JBrunoJSBC6

So I decided to upgrade to what I thought would be an upgrade in spark plugs which were the NGK TR5 V-Power plugs from my stock LS3 AC/Delco plugs.

My car has minor boltons: CAI/Headers/Tune/etc...

I ran the AC/Delco plugs about a week and a half ago in 800 DA and saw 0 KR (Knock Ratio) with HP Tuners.

Fast forward to this past Sunday and me putting in the new NGK TR5 plugs. I made 0 changes to the tune, DA was 1900, meaning that the air was fatter and I shouldn't have seen any knock whatsoever. Wound up getting about 6.7 KR through 2nd and 3rd gear. I could only imagine how bad the knock would have been in lower DA.

Anyways,

I'm going to be switching back to AC/Delco plugs, but haven't decided on LS7 plugs or LS9 plugs. I'd like your input and thoughts.

Thanks,
Jason

sevinn

Interesting, you did go 2 steps colder than stock with the tr5's so I wonder if that could be the reason (I honestly have no idea)..this is assuming you have an ls3.

I recently swapped from my delco plugs to tr6ix's on mine and got rid of the knock I was seeing in my scans. I can't add any timing but the stock timing table no longer knocks.

JBrunoJSBC6

Yes its an LS3 car. The TR5's I got are the Nickel plugs not the Iridium plugs. I wonder if that has something to do with it?

dennis50nj

what was the gap difference ? and you would see more kr if the DA was higher, thats 1100 ft what was the et difference ?

JBrunoJSBC6

Plug gap is the same 40 gap.

I think you have that backwards Dennis. Lets say for example if I run 25 degrees of timing, if the DA is 1000 and I get 5 KR I know I need to take out timing or add fuel.

With that same 25 degrees of timing, if the DA is 0, KR will be much higher than 5 KR because of the denser colder air charge, making the car run more lean.

KC Slider

I have had good luck with the E3 plugs in my Harley - Davidson. I do not have them in my 13 GS but would not hesitate to do so. I believe the part number is 3.54 for the LS3 engine. Probably the same for an LS2. I'm not going to change out my plugs yet since I only have 3k miles on the car, but would try the E3's when it is time.

dennis50nj

if you run a lower DA more air fits in to the cylinder changing the volumetric pressure so you do need more fuel hence making more hp, now if you are running a maff tune and not speed density the maff adds the fuel, usually a lower DA means a colder air charge and lower iat's and engine temps needing more timing. seems to work for me I have ran tr5 and tr6 in many +2000 ft DA & -2000 ft DA with no KR and no tuning changes

dennis50nj

I do use 93 sunoco and maybe the higher rpm of the converter keeps it in a range of no lug

timd38

Wish I was smart enough to know what all this means!

dennis50nj

Me too!

juanvaldez

Harleys make so little hp almost any plug will work. Iridium plugs last a long time but standard plugs make more hp. I use NGK plugs in my *** bikes but AC-Delco plugs in my GM stuff.

Guinzu

Hmm....who makes the A/C Delco plugs?

juanvaldez

Does it matter, they make them to AC-Delco specs. Who makes AC-Delco oil filters?

timd38

NGK and Denso the last time I checked. But they could change suppliers at any time!

c5racr1

Try the stock heat range. Unless you are running FI or on thebottle

timd38

http://www.champlabs.com/content/oil-filters

erick_e

Denso Iridium plugs..