DENSO Iridium plugs...

[mbeach]

I used Denso Iridiums in my Vishnu WRX. They were only 1 step colder (HR7), when pushing 21 pounds of boost. I pulled them to check their condition after 20k miles and they looked like new. I even ran extremely rich (most WRX's do -I was almost 8:1 at 6000rpm) most of the time.

I would recommend these to anyone doing forced induction. I don't know about going two heat ranges colder, especially with such modest amounts of boost, but I suppose the Toyota guys know what they are doing though.

[Cyrk]

The more I am reading I think the 2 step cooler plugs are overkill for just 5psi... going to see if I can get the one step cooler (IK20's) instead if my order has not already shipped. Might be fine in the Toyota's motors but who knows in our Isuzu motors what will work better... Time to play guinea pig.

[Cyrk]

Got the plugs and installed them this weekend... They did not need to be gapped as they were all at 0.040, which is stock on the VX. I must say that I am pleasantly surprised by the increase throttle and there is an extra crispness in my exhaust note. The VX kinda dies out at 100 but had much more pull passed it and was able to hit 115 with no problem.

Around town the VX seemed to shift smoother and pull harder. I was running Bosch +4 and had this weird idle problem at start up that these plugs eliminated. I would definitely recommend these plugs to any SC VXer looking for and improvement over stock spark plugs or platinums.

On the box is says it improves 0-60 times by 0.07 sec, and on the site talks about 4 HP added on the dyno. Not sure how accurate this is but my butt feels a difference. Again I went with the One step cooler - DENSO IK20.

Very happy with my $78.94 investment.

[james1_10018]

what do you guys suggest for Non- SC VXs

James

[Cyrk]

I would try the DENSO IRIDIUM IK16...
http://www.urdusa.com/Merchant2/merc...ory_Code=Plugs

Denso's listing for the VX:
http://www.iridiumpower.com/find_par...&action=Search

[Ruflyf]

Hey cyrk, was wondering why "cooler" is better in the combustion chamber, I am needing new plugs and trying to decide betwen the 20's or 22's. i have a s/c with a 5psi pulley. I will probably get the 20's since you are satified, just confused on the "why cooler is better" part.

[Cyrk]

To lower the temperature of the combusting air and fuel is to run cooler heat range spark plugs. Many supercharger manufacturers will recommend cooler plugs for supercharged engines. Go with the IK20, 22 is way overkill.