I have received a full set of new Bosch Iridium 9655's to test and compare. I normally use the NGK Iridium 7164's and have gotten 10k miles from my last set before the motor would no longer start. 4 of the Bosch plugs were installed on 9/20 with 124,370 miles on the odometer. i received the other 4 plugs and will install them as i change my transmission which has issues. I hope to start on that tomorrow.

 

Let me know what u think of them... looking for some good plugs to put in over the winter when I put on my headers

 

I used bosch plugs when they first came out. and only change them at
about 85K. Note they are plated threads (they will not rust on.) you need to install them when the engine is cold and check them later on with iron heads.

 

ok i have all 8 in and have the rearend in and stock trans back in. ssoooo back on the road finally. 125,498 on the odometer. the test has begun, had a lose header on the passenger side, got that fixed. testing the mpg today with a run to forks, 300 miles round trip.

 

19 mpg on a 300 mile trip. i would get more if i took the 315s off and used the 245s on the back.

 

this trip to forks i put in new 02 sensors and brought the tire air pressure to 36lbs and got 21 mpg. remember the drive is through the olympic national park so lots of mountains and great corners.

 

So, what do you think of the plugs so far?

 

still running good. the longest i have went before failing was 10k miles with ngk irridiums.

 

6500 miles and still goin strong

 

Why are you only getting 10K miles from a set of plugs? I know that your engine is heavily modded, but I wouldn't think that would kill plugs so quickly.