RE: Few kinds of hpi baja engine makers.
Hi Wan, havent seen you in awhile.
As for O'Niels (ONB), Earthsurfer (ESP), DDM, Trevor Simpson (TS), Tom Bowlin, CAD, these guys are modders and they take existing engines and mod them to make some really nice power out of them. The more expensive modded engines really like to use the Zenoah engines as thier base platform. Others will also use CY engines especially since CYs are very plentiful and they are the base engines that come on HPI.
Now, some modders so extensively have created their own custom designed parts that the engines they mod almost actually become a totally different engine from what their base was. A fully modded TS with all the TS custom parts actually has less parts of the original engine. So, lest say TS started with a Zenoah, when he is through with it, the only original Zenoah parts that might be left are the head, piston, the flywheel, and the spark coil and wire while everything else is not TS custom fabricated parts,