jgkurz Posted April 4, 2007 Share Posted April 4, 2007 NGK BPR7ES .030 on 92 pump gas at 15psi NGK BR8ES .030 on 104 race gas at 23+psi I like to run the projected insulator plugs (BPR7ES) on the street. I think the engine starts a little easier and idles a little smoother than the non-projected (BR8ES), especially when cold. For an extreme turbo engine it's usually better run the non-projected plugs. The theory is that the engine will be less susceptible to pre-ignition. I also file the ground electrode back so the end is exactly in the middle of the center electrode tip. I then radius and smooth all the sharp edges. I can't really say for sure whether it helps combustion or reduces pre-ignition but I know it doesn't hurt anything. Quote Link to comment Share on other sites More sharing options...
big-phil Posted April 4, 2007 Author Share Posted April 4, 2007 NGK BPR7ES .030 on 92 pump gas at 15psi NGK BR8ES .030 on 104 race gas at 23+psi I like to run the projected insulator plugs (BPR7ES) on the street. I think the engine starts a little easier and idles a little smoother than the non-projected (BR8ES). For an extreme turbo engine it's usually better run the non-projected plugs. The theory is that the engine will be less susceptible to pre-ignition. I also file the ground electrode back so the end is exactly in the middle of the center electrode tip. I then radius and smooth all the sharp edges. I can't really say for sure whether it helps combustion or reduces pre-ignition but I know it doesn't hurt anything. I've always run the "projected" type, I'll give the non a try. Thanks for the info! Quote Link to comment Share on other sites More sharing options...
rztmartini Posted April 5, 2007 Share Posted April 5, 2007 I then radius and smooth all the sharp edges. I can't really say for sure whether it helps combustion or reduces pre-ignition but I know it doesn't hurt anything. I read in a Performance Ignition book (By Dr. Jacobs ((formerly)) of Jacobs Electronics) and i recall that the spark jumps better from a sharp corner than from a radius edge. I see that by eliminating the sharp edges you dont get any hot spots, but i guess if the ignition system is powerful enough it wont matter sharp vs rounded corners... correct me if im wrong... Quote Link to comment Share on other sites More sharing options...
HB280ZT Posted April 6, 2007 Share Posted April 6, 2007 I am using NGK BKR7E-11 V-groove plugs at 15psi of boost, gapped to .028. Has anyone tried these: http://www.ngksparkplugs.com/products/spark_plugs/racing.asp?mode=nml# They look pretty interesting but the price is a bit steep at $9.50 each. I will have to look into the BKR7E plugs without the -11! Maybe I will not have to bend the electrode over to get the correct gap. HB280ZT Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted April 6, 2007 Share Posted April 6, 2007 You need the sharp edges for the spark to jump on to. That's one reason you replace the plugs. Quote Link to comment Share on other sites More sharing options...
linluv84 Posted April 6, 2007 Share Posted April 6, 2007 Does the colder plug help THAT much with pinging? A more appropriate solution would be running less timing, but maybe colder plug and aggressive timing makes more power? I've never delved that far into the realm of plug heat ranges... Quote Link to comment Share on other sites More sharing options...
jgkurz Posted April 6, 2007 Share Posted April 6, 2007 I read in a Performance Ignition book (By Dr. Jacobs ((formerly)) of Jacobs Electronics) and i recall that the spark jumps better from a sharp corner than from a radius edge. I see that by eliminating the sharp edges you dont get any hot spots, but i guess if the ignition system is powerful enough it wont matter sharp vs rounded corners... correct me if im wrong... I agree that the sharp edges will allow the spark to jump easier. However, in a turbocharged or high compression engine those sharp edges will cause hot spots resulting in pre-ignition. When I radius and smooth the edges of the ground electrode I don't make it round and blunt just less sharp after filing. Does the colder plug help THAT much with pinging? A more appropriate solution would be running less timing, but maybe colder plug and aggressive timing makes more power? I've never delved that far into the realm of plug heat ranges... Yes, colder plugs make a HUGE difference in engine survivability. As you say, proper ignition timing is also a factor but you can only pull back timing so far. Running colder plugs is not necessarily about more power but about keeping the engine from detonating itself to death. Try running 30psi boost or nitrous or 15:1 compression without a much colder plug and you'll end up with a dead engine. Quote Link to comment Share on other sites More sharing options...
linluv84 Posted April 6, 2007 Share Posted April 6, 2007 Just 8psi, non intercooled, 91 octane, 8.8:1, and too much timing. The AFRs are good, its just I really need to hook up spark and find a factory heat shield for the intake. I just thought maybe a colder plug would be a little safer in the vegas heat or the occasional crappy fuel. Also of course as a band-aid until my lazy ass hooks up spark... Quote Link to comment Share on other sites More sharing options...
m1ghtymaxXx Posted April 6, 2007 Share Posted April 6, 2007 Here's the recommended plug for 1981 L28E and L28ET: NGK BPR6ES-11 gap .039-.042 in. BPR5 for hot and BPR7 for cold. This is per the Factory Service Manual.I'm sure once the boost goes up you gotta close that gap but that's the factory specs. Just for the hell of it here's the gap for the 1978 L28E. NGK B6ES for normal, B5ES for hot, B7ES for cold, gap is .025-.029 unless it's a ES-11 where it's .039-.043 also. (I have FSM for 77, 78, and 81 z cars) Mightymax, Even if they had iridium plugs in the 70's (i doubt it) there is no way an economy minded company like Datsun (thier slogan was "datsun saves") would have recommended such expensive plugs. I don't either, NGK copper core plugs are fine, it's not like it's hard to change 'em out on an L28..if it takes you 10 minutes on an L28 you're taking your time, so why bother with plugs that last 60-100K miles, when with a turbo you're gonna be changing them often anyway. Iridium sure seems like a waste of money to me. To answer phil's Q I'm running the BPR6ES-11's with a .039 gap. So far I've only been running 7psi of boost. Found them laying around at work so i got em for free. Otherwise i would've bought ngk v-powers. I'm not complaining. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted April 8, 2007 Share Posted April 8, 2007 Phil, I was running into some really similar problems to what you are describing. I chased the ignition gremlins for a long time before I figured it out. I also had the same symptoms, when you decrease gap, problem gets better. I bought a hotter coil, but still couldn't get the problem to go away. Turns out, it wasn't an ignition problem at all. My problem was a setting on the megasquirt for decel fuel cut was set too sensitive. At high rpm, high power load, I was getting more noise in the signals into the megasquirt and it was briefly triggering a fuel cut, which translated to really bad misses. Take a look at your datalogs and see if you are getting sudden decreases in pulsewidth. Why my problems with this got better by dinking with the ignitino system, I do not know, but I'm not complaining that it is fixed. Jeremy Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 25, 2007 Share Posted April 25, 2007 I installed some BPR8ES plugs today at .030" and had great success 15psi at this altitude which is equivelant to 12psi at sea level. MSD Blaster 2 coil, Megasquirt n Spark with a 83 dizzy Quote Link to comment Share on other sites More sharing options...
big-phil Posted April 26, 2007 Author Share Posted April 26, 2007 I installed some BPR8ES plugs today at .030" and had great success 15psi at this altitude which is equivelant to 12psi at sea level. MSD Blaster 2 coil, Megasquirt n Spark with a 83 dizzy thanks, I still have this dam sputter. I'm shopping for a good fuel pump to see if the problem is fuel related??????????????? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted April 26, 2007 Share Posted April 26, 2007 what rpm does the sputter kick in on? only under boost ? Quote Link to comment Share on other sites More sharing options...
big-phil Posted April 27, 2007 Author Share Posted April 27, 2007 what rpm does the sputter kick in on? only under boost ? only under boost, at 14 pounds its awesome all the way to redline. Above that 16, 18, 20 pounds its sputters, but will clear out from time to time. I've gone through several sets of plugs, leaned, richened, retarted advanced spark. The wideband reads about 10.5 at wide open, then when it sputters it jumps around to about 12.5. So maybe (1) of my fuel pumps is going?? I'm looking at getting an Aeromotive a1000 pump, and replace the stock, and holly that I have now. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted April 27, 2007 Share Posted April 27, 2007 I'm looking at getting an Aeromotive a1000 pump, and replace the stock, and holly that I have now. Phil, Sounds like you are on the right track. I have been very pleased with my Walbro GSL392 inline pump. It's quiet and hasn't missed a beat since I installed it. I've also heard good things about MSD and Bosch pumps. The Aeromotive is probably a quality unit but I don't know anyone running one. Quote Link to comment Share on other sites More sharing options...
big-phil Posted April 27, 2007 Author Share Posted April 27, 2007 Phil, Sounds like you are on the right track. I have been very pleased with my Walbro GSL392 inline pump. It's quiet and hasn't missed a beat since I installed it. I've also heard good things about MSD and Bosch pumps. The Aeromotive is probably a quality unit but I don't know anyone running one. My buddy Chris's 240z in this video has an Aeromotive A1000, he likes it, and his car is KICKASS, so if it works for him, it should do me good? Quote Link to comment Share on other sites More sharing options...
Mayolives Posted April 27, 2007 Share Posted April 27, 2007 Big-Phil- I had a similar problem when tuning my L28. It would sputter at higher rpm and boost pulls. I'm running an Electromotive Tec3R ignition/management system along with an Aeromotive 1000 pump with matching regulator. I had the fuel pressure turned up very high (65lbs) but it was starving for fuel due to the duty cycle of the 55lb injectors. After installing 70lb. injectors, the sputtering went away and we were able to turn the fuel pressure down to 45lbs. All is well. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted April 27, 2007 Share Posted April 27, 2007 Big-Phil- I had a similar problem when tuning my L28. It would sputter at higher rpm and boost pulls. I'm running an Electromotive Tec3R ignition/management system along with an Aeromotive 1000 pump with matching regulator. I had the fuel pressure turned up very high (65lbs) but it was starving for fuel due to the duty cycle of the 55lb injectors. After installing 70lb. injectors, the sputtering went away and we were able to turn the fuel pressure down to 45lbs. All is well. At 43.5psi and 85% duty cycle, 55lb injectors will easily support 500HP at the crank. You must be making some serious HP if you needed to go from 55 to 70lb. Quote Link to comment Share on other sites More sharing options...
big-phil Posted May 6, 2007 Author Share Posted May 6, 2007 I found my sputter problem. My dwell in the megasquirt was set as 6.0 2.5 1.5 I changed the running dwell from 2.5 to 6.0 and the car pulls hard with no sputter at all, at 19 pounds boost, but I think that was too much dwell and I burned up my vb921 in the MS. the vb921 gets hot to the touch when cranking, megatune sees RPM when cranking but I have no spark. I just orderd another vb921 ($5) then I'll try a 3.0 dwell and work my way up slowly? Quote Link to comment Share on other sites More sharing options...
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