Sparkplugs (Hks) Plus Supercharged And Lpg'd

[LennyLexus]

Hi All,

Does anyone know how long HKS plugs are supposed to last? I've done 40k/9 years and its misfiring. Coil(s) likely to need replacing.

Can anyone suggest suitable replacements and intervals given the supercharger and lpg conversion?

IK22 and 30k? Is there a cheaper NGK equivalent?

Thanks,

[Mars]

Booklet says "iridium Spark Plugs" to be changed every 60,000 miles.

[LennyLexus]

Thanks Mars, this seems to change with mods and not using OEM (dense sk20).

I have spoken to a friend who was a top lexus techie, he has recommended going for NGK (Denso isn't worth the extra, avoid Bosch and Champion. He also recommended getting them changed more frequently due to the lpg and blower.

Does anyone know what the NGK version of the IK22 is?

[ColinBarber]

I would think the HKS plugs are performance ones rather than standard and therefore have a change interval or 30k miles - I suspect these are just rebadged Denso IK plugs as HKS don't manufacture them themselves.

SK20 (standard OEM with 60k change internal) have a performance equivalent of IK20 (30k change interval).

You should run a colder plug on a supercharged IS, therefore IK22. If you want a longer lasting plug then look at the VK22.

Don't know the NGK alternative - nothing wrong with them but personally I just always stay with Denso, for no reason other than they are partly owned by Toyota and are the first choice OEM.

[lexus22]

Having cambelt changed this week and thought it would be an idea to replace the spark plugs at the same time.

Fancy using Denso's but Eurocarparts list more than one, does anyone know the correct plug number?

[Dean1309]

Hi the correct Denso plugs are SK20R11.
I just changed the plugs on my second IS200 for the SK20R11, I very luckily managed to grab some for £41 on bid. Someone had bought them for their RX300 but sold the car before they got to fit them. Keep an eye out on eBay.