NGK TR6 (4177), BR6EF (3177), BR7EF (3346) users?

[Eric Stage I]

Why do you prefer projected tip?

In general, projected plugs are better in every way for 99% of us. Closer to the center of the combustion chamber (less timing required, helps with detonation), wider heat range keeps plugs clean (hotter at low RPM, then cooler at higher RPM), etc.

However, with a higher HP car, say 150hp per cylinder, some may need to consider a non-projected plug to back the tip out of the war zone, even if it is less efficient. In these cases, you may be running race fuel, and changing plugs often anyway.

 

[MNwe4]

Ok, some notes after going to the track and cruising with these plugs. First thing I noticed is that start up and idle is a little rougher. It might take a few more cranks to start and once idling rpm seems a bit lower. To get it idling happy I'd rev it a couple times. I wouldn't say it's bad, but it's not as smooth.

Cruising the plugs seemed great. Throttle response was good and the car never missed a beat the 83 miles to and from the track. Had some back country road fun.

At the track I didn't experience a single count of knock in my 5 passes. The plugs probably helped in this regard as in the past I would occasionally tickle the knock sensor. The weird part though is that I ended up running more boost and timing than last year, but the car wasn't any faster. I ended up just touching 24 psi on the run, with 1/2 gear timing at 24 degrees and 3rd gear timing at 23 degrees. Last year I was 22 psi with timing at 23/22. No matter how hard I tried the best sixty foot I could get was 1.74 vs last year being at 1.67, so the result was a 7.10 at 102 (1/8th mile track). Plugs are the only thing that has changed.

Is it possible that a colder/recessed plug has the effect of fattening up the a/f ratio and killing off the line performance? Despite running slightly more boost my injector duty cycle was also lower than last year. Just wondering if plugs can have this effect.

 

[vacuum 6]

In general, projected plugs are better in every way for 99% of us. Closer to the center of the combustion chamber (less timing required, helps with detonation), wider heat range keeps plugs clean (hotter at low RPM, then cooler at higher RPM), etc.

However, with a higher HP car, say 150hp per cylinder, some may need to consider a non-projected plug to back the tip out of the war zone, even if it is less efficient. In these cases, you may be running race fuel, and changing plugs often anyway.

Good point Eric. I'm running alky and your chip. I've had very good success with the projected plugs. My experience...switched 103s with 104s and pickup 5 mph. [emoji8]

 

[MNwe4]

In general, projected plugs are better in every way for 99% of us. Closer to the center of the combustion chamber (less timing required, helps with detonation), wider heat range keeps plugs clean (hotter at low RPM, then cooler at higher RPM), etc.

However, with a higher HP car, say 150hp per cylinder, some may need to consider a non-projected plug to back the tip out of the war zone, even if it is less efficient. In these cases, you may be running race fuel, and changing plugs often anyway.

Eric, so in your experience does moving to a non-projected tip reduce the "effective" timing, is that what you're saying? If so then advancing a few degrees may result in the same in cylinder condition, right?

Does going to a colder plug have this effect as well or does it just make the plug more prone to fouling?

Out of curiosity what plugs do you like to run on cars with aluminum heads running in the high 10's, preferably on E85 of course?

 

[Paul69camaro]

Heat range has nothing to do with the "effective timing" Eric is talking about. That is related to the position of the spark relative to the combustion chamber. What he is saying is that projected plugs place the spark closer to the center of the combustion chamber and therefore requires less time to ignite the fuel mixture.

 

[MNwe4]

Heat range has nothing to do with the "effective timing" Eric is talking about. That is related to the position of the spark relative to the combustion chamber. What he is saying is that projected plugs place the spark closer to the center of the combustion chamber and therefore requires less time to ignite the fuel mixture.

That's what I thought he was getting at,thank you. So since I installed the recessed plugs the car is noticeably slower off the starting line with the same tune. It's conceivable then that this is due to the reduced "effective" timing, right? In that case what I need to do is keep the same heat range plug, but go back to a projected tip.

My rational is that even though I added timing using his chip's parameters, these may not take effect until the car is past a certain load condition. I may not be there since I can't hold more than 6-8 lbs of boost before the car pushes through the beams. I know there's other methods (better brakes, trans brake, 2 step, etc), but I like to know the science behind what's happening.

 

[Paul69camaro]

I don't know enough about how the chip's operate except for the SD2. I would assume that there is no delay in the commanded timing but like I said I don't really know. On my car, I'm able to light the tires up almost immediately, there is no hesitation down low when everything is running correctly. I have heard other people (different platforms) complain that the idle and drive-ability suffer with the BR7EF plugs but the only issue I've noticed in the past is like you said, cold start, after it runs for 10 seconds everything was back to normal.

 

[MNwe4]

Figured I'd post a year update after running the NGK BR7EF plugs. I also went to the same 1/8 mile track a few weeks ago. Happy to report the results are the same. Makes sense since nothing on the car has changed. Zero knock in the 4 passes I made that day (had to wait 2hrs due to an oil down). Car runs hard to 7.0 at 103, but still seems lazier out of the hole compared to when I ran the Autolite 103's two years ago. It just doesn't get on boost quite as fast and I really have to try hard to brake torque. Debating if I have time in the short season up here to make it back with 103's to compare. The other things I've noticed have been covered, hard to start at times, stumbles at idle sometimes. The exhaust also seems more smelly, which could be possible if the plugs aren't lighting off the mixture as efficiently. Anyone have similar experiences?

I definitely think the BR7EF is a great plug for a street/strip car that already builds boost rapidly, has a t-brake, or goes to the track more than twice a year. I'd gladly live with the cold start and slight stumbles if it was more race car.

 

[turbo nasty]

Figured I'd post a year update after running the NGK BR7EF plugs. I also went to the same 1/8 mile track a few weeks ago. Happy to report the results are the same. Makes sense since nothing on the car has changed. Zero knock in the 4 passes I made that day (had to wait 2hrs due to an oil down). Car runs hard to 7.0 at 103, but still seems lazier out of the hole compared to when I ran the Autolite 103's two years ago. It just doesn't get on boost quite as fast and I really have to try hard to brake torque. Debating if I have time in the short season up here to make it back with 103's to compare. The other things I've noticed have been covered, hard to start at times, stumbles at idle sometimes. The exhaust also seems more smelly, which could be possible if the plugs aren't lighting off the mixture as efficiently. Anyone have similar experiences?

I definitely think the BR7EF is a great plug for a street/strip car that already builds boost rapidly, has a t-brake, or goes to the track more than twice a year. I'd gladly live with the cold start and slight stumbles if it was more race car.

Are you logging start up and tip in? If not why blame the plugs? Have you checked the coil pack lately? Battery voltage at WOT?

 

[MNwe4]

I'm just saying this is a difference I noticed when the only thing on the car that changed was the plugs. The car doesn't stumble ever on throttle application (I meant while idling), so tip in isn't an issue. Cruise is beautiful. WOT voltage with Casper's booster is 15-15.2v. Never a miss or pop cruising or racing. Observation was that the plugs appear to offer an extra safety margin at WOT, but are not quite as street friendly. I'm not saying they're fouling though.

Interesting note, the behavior seems more exaggerated on E85 than on gasoline. Is this due to gas being more energy dense and possibly easier to burn? Of course switching fuels currently requires a chip swap, so there's too many variables to draw a precise conclusion.

I'm limited by my 80lb injectors, so boost is stuck in the 22 psi range and I'm fine with that for now. It's plenty fast at 7.0 with no extra safety gear on the car and 275's that spin on the street. The reasoning behind a non-projected tip is sound, but I may not be pushing the limit to where it is required.

 

[TTA976]

The projected tip versus non projected tip argument has been going on forever...it's hard to argue with a tuner like Eric on his recommendation. I understand both views but if something fails you would probably has something else going on. TTA uses 1 heat range cooler plug than GN. I'm not sure what Eric recommends as far as heat range but I would only go ONE heat range cooler. Like NGK UR5 V power or Autolite equivalent for 98% of us....

 

[jasjamz]

I'm just saying this is a difference I noticed when the only thing on the car that changed was the plugs. The car doesn't stumble ever on throttle application (I meant while idling), so tip in isn't an issue. Cruise is beautiful. WOT voltage with Casper's booster is 15-15.2v. Never a miss or pop cruising or racing. Observation was that the plugs appear to offer an extra safety margin at WOT, but are not quite as street friendly. I'm not saying they're fouling though.

Interesting note, the behavior seems more exaggerated on E85 than on gasoline. Is this due to gas being more energy dense and possibly easier to burn? Of course switching fuels currently requires a chip swap, so there's too many variables to draw a precise conclusion.

I'm limited by my 80lb injectors, so boost is stuck in the 22 psi range and I'm fine with that for now. It's plenty fast at 7.0 with no extra safety gear on the car and 275's that spin on the street. The reasoning behind a non-projected tip is sound, but I may not be pushing the limit to where it is required.

Do you have a powerlogger?
Can you post a log?
What converter?
Launch Boost?
A/ F ratio at WOT?

 

[MNwe4]

Just hit the track again this weekend with the Autolite 103's back in the car. Gapped to .028", so same gap. There's definitely a difference. Only change to the car setup was that I pulled a degree of timing from the tune due to my theory. The car left the line noticeably harder flopping the passenger floor mat back. The absolute best 60' I could muster before was a 1.69. With the plug swap I did back to back 1.62's. 1/8th mile time dropped to 6.84. It ran out the back door hard to a 10.70 at 127. 200 mile round trip drive as well. It's nice when a theory works out.

Jasjamz, I do have a powerlogger. Launch boost was still around 7psi (my brakes aren't great). Converter is from David Husek. A/F ratio was 10.8-11.1 during the run on the gas scale (I run E85). 22 psi boost. Zero knock. I can post a log once I get the other computer out and transfer files over. It's an old XP machine that now has 1 job only. I'm well aware I need more injector also.

 

[MNwe4]

My intent of keeping the thread going was to post findings along with gathering any experiences others have had. Maybe the moral of the story here is that when looking for a plug for a new combo, don't just jump to race car stuff like seems to be recommended on many forums. The majority of cars here, mine included, are still street drivers and aren't really that wild. I'm glad I tried the BR7EF because it is a good plug and I wouldn't hesitate to use it again if my combo got more aggressive (more boost and t-brake maybe?). Thanks for all the input everyone.

 

[jasjamz]

Good info! I believe I was using a 7 heat range plug in my old M&A Heads with E85. Boost was 35psi and a lot of street driving. They did not like too much street time without blowing 25psi plus threw the engine time to time. It would stumble at part or wot. Then after a blast it was back to normal.
This was mainly a grudge race car so i kept it set to go. Never had those issue with the 6.

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