Mgpeagle

iTrader: (6)

I tried some colder plugs for the GXP and what a pain in the *** to change the plugs!!! I went with Autolite Iridium XP-5243's and my mileage went up almost 2mpg after the change. Kept watch for a week... I gapped them at .046 instead of the factory .040. It seems to idle better and the throttle response is a little bit better. In theory this should eliminate some knock because it keeps the combustion chambers a little bit cooler but not too cold. Still want the fuel to burn... I don't get as much black soot on the exhaust tips either. In short, the car seems to run better. You guys with a lot of mods should look into a plug that is a heat range or two colder; especially if you plan on a turbo or supercharger for it. I would love a CSC kit for these cars... Anyway, just thought I'd share.

-Mike

Scarhead

iTrader: (1)

Thanks for the tip....I noticed in your sig you have one of those tranny pans with the heat sync fins on it...did it do anything to help the tranny temps at all?

Mgpeagle

iTrader: (6)

It drops the tranny temps about 8 to 12 degrees. The highest I ever had on the DIC was 212 degrees and now I have never gone over 204 degrees. It also has a drain plug on it for easier fluid changes. The tranny plug is also magnetic; since the tranny pan is aluminum and we cannot use a magnet at the bottom of the pan like on the factory pan. It takes less time for the temps to drop down too. The fins really help.

-Mike

Scarhead

iTrader: (1)

Cool, thanks for the info!

nasscargxp

I'm using the Autolite 104 Double Platinum gapped at .038. Throttle response is better than stock and KR dropped about 1 or 2 degrees under the same engine heat conditions. I would highly recommend them.

Forgot to mention that these are about 1/2 heat range colder than stock.

Count of Monte Carlo

Sounds like an interesting idea...

bdyman

and where did you get this trans pan at??

CardinalsRed

whats the part number on that Finned Aluminum Tranny Pan

06WHITEMCSS

Has anyone done any testing, before and after a colder plug swap? I'm thinking there maybe some trouble down the line. Meaning EGT's maybe reduced, not alowing for a complete burn, and eventually destroying your cat.! If you are going to do this swap, I suggest you do a little research, if your not getting a complete burn its going to trick the computer into leaning the car out to much and may even burn pistons/rings. If you have a pyrometer shoot the cat. Before and after the swap. I might even consider a wide band 02 sensor, to get your true A/F ratio, as you lean it out it will use less fuel and increase MPG and possibly run a bit cleaner, since looking at my exhaust tips tells me she runs a bit fat anyway. Just my thoughts.

dcrews

iTrader: (3)

The 3.8SC guys have been using colder plugs for years and years with no adverse effects..

06WHITEMCSS

There is a huge differnce between an FI engine and a NA engine, colder plugs in a FI engine are going to lesson the pre-detenation or pinning you can hear, especially if using a low grade/octane fuel. Other than that I see no advantage to a colder plug in a. NA engine, especially if you increase gap as well. To reduce spark heat, all you have to do is increase the gap. The closer the gap the more intense the spark becomes.

scarlett

I used to have Autolite Platinum's I installed those last summer when I put in my rockers. And they were all over the place in gap size from heat etc. I installed these and have ran test (HP Tuner) and everything seems fine for spark etc and no loss of power.

http://www.boschautoparts.com/Produc...Plugs/IrFusion