Plug Gap on NGK UR5's...

[TxSy1430]

Im switching out my Iridiums with the NGK UR5's. It doesnt pull very hard while running 21psi with meth. my datamaster doesnt show any knock and is only pulling 3 degrees max out of timing. Inlet temps with the meth have been in the low to mid 30's, with an AFR between 11.5 and 12.2. so im guessing that the boost is blowing out the flame. I have an MSD digital 6 and MSD HVC 2 coil as well as Taylor 8mm wires. right now im running .030 gap, should i try a tighter gap..say .025? any suggestions??

 

[turbodig]

Re: Plug Gap on NGK UR5's...

Im switching out my Iridiums with the NGK UR5's. It doesnt pull very hard while running 21psi with meth. my datamaster doesnt show any knock and is only pulling 3 degrees max out of timing. Inlet temps with the meth have been in the low to mid 30's, with an AFR between 11.5 and 12.2. so im guessing that the boost is blowing out the flame. I have an MSD digital 6 and MSD HVC 2 coil as well as Taylor 8mm wires. right now im running .030 gap, should i try a tighter gap..say .025? any suggestions??

Won't hurt to try that.

"Doesn't show any knock" and "only pulling 3 degrees" are contradictory statements. What are you getting for timing overall at full boost? Depending on what chip you're running, some chips pull a lot of timing about street boost levels.

Something to try... back it down to 18 psi and see what happens.

 

[NecroWolf]

Re: Plug Gap on NGK UR5's...

i would think if it was blowing out the spark it would spike the afr

 

[BoostedSUV]

Re: Plug Gap on NGK UR5's...

I had to gap my plugs to .025 because I was blowing out the spark. My truck felt like it hit a rev limiter when it did it. I had a severe case of that spark blow out.

 

[Don W.]

Re: Plug Gap on NGK UR5's...

On the flip side I tried .025 with these plugs, MSD 6al, direct replacement blaster coil, and had all kinds of missing under boost w/meth. Re-gappd back to .035 and all was well. I would try the wider gap with that setup just to be sure.