NGK UR-5 plug gap

[V6POWER]

I did a search and I found people were gapping these plugs from .029 to .035. What is the best gap for my combo, running 24# boost with alcohol? Thanks.

 

[Chyke]

Couple of things. I looked over your sig and did not see any type off ignition amplifier, ie MSD. I also did not see any reference to the current plugs you are running. The NGK ur5's seem to be a colder plug than advertised. I have some interesting experiences with these. I would recommend gapping them at 0.32. I would also make sure you do a dyno pull and check everything out. I switched to these plugs in my Mustang and had to retune due to a miss fire problem that developed.

 

[V6POWER]

I have the stock ignition/ECM and I am running Autolite 23s gapped at .035.

 

[Steve Wood]

I normally run the Autolites but I had good luck with the NGKs at .032 at similar boosts. There is no need for an ignition amplifier.

 

[V6POWER]

Thanks Steve.

 

[U1ARUNIT]

I have my UR5's gapped at .033".

 

[V6POWER]

Thanks Mark. Guess I will go with .0325.

 

[V6POWER]

Steve--What gap did you use on the Autolites? What is the reason for the tight gap with the NGKs?

 

[U1ARUNIT]

Jim..

That tight of a gap can/should be run with any brand plug in this application. I gapped my AC CR43TS/CR42TS plugs the same.

 

[V6POWER]

Thanks Mark. Is the reason the higher boost?

 

[Steve Wood]

I run .032 to a tight 035 on the Autolites depending on the mood I am in at the moment. Yes, we run tight gaps due to the very high cylinder pressures encountered.

I usually run closer to 032 on one of my cars that turns more rpm and closer to 035 on the ones that shift around 5200.

 

[V6POWER]

Thanks Steve. My car shifts around 5,000 so I will adjust gap accordingly.

 

[U1ARUNIT]

Yes Jim, it is. Mine will pop at anything over 23# boost unless I close the gap up as stated.