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10-08-2008
Well I was going to drop pulley and add front powerlog in the spring but I can't really wait anymore. I just installed some Autolite 605's. Would it be ok to keep those in there instead of install 104's with a 3.6 pulley and plog?
ZZp's site says that a totally stock 04+ can handle a 3.6 pulley. So that makes me assume that stock spark plugs are ok with a 3.6. 605's being one degree colder should be fine with a 3.6?
It seems that most people on here who drop pulleys most always have 104's.
10-08-2008
Overkills spark plug guide says this:
Non-intercooled:
3.8” factory: Autolite 605 @ .055-.057” gap (or AP605/APP605 platinums @.060”)
3.4-3.25” pulley: Autolite 104 @ .052-.054” gap
3.1-3.0” pulley: Autolite 103 @ .047-.050” gap
2.9-2.7” pulley: Autolite AR94 (4 range colder race plug) @ .044-.046”
ZZP's website says cars cars with "basic bolt on mods" should drop 2 heat ranges.
Theres kind of a gray area in the information here, but if its ok for my car I would like to keep the 605's in there (which are gapped at .055). If not then I will change them out and probably put new wires in which is more $$$.
10-08-2008
In reality you want to run the highest heat range you can without getting Kr. The simple answer is put on your mods, scan for Kr and if you have any at all drop to the 104's.
10-08-2008
Yea right after i posted this I was wondering about that route then I realized I have an Autotap in my trunk. Ill do that. Hopefully I don't have any KR so I won't have to deal with the spark plugs again.
10-08-2008
You shouldn't get much doping form the 3.8 to a 3.6 with your mods. Make sure you tell us how it goes tho.Originally Posted by 04CompG
10-08-2008
I was considering dropping to a 3.5 but from what I hear a 3.5 to the GenV is like a 3.4 to the Gen3. I don't want to put a 3.5 on my genv without rockers or something. +2lbs of boost should be something noticeable out of the 3.6. Thats like 25% more power I'm going to be asking out of the eaton. And I'm going to put a plog on the same time I do the pulley.
Last edited by 04CompG; 10-08-2008 at 12:02 PM.
10-08-2008
You'll be fine with the 605's. Like DnaProdigy said you want to be able to run the hottest plug you can without KR.
10-09-2008
Greetings!
I'm Dave Buckshaw (of DHP) and by day I'm a technical trainer for Autolite spark plugs. I would suggest using our 104 heat range plug as it is 15% cooler than the 605's and the 3800 really likes a colder plug when you start bringing up the boost. I run 104's in my GTP motor swapped Montana with a freeflowing exhaust, rockers and a 3.4" pulley. A colder plug helps rid the plug electrodes and combustion chamber of detonation causing heat faster and this is important especially on a non intercooled application that has very air inlet temp deltas, (changes), and runs close to the knock window already.
The only "worry" to using a cold plug could be some low tempurature misfires. Too hot of plug can MELT parts and destroy an engine! The 104 however is a factory spec'd heat range for many OE engine applications including older 3800's and I don't find it too cold. That being said, if you are worried at all about cold operating misfires I'd run our XP Iridium plugs, (XP104), but since they require about 10% less voltage to fire than a standard electrode spark plug there's MORE available voltage at the electrode and this helps prevent misfires all over the RPM range. How else can you really improve the output of the OE DIS system for a small cost? Coils? MSD?
You may have heard not to use a "Double Platinum" type plug in a GTP application. The issues that many have experienced with DP's are because DP plugs have precious metal pads welded to the electrodes and the resistance increases a bit due to the pads and high RPM misfires can result with a modded car that has increased boost. An Iridium plug however radically necks down electrodes to a .6mm point and than adds it's precious metal pads to the electrodes. The huge benefit here is that my personal experience in our lab doing some extreme pressure bomb testing is that the Iridium XP's required about the same voltage as our racing plugs with cut back center electrodes! That's pretty darn good IMHO!
Keep in mind that a standard copper core plug will suffer significant gap growth and erosion on 1/2 of the plugs on a DIS ignition in a rather short period of time as 1/2 of your plugs initiate the "arc" from the sidewire to the centerwire and the other 1/2 fire conventionally from center wire down. A standard sidewire firing reverse like this may only last 18,000-20,000 miles before that erosion cause the gap to get large enough to cause issues on the "big end" under boost. Autolite DP's also have a necked down center to help combat the increased resistance of the platium pads but it isn't nearly as radical as the XP's design.
Mostly I see guys running .045-.050 gaps with DP's and even copper cores and on the Delco DIS with aggressive boost I myself like to run .035. The Grand National guys will even run .028-.030 gap when their boost goes up. I'm also a Grand National guy so I know all too well about misfires!
So for a street car I'd be using on IR plug without any worry and take advantages of of its ability to launch the flame kernal quicker than a standard plug, (which helps convert more of your chemical energy to kinetic energy), and its ability to fire leaner mixtures that can result from tuning issues or transient conditions not account for in the PCM due to mods. As a side note GM uses IR plugs in the LS7 and the ZR1 V8's. When I did development work on the LSX V8 at another company we made 810 hp on a 2300 Eaton Blower on 428 CID of LS V8 on finewires!
I've had no issues with finewires at even 20+ psi of boost on a turbocharged 3800. What's nice is the suffer virtually ZERO gap growth or Erosion for a long period of time and that means you'll have one less thing to worry about. For an all out race car or a car where you change your plugs very frequently, (for fun?) I'd run standard copper cores, (104's) or our AR racing plugs if you have a max effort car.
Forgive my long windedness here. The 3800 V6 is my engine of passion and choice and I want to be sure you guys are getting some decent information from a technical point of view. It's good to see solid information from your fellow board members as well. This community has been through most of the bad combinations and setups already!
Dave
Last edited by daveautolite; 10-09-2008 at 10:25 AM.
10-10-2008
what about with a 3.5 pulley should i just stick with the Autolite 605's ?
10-10-2008
Dave....I want to know MOAR!
And welcome aboard. This is one subject of CONSTANT concern and debate.
I myself have had great success with the 104's down to a 3.2, and then the 103's from 3.0-2.8 pulleys on a Methanol setup.
10-10-2008
Comes in for 1 post, doesn't even hit the intro forums haha
10-10-2008
I installed 104 ar's in my ride yesterday along with an oil change and man my car runs so much smother.
teh electrodes on the ngks that were in there were gone, they only had 30,000 miles on them. I thought that this was excelerated wear, dont know why but I bout $hit a brick when I saw them.
10-11-2008
I guess put the pulley on, scan and find out. thats what im going to do but with a 3.6 pulley and 605's.
10-11-2008
The 605's are indeed one heat range colder than stock and as long as your KR is under control these are a solid choice for a mild street setup. I'm partial to the 104's for the 3.4 and 3.5 pulleys especially if you don't have rockers or a cam.
10-11-2008
Sorry gang! I was in Mexico City at an international training conference for Autolite and Fram and the bandwidth was pretty horrible!
10-11-2008
Were they gone like disintegrated gone or were they really worn? If they were melted away I'd be a bit worried about some Pre Ignition or Detonation that could have been caused by the wrong heat range for your setup, misapplication, or an operating condition like a lean fuel mixture, high supercharger outlet temps, (small pulleys high outside temps), or something else.I installed 104 ar's in my ride yesterday along with an oil change and man my car runs so much smother.
teh electrodes on the ngks that were in there were gone
If your electrodes were just worn on 3 of the sidewires then I'd say it was just the effect of a DIS system on a conventional electrode plug and they reached the end due to the reverse firing for 30K.
The AR's work really well but will not go much past your 20-30K IMHO on the reverse firing plugs as they are conventional electrodes. The XP104's are just as robust as far as spark is concerned, (maybe a bit better with flame kernal growth and flame front shrouding due to the fine centerwire and profiled sidewire) and will go the distance especially in a street application.
AR's are by no means chopped liver and are built with great care at the plant!
Dave
10-11-2008
they were just worn. on both sides.
10-11-2008
what did you gap them at ?I installed 104 ar's in my ride yesterday along with an oil change and man my car runs so much smother.
teh electrodes on the ngks that were in there were gone
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