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Hey guys, So I pulled the plugs on my Cobra a few weeks ago, First time I’ve ever changed the plugs on this car since I’ve owned it for about a year. Anyways I took some pictures of the plugs and I honestly though they look in pretty bad shape. But for the most part, How does everybody think they look? Anyways, any and all input is appreciated! Thanks guys!
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You will have to talk to someone who does dyno work and performance engine tuning regarding plugs and there gap.
And the carbon buildup may have been there prior to the vehicle being modded.
I noticed that you are running a 180 degree thermostat in your car (which is BAD@SS btw). What does the factory call for? That seems a little cold to me, but I’m not sure what the normal would be for a supercharged Cobra. If the car is running relatively cold due to a lower temp thermostat, that could explain the rich condition.
It calls for a 180 degree one as well. But this one is modified similar to the one I’m about to post. But yeah, The car runs VERY Cool. It has several upgraded cooling modifications for it. The main reason the Cobra has so many cooling modifications is because these things generate alot of heat. But, I might be running too cold of a plug and too small of a gap and it may be fouling out. You think that may be the problem?
Anyways, Take a look at this. It explains the thermostat question for the most part.
http://reischeperformance.com/tstatinfo.htmlWell, like I said, it seemed like a cooler temperature than what I’m used to, as the average one I see is rated around 195 degrees. But I’ve never worked on a performance app like yours. If you are running too cold of a plug or too cold of a thermostat, it COULD account for you running rich. The PCM will see the temperature as low and dump more gas, or the plugs may not be firing hot enough to burn all the fuel. But being that your car is not even close to stock, I’m sure you are better informed about what you should be using than me. I just noticed your temp stat in your bio, and pointed it out. But as you said, it’s the right one from the factory. So I’m kind of left without a leg to stand on. I think you would be better served on forums dedicated to cars beyond the norm like yours, but I bet Eric would have solid advice. You could always try the engine modifications section of this forum as well.
How many miles on them?
If they have 500 miles on them i think they look terrible, but if they have 50,000 miles I think they look like what I’d expect – maybe just a little sooty. Is the car running a custom calibration or ‘chipped’? Using any oil?
I going to go out on a limb and assume you do have some aftermarket mods to your vehicle.
Again i agree with the above post. It does look like you are running rich. But again, it depends on the mileage of the plugs. Do the plugs feel oil foulded?
I agree, they look a lil’ soot-ish. Seems like it is running pretty rich. I also wanna know how many miles you got on em.
No idea on how many miles on them. But since I’ve owned the car I’ve put over 1300 miles on them. From the condition of the rest of the plugs. I’d probably have to say they have over 10k miles on them or so. The car current has 62k miles on it. Runs like a top and strong as a Ox.
But yeah, The car is custom tuned. Quite a few aftermarket modifications done to the car. The only thing I have no gotten a new tune for is the missing EGR system that I took off. So that may explain the slight rich condition. Could there be any ill effects to running a little rich? I mean because I’d rather a little rich then lean to be honest.
Because I don’t want to hurt the Motor. But yeah, if you want to see the full modification list. Its in my profile. Oh by the way, Could the rich condition cause carbon build up on the top of the pistons? I noticed that when I was changing out my plugs. Looked down the plug holes and saw quite a bit of build up.
Thanks though guys, Any more input will be helpful!
Edit: Could they be fouling just a little because of the fact that the gap is too small? .32? Maybe I should bump it to .35 or so. These plugs are 2 ranges colder then stock plugs. But that is also because I’m running 500 Rwhp. Any input?
P6, P7, P8, D3, D4 look fine, rest look bad but that could be cause of what the above posts say.
Running rich
Yeah, I see what you’re all saying. I did make a post on SVTPerformance and honesty only got 2 posts and they both were far from helpful so. I might post up in the Engine modifications section just to see what the say. I’m probably running too cold of a plug, that does not burn off all of the fuel so that explains my excess of carbon build up on the pistons. Hmm…Shame, I just put the plugs in too. I’m thinking of widening the gap to about .35 so it burns a little hotter and then pulling them in 1000 miles and seeing how they look.
But honestly, I plan on changing my plugs every two oil changes or 6000 miles. Plugs are cheap honestly and forced induction is pretty harsh on plugs. But the main reason I wanted to kind of stick with a colder plug is for anti-detination property’s. But anyways, Thanks for ALL of your input. Its helped alot. If you got any other ideas or anything. Feel free to post them.
Thanks guys!
Quoted From SVTDice:
But honestly, I plan on changing my plugs every two oil changes or 6000 miles. Plugs are cheap honestly and forced induction is pretty harsh on plugs. But the main reason I wanted to kind of stick with a colder plug is for anti-detination property’s. But anyways, Thanks for ALL of your input. Its helped alot. If you got any other ideas or anything. Feel free to post them.That’s a shame about the SVT forum, maybe as you mentioned, posting in the other area might yield more responses?
As for the plugs, I agree, with a high performance engine like that, plugs are cheap insurance.
Just out of curiosity, what octane fuel are you running? I know that can make a big difference in slow/fast detonation.
Keep us updated on what you find, and certainly what new/re-gaped plugs look like after a 1,000 miles.
It’s not uncommon for performance engines to run lower temp thermostats – I know on the Chevy side that 2 premier tuners (Lingenfelter and Callaway) spec out 160 degree thermostats on their modified engines. The key is that they also have a calibration that supports that change, they aren’t sticking a 160 thermostat in a car running a stock calibration, that would really mess things up. So, by comparison, a 180 thermostat in a car that expects it isn’t really that low.
If it were me and the car is running strong, I’d have to decide to either leave it alone (don’t fix what isn’t broken) or maybe try a 1 step hotter plug and see if that clears things up and doesn’t cause detonation.
If you are worried about carbon buildup, in the old days there was a highly technical process called ‘blowing out the carbon’…I’m sure that still works the same today!
I’m running 93 Octane with the timing of about 22 degree’s. One possibility is that the thermostat could be getting stuck open. Allowing the engine to over cool its self. Thus allowing the ECM To overcompensate and push to much fuel. But I guess thats just a shot in the dark because I Would have no idea how to even diagnose a sticking T-stat. I might need to go to a tuner soon however. To check if my A/F Is spot on just to be sure.
But for the most part. I think what I might do is either leave the plugs in the way they are. Or Pull them and open up the gap a little. Maybe .32 to .35? You think that would be a little to much? Its just I’d rather run rich then too lean and then that opens the chance of detention issues. I guess it kind of falls into the area of. “If its not broke, Don’t fix it” But yeah, I’m going to have to give her the good old Italian tune up with my right foot later tonight just to kill off some carbon.
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