The jeeps and rams use different intake manifolds. The rams have an active runner valve within the manifold that allows for more torque. This is mainly for the fact that it's a truck and is expected to haul/tow. The exhuast and tuning is also a bit different as well. If you want that extra power it's very easy to obtain with a little money. Intake/exhaust/93tune adds over 50 hp and 60 tq. Depending on parts the increase can be even greater.That is the set that I used, NGK plugs made for the Hemi.
The owners manual states a gap of 0.043", I had to adjust the NGK plugs as they were all around 0.041". I used a set off feeler gages to check and set the gap.
I know many would rather use the Iridium plugs as they are good for 100,000 miles and are now listed by Mopar. I don't mind changing the plugs every 30K miles, especially being as easy as they are to change.
I would like to learn more about the ignition system and maybe upgrading the coil packs. There has to more that can be pulled from these great engines, especially considering that the Rams are stock at 390HP and the Jeeps are at 360HP, why the difference? Just in the Tuning?
Sorry, not trying to highjack a thread, I will also search the forum to see what I can find.
What about 2005 Jeep Grand Cherokee 5.7 hemi?5.7 V8 Hemi (2011-2013)
Mopar p/n 05149177AB (NGK Yttrium ZFR5C-11)
(.043 gap, 16 plugs, tighten to 18.5 - 22 ft. lbs.)
5.7 V8 Hemi (2014-2015)
Mopar p/n SP143877AA (NGK Iridium 1LZFR5E-11)
(.044 gap, 16 plugs, tighten to 18.5 - 22 ft. lbs.)
I suspect its because the typical life of standard steel plugs is usually ~30k miles in most engines. Most engine also do NOT have dual plugs per cylinder nor have a semi-hemispherical head shape.....I definitely do not see the need to replace plugs at the Jeep specified 32K miles....