DomLS3

I'm looking at changing out my plugs. I've read some people going with Brisk and some people going with NGK. I called NGK and they said they only have the LTR7IX-11 and I was wanting one step colder than stock but the guy I talked to said he isn't sure what the stock heat range is and said the LTR7 is the only one he has anyway. I was looking at the Brisk RR14 or 12 as well. Can anyone give me a part number for a plug for either Brisk or NGK that's one step colder than stock?

Thanks

musclesbmf

1 step colder on the Brisk is 14RR. Katech sells them.

DomLS3

Is there a non projected tip version?

musclesbmf

I thought those were non-projected. I run the 12's (with FBO) and those are not projected.

9T3VETTE

All small block plugs from the factory are DENSO.

C7 ZR1's use one step colder plugs than Zo6's. Higher number = colder

LT1 = DENSO #16 heat range, 1.02mm gap
LT4 = DENSO #20 heat range, 0.8mm gap
LT5 = DENSO #22 heat range, 0.8mm gap

3 Z06ZR1

You mean Delco A/C? I see Delco coming out of mine?

C5-VERT

9T3VETTE

Same plug, they are manufactured by DENSO but have an AC Delco logo. If you close at the housing you will see they say "assembled in the USA with Japanese and USA parts" --> DENSO = Japanese Company

GM forces suppliers to put AC Delco logos on parts so you will purchase replacements from GM directly. That way they can mark them up and make boat loads of $$ on replacement parts.

avtarv

Thank you for this info. I just ordered a set of ZR1 plugs today because I didn't like that I had to gap the NGK iridiums.

dar02081961

For the record the NGK LTR7IX-11 is one heat range colder than the stock ACDELCO 41128.
It also comes gaped at .44 rather than the stock .30.

Not sure if the Denso's are exactly the same as what they provide for AC Delco.
The Denso's I have seen have a ridged insulator and the AC Delco's have a smooth insulator.

https://www.rockauto.com/en/catalog/...park+plug,7212

3 Z06ZR1

Good catch!
I have seen that same A/C plug for a long time they use it in other models too using different gaps .. it is really good plug for about 75-80k at 100k it is a little too worn for me.

9T3VETTE

Z0HS1CK

Are you changing out the plugs because you're modified or because the stock plugs are inefficient?

DomLS3

Modified.

DomLS3

I've gotten conflicting responses on asking if the LTR7IX-11 is one step colder or stock heat range. Vengeance says it's stock, NGK says it's stock. But two other people I've spoken to say it's one step colder, and you're now the third that says it's one step colder.

MacRoadie

I'm running RR10S with a 9% Innovators West pulley and a tune. Went two steps colder due to higher boost pressure (at my tuner's direction). The RR's from Brisk are their Racing Silver model and are all non-projected.

megan.andrews

I have a holden vy ss ls1 5.7lt now any of these spark plugs

Hope would be great for my car

dar02081961

Ok I understand exactly how you feel. Been through this and still am not 100% sure.

But here is how I came to my position.
If in fact Denso makes AC Delco's plugs and the heat range numbers for the two are the same we can deduce the following.

1. The OEM ACDELCO 41128 has a heat range of 20 according to info posted on Rock Auto for the plug. https://www.rockauto.com/en/moreinfo.php?pk=6500556&cc=3315156&jsn=4 21

So

2. If we take the Denso heat range of 20 and plug into this cross reference we will see this equates to a heat range of 6 for NGK plugs. https://www.pacificcustoms.com/boschwr8dc.html

Therefore a NGK plug with a heat range of 7 is 1 range colder than the OEM AC Delco 41128.
But not to go on just one example. If you cross the BOSCH 96313 which is the recommended Bosch replacement for the OEM AC Delco 41128 you will see that it's heat range of 7 equates to Denso's 20 and NGKs 6. This all but confirms the NGK LTR7IX-11 (heat range of 7) is 1 range cooler than the OEM plug.
https://www.rockauto.com/en/moreinfo.php?pk=8103676&cc=3315156&jsn=4 23&jsn=423

Of course I am assuming this cross reference chart is correct and NGK or Denso haven't changed their heat range classification strategy since this info was posted.

Other than this all we have is hearsay.

Happy Thanksgiving Folks!!!

Raul Gonzalez

Do you know what they should be gapped to for my 2015 ZO6? Thanks

Higgs Boson

.025