RE: best glow plug for TT pro 40
Yes the colder plugs can yield close to 300 more RPMs.
The ambient air temp, air density (depending on alt vs temp) and cooling capabilities of your engine all plays into it. Though it is true the glow plug generally is determined by the heat range of the engine, you must consider high rpms are adding heat, what % of nitro you are using, are you starting and stopping or running long straights, the oil content of your nitro. Many things are factored in.
We only tested the OS plugs, and there is a very good chance other manufacturers may yiled even more. We ran it with the baffle in and with it out (on muffler) and saw less RPM with it out.
Go figure on that??
TT used to use head shims but all the new ones I am seeing no longer use any.