Originally Posted by
ConciliumDesign
Should one tune the same for the long LSN as a short LSN? I have about 1/2 turn in the top of my gen5 7 port with a short LSN and it's still running rich. The bottom is still rich with about 1.5 tuns in with a little over gallon through it and it still has metal pinch. I still have the same plug in it from when I first started to break it in.
What other engine heads are compatible with the GO's? I'm thinking about trying out a NOVA cold weather head on my 7 port for some cold weather racing.
http://www.novarcproducts.com/coolweatherheads.html
Also, does anyone have a used and usable Go 2047 lying around that they want to sell?
No - the tune for long and short LSN's are different. Because the long LSN stays in the spray bar at full throttle you need a richer top end to compensate for this.
It depends on fuel, pipe, climate etc, but here is a good guideline for race tune :
Short LSN:
LSN 2.5 - 3 turns in
HSN 2 - 2.5 turns in
Long LSN
LSN 2 - 2.5 turns in
HSN .5 - 1 turn in max
As you can see the LSN's are similar, but the HSN is a lot richer with the long needle.
Think of the HSN as the tap on your garden hose (it controls total fuel flow into the engine), and the LSN as the nozzle on the end of the hose (what you get out of the nozzle depends on how much you have turned on the tap).
If you lean or richen the HSN, you will lean and richen the LSN accordingly, so tune the HSN first for peak full throttle performance, then tune LSN for smooth idle and good take off from standing start.