What restrictor are most of you guys running? Or what should I start out with? I run on a medium size track(30 sec) average lap time, low-med bite track and gets pretty hot here.

I run 7mm restrictor. If it gets warmer than 25~28 degrees C, I switch to P4 plug.

I need some info on the new GTR-II. Can someone give me the ball park needle settings, recommended plug and does it like to be rich on bottom and leaner on top or the other way around? Love it so far but feel it has alot more in it.

P.s. I'm not the best tunner. Lol. Thanks

Mid - 2 turn out from flush at 2 oclock
Low - 1 turn in from flush
hsn- keep leaning it until you get good top end speed and god temps. I think most use a p3 plug.

Rex

Thanks Rex, I'll give that a shot. Any idea what temps people are running?

I dont run the Arrow very often but I think 230-250 deg.

Rex

How is the VP-Pro Ultra Hot P3 Glow Plug working in this engine? Do they perform the same as their OS P3 counterpart?

Mine runs 260-280'F. Anything under 300'F is fine as long as there is smoke and no bogging.

Whats the bearing size for the GTR plus 21?

Thanks

14x25.4x6mm

And the front?

Same as all .21 engines.
7x19x6mm

Thanks, should have known

Anyone have put the arrow piston and sleeve in the hara speed yet?

I really don't think they'll fit. That's an XZ-B engine.
From what I know this will only fit a VZ-B.
I put mine in a Ninja case with an OS carb. Runs great!
So possible candidates would be VZ-B (and Speed vz-b), JQ Engine, Ninja.
I don't really know if there are any others.