Your vehicle
Start here — this choice sets everything below it. The engine controller changes between model years even when the badge does not, so each of these is a different license at a different price.
Transmission
Choose your year and engine first.
Fuel you will run
Pick a transmission first.
What is on the car
Choose a fuel first.
How it reaches your car
Declare your modifications first.
Calibrate the transmission too
OptionalDeclare your modifications first.
In plain terms
What actually gets rewritten
“Custom tune” is a phrase that can mean anything, which is why we would rather itemize it. This is the scope of the work on a GMC Safari — and several of these lines are sold as separate add-ons elsewhere.
If a behavior you care about is not on this list, ask before you order. If it cannot be changed on your controller, we say so — that is cheaper for both of us than finding out after.
On every calibration
- Fuelling and spark
- The fuel and ignition tables rewritten for the fuel you declared, verified against knock on every revision.
- Torque management
- The factory torque limits that blunt response, reshaped deliberately rather than crudely zeroed out.
- Throttle mapping
- Pedal position to throttle angle, remapped so the car does what your foot actually asked.
- Rev and speed limiters
- Moved deliberately, within what the rotating hardware and the tires are rated for.
- Cooling fan strategy
- Fans brought in earlier and harder. Heat is the tax on every additional horsepower, so it is managed, not ignored.
On this engine
Derived from what is actually fitted to this vehicle — this list changes from platform to platform.
- Speedometer and gearing correction
- Changed tire size or ring-and-pinion? The speedometer and the tables that depend on it get corrected to match.
Every Safari we support
Each has its own page with the full specification, the catalog notes and the requirements in detail.
In-shop — dyno service in Corona
Why this platform is tuned in the shop
Custom Dyno Tune, in Corona
The RTD4 cannot connect to the GMC Safari, so the car comes to Corona, goes on the Mainline ProHub, and is flashed with our own interface. We are not going to sell you a device that will not talk to your car.
$500 tuning + $350 dyno session + licensing — from $950 on this platform.
Before you decide
Asked on every one of these
The answers that cost us sales, kept on the page anyway.
All the questionsLonger answers: how dyno numbers get inflated.
Something specific to your car? (951) 405-4465 — a two-minute call beats a form.
- Can you ship a tune for my car?
- For 285 of the 775 vehicles in our catalog, yes. The rest are supported only as in-shop work because their ECMs cannot be reached over the Tune Delivery Network. Search your vehicle and the page states which applies before you buy.
- Why does a hub dyno matter?
- Because a roller dyno measures power after it has passed through the tire, so tire compound, pressure and temperature move the number. Our Mainline ProHub bolts to the hubs, which removes that variable and makes results repeatable between visits. Repeatability is the only property that makes a before-and-after comparison mean anything.
- Do I get the full sheet?
- Always, including runs we were not happy with. Cropping to the peak is how the industry hides work it does not want compared.
- Will my car stay smog-legal?
- No. Calibration alters emissions-related engine management. Our work is sold for off-road and competition use. We would rather you hear that here than at a testing station.