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I entered the banner to try out the new Bosh Iridium plugs and was given 10 of them for my 99 F250 Super Duty, Super Cab, 6.8L V10, 4x4 with 255,000 miles. Part Number 9608 (HR 6 KII 33 X)
I got them the week before my vacation trip half way across the US. I was getting it ready for the trip so I decided to try them. The plug change went without any problem. I was a little worried about it but I don't think the Autolites I took out had been in for more then 50,000. Other then a little whitening they looked pretty good.
The bosh plugs are cool looking. The small wire electrode gives the impression that the spark would be sharp and you can just make out where they welded the piece into the ground electrode.
They came pre-gapped at .044. I don’t think I’d want to mess with the gap if I thought I had to. I used a little never seize and torqued to 15Ft Lbs. Something I do like about the packaging is that all the information on gap and torque is on the box. Even gives you the angle torque (15deg) for vehicles that use that method. The box also says last 4x longer. I don’t think I’ll be leaving these or any plug in my engine for 400,000 miles. With these heads I’d probably never get them back out without a machine shop.
After the plug change it ran real good. My trip took me from California, through the Tetons, Yellowstone, over to Crazy Horse and Mt Rushmore, down the Black Hills, around the Badlands, and up to Wisconsin (to visit mom). Came back down to Indiana to visit family then a mad dash (two days with no night driving) back to California. In total about 6000 miles.
I ran into some slight pinging at moderate load. I had a Polaris 800 Sportsman X2 and camping gear loaded and if I was climbing a hill and holding speed it would ping a little but I don’t think it was the plugs as much as altitude and higher ethanol percentage. I also discovered a small exhaust leak when I got back and I have a few other things to check. Even so I never got less then 11MPG (and that was on the way back on 80 doing…..90ish. My best mileage was about 15 doing 87. I happened to pick up a big rig doing a steady 87 going east. I was able to set my cruse control to him. I kept a mileage log and averaged about 12.5 – 13MPG for the whole trip.
The truck still runs smooth even with the exhaust leak. The leak in more noticeable when it’s cold. I just recently bought the truck so I don’t have a lot of before data to compare them to but all in all not bad performance for the workout I gave them. I’m looking into the pinging. I’m also running 5 star mikes 87 Performance tune. I was able to clear up most of the pinging by using higher grade fuel.
Would I buy them? Well at the price I might shy away from them but ask me again in another 94K when I pull them and see if they need replacing. If they live up to their longevity claim then I’d just inspect them and put them back. That’s where the value would really show up.
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