause they have been set at he factory with a flow meter and are close enough for the run in.If you are going to richen it at all(nova .12)i wouldn't touch the low speed(leave it were it is)but maybe a half a turn on the high speed just to keep you mind happy,:p a temp gauge also is always a nice tool to have by your side!

EVO, I think he mentioned that he already did a run in on his engine. Sounds like he screwed up the needle settings. That is the reason why I mentioned to turn out the needles. On older engines, 4 or 5 rounds was more than sufficient to get it on the rich side. These days, I notice that these powerful engines need more than 4 to 5 turns out to make it on the rich settings. 4 to 5 turns out could be their optimal needle settings. That is why I mentioned 6 to 7 turns out on the HSN.

I agree on you on not disturbing the LSN. On the last engine that I broke in, I just richen the HSN and did not touch the LSN and when the breaking in process was finish, I just leaned the needle settings back to the stock and was spot on:nod:

Ummm, come to think of it, 8 tanks may not be even enough to break in the NS12S5... Just a thought. Robbie C also mentioned that these new engines take a long time to break in.

I think there is a difference between the running in period and when an engine starts to really free up which can be dozens of tanks after the initial running in,it will continue to improve as it gets a bit less tight.I usually take around 7 or 8 tanks for the initial running in,with the first being at idle.Then i just put a race tune on it and let it reach normal operating temp and it will continue to rev more freely and make more power once it frees up,JMI. :sneaky:

All great advise...the only thing I would add,is make sure you're engine is FULLY warmed up....

And the way I check high speed running,is to lock out second gear...then take it to a parking lot,get the car moving a few mph,and then gas it from mid range to high speed..this way,my ability to see mid range pull is not affected by the Low speed needle.....

I lock out second gear so the car isn't half way to Timbuctoo befire i can't hear the engine or see smoke...

Thanks for the great advice. With 4 turns out on HSN and 3 turns out on LSN, there's alot of smoke coming out and spitting fuel from the exhaust, so the engine is not lean if i'm not wrong. But i certainly will give it a try with 7 turns out HSN and 5 on LSN. I'll let you know.


thanks again.



Lucas

Tell me about it...my flywheel still locking up on me on my 8th tank...can't believe how tight it is :p

the tighter the better..last you longer..:sneaky: :lol:

there is no reference needle setting as there are some factors hinder the carb needles setting such as use of pipe, track temp, fuel, length of fuel and pressure line. but i always go back to the following starting point when i am totally confused on needle setting of an engine.

LSN: 3.5 turn out
HSN: 4.5 turn out

and adjust from that points.