Engine NGK plugs....OE or IX???

NGK plugs....OE or IX???

I have two questions:

1) the user manual says NGK ifr5A11 (notice that "A" in the middle), however, advance auto website, as well as NGK's website say that the OE plug is ifr5T11 (notice the "T")...is there a difference? Are they the same?

2) Iridium IX plugs, apparently are better with the slimmer center electrode. NGK actually has the BKR5EIX-11 (which is one of their iridium IX plugs) listed for the 2003 Corolla. Advance Auto website also cites this plug for the 2003 Corolla. Is it okay to use this plug? Are the heat ranges the same as OE and all that good stuff? Would you all recommend the IX's?

Late,
Trav

I have a 99 rolla and I just replaced my bosch plat +4 with NGK iridium, they work alot better. The jerk I got from accelerating then releasing dissapeared after using the NGK. go with iridium they are best for corolla.

yep even on the engine, it says "use iridium plugs only"

Well, I know. The OE plugs are iridium. The plugs I was referring to ( ifr5A11, ifr5T11, AND BKR5EIX-11 ) are ALL iridium plugs. However, the iridium IX plugs (i.e., BKR5EIX-11) is just a higher performance spark plug.

Trav

just get which ever one you think is the best one for your car. You really won't tell the difference

NGK's IFR5A11 is an regular OE iridium plug with 0.8 mm diameter center electrode, similar to original Denso's.
IFR5T11 is their 'premium' iridium plug with 0.7 mm center electrode.
IX iridium has a 0.6 mm center electrode and taper cut ground electrode. It's the best available plug and I highly recommend it.
http://www.ngkspark.com.au/feature_product.html

Thanks dominator!

Even though I only have 56,000 miles on my '03, whenever I had the AEM CAI and all the detonation problems I had, I actually did adjust the plug gap on the Denso's that are in the engine. I opened the gap ever so slightly - an that is a no-no with platinum and iridium plugs. I'm assuming it's just due to possibly damaging the center electrode since it's so small or the platinum disc on the ground electrode. The ceramic on the plugs are slightly blistered...no visible wear on them otherwise. However, I think replacing them might not be a bad idea. I'm getting somewhat lower fuel mileage (32-34 rather than the previous rock-solid 35-37). Plus, the IX's are a better design and I have heard good things about them.

Trav

Either get the IX or get the Denso IK16's. Actually, the Densos are a little better quality, but the NGK's are right there with them, and they're probably a little cheaper than the Densos.

search IK16 on ebay..

i get mine for $38 shipped on ebay from performancepartsstore or something like that. very good people.