hey guys i have just recently changed my sparkplugs in my ca18det when i got it it had normal plugs in it and i thought id change them as they were really black. problem is the only listing for the ca is the platinum plugs and ever since i put them in it seems to detonate at much less boost than with the regular plugs. used to be able to go past 14psi without detonation now if i flatten it it will detonate before 10psi. can anyone tell me if this is something wrong with motor or whether maybe the timing needs to be changed to compensate for the extra spark ???

NGK are the only way to go.
NOT Bosch, NOT Champion, NOT anything else.

BCPR6's for standard (gap of 1.1mm)

Maybe less than $10 for all 4.

I use platinums on my CA, but I know my upper cylinders are clean, and I run Autronic CDI.

Detonation is not the plugs fault. crap in the upper cylinder which is increasing the compression ratio to skyrocket, is the cause for that. This is why it is getting worse.

Always use a catch can, and never overboost the stock turbo more than 12psi max.

Clean the terminals on your coils connectors. See if you can borrow a laser temperature probe and look for the hottest coils. replace any that are much hotter than the others.

Is your 02 sensor working? that will result in overly rich mixture.

I agree with Dattodude. I run the next range colder (NGK BCPR7ES) and have found these to be best on my motor at 15psi.
Matty

Quote:

NOT Bosch....sniff sniff...

Had one of the super 4s blow up on me in under an hour. Everything else Bosch is great.

Sorry Mate

Ahh that's OK....a lot of the spark plugs are made in Russia these days...I might stick to NGK too. Or at least keep away from the super 4's.

Maybe they can't really handle the boost.

the plugs in it now are pfr6a-11 platinum i just checked and the ones that were in it were bcpr6.when i changed them i noticed there was alot of crap in the cylinder head and the tops of the pistons i put a whole bottle of wynn's engine cleaner at double concentration (30 litres instead of 60) and it seemed to do a bit but still pretty dirty. i heard there is some stuff they use on the subaru motors because they are prone to the same problem ???
should i get rid of the platinums and use the normal ones?
i wonder if any ofthis has anythingto do with it running so poorly, has bad flat spot as i accelerate just before coming onto boost.
i really need to get it tuned on a dyno coz its getting pretty bad.

Did you gap them right?

i'm running these plugs pfr6a-11 as well, what's the advantages or dis-advantages of these plugs compared to BCPR7ES,

at work we had a ford gt that i had to work on and he was complaining about pinging when he was sitting on 100 then put his foot down lol, we used "subaru upper engine cleaner" its a foam substance wich u spray half the can into a vacuum after the throttle body, start the engine and spray the remainder of the can in while keeping the engine from stalling. it stopped the pinging in the gt......... not sure if you can buy it commercially tho, ull have to try your nearest subaru deal i spose