xj_

hey all i have a 97 cherokee with just over 110k on the clock. 5 ish inches of lift 33s locked f&r blah blah blah... anyways i have some cheap champion sparkplugs in my jeep now and have been using them for a while now with no issues..durring the summer i swapped to a 99+ intake, 783's, apn header, cat delete, iat relocation, flowmaster 40 series dumped before the axle, and i made an intake with box that is insulated to help with under the hood temps. My question for you fellow jeepers is about gained performance with new plugs. i have a set of e3's that i ran for about 500 miles before all these modifications and didnt see a gain in mpg or performance. so after all this has been done do you think i will see any gains? its not hard to change plugs i may as well just try it out and see. just curious if anyone else has similar setups? Thanks!!

93XJLI

cheap champions. unless you have the coil-on-pack (2000+) the 4.0s dont like fancy plugs. will you see a difference? probably not. but i know people (personally... not on the interweb) who had issues with fancy plugs in a 4.0. switched to copper and then the motor ran fine.

xj_

thats why i have the coppers in mine now (well before the mods). but now that i have increased air coming in, better fuel atomizaion, and a lot better exhaust these may be a benefit due to the increased spark volume?

93XJLI

nah. you still have an old *** aint care tractor motor under the hood.

Donnie_K

Champion Copper tops will make your motor the happiest.

1998redxj

I agree! Champion copper tops work the best. I just bought 10 brand new ones off of ebay for 20 bucks with free shipping. There cheap and its always good to have spares. Just my 2 cents

Donnie_K

they're that cheap at advance auto... lol

1998redxj

The nearest parts store is a few miles away. I dont need em right this second so i ordered em. I also have a ebay company selling keyless entry remote fobs so i get points with each purchase.

salad

Champion RC12ECC or NGK ZFR5N coppers are the best for these beasts (other P/Ns on other years). If you upgrade the ignition system too you could probably play with a larger gap, but with the design of these things just use the OEM plugs. Unless you have excellent compression and really clean fuel you'll want to change the plugs regularly anyway, which defeats the purpose of the fancy "long-life" plugs.

nopi

I would say champion youre horsepower gain is 20 to 30 hp its not like 100 hp gain probably run it a step hotter for torquw gain.

93XJLI

Lol wut

1998redxj

Lmao and stickers add 100 hp.

xj_

Do you think a .40 or .45 gap would be better then

wiggles

...your not going to get even close to 20 out of just plugs
Keep it between .35 and .40

EvstaG

I believe .035 is factory spec... That's what I gap mine to. I have always wondered what it is about the fancy plugs that can cause issues with the older 4.0s.