Has anyone run 10.5's on the street? Anybody have any opinions on whether or not they're too cold for street use? I am considering switching to them and dumping the 9's.



B

there great for the street but there is a huge downside to it, they tend to fowel out very easy in stop n go traffic and need to be changed alot. if anything run 9s leading and 10.5s trailing.

i could see running them as trailings, unless the car got used HARD on the street

I run 11's and 11.5's on the street, I use a msd box , premix and my idle is in the mid 13:1's.. Fowling is not an issue if your idle is setup right... They last a hell of alot longer than other plugs to...

hmm msd + good tuning.



and sorry fowl is a bird. you foul a plug.

Now thats chicken ****.. https://www.nopistons.com/forums/pub...#>/biggrin.png ...but you are right... https://www.nopistons.com/forums/pub...1047683785.gif







The only downside is the cost, I am paying about 26/plug US right now for the race plugs but they last twice as long under boost as normal plugs.. I get about 10,000 miles per set..



I read somewhere that they are not good for street use, but I think who ever thought that one up is on glue, they work fine on the street.. Thats about the only plugs they used in Japan even in daily driven cars, no one seemed to stock the oem 7/9 combo.....



I know alot of people go on about those cheap bgev 10 or whatever plugs, but I also read from NGK that heat range of plugs is not a straight across the board measure of what they call, "theramic values". The heat range of a plug is application specific, so even though the bgev10's say 10, they probably arent a "10" by rotary plug standards. As the heat dissipation by the plug would also be affected by cylinder block material, coolant passage location, spark plug locations, and type of cooling medium..

so you're saying the bzblahblah10 for a chrysler 440 isnt the same heat range as a 10 rotary? that does make sense.



i wonder if they arent for street use because the only book we've got that mentions it is the 79 race prep book? i would imagine a pp12a with a weber carb and those plugs isnt the hot street setup...



kinda too bad theres not more info on some of these engines, yours runs, why? cause you know how to build it right. in the usa we just dont have the info, so its "not for street use" or "unreliable" or "too loud"



ive driven a full bridge car that was neither of the 3 , and got 26mpg highway to boot! maybe not something you'd want to drive everyday, but you could

Sounds like I need to give them a try, then.



B

I use 10.5 plugs never had any foul up problems.

So for a High HP street car, driven occaisionally, would it be better to run 9's leading, and 10.5's trailing, or 10.5's all the way around?