I have heard about reading spark plugs and learning how to really read the plug on how it looks as to diagnose a rich/lean situation. I changed out my plugs a while back, before upgrading to a walbro 255 fuel pump and going to Br7ef plugs for a 150wet shot. The plug show is a one of the TR6s I pulled I had been running on them for a while with the stock fuel pump, stock injectors 28.xx on my 02 C5 and spraying 100 wet shot just a few times for some fun runs. My question is does this mean I had been running rich or lean and how do you tell? keep in mind I had the plugs in for about 6 months before changing.
I am going to a ported fast 78 here next week and I wanted to keep the stock injectors the car made just over 400whp on my current cam, stock 241 heads/full bolt on setup. by looking at the plugs does it look like I am running lean at all already on the stock injectors? I do have the upgraded fuel pump now so I would think that is some added security.
The correct way to read plugs is put a new one in and make a pass at the strip and pull it out right away. It should look light tan. There is alot more to reading them also that i know little about. Like there will be a blueish ring on the strap, it will tell you how your timing is and if you need a hotter or colder plug. A black plug would be rich a white plug would be lean.
I would suggest a wideband or borrow one. 7 heat range plugs are too cold for only a 150hp shot. TR6 are plenty cold enough for safety. Also just use std coppers not platinum or iridiums like you have pictured. FYI most out of the box nitrous kits are very conservative (rich) AFR with jetting on the card. I have tuned cars and dropped 2 fuel jets sizes and was still very safe
Only one pull doesnt always do it. Your plugs and engine actually need to see some heat. Mostly because spark plugs have a heat range at which they “clean” themselves, and one pull may not get them up to that heat This is some seriously oldschool type shit that you dont hear much about these days. Shit i had kid once ask me If I knew what a carburetor was and where he could find it in the car he inherited. With that said… Go to Autozone, Look in the inside of the back cover, of i think any of their haynes manuals, and there you should see pictures of what your plugs should and should not look like. But looking at the picture above your plug actually doesnt look like its bad at all. Then again its a pic so I could be wrong
I will agree with the 7’s being too aggressive. I ran a 150 shot on my forged 347 90/90 h/c. I ran 6’s at first then switched to 7’s and went right back to 6’s. With 7’s the idle was shit and never really got to a hot enough temp for the 7’s. I picked up 2 tenths going back to the 6’s. I also ran the 150 nitrous jet and the 125 fuel jet which put me at 11.3:1 AFR. A little rich but safe. Do you know what kind of timing you are running for the 150 shot? Do you have a box to pull timing or running around on a nitrous tune all the time? What is your injector duty cycle and AFR? Without this we can’t know if your car is getting the proper fuel because it’s a crap shoot then.
Looks like the heat range is fine but beyond that you’d have to make a run and shut down immediately to get a good look at what’s going on. Either way I would most def avoid platinums or any kind of trick plug, just stick to the coppers. Even if you have enough fuel what are you doing for ignition retard when spraying?
Yea car runs great on the 7s gaped at .035 a little choppier at idle but no issues the tr6s were fine too I had them gaped at .048 but I was told on ls1 tech to run 7s with my mods for the 150 shot It mad 411whp on current setup 518whp on the 100shot. Also I am running 62N 33 Fuel for the 150 shot now Nitrous outlet recommends 62/38 for the plate I have nx solenoids seems good on the 150 I tried it with the 38fuel and didnt feel as strong as my 100shot before but I am getting it tuned next week with the addition of the fast intake I will see where its at.
Yea Idk the tr6s were fine and the Br7ef plugs are good as well no issues with the car, I was just under the impression it was better to run as cold of a plug as possible and that non projected tiped plugs were the way to go on nitrous
Keep in mind that when you are reading a plug you are reading the “average” of every firing sequence the plug went through from when you first fired that plug until you pulled it out. Old school drag racers read plugs, new guys still do but they datalog every bit of data that they can as well. I’ll give you an example of why relying on a plug reading is not always the best.
Ex: You get your car running decent so you take it to the track. Engine is fully warmed up. You change plugs in the pits in 15 minutes. They call your class so you fire it up and start to creep up. Then you roll through the water and do your burnout. You stage and footbrake it hard, and then finally launch. 12 seconds (or whatever) later you cross the beams, then you cruise around and get your slip and pull back into the pits. You pull a plug and it looks perfect so you think the tune is nailed, but you may be WRONG. You tune might be too rich at idle and through part throttle, and then too lean on the topend. The plugs might be slightly loaded up as you creep through the lines and as you are staging. 3 or 4 seconds into your pass the cylinder pressure (heat) is so high that it burns all of the excess fuel off of the plug and turns it a golden brown. It may just start to detonate on the topend and pull timing but you can’t hear it over the exhaust and the knock sensors are doing their job. In a case like that you’d be leaving .2-.3 on the table on a 12 second car. A datalog of the o2’s, knock counts, etc, is far more valuable.
You need a wideband man end of story… I would personally never run an F/I or Nitrous car without a wideband. I’m not far from you if you need help with logging and/or the tuning of the car just let me know over on the 607 forums
