.040 spark plug gap

[Stonep185]

Does anyone know a reason why the previous owner of my car gapped the stock champion spark plugs at .040? Recommended gap is .032, which is what i set the new ones at. I think Im making it up in my mind, but the car seems to be running richer after I changed the plugs. Is running richer a good thing or not? No real difference in performance but it seems smoother through revs...

 

[Roysviper]

Does anyone know a reason why the previous owner of my car gapped the stock champion spark plugs at .040? Recommended gap is .032, which is what i set the new ones at. I think Im making it up in my mind, but the car seems to be running richer after I changed the plugs. Is running richer a good thing or not? No real difference in performance but it seems smoother through revs...

When I had my Heffner Twin Turbo, Jason told me to only use AUTOLITEs and gap them at .28..........every since then that is what I do in all my Vipers..........

 

[Stonep185]

Ive heard that gapping between .028 and .032 is the best, but going to .040 seems excessive on the opposite spectrum! Im wondering why they were that way and what benefit they thought it gave...

 

[Dom426h]

Stone,
Are you assuming they were new plugs you pulled out? Is it possible the center electrode/wire was just wore down from normal use?
The more you drive the bigger the gap gets...

Roy,
A TT motor has diff spark requirements than an N/A motor.(Boost typically requires a diff(colder) heat range plug)
Just because something is good for a boosted motor does not necessarily mean that it is good for an N/A motor.

 

[Stonep185]

I am assuming they were not original plugs and that they had been changed at some point. At 44k miles i figure someone changed them before me. Although the plugs seemed more tarnished than I expected so maybe they were stock plugs. That makes me wonder what else is stock.. What color plug wires come on a '96 GTS? Blue 8.5mm Mopars with gray boots?

 

[roller]

Mine are black, '96 GTS with 24000 miles.

Frank

 

[Roysviper]

Stone,
Are you assuming they were new plugs you pulled out? Is it possible the center electrode/wire was just wore down from normal use?
The more you drive the bigger the gap gets...

Roy,
A TT motor has diff spark requirements than an N/A motor.(Boost typically requires a diff(colder) heat range plug)
Just because something is good for a boosted motor does not necessarily mean that it is good for an N/A motor.

I figured that but I still have another TT Viper so I still go by that.....thanks for setting me straight, ha.....

 

[latamud]

Interesting. Roy and I were discussing this a few days ago. I pulled my plug on my Paxton-ed Viper and the plugs were gapped at .050, granted they were old ngk zfr6f-11. I replaced with new zfr6f plugs gapped at .032 and I'm running richer than before. My wideband gauge reads 9.xx:1 at WOT so I've been keeping out of boost.

 

[Roysviper]

Interesting. Roy and I were discussing this a few days ago. I pulled my plug on my Paxton-ed Viper and the plugs were gapped at .050, granted they were old ngk zfr6f-11. I replaced with new zfr6f plugs gapped at .032 and I'm running richer than before. My wideband gauge reads 9.xx:1 at WOT so I've been keeping out of boost.

running richer is OK.....lean is not OK.....

 

[latamud]

running richer is OK.....lean is not OK.....

Right, but I think I should be closer to 11:1 at wot.

 

[Roysviper]

Right, but I think I should be closer to 11:1 at wot.

Bart....LAViper wants to know if u wanna sell your old hood that you took off????? I love that Carbon Fiber hood you put on yours......very very nice touch.....Roy

 

[bluesrt]

bigger gap is good, actually it will run better with a bigger gap.. you guys changing your plugs like underware just beacause, is a waste of money, if it runs good, leave the car alone.... your not helping anything. bigger gap i have seen better torque rateings, but not for all.... unless its all radicaled out, stock you can run 80 to 100k miles on a plug....... period..... in my exsperiance, like wine- plugs run better with age (stock) engine

 

[latamud]

Bart....LAViper wants to know if u wanna sell your old hood that you took off????? I love that Carbon Fiber hood you put on yours......very very nice touch.....Roy

My original hood is the 2003 hood, not the 2008. I'm interested in getting rid of it if that's what he's looking for and I will be hauling it in about 2 weeks, passing through Crestview again.

bigger gap is good, actually it will run better with a bigger gap.. you guys changing your plugs like underware just beacause, is a waste of money, if it runs good, leave the car alone.... your not helping anything. bigger gap i have seen better torque rateings, but not for all.... unless its all radicaled out, stock you can run 80 to 100k miles on a plug....... period..... in my exsperiance, like wine- plugs run better with age (stock) engine

This was my first time changing the plugs on my Paxton 2003. I did have the car Dyno-ed a couple months ago and did notice the engine miss and blow black smoke out a side pipe. The guy running the Dyno said I was running around 10:1 on the top end and that I was probably blowing out spark at WOT because the plugs probably hadn't been replaced in a while. I pulled my plugs, replaced with same part number but the old plugs were gaped .050. I had already gapped my new plugs to .032 before I flew to Ohio to pick up the car. After install I noticed my the wideband reads richer at WOT. I'm wondering if the gap is causing this. I don't mind running rich but 9.xx:1 I think will cause issues with extended use. I'm thinking if widening the gap will help maybe pull them out and run .040. Or, maybe I need 1 step colder plug to zr7f

 

[bluesrt]

bigger gap, more ball of fire, try it dont know- too rich will kill plugs cold after some time.... trial and error

 

[latamud]

True, but the bigger gap with all that fuel could blow out too I imagine. I'll try it and post findings. I'm dealing with a broken window regulator first.

 

[bluesrt]

somebody make a dam regulater that wont break after 20 hours of use please..... thats bull **** people!!!!!!

 

[latamud]

somebody make a dam regulater that wont break after 20 hours of use please..... thats bull **** people!!!!!!

I will.................

 

[plumcrazy]

you dont want too rich either. it can wash the rings

 

[MADMAX]

MY 96 GTS service manual says plug gaps should be between 33 and 38 thou.

 

[latamud]

I've been doing some research, I think I have a bad wideband sensor.

 

[Stonep185]

I gapped the plugs back to.037 and the hp feels about 50 higher, throttle response is better, and it is not running as rich anymore. Doing things by the book does work sometimes!