Losiracer2

I wanted to change my old plugs on my 99' LS400 due to them being over 14 years old and having about 62k miles from the previous owner done at a Lexus dealer during a timing belt change. I upgraded the factory SK20R11 Denso Iridium conventional style spark plug to this new, IK20TT Denso TT (twin tip) Iridium plug design which Denso claims a 2.4% fuel economy improvement over a conventional iridium plug, better cold starts, smoother idle, faster acceleration and a service life of well over 100,000 miles. They also mention higher ignitability, and a more complete combustion.

https://www.denso.com/global/en/prod...lug/iridiumtt/

http://densoautoparts.com/blog-not-a...d-equal-part-2

For the most part, these are just like a factory Iridium plug, but have a 0.4mm center Iridium/Rhodium electrode which appears to be half the size of the OEM factory Denso iridium along with a 0.7mm Platinum ground electrode opposite . I purchased these for $6.63 at Napa Auto Parts since they had a special on them, but can be had on RockAuto for $5.36 a plug if you're willing to wait a couple days.

Things I immediately noticed:
-quicker engine response, engine feels easier to rev
-faster acceleration on on-ramps 30-100mph
-0-60 seems quicker, engine feels like it does have more power in the seat of the pants "butt dyno"
-can't say about fuel economy yet, since I've only put on 30 miles since install last night

Pictures of install:

RA40

iTrader: (6)

Cool! Will be interested in any MPG gains.

spuds

New plugs,a definite like!Looks like a winner for sure.Nothing like a tune up,eh?

My uncle worked for a place that made shock absorbers that didnt sell all that great.So they added 'cooling fins' which looked real snazzy....33% (or some such bogus claim) more cooling they said,which was total BS.They did nothing.
BUT,sales took off. Just saying.....