TL;DR: Yes, delete it. The stock grid heater restricts airflow and risks catastrophic engine damage via the "killer bolt." SPELAB’s intake horn upgrade resolves these issues while offering an optional coil heater port. This setup ensures maximum performance and safety without sacrificing cold-start reliability.
You’ve decided to upgrade your truck with a SPELAB 6.7 Cummins Intake Horn to boost airflow and performance. But as you prepare for the installation, a critical question arises: Should you keep the stock grid heater, or is this the perfect time to delete it?
The factory grid heater is a known bottleneck in the 6.7L Cummins intake system. While it aids cold starts, it also restricts the massive airflow potential that your new SPELAB Intake Horn is designed to deliver. Worse yet, the infamous "killer grid heater bolt" poses a catastrophic risk to your engine.
In this guide, we’ll analyze why most owners choose to delete the grid heater during this upgrade and how SPELAB provides a solution that maintains cold-weather reliability.
1. The Problem: Why Installing a High-Flow Horn on a Stock Heater is a Compromise
Installing a high-performance intake horn while keeping the restrictive stock grid heater is like putting a fire hose nozzle on a garden hose. You improve one part of the system, but the blockage remains downstream.
1.1 The Airflow Bottleneck
The SPELAB Intake Horn increases airflow volume by up to 88% compared to stock. However, the OEM grid heater sits directly below the horn, filled with heating coils that disrupt and slow down this air before it reaches the cylinders. Keeping it limits the performance gains you paid for.
1.2 The "Killer Bolt" Risk
The most compelling reason to delete the grid heater during your install isn't just performance—it's safety. The factory grid heater has a bolt on the bottom that is prone to vibrating loose due to heat cycles and age. If this bolt falls, it drops directly into cylinder #6, often destroying the piston, valves, and cylinder head.
2. The Solution: SPELAB’s "Best of Both Worlds" Approach
Many owners hesitate to delete the grid heater because they live in cold climates and fear their truck won't start in winter. SPELAB has solved this dilemma.
2.1 The Grid Heater Delete Plate
When installing the SPELAB Intake Horn, you can replace the stock heater block with a Grid Heater Delete Plate. This plate is completely open, allowing the massive airflow from the SPELAB horn to pass unobstructed into the engine plenum. It also eliminates the "killer bolt" risk entirely.
2.2 The Integrated Coil Heater (For Cold Starts)
You don't have to sacrifice cold starts for performance. The SPELAB Intake Horn features pre-drilled, threaded ports designed to accept an optional Coil Heater element.
- How it works: Instead of a restrictive grid blocking the air path, a single, efficient heating coil is inserted into the side of the horn.
- The Benefit: You get the open airflow of a delete plate AND the cold-start ability of a heater.
3. Decision Guide: Should You Delete It?
When installing your SPELAB Intake Horn, use this guide to decide your setup:
| Your Scenario | Recommended Setup | Why? |
|---|---|---|
|
Max Performance / Warm Climate (Temps rarely below 32°F/0°C) |
Intake Horn + Delete Plate (No Heater) | Maximizes airflow (88% increase). Completely removes failure points. Your truck will start fine without a heater in mild weather. |
|
Daily Driver / Cold Climate (Regularly sees freezing temps) |
Intake Horn + Delete Plate + Coil Heater | Recommended. You get the safety of deleting the stock "killer bolt" unit, the performance of the high-flow horn, AND reliable starts in winter. |
| Budget Build / Mild Climate | Intake Horn Only (Keep Stock Heater) | The SPELAB horn fits on top of the stock heater. However, you still risk the bolt failure and lose some airflow potential. |
4. Frequently Asked Questions
Q1: If I delete the grid heater, will I get a Check Engine Light (CEL)?
A1: On 2007-2024 models, disconnecting the factory grid heater solenoid usually triggers a P2609 code. It generally does not affect drivability. You can clear this via tuning or leave the solenoid electrically connected (but disconnected from the heater) to bypass the error.
Q2: Is the SPELAB Coil Heater as effective as the stock grid?
A2: For most winter conditions, yes. While the stock grid covers a larger surface area, the SPELAB coil heater provides sufficient localized heat to aid ignition during cold starts without choking the engine's airflow like the stock unit.
Q3: How hard is it to install the Delete Plate with the Horn?
A3: It adds very little time to the job. Since you are already removing the stock intake horn, fuel rail, and lines to install the upgrade, swapping the plate underneath only adds a few minutes to the total installation time.
Q4: Will this upgrade lower my EGTs (Exhaust Gas Temperatures)?
A4: Yes. By removing the restriction of the stock grid heater and increasing the intake diameter to 3.5 inches, the engine breathes easier. Better airflow typically results in lower EGTs, especially when towing heavy loads.
Q5: What exactly is the "Killer Grid Heater Bolt"?
A5: It is the nut/bolt assembly on the bottom of the stock intake heating element. Over time, vibration and heat cycles cause it to loosen and fall directly into cylinder #6, causing immediate and catastrophic piston and valve damage.
Q6: Does this work with an EGR Delete kit?
A6: Absolutely. The SPELAB Intake Horn is designed to work seamlessly with EGR delete kits. In fact, doing both upgrades at the same time is the most effective way to maximize airflow and engine reliability.
Q7: Will I see an improvement in fuel economy (MPG)?
A7: Most owners report a modest improvement in MPG. By removing the airflow restriction, the engine doesn't have to work as hard to pull in air, which improves overall volumetric efficiency and can lead to better fuel mileage.
Q8: Does the kit come with new gaskets?
A8: Yes, the SPELAB Intake Horn kit includes all necessary heavy-duty gaskets, O-rings, and extended hardware required for installation, so you don't need to reuse old, worn-out factory seals.
Conclusion
So, do you need to delete the grid heater when installing a SPELAB Intake Horn? Technically, no—the horn fits over the stock unit. But should you? Absolutely.
Leaving the restrictive, risky stock heater in place undermines the performance gains of your new intake horn. By pairing the SPELAB 6.7 Cummins Intake Horn with a Grid Heater Delete Plate (and adding the coil heater if you live in the cold), you protect your engine from catastrophic failure and unlock the true potential of your Cummins.
John Lee
Mechanical Engineer | 10+ Years Experience
John has spent the last decade engineering and testing high-performance automotive components. Specializing in drivetrain durability and thermal management across Powerstroke, Cummins, and Duramax applications, he bridges the gap between OEM limitations and aftermarket performance. His philosophy: "Factory parts are just a starting point."
