Joe C

ACDelco RAPIDFIRE Performance Platinum or Bosch OE Iridium?

having a tough time deciding - probably putting way too much into this, but getting ready to place an order with summit. comments???

GKK

I tried both of those plugs before but, my 91 L98 ran a lot smoother with the regular AC Delco FR5LS plugs...






.

MrWillys

This is what GM recommends for this cylinder head.

94z07fx3

I use NGK Iridium IX in everything that that I have that they're made for.

I think the NGK Iridiums have 10 or even 15 percent more hype than any other plug and like the hype.

WW7

You can buy what you want, but you are just spending more money for nothing ...The motor runs as it should with AC Delco FR5LS plugs and thats what I ended up using after trying them all... These are the plugs designed for the motor......WW

94z07fx3

As usual everything you post is 100% correct.

But even though there is zero performance gain in the pricier plugs, they do have significantly more hype. I don't know why I fall for it. But when I'm at the counter or on RockAuto I just can't resist the urge to buy the NGKs.

Maybe if AC Delco could put out a fancy ad with a young flat belly ooing and ahhing over the OEM plugs?

Joe C

here ya go...



i'm sold - OEM FR5LS for me -

94z07fx3

milsurpman

I will say one thing its getting harder to get FR5lS plugs. I have to order them in as i cant get them locally anymore and even online sellers dont have a ton of em. I just ordered a pile of em. I think this number is on the endangered species list.

Klyde

I spent the extra money for the NGK Iridiums not for the hype but because it is such a pain in the butt to change plugs that I don't ever want to do it again (5 hours and lots of flesh). They are good for 100k+ miles so I will never have to worry about them again. Well worth the extra money.

WW7

I wouldn't suggest leaving any plugs in your motor for 100,000 miles without checking them... I can almost guarantee if you do, you will never get them out without stripping the threads on some...Also, using antiseize on the threads is a must on aluminum heads ....WW

Klyde

I'll be dead when the next owner tries to change plugs. I also put never seize on the threads before installing. My wife has a 370Z and it has 32k miles on it so when she took it in for an oil change I told her to have them change plugs also. They told her they would have to remove the engine to do that and it would cost a huge sum of money. They told her the plugs are good for 100k miles and not to worry about them. What's good for the goose is good for the gander. I found out what plugs they use and put them in my vette.

cv67

Tried both went back to Delcos

All you need is a spark to light that fire off thats it.

Have the original plugs in my silverado 150k mi.
course thecar I never drive just got fresh ones. Hmm.
Prirorities lol

C409

...... I changed plugs on an 05 Equinox and the ceramic said Delco but the metal was stamped NGK ............

BillC89

I just put in a set of RAPIDFIRE #5 Platinum, they look and work like the FR5LS. I'm not sure if there worth the extra $4 each, I'll have to see how they work long term.

davewhtt

Delco in my 93 and NGK in my Yamaha outboard!

RapidRick

NGK FR45 for here in So. Florida.
Just a tad colder than the stock FR4 replacements.

Car had a funny idle flutter, with good fuel system in my 44k mile, '89 Automatic G92 model.

I found inside, and removed the Bosch Platinum Fusion's out (4 electrode type) and car now runs great, get's better mileage avg. believe it or not these past 500 miles or so, by +1.5 mpg, and I'm happy.

I use NGK TR55's in my modded '01 LS1 Formula as well. Love these plugs for over 35 years ever since using the BP5ES in my '69 Camaro w/454BB way back then, and NHRA SS/H car as well.