10/21/2026
This 2013 Silverado came to us with concerns about a lack of power and performance potential due to a poorly calibrated tune.
Before we even strapped the truck to the dyno, we started by reviewing the existing tune to make sure there wasn’t anything that could potentially put the engine at risk. Once we determined it was safe to proceed, we performed a baseline dyno pull while data logging the existing calibration.
Let’s just say we found MULTIPLE problems!
Luckily, this customer was extremely knowledgeable and mechanically inclined, which helped us narrow down several issues before the truck even arrived.
PROBLEM #1 — VIRTUAL FLEX FUEL!
The previous tuner had left virtual flex fuel enabled. On these late-model GM vehicles without a physical ethanol content sensor, the ECM uses oxygen sensor feedback to estimate ethanol content.
Throw an aftermarket camshaft into the equation, and those readings can become extremely misleading!
In this case, the ECM was falsely entering flex fuel mode while the truck was running on regular gasoline, causing the commanded fueling to become excessively rich.
The customer had already experienced a no-start condition one morning, along with several other symptoms that had us concerned about the factory catalytic converters.
Because the truck still had factory exhaust manifolds and catalytic converters, we suspected that the excessively rich conditions may have damaged or plugged the cats.
We discussed the possibilities with the customer and prepared for the worst-case scenario. Luckily, we had a set of long-tube headers IN STOCK and ready to go!
Once the truck arrived, we performed an exhaust backpressure test.
Sure enough, the factory catalytic converters were COMPLETELY PLUGGED!
TIME FOR SOME UPGRADES!
We installed a set of long-tube headers along with one of our signature custom stainless steel exhaust systems!
After completing the exhaust work, we went back into the ECM and performed a complete custom dyno tune, correcting the issues we found in the previous calibration.
📊 THE RESULTS SPEAK FOR THEMSELVES!
BEFORE: 297 WHP
AFTER: 349 WHP
💪 THAT’S A 52-WHEEL-HORSEPOWER GAIN!
Now, before anyone jumps to conclusions, YES, the long-tube headers and custom exhaust absolutely contributed to those gains. We estimate approximately 20–30 horsepower could be attributed to the exhaust improvements alone.
But here’s where things get interesting!
The original dyno graph was extremely inconsistent and nonlinear. On top of that, the previous tuner had the REV LIMITER SET AT 5,500 RPM!
5,500 RPM!!!
Right about where this particular camshaft combination was finally starting to come alive!
Imagine spending your hard-earned money on performance upgrades, only to have someone leave a significant amount of your engine’s potential on the table because they don’t fully understand the combination they’re tuning.
MORAL OF THE STORY!
Just because you understand the basics of tuning, or you’ve successfully tuned your own personal vehicle once or twice, DOES NOT mean you’re qualified to tune every vehicle that comes your way!
There is a HUGE difference between making a vehicle run and actually understanding what the engine wants, how the ECM operates, and how to safely extract the performance that the combination is capable of producing.
Improper tuning doesn’t just cost you horsepower. It can cost you drivability, fuel economy, and potentially an entire engine!
At BT Speed Shop, we don’t just throw some numbers into a table and call it a tune. We review, diagnose, data log, make changes, and VERIFY our results on the chassis dyno!
That’s the BT SPEED SHOP DIFFERENCE! 💪
📍 BT Speed Shop — Coleman, WI
📲 Call, text, or message us to get your vehicle scheduled!
