My 30,000 mile tune up

[Jason.MZW20]

The Rundown:
Engine: 1GR-FE
Mileage: 31,761
Original plugs: NGK LFR6C11 V-power traditional plugs (left bank) and Denso K20HR-U11 (right bank)
- Fuel economy on old plugs: 16mpg during mixed spirited driving, 18mpg max during conservative driving (avg)
New plugs: Denso SK20HR11 extra long-life Iridium (0.7mm iridium tip) plugs with flat platinum ground and copper core
- The OEM 2GR-FE spark plug is better: FK20HR11, double tipped (0.5mm iridium electrode tip, 0.7mm platinum ground electrode tip)

- Fuel economy on new plugs: (avg)
Tools: 10mm socket, 16mm spark plug socket, various extensions, torque wrench set at 19ft-lbs

Notes on the old plugs: Wear was pretty typical for a traditional plug. The NGK's have less electrode than the Densos. I guess they are designed that way since NGK puts a cut in it. There were no obvious signs of excessive wear, running rich, or lean on the plugs. My engine had both Denso and NGK spark plugs in it.

The tuneup took roughly 45 minutes and some patience. It also took a couple of long extensions to avoid hitting emissions stuff. The left bank was the more difficult bank to do, so I did that one first. That one took about 30 minutes. I used a small flathead screwdriver to pop the tabs up on the COP (coil on plug) connector. There wasn't enough space for me to squeeze the tab, so it was just easier this way. I then used a 16mm (or 5/8ths) spark plug socket to remove the plugs. I did have to disconnect the PCV hose and move it out of the way temporarily. The spring clamp didn't have too much tension so you can squeeze it with your fingers and pull the hose off. Two other hoses on clamps had to be moved near the 2nd cylinder. I just popped them out of their holder clamp and moved them as needed. The right bank was ridiculously easy. Just remove the air filter and holder, and you have complete access to all of the plugs.

With the new plugs, the engine seems to idle a bit smoother, and power is good as always. Can't really say too much on them since I've only driven 300 miles since the tuneup. I'm trying to determine if there's a significant fuel economy improvement using real empirical data. I've never broken 20mpg on my truck. Here's to hoping.

Some pics:

[NHTundra]

Nice write up. Have you noticed any increased gas mileage?

[Jason.MZW20]

Okay, so I regapped my iridium plugs (yeah, yeah, I know, they say not to) to 0.062" (1.57mm). I get a little knock on startup with 87 octane, but with 91 it's fine. That is most likely due to the volatility of 87 octane. The knock sensors correct it quite quickly. I've pretty much limited use to 91 octane though. It also sounds quite sickly with excessive exhaust tick under load when cold, which is likely attributed to increased pinging on 87 octane due to the larger spark kernel (ignites the fuel just a few milliseconds earlier like advancing the timing).

However, here are some gas mileage figures:

87 octane, winter blend, ~50 deg F (with 25-30 deg F cold starts) ambient temps, 0.044" gap:
Averages: 15-17.7 mpg*
*timing retarded
(excessive soot formation at the tailpipe and quarter panel)

91 octane, winter blend, ~50 deg F (with 25-30 deg F cold starts) ambient temps, 0.044" gap:
Averages: 14-16.9 mpg
(excessive soot formation at the tailpipe and quarter panel)

87 octane, winter blend, ~60 deg F (no freezing cold starts) ambient temps, 0.062" gap:
Averages: 19-21.1 mpg*
* timing retarded due to knock detection/pinging
(some soot formation, but not excessive)

I'm doing some testing with 91 octane and the 0.062" gap, and I'm also doing an analysis on how much intake air temps affect gas mileage figures. The next one will be on a summer blend though, so that will also affect things.

[Gregory_K]

Same plugs I used. Only the left bank had taken me a bit more time than 30 mins. that front left plug was a pain. I am willing to bet I spent 30 mins on that plug alone. The rest of the plugs were a snap after that one.

I've noticed any gas milage difference.

[NATEDAWG3256]

Just wondering if you bought your plugs online, or if you reccomend a place, no one near me sells denso iridium, the parts stores near me only have regular ngk, and autolite.
Thanks in advance

[Jason.MZW20]

sparkplugs.com

If I were to buy some again, I'd go for the FK20HR11s.

[Gregory_K]

sparkplugs.com

[NATEDAWG3256]

Thanks guys just ordered mine. searched around and found a coupon code for 10% off iridium plugs. SRTIRIDIUM

[david37]

Wondering why you would go with the FK20HR11, if you did it all over again. What didn't you like about the SK20HR11?

[Jason.MZW20]

Originally Posted by david 37

Wondering why you would go with the FK20HR11, if you did it all over again. What didn't you like about the SK20HR11?

Oh no, the SK20s are fine, but the FK20s just have a ground needle tip, which provides a more accurate termination point for the spark and they are the 120,000 mile OEM plugs in the 2GR-FE (Camry V6, etc.) and 2GR-FSE (IS350, GS350).

They are priced similarly, so I'd go for the FKs if I bought again.

[NATEDAWG3256]

I received and installed my plugs today. The sk20hr's, install was pretty easy with the one exception, the pigtail on the coil pack closet to the oil filter was a pain to get off. Got them at sparkplugs.com

[05Moose]

Originally Posted by NATEDAWG3256

... the pigtail on the coil pack closet to the oil filter was a pain to get off...

No Kidding! Why they didn't make that thing a little longer is beyond me...that one plug took longer than all 5 others combined!

[Gregory_K]

"that one plug took longer than all 5 others combined" +1.

Just enough height to get the pt off.

[USAFTUNDRA]

Hey thanks for the great info. I just did my plugs and a 3M complete fuel cleaning system in 2hrs today. Great stuff. Saved $350 from doing it at the dealer.