Spark blowout!.........need KB BAS?
11-04-2009, 09:35 AM
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Join Date: Dec 2008
Location: Kentucky
Posts: 164
Spark blowout!.........need KB BAS?
As some of you know, I had spark blowout on my last dynotune.
I made 525rwhp at 6400rpm before I added a 10% OD IW crank pulley and went from a 2.85 to 2.70 supercharger pulley. Before was around 14lbs. of boost with no issues. 19-degrees timing, 93 octane, TR-6 plugs gapped at .032", FMS plug wires, MSD coil packs. I did at one time have a DIS-4, but that starting causing a miss, so I plugged in the bypass and have been running like that for years.
About a week ago, the car made 548rwhp at 5600rpm with 15.1 lbs. of boost, 18-degrees timing. It was making 16.2lbs. at 5900rpm, so the belt was not slipping, but the power starting zig-zagging up and down after 5600rpm. You could clearly hear the car cutting out bad up top.
Since then I have put in some BR7EF's gapped at .028". I drove on the street to see how it felt and still had alot of missing/cutting out up top. Pulls hard to 5600rpm, then just stops. I am re-gapping tonight to .024", but I am not sure where to go from there.
I did check secondary resistance on the coils, and there were like this......on the 20k-ohm setting (13.4, 13.4, 13.5, 13.07)
I did check the primary resistance on the coils, and they were like this....on the 20-ohm setting (.09, .09, .08, .03)
Although 1 coil in particular had some lower values, those are all in the range of a good coil. I did check a factory coil that I had laying around and it was like this (13.07, 13.07 for secondary), (.08, .08 for primary).
All in all pretty good numbers, but I don't really understand how that check really confirms good coils?
Alternator voltage was logged and is good (13.7@idle-13.0@WOT). A/F ratio was logged and good (11.2-11.8). MAF is not pegging (about 910 A/D counts at 5900rpm). Pump is A1000 and injectors are 60lbers.
My motor is under 9:1 compression, so I didn't think I would have really high pressure in the cylinders that would cause spark blowout. Compression checks all are in the 150-160psi range for all cylinders.
I guess my question is...........IF the .024" gap does not work tonight, should I fork out the money and buy a Kenne Bell Boost-A-Spark? I would like real world input that this device fixes spark blowout.
We did try to add 3-degrees (21 total) to see if the car would take it and it made 15rwhp more to 563rwhp........not sure what that means, but we backed it down for safety.
Thanks,
Derrick
I made 525rwhp at 6400rpm before I added a 10% OD IW crank pulley and went from a 2.85 to 2.70 supercharger pulley. Before was around 14lbs. of boost with no issues. 19-degrees timing, 93 octane, TR-6 plugs gapped at .032", FMS plug wires, MSD coil packs. I did at one time have a DIS-4, but that starting causing a miss, so I plugged in the bypass and have been running like that for years.
About a week ago, the car made 548rwhp at 5600rpm with 15.1 lbs. of boost, 18-degrees timing. It was making 16.2lbs. at 5900rpm, so the belt was not slipping, but the power starting zig-zagging up and down after 5600rpm. You could clearly hear the car cutting out bad up top.
Since then I have put in some BR7EF's gapped at .028". I drove on the street to see how it felt and still had alot of missing/cutting out up top. Pulls hard to 5600rpm, then just stops. I am re-gapping tonight to .024", but I am not sure where to go from there.
I did check secondary resistance on the coils, and there were like this......on the 20k-ohm setting (13.4, 13.4, 13.5, 13.07)
I did check the primary resistance on the coils, and they were like this....on the 20-ohm setting (.09, .09, .08, .03)
Although 1 coil in particular had some lower values, those are all in the range of a good coil. I did check a factory coil that I had laying around and it was like this (13.07, 13.07 for secondary), (.08, .08 for primary).
All in all pretty good numbers, but I don't really understand how that check really confirms good coils?
Alternator voltage was logged and is good (13.7@idle-13.0@WOT). A/F ratio was logged and good (11.2-11.8). MAF is not pegging (about 910 A/D counts at 5900rpm). Pump is A1000 and injectors are 60lbers.
My motor is under 9:1 compression, so I didn't think I would have really high pressure in the cylinders that would cause spark blowout. Compression checks all are in the 150-160psi range for all cylinders.
I guess my question is...........IF the .024" gap does not work tonight, should I fork out the money and buy a Kenne Bell Boost-A-Spark? I would like real world input that this device fixes spark blowout.
We did try to add 3-degrees (21 total) to see if the car would take it and it made 15rwhp more to 563rwhp........not sure what that means, but we backed it down for safety.
Thanks,
Derrick
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