Not sure about overall performance, but I read somewhere that tumbleweed is good for keeping a less reliable car going. It worked well for me when I had an old sedan, anyway.
My husband is what I like to call a technomancer, he’s able to achieve unbelievable results with computers and vehicles. I would like to point out that if the car is old enough (and by that I mean still made of steel and metal as opposed to the plastics of newer models) you can use the crystaline structure of the metal itself in place of sticking objects say to the roof or the dash in the even of an accident. In a sense you could charge the vehicle’s frame with the energies of say protection or speed enhancement. I did this with my 92 Tercel and the lil bean was phenomenal to drive!
I have a protection Solomon seal in my car with copper coil and radionic booster also. It is like a talisman first the topp part any seal you like and then put some aluminium tejp on the back of the seal a4 papper.
Then put a coil fasing down and vire upp penetrating the seal in a way you dont fuck it up.
And some more aluminium tejp and finaly a radionic bosster symbol in the back of it all with a layer of aluminium tejp. So 5 layers it will bee i belive.
In my little volkswagen i have a tiny vial hanging from my rear view mirror that has chips of clear quartz charged with protecting the car from accidents and theft. And hidden in a cubbie thing above the radio i have a cloth baggie i made that has herbs of protection and for just keeping the good vibes along for everyone riding with me
In a sense you would imbue energy directly into the vehicle instead of an object you would place on your dashboard. Most objects can be enchanted/charged, the way you would go about doing so to a quartz.
So what we do is in essence, wrapping our energy around the vehicle from inside or without, and steadily infuse it into every piece of the machine.
My hubby sort of projects his consciousness around the vehicles as he drives, feeling the grip on the road, able to pick up on people around him, and most helpful of all, through this connection he can locate specific problem pieces before they start breaking.
As for horsepower increasing with crystals, I would suggest it might have a more notable change with a tesla. As most engines still operate with combustion there isn’t much for a magnetic field to play with aside from the potential spark size caused by Piso electric sparkplugs.
If you’re interested in other radionic devices rumored to improve things like fuel economy I would suggest an orgone generator, (resin, crystals and metal often found in pyramid shapes). I’ve only just started seriously looking at these devices an I’m curious of other reports of them being used in cars.