Quote:
Originally Posted by JaredG_F30
The NGK 97506 are one step colder than the stock Bosch plugs. As a rule of thumb, you can expect to require one heat range colder than the factory-supplied plugs for every 75-100 horsepower you’ve added with your modifications however, I have read that the stock plugs are good for 500hp but I have not confirmed that.
This is a good read
https://www.enginebuildermag.com/201...ug-heat-range/
Secondly, the NGK plugs can be gapped, whereas the Bosch plugs can not. PTF recommends a 0.020"-0.022" gap. This is because a tuned engine has higher cylinder pressures which require a small intense spark. Alternatively, you could run stock gap with upgraded ignition coils, like PR, which supply higher voltage and amperage to the plug resulting in a more intense spark. This is actually a better solution as the larger gap, say 0.032" with upgraded coils provides an larger intense spark which results in a more uniform flame front upon ignition.
:TLDR...physics |
I can confirm that stock plugs are good for 24psi on Pure Stage2 (100% WGDC) with 100% meth for added fuel. This equated to 495whp on a DynoDynamics.