[donaldp]

Replacing my spark plugs for the first time on my 2017 ZL1. What is the recommended gap for stock plugs? I cannot seem to find this answer anywhere.

[donaldp]

I'm not looking for a gap range, Im looking for a specific gap size.

[2SS Capt]

Originally Posted by donaldp

Replacing my spark plugs for the first time on my 2017 ZL1. What is the recommended gap for stock plugs? I cannot seem to find this answer anywhere.

From everything I've found (including the service manual) they should come pre-gapped...

However, I also found this, which sounds reasonable as well:

"The recommended spark plug gap for a 2017 Chevrolet ZL1 with the LT4 engine is 0.037 to 0.043 inches (0.95 to 1.10 mm). Always check and verify the gap on new spark plugs before installation, even if they appear to be pre-gapped, to ensure proper performance and avoid engine issues."

To me it sounds like the pretty much standard, 40 thousands... 0.040"...

[RobZL1]

From the LT4 supplement manual:

[Joshinator99]

Originally Posted by 2SS Capt

From everything I've found (including the service manual) they should come pre-gapped...

However, I also found this, which sounds reasonable as well:



To me it sounds like the pretty much standard, 40 thousands... 0.040"...

.040” is too much on a boosted engine.

@RobZL1’s post makes much more sense.

[2SS Capt]

Originally Posted by RobZL1

From the LT4 supplement manual:

Originally Posted by Joshinator99

.040” is too much on a boosted engine.

@RobZL1’s post makes much more sense.

Yeah, I was just trying to find it online, looks like he got it right out of the supplemental manual for the LT-4 so definitely go with that...

[donaldp]

Originally Posted by RobZL1

From the LT4 supplement manual:

I have a 6-speed manual. This proves my point, everywhere I look I find different data.
This is definitely the best answer, thank you.

[Patriot Motorsports USA]

The Brisk RR14S plugs are the only ones I recommend for the ZL1 LT4 engine and once again this thread proves what I learned when I first began driving my car, the internet if full of bad data. As others have said, you want a tight gap on the LT4 because of its boosted life. The Brisk plugs are a very conductive silver construction and come with the necessary .026” gap.

I stock the plugs and the proper resistance Katech wires that we modify to increase their strength, reliability and performance over extended use.

LMK if I can help!

[Joshinator99]

Originally Posted by Patriot Motorsports USA

The Brisk RR14S plugs are the only ones I recommend for the ZL1 LT4 engine and once again this thread proves what I learned when I first began driving my car, the internet if full of bad data. As others have said, you want a tight gap on the LT4 because of its boosted life. The Brisk plugs are a very conductive silver construction and come with the necessary .026” gap.

I stock the plugs and the proper resistance Katech wires that we modify to increase their strength, reliability and performance over extended use.

LMK if I can help!

Agreed, Brisk is a great way to go and upgrades over the factory wires are a no brainer. The OEM ones are pretty flimsy.