Why lengthen plug reach increasing turbo boost?

Why lengthen plug reach increasing turbo boost?

Author
Discussion

Mark300zx

Original Poster:

780 posts

182 months

Tuesday 22nd April 2003
quotequote all
Answers on a postcard please

Mr2Mike

19,216 posts

185 months

Tuesday 22nd April 2003
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Could we have a clearer question first please?

Are you asking why increasing the plug reach increases boost, or why you have to increase plug reach if boost is increased, or something else?

deltaf

6,806 posts

183 months

Tuesday 22nd April 2003
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Not heard of this before. Thought the idea was to run the coldest possible plug that wont foul under normal driving conditions, for the road at least.
Gives the best power output without overheating the plug.
Dont see that a longer reach plug will accoplish much, short of overheating due to the longer heat path...?
Oh and a possible coming together with a nice shiney new piston perhaps?
Feel free to correct me tho..

kevinday

8,168 posts

210 months

Wednesday 23rd April 2003
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deltaf said: Oh and a possible coming together with a nice shiney new piston perhaps?




This was my immediate thought as well.

plipton

1,302 posts

188 months

Wednesday 23rd April 2003
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kevinday said:

deltaf said: Oh and a possible coming together with a nice shiney new piston perhaps?




This was my immediate thought as well.


Indeed - if it doesn't hit the piston it might increase the compression a smidgen but not boost (you need something like a Dawes Device for that).

I would suggest this is not a good idea (wrong plug reach, that is) as the head is designed to take a specific plug size.

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boosted ls1

17,261 posts

190 months

Wednesday 23rd April 2003
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I think the question relates to projected nose type spark plugs as used in my 2 stroke bike engines.

The idea is to have the electrode projecting further into the centre of the combustion chamber. I used to do this on turbocharged RV8's and used NGK BP8EGV if memory serves me correctly. You can still achieve the same heat range as that relates more to the length of the insulator.