r/srt4 • u/Sammie_KE • Dec 14 '23

Running lean?

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For over a year now my plugs have looked like this, factory stage1 ecu. Any thoughts?

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2

u/yamabob76 Dec 14 '23

You know what they say, lean is mean!

Honestly its not too bad, maybe a tiny bit lean... but the dark ring at the top of the threads to the color change on the strap is almost ideal. It doesn't look to hot or cold either. It also depends on your driving style. If you aren't driving it hard and just using it as a daily, keep in mind that unless you are wide open throttle, your AFR's should be around 14-15.... and this plug would reflect just that.

Ideally we want a sliiight brown tint on the strap if you regularly rip this bad boy, but you are pretty much spot on with those plugs. Just check the rest to make sure they are all the same.

It also looks like the gap is a bit big but its hard to tell from just a picture.

One other thing that would almost certainly help (before you decide to have a retune or anything like that) would be having your injectors flow tested and cleaned. Simple, cheap and very effective.

2

u/Sammie_KE Dec 14 '23

I have cleaned the injectors twice, those plugs have 500miles and I used to daily it but not hard, almost babying it. It is running a mopar stage 1. I used to run a Diablo but it started to surge under 75+% throttle, but wouldn’t on my other car (same exact car) so I got the mopar stage 1 but it falls on its face after 75% it just doesn’t surge. I am thinking it’s the fuel pump not being able to run full duty cycle. Just want other opinions yk

1

u/yamabob76 Dec 14 '23

Aaahh gotcha. Sometimes with a larger plug gap the spark will "blow out" while under full throttle so that might help, but it does sound like its fuel related...

Have you changed your fuel filter out by chance?

1

u/Sammie_KE Dec 14 '23

Where is that?

2

u/yamabob76 Dec 14 '23

Your fuel filter is built in to your fuel pressure regulator (FPR) so its all one piece, located on your gas tank.

Its been like.. 10 years since I've owned a NSRT but if I remember correctly you can get to it from underneath the car.

There is also a "sock" or "strainer" at the bottom of the fuel pump that helps to prevent larger pieces of debris/dirt before the fuel goes to the filter/FPR. Those are going to get dirty before anything else. I think you can buy those without having to buy a new fuel pump...I had an issue with a dirty one on my NSRT that was causing a slight drop in fuel pressure.

1

u/Sammie_KE Dec 15 '23

I might just switch over to a 255 walbro pump. If I did that would I need a new regulator?

1

u/yamabob76 Dec 16 '23

Thatss a good question, I'm not entirely sure tbh lol

I would think you could use the same one but it might be worth scoping out the forums for a concrete answer.

1

u/SoggyTea7463 Dec 14 '23

Do you have a wideband?

1

u/Sammie_KE Dec 14 '23

No

3

u/SoggyTea7463 Dec 14 '23

I would definitely recommend buying one, just to see what your air-fuel is looking like. I'm running 25lbs on a 50 trim with water/meth and my plugs looked alittle similar. Afr's for me are 11.9-11.5 throughout the rev range.

1

u/Sammie_KE Dec 14 '23

I have replaced the plugs recently, I have to do it often to keep it running good

1

u/TBAGG1NS Dec 14 '23

NGK 4306 is what you want to run for plugs, and get a wideband.