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7 spark plugs just a bandaid?

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bcjjones

10+ Year Contributor
509
4
Nov 3, 2011
Austin, Texas
My current set up is a 1991 gvr4 with a bastard 20g internally gated, fic 950s, 1g vrsf intercooler kit, fp2 cams and a walbro 255. Running 20 psi on 93 octane, with afrs about 10.5 to 11 by redline.

Im having a problem with spark blow out. I bought some brand new 6's and gapped them at .025. It helped but still blows out at full throttle, it won't at part throttle though. So i regapped them down to .020 and I still have blow out.

Should I now try switching to some 7's or is that just a bandaid to a weak ignition problem?
 
I run a similar setup and I had bad misfire last month at 15+psi so I changed my good but not new spark plug wires for new NGK 7mm wires and now no more misfires. I run BR7ES gapped at .028. For your setup you should run 7es plugs but forget the BPR and run the BR they are better if you really get spark blowout.
 
If your running bpr6es try some br7es which are motorcycle plugs and dont protrude as much as normal plugs. Gap them at .020 and see if that works. If not gap them down more and more like .018,.016,.014, u shouldn't half to go that low.
 
Yea the non project (BR6ES) plugs have helped quite a few (myself included) with blow out. With your gap being that tight, I'd look into a set of BR7ES plugs and be done with it.
 
Wow, don't listen to any of these guys. So much wrong info. A stock ignition setup should support what your trying to do. You need to make sure your wires are good and the coils are clean and the plugs are new and at about .025" gap. Lean it out a bit too. No reason to go past 12 on gas

Changing heat range will have no effect on blow-out.

Going to a non projected plug should help blow out, but it also has the effect of retarding the timing a few degress

Going to non projected plugs and cooler plugs have more of an effect on fighting detonaton.

For reference, I run BR8ES at 0.024 and 35psi with stock wires and no box.
 
BastardDsm, you're right about plugs heat range has nothing to do with spark blowout. I was just suggesting to go with BR plugs for the blowout and for that setup I think that the 7's plugs are a better choice.
 
Wow, don't listen to any of these guys. So much wrong info. A stock ignition setup should support what your trying to do. You need to make sure your wires are good and the coils are clean and the plugs are new and at about .025" gap. Lean it out a bit too. No reason to go past 12 on gas

Changing heat range will have no effect on blow-out.

Going to a non projected plug should help blow out, but it also has the effect of retarding the timing a few degress

Going to non projected plugs and cooler plugs have more of an effect on fighting detonaton.

For reference, I run BR8ES at 0.024 and 35psi with stock wires and no box.

I run br7es gapped to 0.020 I'll be getting te iridiums since evos run them. Probably get 8's nom purtruding
 
Stock coils? Are they grounded well? I actually added an extra ground wire from mine to the chassis since they are relocated.

It could be plug wires. I had the same issue last year and had to replace mine. They were only 5 year old NGK wires with about 20k miles on them and they "looked" fine.

Go to advanceautoparts.com put the NGK wires in your shopping cart and put in the promo code ES123 and pick them up at a local store for about $35 :thumb:
 
agreed, your just trying to cover up a problem, buy new wires and set your gap back to factory and see where it leads you.
 
+1 Check wiring & grounds for the coils & wires.
 
12 or lower. WOT 93 oct you want to shoot for 11.3-11.7 max 12+ is way too lean for pump. E85 eh ok but 93 11.3
 
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