Originally posted by daniz24
Thanks, I think 9XT is for .21 engine?
The package on the 97t says 1/8th that is true, but if you are using over 20% nitro in a 1/10th then use this plug.
Straight for Steve O'Donnells mouth:
"Low nitro 1/10th use the 77t"
"High nitro 1/10th use the 97t"
"1/8th use the 99t"
I asked what is the low/high definition. He said 20% is the cutoff. He told me that above 20% nitro, the plug wire will distort on the 77t, which is exactly what I have found to be the case.
The reason there are only 2 non turbo and 3 turbo plugs are as follows:
In offroad, most people run 20% in 1/10th and 30% in 1/8. Of course there are exceptions, but that is the case most of the time.
Offroad, is where the standard plug is more prominent.
Onroad is where the turbo plug is more prominent. In onroad, the nitro percentages are less standard, and the turbos are slightly more finicky, so there are three plugs instead of two.
If it makes you feel better, instead of thinking of the plugs as 1/10th and 1/8th, think of the turbo plugs like this:
77t Hot
97t Med
99t Cold
Tune your engine accordingly, and I hope this helps some.