jtl12419

iTrader: (13)

I can't seem to make my search function work, sorry.

What are some spark plug choices for LS2/L92 fuel injected, roadrace engine?

03 BUSA

iTrader: (25)

If you are going NA then use the TR55's if a power adder is used then go with the Tr6's

jtl12419

iTrader: (13)

That's a common recommendation. I am trying to find specs on the TR55, and cross reference to other spark plugs, for other options. Heat range info would be great.

The LS7 recommend TR6- but I'm not certain if head and combustion chamber design make a difference from the LS2.

Again, I am using this on a road race engine. Might need to run heat range colder.

03 BUSA

iTrader: (25)

I am running the TR6's on my LS7 but my compression is 11.99.1 so I am trying to keep everything as cool as possible. I would think that might work for your app as well.

jtl12419

iTrader: (13)

Searched again today for specs on the TR55ix and Tr6- unable to find. Have sent email to tech at NGK and left them a phone message.

S1LV3R

iTrader: (5)

see if this helps. Click "NGK" at the bottom and it has NGK's break down. For some reason that info didn't come with the pic I posted. http://www.ngk.com/sparkplug411.asp

TheLS1Kid

iTrader: (12)

I run TR6's on my N/A 11.5:1 compression LS1.

jtl12419

iTrader: (13)

I think we are all in the right ballpark. Did get a hold of a tech rep at NGK.

The NGK plugs for LS engines starts with the TR5 or TR55. The next heat range colder is TR6, and after that TR7, and so on.

Iridiums, are suitable for racing.

Thanks for the input and charts from all.

jtl12419

iTrader: (13)

More specs from the charts:

14mm, .708"(18mm) reach, 5/8" hex, tapered seat, resistor, projected tip spark plugs

Suitable NGK racing plugs are, in increasing coldness:
R5724-8
R5724-9
R5724-10

None of the NGK racing plugs have a heat range below 7, for perspective.

Flash99

iTrader: (48)

P/n 3789 Tr55ix ???.