Gapping Plugs for Supercharged Engine - TCCoA Forums
 
LinkBack Thread Tools
post #1 of 25 (permalink) Old 06-23-2005, 10:13 PM Thread Starter
Don't call me a Newbie
 
RoushTBirdNo1of6's Avatar
 
Join Date: Feb 2003
Location: Poulsbo, WA
Age: 57
Posts: 397
Gapping Plugs for Supercharged Engine

I was searching around to determine where to gap the Motorcraft 12c's for my recently aquired Vortech Blown 4.6L '96 TBird. It looks like it breaks down into two camps:
  1. Big Gap - 0.052"-0.060" (stock being 0.052"-0.056")
  2. Small Gap - 0.032"-0.040"
I found Supercharged cars in both camps. Well, THAT helped.

Some seem to think that the biggest gap that the ignition system will support, is the way to go. Others seem to be concerned with the spark being "blown out" in the larger gap range.

I even found someone running a 0.025" gap, and he swears by it.

For the record, this is what Vortech has in the FAQ on their site:
Quote:
11. What spark plugs should I use with a Vortech supercharger system?

Always utilize the stock specified heat range for street legal applications. For continuous heavy-duty racing, off road use only, use one heat range colder than stock and reduce the gap to 0.032 to .040". (NOTE: the gap requirement varies per the application and intended use). It is suggested that you follow the manufacturers suggested recommendation for spark plugs. Do not use platinum plugs, as they are considered long life spark plugs and are not performance spark plugs. For higher performance engines, consult the spark plug manufacturers for their specific suggestions.
So they suggest the stock plug and gap, unless racing...then only one step colder and the smaller gap range. Of course, the mantra around here is TWO steps colder (How cold of a plug to use, is a different issue that I am MORE than satisfied with...hence the 12c's going in my car ). At least Vortech agrees on Copper over Platinum, as most people here seem to.

Now, I'm not trying to start a knife fight. I know that some peoples mechanical beliefs are more sacred than their religious beliefs. However, I'd like to hear what gap people are running on Supercharged cars and why; preferably backed up by some sort of reference, documentation or something beyond a gut feeling or "I was told to". The old Try-Test-Change-Repeat process, for finding what works, is valid...IMHO.

Ok folks, have at it....but try to play nice.



Wayne Hazard Wife is back from Kuwait - Welcome Back, Chief! My Multiply Site
1995 4.6L Thunderbird LX - Daily Driver...1 3/4 Miles to Work and Back
1996 4.6L Thunderbird LX, Vortech V-2 SQ Blown - Heart transplant in the works.
   (If SC+V6 = SuperCoupe, wouldn't SC+V8 = SuperDuperCoupe?)
1997 Mark Martin Signature Thunderbird (AKA: "1 of 6")* - 25k mi Garage Queen
   *A Significant Thunderbird in the Thunderbird RegistryAww, man...I can't believe Mark drives a freekin' Chevy now.
 
RoushTBirdNo1of6 is offline  
Sponsored Links
Advertisement
 
post #2 of 25 (permalink) Old 06-23-2005, 10:28 PM
PostWhore
 
ZackG's Avatar
 
Join Date: Jul 2002
Location: SW PA
Age: 37
Posts: 1,798
Send a message via AIM to ZackG Send a message via Yahoo to ZackG
mine are personally gapped at .030 and i run 12c's

97 Tbird 4.6
VT built block, fox lake PI heads
Vortech at XY psi
4.10's, KB boost a spark.
Yummy.
http://www.cardomain.com/ride/2147246
ZackG is offline  
post #3 of 25 (permalink) Old 06-23-2005, 10:37 PM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
im going one step colder than stock and will gap at .035

im also gonna do the gap test runs until i get my best trap speeds... then leave it at that faster gap. but im starting at .035 SCT recommended .035

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
Sponsored Links
Advertisement
 
post #4 of 25 (permalink) Old 06-24-2005, 07:06 AM
On Probation
 
blown96bird's Avatar
 
Join Date: Jul 2002
Location: banned
Age: 59
Posts: 2,019
spark plug gap

I currently run the awsfa 12 c plugs gaped at .35 of inch. When I gaped them at .41 I had spark blowout. I was advised by The Man to use 2 steps colder than stock and gap them from .35-.37.

On you gauge cluster if you want a sc cluster this is what I done on mine. I purchaced a 95 sc cluster and swaped out the cluster but I had to take my v8 tack out of the old cluster and install it into the old one because the v6 one is diffrent. I did take the face off the supercoupe one and put it on the v8 one so it would say premiumin unlead only.


Last edited by blown96bird; 06-24-2005 at 08:40 AM.
blown96bird is offline  
post #5 of 25 (permalink) Old 06-24-2005, 09:13 AM
6th Gear Poster
 
Blown306's Avatar
 
Join Date: Jul 2002
Location: Chicagoland Area
Posts: 647
The Man gave me the blessing on .040", one step colder...but I have a MSD 6A ignition and Blaster coil. With the factory ignition, .035" was recommended by Kenne Bell as well as the Man. I can't see how a big gap would work, unless running pretty low boost levels (< 6#) and staying out of the throttle...but who in the world would want to do that!

- Blown306 "Putting the THUNDER back in the BIRD"
Past President, Webmaster - Chicagoland Thunderbirds
'93 LX Kenne Bell 306
'01 Mustang GT Convertible
'02 Excursion Limited Ultimate Diesel
'03 Harley V-Rod - Two Tone Anniversary
Blown306 is offline  
post #6 of 25 (permalink) Old 06-24-2005, 09:35 AM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
to think i first ran with boost a 12 uradium/platinum plug at .044... recommended from AED themselves... VERY FRUSTRATING!!!

glad I found this site!!!

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
post #7 of 25 (permalink) Old 06-24-2005, 10:39 AM
02 Explorer Pioneer
 
timb's Avatar
 
Join Date: Jul 2002
Location: Cumming, GA
Age: 51
Posts: 2,880
I run .32

Birdless

There is no limit to what you can acheive if you don't care who gets the credit.
timb is offline  
post #8 of 25 (permalink) Old 06-24-2005, 10:28 PM
AED Specialist
 
A-Train's Avatar
 
Join Date: Jul 2002
Location: Somewhere in NJ
Age: 42
Posts: 1,277
AGSF-12FM1 gapped at 0.037". Works great for me.

A-Train

2008 Acura TSX (5AT)
2012 Honda Ridgeline RTL (w/Navi)

Ex toy: 1995 T-Bird LX - ALLEN supercharged, 2000 Mustang GT 4.6L PI engine, lot's of goodies...
12.74 @ 109.45 mph (BEST E.T. BEST MPH)
325 RWHP/380 RWTQ (SAE) on a dynojet
Tuned by Jerry W. from SCT
A-Train is offline  
post #9 of 25 (permalink) Old 06-24-2005, 10:58 PM Thread Starter
Don't call me a Newbie
 
RoushTBirdNo1of6's Avatar
 
Join Date: Feb 2003
Location: Poulsbo, WA
Age: 57
Posts: 397
Thanks, one and all, for the replies! Seems that the majority are in the 0.035" (give or take a couple of thousanths) camp. I suppose, being the conservative type of guy that I am, I'll do 0.035" for the moment. Once I have some other kinks ironed out of the car, I'll do some testing with some other gaps.

So if you'll excuse me...I'm going do a little prep work for tomorrow...






Wayne Hazard Wife is back from Kuwait - Welcome Back, Chief! My Multiply Site
1995 4.6L Thunderbird LX - Daily Driver...1 3/4 Miles to Work and Back
1996 4.6L Thunderbird LX, Vortech V-2 SQ Blown - Heart transplant in the works.
   (If SC+V6 = SuperCoupe, wouldn't SC+V8 = SuperDuperCoupe?)
1997 Mark Martin Signature Thunderbird (AKA: "1 of 6")* - 25k mi Garage Queen
   *A Significant Thunderbird in the Thunderbird RegistryAww, man...I can't believe Mark drives a freekin' Chevy now.
 
RoushTBirdNo1of6 is offline  
post #10 of 25 (permalink) Old 06-24-2005, 11:20 PM
PostWhore
 
CobraRThunder's Avatar
 
Join Date: Jul 2002
Location: Beavercreek Ohio
Age: 36
Posts: 1,779
Send a message via AIM to CobraRThunder
you back in town? Give me a ring...mine is still down and I am antsy in my pantsy to see the car.

4R70W From DirtyDog
VORTECH BLOWN w/3.12" Reichard ultra-grip pulley
TEA Stage2 PI Heads, 9.5:1 manley slugs/manley H-beams, cobra crank, VTStage3 blower cams, Trick Flow track heat intake, FMIC TR1245 intercooler, ART Dual 2.5" exhaust/Stainless/no cats, KOOKS coated headers, 4.10 w/ Auburn Pro, aluminum 8.8 housing, Dynotech driveshaft, Koni's, Eibach Springs, Baer 13" big brake kit. cobra rear brake/hub conversion, VMP Slot Blowthru setup, #60 Inj. 75mm TB,
615 rwhp/500 torque 15.5psi best of [email protected] still needs tuning.
CarDomain http://www.cardomain.com/ride/426794
CobraRThunder is offline  
post #11 of 25 (permalink) Old 06-24-2005, 11:32 PM Thread Starter
Don't call me a Newbie
 
RoushTBirdNo1of6's Avatar
 
Join Date: Feb 2003
Location: Poulsbo, WA
Age: 57
Posts: 397
Quote:
Originally Posted by CobraRThunder
you back in town? Give me a ring...mine is still down and I am antsy in my pantsy to see the car.
Yep, I'll give you a ring tomorrow. Or if you drive by and see the hood up on a red TBird...there's a good chance that it'll be me.



Wayne Hazard Wife is back from Kuwait - Welcome Back, Chief! My Multiply Site
1995 4.6L Thunderbird LX - Daily Driver...1 3/4 Miles to Work and Back
1996 4.6L Thunderbird LX, Vortech V-2 SQ Blown - Heart transplant in the works.
   (If SC+V6 = SuperCoupe, wouldn't SC+V8 = SuperDuperCoupe?)
1997 Mark Martin Signature Thunderbird (AKA: "1 of 6")* - 25k mi Garage Queen
   *A Significant Thunderbird in the Thunderbird RegistryAww, man...I can't believe Mark drives a freekin' Chevy now.
 
RoushTBirdNo1of6 is offline  
post #12 of 25 (permalink) Old 06-25-2005, 11:44 AM
3rd Gear Poster
 
Rude's Avatar
 
Join Date: Jul 2002
Location: Poway, California
Age: 66
Posts: 128
Send a message via AIM to Rude Send a message via Skype™ to Rude
Quote:
Originally Posted by A-Train
AGSF-12FM1 gapped at 0.037". Works great for me.

A-Train

Ditto



Rudeman
Rude is offline  
post #13 of 25 (permalink) Old 06-25-2005, 11:56 AM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
Quote:
Originally Posted by Rude
Ditto



Rudeman
I guess I was just gapped to big with the 12FM1...

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
post #14 of 25 (permalink) Old 06-26-2005, 03:17 PM
PostWhore
 
AEDM8's Avatar
 
Join Date: Aug 2002
Location: Central MN
Age: 38
Posts: 1,702
Didnt like the FM1's. Waste of money IMO.

Some supercharged cars blow.......Others just pick up and move.
AEDM8 is offline  
post #15 of 25 (permalink) Old 07-05-2005, 01:12 PM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
Quote:
Originally Posted by AEDM8
Didnt like the FM1's. Waste of money IMO.
I just replaced my plugs from FM1s to copper one step colder than stock and gapped .at 35.... HOLLY COW!!!

day and night.... these copper plugs stuck me to the seat.... huge difference.

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
post #16 of 25 (permalink) Old 07-05-2005, 07:48 PM
PostWhore
 
AEDM8's Avatar
 
Join Date: Aug 2002
Location: Central MN
Age: 38
Posts: 1,702
Good deal. What gap did you go with?

Some supercharged cars blow.......Others just pick up and move.
AEDM8 is offline  
post #17 of 25 (permalink) Old 07-05-2005, 08:04 PM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
Quote:
Originally Posted by AEDM8
Good deal. What gap did you go with?
gapped at 35....

feels like a muscle suv now

its a trip. with the FM1's at say ... coming out of a stop light.... at about 2k... i would wak it ... and she felt hesitent and climbed ok.... and I tested two sets of plugs... so my plugs were good.

Now... i waked it the same way.... BAM... instant trust... slammed me to the seat with NO hesitation. Tried it through different rpm's and same... VERY quick responce... I can finally feel what all the hype is about an AED being a bottom end king.

I cant wait to get her tuned and switch to 9psi!!!

I suppose I could have been gapped really wrong with the FM1's. Jim said .44

What ever the case.... im happy with these plugs.

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
post #18 of 25 (permalink) Old 07-05-2005, 08:54 PM
AED Specialist
 
A-Train's Avatar
 
Join Date: Jul 2002
Location: Somewhere in NJ
Age: 42
Posts: 1,277
Yeap, gapping a plug at or over 0.044" with 6-9 psi of boost will blow the spark out. So you are now enjoying the power you were missing. Happened to me as well.

Ran 14.5 @ 94 mph with 0.054" gap
Ran 14.1 @ 99 mph with 0.040" gap
Ran 13.9 @ 100 mph with 0.035" gap

I settled for 0.037" since 0.035" felt like it was dropping cylinders at idle.

IMHO, I ran many different types of spark plugs with my 10 year old T-Bird. 5 years under boost too. I used AWSF-32C, AWSF-32PP/EE, AWSFA-12C, AGSF-12EE, AGSF-12-FM1, AGSF-22 FM1...etc.

I like AGSF-12 FM1's gapped at 0.037". Coppers work well, but I wanted a plug that was slightly more durable.

A-Train

2008 Acura TSX (5AT)
2012 Honda Ridgeline RTL (w/Navi)

Ex toy: 1995 T-Bird LX - ALLEN supercharged, 2000 Mustang GT 4.6L PI engine, lot's of goodies...
12.74 @ 109.45 mph (BEST E.T. BEST MPH)
325 RWHP/380 RWTQ (SAE) on a dynojet
Tuned by Jerry W. from SCT
A-Train is offline  
post #19 of 25 (permalink) Old 07-05-2005, 10:26 PM
PostWhore
 
AEDM8's Avatar
 
Join Date: Aug 2002
Location: Central MN
Age: 38
Posts: 1,702
Durable and 4X the price.

Im not sure how much longer Ill have the AED under the hood but if it ends up being more than a year I want to pick up a KB BAS and see what I gain by going with a little bit larger gap.

Im currently at .037 but feel that there is power left if I can get the spark to jump that gap. Just need to make up my mind on how I want to get to my power goals.

Some supercharged cars blow.......Others just pick up and move.
AEDM8 is offline  
post #20 of 25 (permalink) Old 07-05-2005, 10:28 PM
PostWhore
 
ZackG's Avatar
 
Join Date: Jul 2002
Location: SW PA
Age: 37
Posts: 1,798
Send a message via AIM to ZackG Send a message via Yahoo to ZackG
after i get mine running right again, i think im going to open the gap up alittle more. .035 or .037

97 Tbird 4.6
VT built block, fox lake PI heads
Vortech at XY psi
4.10's, KB boost a spark.
Yummy.
http://www.cardomain.com/ride/2147246
ZackG is offline  
post #21 of 25 (permalink) Old 07-06-2005, 09:28 AM
2nd Gear Poster
 
prsrizdgt's Avatar
 
Join Date: Oct 2004
Location: St Louis area
Posts: 80
Quote:
Originally Posted by A-Train
AGSF-12FM1 gapped at 0.037". Works great for me.

A-Train
This is the Lightning (iridium) plug correct? That is what I am running anyway with no ill-effects gapped at .035.

I am curious about the post refering to low rpm power. He was saying switching to copper made a huge differance. Isn't it more likely that the gap was the problem and not so much the plug type?

AED Supercharged Mustang GT
prsrizdgt is offline  
post #22 of 25 (permalink) Old 07-06-2005, 09:56 AM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
Quote:
Originally Posted by prsrizdgt
This is the Lightning (iridium) plug correct? That is what I am running anyway with no ill-effects gapped at .035.

I am curious about the post refering to low rpm power. He was saying switching to copper made a huge differance. Isn't it more likely that the gap was the problem and not so much the plug type?
Yes that is the lighting plug.

And yes most likely or VERY likely my power problem with the FM1's was running the wrong gap size.

I dont know how true this is please someone correct me if im wrong, but I have heard that with platinum/iridium (maybe just platinum)plugs under heavy boost the plug can almost stay lit like a "glow plug" and cause premature (EDIT) ignition or detonation. With copper that problem is eliminated.

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC

Last edited by awdRocks; 07-06-2005 at 10:17 AM.
awdRocks is offline  
post #23 of 25 (permalink) Old 07-07-2005, 05:59 PM
On Probation
 
blown96bird's Avatar
 
Join Date: Jul 2002
Location: banned
Age: 59
Posts: 2,019
plug gaps

I regaped my plugs making the plug gap more consistant. I had them gaped any where from .32 to .37. I tried to open the gap up to .38 and .37 and experienced spark blow out in the upper rpms around 5300-5800. I regaped them to a .35 keeping a eye on tight tolerences. The car idles smoother and has slightly more vacuum and no spark blow out in the upper rpm area.
blown96bird is offline  
post #24 of 25 (permalink) Old 07-08-2005, 05:48 AM
2nd Gear Poster
 
prsrizdgt's Avatar
 
Join Date: Oct 2004
Location: St Louis area
Posts: 80
What are you guys experiencing that indicates "spark blow-out"???

Is it as obvious as a clearly felt miss or cutting out under boost, or is it more subtle like it is just sluggish or loosing a little power under boost?

AED Supercharged Mustang GT
prsrizdgt is offline  
post #25 of 25 (permalink) Old 07-08-2005, 07:14 AM
PostWhore
 
awdRocks's Avatar
 
Join Date: Apr 2005
Location: Cancun Mexico
Age: 46
Posts: 1,522
Quote:
Originally Posted by prsrizdgt
What are you guys experiencing that indicates "spark blow-out"???

Is it as obvious as a clearly felt miss or cutting out under boost, or is it more subtle like it is just sluggish or loosing a little power under boost?
well i was gapped 44 and i had no power... sluggish... and felt like it missed.... like missing a cyclinder. i thought it was because because my tune is so rich...

even with the new plugs im still rich at 8mpg but finally has power.

2002 EXPLORER: 400+whp 2v/M90 434tq / 401rwhp @ 9psi.. suv, 20's, IRS, slush box
COMING SOON: Modular Performance 324ci, Trick Flow Heads w/custom grind cams, Tork Tech TVS SC
awdRocks is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome