This gets me. The CR6E is the hotter plug right? Yes, it is. Back before I knew this, I replace that stock 6 with a CR8E thinking I would get more out of it. Well, the 8 isn't the hotter plug, but after putting another 6 back in it a few months ago, I've lost at least 4mph in top end.
On the steepest paved downhill I can find, with the big tires, I can only get it to read maybe 51. With the other plug, I was hitting 55-56 all the time. 54 on the flat stuff. Anyone else know anything about the plugs?

 

Basically the hotter plug causes the flame to start a little bit sooner in the cyclinder. Good for cooler climates and starts/warm-up. Once the engine is at operating temp or a little hot such as full throttle runs it can have the effect of increase the timing of the engine. You could be losing power this way since the combustion is occuring too soon at top end. I now with the race cars I play/work on we retard some timing for sustained high speeds. We also run the coolest plug that will make the engine idle and run without fouling the plugs or stumble off idle. There's a reason turbo/supercharged cars run cooler plugs: heat at WOT(wide open throttle). Try a little experiement by running some higher octane gas with the hotter plug and see what happens. Octane slows down the combustion process. Now you have me thinking I should go play with my plugs and gas.

 

Andy:
Do you remember quite some time back, when Boner posted something like this? He basically stated similar results to what you just mentioned. I tried it, upon his suggestion and found the same thing to be true, yet when mentioned on the board, several people thought we were crazy. Oh well, such is life I guess. You are right though, the 6 is the hotter plug, 8 is colder. I do get better performance out of the CR8E than I did with the 6, so I'm sticking with it.

Thanks too Dakotart! I'm taking an engines and tractors class here while working on a second degree, we just went over basically what you just mentioned. Thanks for not only the explanation, but also for reminding me I've got some unfinished homework to get after!

Mike

 

Cowboy,

I am a school teacher. We are psyhic. I knew you had homework.

Laters

 

Cowboy,

To comment about your statement. Andy was one of the people who IN A WAY, KINDA BLEW IT OFF. He said he noticed little to no difference then. I guess now that he has LOST the performance instead of gaining it it's more noticeable now.

 

I just pulled the CR8E out of mine as it was getting bad gas mileage,and when I did finally take it out it was black with carbon. I was running it under constant load, [deep snow] in cold weather, but none the less it fouled. I put the CR6E back in and will know soon enough. Hopefully the mileage will improve. As far as performance goes I didn't notice any differance.

Cheers Jim

 

jkb,

The hotter 6 plug will do you some good I beleive. Black plugs usually mean rich(too much fuel). Make sure you have fresh gas and after a tank or too pull the new 6 plug. You want a light brown to dark brown color on the insulator of the plug. That's not too hot or too cold. If the color or milege don't improve make sure things like the choke and air bleeds in the carb are working properly so that you aren't running too rich. good luck up there!

 

Forget it. The damn air filter was dirty as crap. I cleaned it out and it runs fine. Probably about time to clean the carb too. I changed back out to the 8 again and didn't notice any difference. I think it was the filter.

 

everything i said about plugs...forget that just go clean your filter and carb. As soon as I read your reply today I felt like a total idiot for not mentioning the obvious...is everything else working properly?

 

I still think that the 8 plug runs a hair better than the 6 for me. Seems like I had that same idea back when I changed out the old 8 for a brand new 6. The filter would have been the same for both too. It doesn't run bad, just doesn't hit the same top speed.