let me no what type of plugs uall using in 3.8 supercharged thanks jeff

 

I'm a strong supporter of the ACDelco premium iridium plugs they will last 100,000 miles, and work the way they were meant too.

 

I used to run Autolite 104's (2 heat ranges colder than stock) in my basic bolt on gtp (3.4" with supporting mods)- and I currently have Autolite 103's (3 heat ranges colder than stock) in my monte (lots of mods).

For a stock supercharged 3800, the Autolite 606 is the factory heat range in a copper plug, although I'd probably consider an Autolite 605 if you plan on doing a few basic mods (say CAI and catback, or something basic).

But it really depends on what mods you have, and if you mind frequently changing plugs. All the copper plugs I mentioned should probably be changed at 10k miles or so- they don't last 100k like stock plugs. If you don't plan on modding much if at all- just get an OEM replacement plug in platinum or iridium and be done with it for the next 100k miles.


Yeah, but if he is planning on modding his 3800 SC, most go to a copper plug for more KR resistance. More maintenance, but better performance in this application.

 

I use Autolite xp104's, which are iridium. I thought it was platinium that we were trying to avoid for KR. I was under the understanding the fine wire of an iridium is ideal. I've scanned and advanced spark - I know I'm not getting any KR.

 

Copper plugs (Autolite 606, 605, 104, 103) are preferred by a lot of the 3800 community. I use Autolite 104's for my fairly modded L67.

Bumpin hit the nail on the head, as always.

 

thanks guys

 

I used the factory Delco Iridiums when I recently tuned up my 2004 Dale Jr.

Wayne

 

It isn't necessarily the specific material of platinum that causes KR- from what I understand, the platinum tip is sharper and the tip physically runs hotter than copper (part of what keeps it from fouling for so long). The higher heat of the tip and the sharpness of it are what make it cause a little extra KR.

From what I understand with iridium, the tip is even thinner? So I would imagine they fall in the same class as platinum as far as causing knock.

I've never personally tested the difference- I just follow what all the hardcore 3800 setups run, and as far as I know- they all run copper (plus there are tons of heat range options with the copper plugs too).

How much WOT timing are you running now? There isn't much sense in going too high with it, if you're getting much above 20* and still have no KR, maybe you should think about adding more boost.

Its hard to make an A-B comparison of knock resistance if you don't have any KR to start with though.

Edit- couldn't find a direct comparison of all 3 from the same brand, but here are some pics for reference (for those who don't know, we're looking at the tip/center electrode here- the piece protruding from the white center, under the strap that hangs off the end:

Copper:



Platinum:



Iridium:

 

I wasn't really thinking about adding more boost, but I didn't know I was being conservative really either. I was just "street tuned" Tuesday, and I'm not totally dialed in on the logistics, but it seems to me we were running about 32 degrees through most of the range. This was just using HP tuners and me trying to understand what Tino was doing over there.

 

I'd say you're definitely conservative if you have absolutely no KR anywhere- depending on what mods you have and how high you have the timing jacked, it may be worth it to drop pulley sizes for more boost, even if you have to back timing down a pinch.

How much timing advance are you running at WOT? (obviously the 32 was from part throttle)- from what I remember, anything much over 20 or 22* at WOT means you really should consider upping boost instead of timing; and the opposite for those who are down around 14-15*.