courtney42

I have a jdm D15
I just bought some NGK plugs and wires. But i looked up the gap and im getting conflicting results.

It says on one site the proper gap for si model is .052 but this is for a b16a. I have a D15 jdm with vtec
A non vtec D15B7 is supposed to have a gap of .o44

Am i supposed to go by the b16 specs since i am running vtec?
Can any one give a link to more info or know off the top of their head?

lhd dc2

.044 and you should be good.

courtney42

What is the difference between .044 - .052?
Would it effect gas millage? Seems like it would.

[713]

its .044.dont know about the effects but id rather not take my chances

newtron63h

im a bit confused. where does the B16 come in to the picture?

courtney42

My car only comes with a b16 in the usa. But i have a jdm D15 in my car. All the charts showing gaps i could find are for US Domestic models.

My engine is reletively the same size but it is a vtec so it stands to reason a different gap would be needed.

Anyone got any more input on this matter?

thumper64

Your spark plug gap has more to do with compression than anything else. As the pressure increases, it's more difficult for the spark to pass between the two electrodes. This is the same reason that boosted engines need a tighter spark gap or a higher voltage coil. I don't feel like looking it up, but I would assume that the B16 uses a different spark plug, necessitating a different gap. Someone correct me if I'm wrong, but I haven't heard of any differences between the D and B ignition systems, as far as differences in voltage.

I say that since the D15B has the same compression ratio as the D16Y8 (9.6:1), run the same gap the D16Y8 calls for; .043in. I figure this because they are both SOHC VTEC engines. But wait, you're only talking 1/1000 of an inch difference between the D15B7 and D16Y8. You're fine, run .044/.043 and it shouldn't matter.

newtron63h

ok, so you or someone swapped a d15b into a car that originally had a b16? is that what im understanding?

courtney42

From what i have read , The jdm D15 has a higher compression then the d16. So with more compression/smaller gap school of thought we are probably good with .044

Thanks for all the input guys. It's been a big help.

newtron63h

higher compression should mean smaller plug gap............is my last post correct?