Planning to get some of these. Thought I would check in for comments on the benefits (or lack of). Thanks.

 

They are good plugs and much cheaper than than the AC's. If you have a 02 Vette I wouldn't think they need to be changed yet. But when they are get the TR 55's and new wires(Magnecor or Taylor), stock ones aren't that good for longevity. :smash:

 

The reasoning was the colder spark, not wear on the existing plugs.

Can anyone quantify the benefit of a colder spark?

 

It's not that the spark is "hotter" or "colder" it's that the plug's "heat range" is hotter or colder. A plug that has a hot heat range transfers heat more slowly to the surrounding cylinder head material. That keeps the spark plug tip hotter and tends to burn off combustion deposits even when the engine is under light load.

A cold heat rang plug is one that transfers head more quickly. They are good at keeping the plug tip at optimal temperature, even, under high load. If they are too cold, however, they can foul under sustained light or no load.

Typically, production engines have fairly hot plugs, such a the 41-974 used in stock LS1s and LS6es or the NGK TR55 or TR55VX. Where stock heat-range plugs can sometimes cause problems is under aggressive driving conditions, such as on a race track. The plug tip gets real hot and can end up a contributor to detonation or, even worse, pre-ignition.

This is why for very aggressive driving situations with engines that do not see starts without warm-ups, I suggest people go one range colder in the heat range.

With the aforementioned NGKs, that would be the TR6.

 

Hib,
Thanks for the thorough explanation.

Based on your post, I assume the NGK TR55's are in the same heat range as the Bosch Platinum's.

Are there other differences between the two? Is it possible the heat range is slightly colder? Would there be any other benefit in changing?

 

Go to http://www.ls1.com/index_faq.html#601 for a break down on plugs and compatiblity. The NGK 55 and the BoschHR9DPX have the same heat range. No they are not colder than stock. You only go to a colder plug with NOS or modifications that require it.

 

Al. The stock heat range is 5.

Going up numerically you get colder.
Going down numerically you get hotter.

You want colder for more intense combustion chamber heat, like nitrous, or sustained high rpm.

The TR6's are one step colder, than TR55, but come gapped at 35. Many open the gap some to 40 or 45. You dont want to go much more than that gap, because you will take the electrode out of a good angle.

In General, you gap smaller with more combustion chamber velocity. This keeps the spark from literally blowing out before its time.

There is somewhat of a relationship between smaller gaps and a colder range.


[Modified by kewlbrz, 11:31 PM 8/4/2002]

 

Great reference. Thanks.

 

Thanks kewl.

 

Al,
I put some in before Big Bend. The car seemed to idle smoother and you know I went over 165 without a problem. I'd do it, if I were you. - C.

 

Shawn, my 02 coupe is prone to detonation, I have been thinking of running the Tr6' at 48 would this be too much gap ?

 

Unless you've altered compression or using NOS,you will get the best performance with the stock gap.(According to the Magnecor website) What kind of mods do you have? Are you running stock fan turn on temps? Are you running 93 octane or higher? You should get the best results with the NGK TR 55's at .057 :crazy:

 

I have the NGK Tr55. I just have a constant detonation,

 

Thanks guys great post :cool:

 

Snake Slayer, did search everyone says it's do most likely to octane of fuel your using, here the thread I read. http://forums.corvetteforum.com/zerothread?id=332933

 

I have the TR-55's and have had no problems with them. My driving style is aggressive street.

 

Changed at 23K smoother idle no difference in power.