What plugs should I run

[Zuffen]

I'm getting close to starting my new engine and I'm curious what plugs others are running.

Essentially the engine is an 8.5:1 build with 15lb of boost.

The ignition system is all new (wires, rotors, caps, coils, & igniters) so that side doesn't need compensating.

 

[Death By Bass]

$3.99 standard plugs.

 

[4000GT]

I vote stock. Maybe one range colder.

 

[cribbj]

Rod, I would go one range colder, and run either the cheapie stock electrode type, or Iridiums.

Iridiums don't foul as easily as the stock type, and they'll clean up easier once you get your tune right and can get some load on the motor.

I would stay away from platinum plugs.

 

[stevechumo]

The pre-ignition chance with platinum plugs are very high. I'd go with 1 range colder plugs. Iridium and cheapo V-power NGK are good so far. I already spent a few hundred bucks just to see what plugs can run with the turbo system. Some platinum plugs even knocked at half open throtle. Some other platinums even melted all the way to the electrodes and looked like they've been hammered.

 

[Zuffen]

Thanks guys.

As I expected 1 range colder and iridiums.

Always worth asking those that have been there before rather than reinventing the wheel.

 

[Death By Bass]

Thanks guys.

As I expected 1 range colder and iridiums.

Always worth asking those that have been there before rather than reinventing the wheel.

I wouldn't waste the money on iridiums.

 

[gloverman]

Hello Rod. As it is a fresh rebuild and new ECU I would recommend standard heat range standard copper core with 0.8mm gap for start up and initial setup. If they foul when setting up the ECU then it's no big deal. I would even do the first few dyno runs on them. Once the tune is better then one range colder as suggested. I normally prefer iridiums but often swap to them after completing the run in procedure at the first oil change. Gives a good chance for another good check over and even a compression test for a comparison later down the track. Always nice to have a New compression number. cheers

 

[XR8tt]

Yep being that it has lower compression std heat range during run in and gapped a little tighter than n/a.. As said .8mm..
I assume you may have colder thermostat which will help a little..
It won't hurt to run a little lean during break in either..
Timing and fuel would be conservative..
Good luck and take video of it....
Imo std.. NGK's..

 

[-Nemesis-]

Without hijacking the thread to much, what about plugs for a standard engine, running petrol/lpg and ~7psi?

I read the big plug thread, but assuming we'd have slightly different considerations due to our own weather/climate here?

 

[XR8tt]

http://www.ngkspark.com.au/sparkplug_cars.php?PageMode=Results&Make=Lexus&Model=SC430&Year=10%2F01on4.3LV83UZ-FE

Enter your model here..
http://www.ngkspark.com.au/sparkplug_vehicle_type.php

 

[-Nemesis-]

I would have thought 7psi boost would change that though?

Doesn't the gapping need to be reduced from the stock -11? Not sure where I heard that. I'm currently running the Iridiums that I put in when I got the motor a few years ago

 

[XR8tt]

7 Lb with 8.5 comp cylinder pressures would be way safe..
But like it says on NGK.. For every 100 h.p over std the general rule is one
range colder..
A turbo 4.0 SOHC Ford six we have run up to 16 Lb with LPG plugs which are one range colder, with 9.4 compression @ 280 rwkw through 3000 converter..
On my Ford with 7.8 compression. It runs quite well on std heat range with over 480rwkw.. If I had better ignition. Such as M&W or MSD DIS 4 etc it would clear cold plugs and be able to maintain wider spark plug gap..Able to run more power & boost levels also..
One range colder won't hurt !! All that'll happen is fouled plugs..
Ummm?? But if they are way too hot ?? The results could be devastating!!
Smaller bore motors and 4 valve heads don't seem to be as critical in this area..
Another reason why std plugs could be used is there would be some oil etc in chamber while rings bed in.. Plus you are NOT really going to be getting up it till some klrs are on engine..
Exhaust temps while tuning is another sign, a good tune cannot be emphasized enough...