Which Plug is best? Need Advice
Thread Starter
Pro
Joined: Apr 2004
Posts: 719
Likes: 21
From: Miami Fl
Which Plug is best? Need Advice
Guys,
The time has come to replace those 100,000 mile stock plugs and was wondering what other vette users out there use. Two options i am considering is the stock 100k mile ac delco ones or the NGK DENSO IRIDIUM, i've heard they perform really well and last very long but kinda of expensive. Let me know what you think.
Ralph
The time has come to replace those 100,000 mile stock plugs and was wondering what other vette users out there use. Two options i am considering is the stock 100k mile ac delco ones or the NGK DENSO IRIDIUM, i've heard they perform really well and last very long but kinda of expensive. Let me know what you think.
Ralph
Instructor
Joined: Oct 2004
Posts: 105
Likes: 4
From: Riverside CA
I just put in the AC Delco 41-985 iridium plugs and there was a noticeable improvement in my performance and it idles much smoother. The original plugs were worn to .070" gap and most other plugs call for a .060" gap, but the 41-985 plugs come with a .040" gap and a warning to not deviate from this setting. I don't know why the smaller gap, but it is a newer plug and it comes right from GM so I figured they know what they are doing.
I bought mine from Pep Boys here in California, but if you can't find it nearby you can by it here:
http://www.autopartsgiant.com/welcom...ds&kwd=NGK.gif
I bought mine from Pep Boys here in California, but if you can't find it nearby you can by it here:
http://www.autopartsgiant.com/welcom...ds&kwd=NGK.gif
Racer
Joined: Aug 2005
Posts: 361
Likes: 1
From: Montara Ca
Originally Posted by Rconce01
yeap i see they tell you not to deviate from the .040 gap must be some new technology going into those plugs
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Safety Car
Joined: Feb 2002
Posts: 3,726
Likes: 368
From: Montoursville Pa
Originally Posted by dudleyd
I'm a bit confused here. After reading the post's here about a warning to not deviate from the 0.040 gap on the 41-985 plugs, I went out and retrived the emty box which contained my newly installed 41-985 out of the trash and have looked over all the print and have found nothing stating that the plug pre-gap should not be changed, to the contrary it says to set gap to vehical specifications which I did, 0.060. At the time I was a little concerned about opening the pre-gap up to 0.060 because it puts the electrode at a slight angle. The car is running strong with fresh plugs and idles nice and smooth with the 0.060 gap. At >$80 for a set of plugs I'm not thrilled about having to replace them in a few thousand miles because of improper gaping at t=0. Where did you guys see the caution about changing the gap?
This is to advise ALL Corvette c5 owners of a bulletin, 03-06-04-060, which updates spark plug application and gap.
This states that as of 24 October 2003, part number 12571164 is the replacement spark plug for ALL c5 Corvette, LS1 and LS6.
However, this also shows us that the new gap, of .040, is set at the factory. Any attempt to regap this plug could damage the plug. We are instructed to NOT USE THE PLUG, if the gap of .040 is not there. DO NOT GAP TO .060.
NOW, the largest point to be made here, is that this plug uses an Iridium tip for the electrodes.
This is the first for Corvette.
Others claim to be Iridium tipped, but are NOT in the GM line.
The ACDelco number is 41-985.
So, with that, please be aware of this and utilize this plug from here on in.
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
Pro
Joined: Mar 2002
Posts: 732
Likes: 138
From: Allen (DFW) Texas
ErnieN85, you commented: So, with that, please be aware of this and utilize this plug from here on in.
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
Team Owner
Joined: Mar 2005
Posts: 20,933
Likes: 905
From: salem OR
Originally Posted by binkysgarage
You probably could go 100k when you start at .040 gap.
Gm says 100k tune, not in the real world might still running but not good.Plugs are toast at 70k
Fancy plugs don't last like they claim and if you regap to .060 it's going to run better.
Last edited by 3 Z06ZR1; Dec 27, 2005 at 06:00 AM.
Team Owner
Joined: Mar 2005
Posts: 20,933
Likes: 905
From: salem OR
Originally Posted by rhneff
ErnieN85, you commented: So, with that, please be aware of this and utilize this plug from here on in.
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
Safety Car
Joined: Feb 2002
Posts: 3,726
Likes: 368
From: Montoursville Pa
Originally Posted by rhneff
ErnieN85, you commented: So, with that, please be aware of this and utilize this plug from here on in.
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
Aside from this, I have contacted GM powertrain on the updating to the PCM control calibration for these new plugs and have been told that the latest calibrations are already set up for the revised plugs. Apparently, they knew these plugs were coming, and compensated accordingly
So does that mean in order to use the new plug in a vehicle manufactured prior to the 2003 date we need to have the PCM reprogrammed?
From what I have heard there is too great a chance of damage to the plug if you try to change the gap.
Drifting
Joined: Oct 2005
Posts: 1,943
Likes: 18
From: Henderson NV
My question is then , for those of us who gapped the plugs to .060 with success and did not damage them are we ok with these settings for this plug, my back cant handle another #7 plug removal right now,lol
Last edited by Pizzano; Dec 27, 2005 at 09:56 AM.
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
NGK TR55'S PART #3951(think of the Ford CID and throw in a 9), this is for a n/a setup, the stock wires are fine, i like to swap the plugs at least once a year or every 10k miles, gives you a good indication of how the motor is doing and only takes about 20 minutes
Advance and Napa carry the ngk's in new england
Advance and Napa carry the ngk's in new england
Safety Car
Joined: Feb 2002
Posts: 3,726
Likes: 368
From: Montoursville Pa
Originally Posted by Pizzano
My question is then , for those of us who gapped the plugs to .060 with succes and did not damage them are we ok with these settings for this plug, my back cant hancle another #7 plug removal right now,lol
as long as you didn't crack the insulator or any thing like that........ you should be good to go.
Drifting
Joined: Oct 2005
Posts: 1,943
Likes: 18
From: Henderson NV
Originally Posted by Pizzano
My question is then , for those of us who gapped the plugs to .060 with success and did not damage them are we ok with these settings for this plug, my back cant handle another #7 plug removal right now,lol
Racer
Joined: Mar 2005
Posts: 288
Likes: 1
From: Maple Ridge British Columbia
I installed the new GM Iridium plugs and new oem wires into my Z06 yesterday. I did not chnage the gap as the dealer told me it was not recommended. I then drove it for a couple of hours. Good weather here do I was able to get on it quite a bit
Car works great and I've had no issues.
Car works great and I've had no issues.