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Looking to finally go ahead and address the tune that's currently in the car. So just out of curiosity I pulled a plug to see how the strap looks. Was a bit surprised to see that the plug appears tho be seeing quite a bit of timing, although it's supposedly at 14 degrees at 21psi. So the question is, are plugs read the same.... be it on Ethanol...or gas? And btw, not claiming to be the final word on reading plugs. Thoughts?
my plugs have the timing mark there after driving around a little (i'm on pump gas though)
No. I was just hanging out in the garage and decided to check a random plug, as I was thinking of putting some timing in it. So i guess I would be better served by making a run, kill it immediately and check the strap?
Little white specs looks like mild detonation to me. I'd pop in a new plug, make a pull and immediately remove it to get a read. Can't really read a plug thats been in an engine as long as that one.
Personally I don't like extended tip plugs on turbo engines either. What heat range is that? BR7EF is the typical go 2 plug for a turbo LS.
Also don't use anti-seize and try to get it out of the threads. It makes it hard to read.
Little white specs looks like mild detonation to me. I'd pop in a new plug, make a pull and immediately remove it to get a read. Can't really read a plug thats been in an engine as long as that one.
Personally I don't like extended tip plugs on turbo engines either. What heat range is that?
Also don't use anti-seize and try to get it out of the threads. It makes it hard to read.
They are NGK tr-6. And yes, it does look a bit like detonation, but when I pulled the motor down last summer.... the p istons looked perfect (plugs looked like this then too). Ive seen a few people who didn't like projected tips on turbo cars, I'm curious to know the logic behind this.
They run hotter since they are farther in the chamber. Ground strap is also longer and holds more heat. It’s like a glow plug in the cylinder when things get hot. Makes it more prone to light off the mixture when it shouldn’t. Assuming that condition ever happens.
That said, projected tip idle better and guys like Stock48 use the TR6 and run better than most of us making huge power. So it’s up to you. Either way, get whatever new plug you’re comfortable with in there and get a good read on it as a first step. I’d suggest the BR7 plug and dropping your current timing 2-3*.
Also better practice to run all new plugs, make a full pass, and get a good read on all of them. That way you can see if you have any cylinders that are leaner than others. Which is pretty common. Once you know the leanest cylinder, tune off that plug after a WOT pull.
Last edited by Forcefed86; May 16, 2017 at 03:27 PM.
They run hotter since they are farther in the chamber. Ground strap is also longer and holds more heat. It’s like a glow plug in the cylinder when things get hot. Makes it more prone to light off the mixture when it shouldn’t. Assuming that condition ever happens.
That said, projected tip idle better and guys like Stock48 use the TR6 and run better than most of us making huge power. So it’s up to you. Either way, get whatever new plug you’re comfortable with in there and get a good read on it as a first step. I’d suggest the BR7 plug.
Also better practice to run all new plugs, make a full pass, and get a good read on all of them. That way you can see if you have any cylinders that are leaner than others. Which is pretty common. Once you know the leanest cylinder, tune off that plug after a WOT pull.
This makes sense. Only one that will be a real problem after a pull is #8.... you know the deal with that one. For convenience sake I wonder if I can achieve the same results (accurately) by getting on the transbrake really good at home (will go 5200 and make 20psi almost instantly). I say this because at home, close to the garage I can access ALL the plugs.
I haven’t tried that but I don’t think it’s the same. You won’t have near the load/heat you’d get with a full pass. As little run time as possible is best but if you are just looking at the ground strap for heat, you can likely cruise home and still get a good read. Or do it at the track.
Once the heat markings are set on the plug, cruising shouldn’t do much to erase that mark on an E85 plug.
what do you guys consider the cut off point for the projected tip tr6 before switching to the br7ef?
power-wise
I'm only guessing here, but it probably depends on the type of fuel you run. This plug I'm running probably won't fly on the same setup that's running gas. Again, just thinking out loud.....i have a lot to learn in the plug department. With that said I'm making 742/1000rw through a Th400 on E85 and the tr6..... and no issues thus far.
what do you guys consider the cut off point for the projected tip tr6 before switching to the br7ef?
power-wise
i NEVER run a tr6 setup on a nitrous or FI setup, period. Running a nonprojected tr7 gives multiple benefits and if you can tune there's no reason it won't idle cruise fine. Conversely, nobody has ever brought any data about why a hotter plug would be better on an FI or N2o setup.
It looks like you have 2 full threads of heat. Target is 1. I would expect similar heat signature with a new set of 6s. As 86 said, put a fresh set of 7s in and see what things look like after a single solid pull. If heat range is right, you'll get a more accurate indication of timing on strap. I suspect it won't be that far around the bend. Looking forward to results.
I wouldn't say there is a HP cutoff for a heat range. It has to do with cylinder temperature which can be drastically changed with the tune, compression, fuel, boost , etc. Around halfway down the strap is considered safe. Start getting 3/4 or to the bend and it's considered hot. Similar deal with the threads. As mentioned, getting into 2 threads is on the edge tuneup wise with turbo stuff.
The only reason I'm aware of to run a hotter plug is if you are fouling out the plug at idle/cruise. With E85 that's not really an issue. I daily drove 9's without fouling problems. I had to change my my 9's every few passes on a race gas build due to fouling.
The projected tip is into the CC farther so you get a little better burn. But it's also likely to run hotter because of the location so generally isn't run with power adders. I noticed better idle quality with a projected tip plug, but I don't run them in my turbo builds.
I wouldn't say there is a HP cutoff for a heat range. It has to do with cylinder temperature which can be drastically changed with the tune, compression, fuel, boost , etc. Around halfway down the strap is considered safe. Start getting 3/4 or to the bend and it's considered hot. Similar deal with the threads. As mentioned, getting into 2 threads is on the edge tuneup wise with turbo stuff.
The only reason I'm aware of to run a hotter plug is if you are fouling out the plug at idle/cruise. With E85 that's not really an issue. I daily drove 9's without fouling problems. I had to change my my 9's every few passes on a race gas build due to fouling.
The projected tip is into the CC farther so you get a little better burn. But it's also likely to run hotter because of the location so generally isn't run with power adders. I noticed better idle quality with a projected tip plug, but I don't run them in my turbo builds.
Since adding timing (within reason) reduces combustion temps, would it stand to reason that a hotter plug would be more acceptable, all Wilde maintaining solid idle quality? Not doubting any of the info given, or being argumentative..... just talking it out. 99% street driven btw.
Running the hotter plug puts you closer to the detonation threshold. Why not try the 7's and see how it does? Swapping plugs isn't a big deal on a highly modified vehicle. I've ran 7's on multiple DD's and never fouled them. Not gonna happen with a good tune. I agree running something like a 9 would be tough, but 7's are easy.
Zero pro’s to running a hotter plug if fouling isn’t’ an issue (that I know of anyway), and many con’s. The BR7 is the coldest resisted plug offered with a conical seal that’s easy found and affordable. So it’s what most use.
There is a set degree of advance at peak torque RPM that will give you the most cylinder pressure that NA guys target. That is usually the hottest point in the RPM band and what is going to be putting the peak heat markings you are reading in the plug. Adding (or removing) timing from that max torque timing point won’t gain you anything.
With the average street/strip build you want to be well away from peak TQ timing levels since the engines most likely to detonate at that point. Goal is to get the highest controllable cylinder pressure across a broad range. So run baby timing (or safe as indicated by the plug) near peak torque and either slowly add timing back or pour on additional boost after PK TQ and you’ll more than make up for running less that optimal timing at PK torque. Also the engines A LOT less likely to eat itself.
I’m intercooled with E85 and water/meth on a BR7 and I still see heat on the strap past halfway and creeping into the second thread around 20lbs and 13-14*. Been planning to switch to 8’s with resisted boots, just been lazy. Don’t pay attention to other people’s timing numbers. Cam and a many other things will determine how much Adv the engine wants. If you read the plug it won’t steer you wrong… Always best to start with a cold plug and very little timing.
Agree with everything, but I thought StevieTurbo posted up some resistive 8 plugs, cant recall who makes them. He also had a link to resistive wires so you could run a colder plug but still have the advantages of a resistor (lower EMI, etc.)
Stevie is in the UK I believe. They make an 8 resisted plug there, but it isn’t available in the US (that I can find anyway) and is expensive to import. I haven't seen resisted wires, but they make boots you screw on the end of any plug wire cheapish. They also make resisted iridium plugs, but the cost is up on those. Not something I’d tune with. When dialing in a motor you can go through 10 plugs in one cylinder easy, so the cheaper the better IMO. After it’s dialed in an iridium would be fine.
Last edited by Forcefed86; May 17, 2017 at 12:38 PM.
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Reading plugs when running Ethanol 
