Spark plugs

[paul95z]

Im having trouble finding plugs to use for my AFR 210s. They take the gasket seat plugs and there doesnt seem to be many options for different heat ranges. I need to go two steps colder than stock. Ive been running the Autolite AR50 on motor which are one step colder. The spark plug refernce thread on that other site only shows one denso plug for two steps colder. Any suggestions?

[BLOWNDFIZ]

I use NGK BKR7E in my AFR's. It's equivilent to an FR1LS AC. The stock number of the NGK plug is 4644 or 6097. I'm not sure why they list two numbers in my system it says to reorder the 4644 from the 6097. Apparently they have either consolidated the line or discoutinued similar plugs.

[paul95z]

Thanks, your reply was a big help. I did some more searching and found that AFR recommends a heat range 9 for the starting point. The plugs you recommended are a heat range 11. They cross reference to an Autolite 3922. Autolite is the manufacturer of AC plugs so they are the same thing but a little cheaper.

The spark plug reference in the sticky at the top of this forum only shows an AR 50 autolite for one step colder in the AFR section. That plug is a 13/16th hex and a real pita to use. The plugs listed in the TFS/Edelbrock section will work for AFR as well since they have the same seat/reach. Just have to find the right heat range for the application.

[BLOWNDFIZ]

I'm pretty sure the BKR7E is a "7" heat range plug. Take a look at this pic.
http://www.ngksparkplugs.com/tech_support/spark_plugs/image/chartheatratingflowpath-2.gif

It's definitely a cold plug and is a direct cross to the AC FR1LS (which is as cold as AC goes).

Here is a link to that page. http://www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml

That pic looks like A$$ so just click the link the pic shows up there much better.

Oh and Edelbrock recommends a Champion RC12YC as the plug to start with on their heads.

[paul95z]

I used this site to cross reference the numbers.
http://www.power-21.com/AutolitePower21i/PartDetail.aspx?b=A&pn=3922
It shows the autolite 3922 as a direct cross and lists it as a heat range D11. Im still trying to figure all this out. Ive found about 10 different autolite and NGk numbers that look exactly the same...That site also will list the plug by cylinder head mfg recommendation. My 1101 AFRs show a AR3910 as the recommended starting point. Which is a heat range 9? So 2 steps colder would put me at 11.. and factory is 5.... Im 13.2:1 CR and gonna hit it with 200+

[tbsimmons]

I know i am not running as much power as a lot on this board, but I would not run the BKR7E plug. It is a projected plug, not good for the bottle or power adder in my opinion.
It is in the 7 heat range. Depending on your compression, amount of shot, etc. I would start in the R5671A-7 range. It is a 7 also, stock number 4091.

Just read your response above again.
13.2 at 200 shot, I would start with around a 9 heat range and see.
NA runs first and see if the plug has any color, with a 200 shot, I would not want much color on the plug in NA form.

[BLOWNDFIZ]

The BKR7E does have a slight projected tip. Not nearly as much as the TR6 which is what most stock head guys run. Here are some pics of the tips for reference. I actually do run the R5671A-8's at my boost level.

TR6
http://partimages.genpt.com/partimages//310496.jpg (http://www.napaprolink.com/Detail.aspx?R=NGK4177_0214911251#)

BKR7E
http://partimages.genpt.com/partimages//310103.jpg (http://www.napaprolink.com/Detail.aspx?R=NGK6097_0213770505#)

R5671A-7
http://partimages.genpt.com/partimages//310491.jpg (http://www.napaprolink.com/Detail.aspx?R=NGK4091_0214911145#)

[paul95z]

Put a set of AR3933 autolites in over the weekend. 9 heat range, non projected. Seems to be ok so far.

[gregrob]

BR7EF is a non-projected tip heat range 7 plug a lot of the big boys are running w spray.