which spark plug??? - Honda Prelude Forum

4glude · 01-23-2002, 07:11 PM

I have a 92 prelude with a JDM vtec motor. I went to napa to buy spark plugs and the girl gave me the NGK ZFR5F-11. Is this the one i should stick with or should i go get the bosch? Thanx

preludechic · 01-23-2002, 10:21 PM

I've heard alot of good stuff about Denso Iridiums. Expensive, but worth it. Part # is IK20. Go straight to the Denso site densoiridium.com they give you info and pricing, but you'll need to put your year under 93 and above because of your VTEC motor. Right now I use NGK's but only until I get my new motor. Has anybody heard and negative things about the Iridiums?

BryanS · 01-23-2002, 11:14 PM

I don't know about the JDM motor but for my USDM 4th gen VTEC everyone seems to recommend the NGK ZFR6F-11. I'm thinking that the ZFR5F-11 are a heat range colder than the stock ones I listed. The ones I listed are like the factory plugs but are copper rather than platinum and are about $8 per plug cheaper.... copper are just as good but don't have as long a lifespan.

4bidden · 01-23-2002, 11:16 PM

actually, zfr5f's are one step hotter plug than zfr6f's. some people run the 7f's, which are one step colder plug than stock and they seem to like those, but they cost more. im currently running zfr6f-11's...work great and cheap.

BryanS · 01-23-2002, 11:16 PM

correction - the 5F is a heat range hotter than the 6F. I don't know if it would make a huge difference but the 6F is the stock plugs and are recommended often.

After looking at NGK's website they state that you should use colder heat range plugs in engines that have mods such as raised compression. The JDM engine should have a higher compression than the USDM so I'd guess that you want the 7F rather than the 5F or 6F.