Gen 4 Grand National
Explore official-source information about the Gen 4 Grand National in iRacing.
Image © iRacing.com Motorsport Simulations
Quick reference
- Wheelbase
- 2,667 mm105 in
- Engine
- 358 cubic-inch V8
- Compression ratio
- 9:1
- Carburettor airflow rating
- 390 CFM
- Approximate power
- 447–485 kW600–650 hp
The NASCAR Gen 4 Grand National represents the category below Cup during the pre-Car of Tomorrow era. It resembles the contemporary Cup cars, but its shorter chassis and restricted V8 make it a distinct specification.
Suspension and chassis
The Grand National chassis has a 105-inch wheelbase despite sharing the visual style of contemporary Cup sheet-metal bodies. The official profile describes it as lighter than the Cup cars of that era.
Engine and electronic systems
The period specification used a 358 cubic-inch V8 with a mandated 9:1 compression ratio and a 390 CFM carburettor. iRacing describes approximately 600–650 hp, so this is a range rather than a single guaranteed output.
Driving character
iRacing highlights preserving momentum and smooth pedal inputs as important to this lighter, less powerful alternative to contemporary Cup machinery.
Official sources
Stop Guessing, Start Improving
Many drivers slam the brakes with all their strength, but the fastest modulate pressure, use the brake to rotate the car, and exit as fast as possible. Train that skill here.
Train Anywhere, Anytime
Browser-based training works with any racing pedals or controllers. Fanatec, Thrustmaster, Logitech, Simucube — no installation required.
Pro-Designed Exercises
Access exercises created by professional sim racers like Suellio Almeida. Learn the exact braking patterns used by the fastest drivers.
Import Gen 4 Grand National Telemetry
Drop your Garage61 lap CSV and extract braking data for every corner. Generate personalized practice exercises based on YOUR telemetry, not generic patterns.
Track Your Progress
View session history, performance trends, and best scores. Watch yourself improve over time and stay motivated to practice.
And There's Much More
Improve your braking technique with this car and much more:
Create Custom Exercises
Build from templates, draw brake curves, or record with your pedal
Schedule Your Training
Plan practice sessions and track your consistency across weeks
Brake Master Ratings
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Exercises & Progress Tracking
Practice exercises and track your progress completely free.
No install needed • Works in browser
General practice tips
Tip 1
Starting point
Start with the official setup and consult the simulator documentation for available controls. Appropriate brake bias depends on the car and conditions.
Tip 2
One variable
Change one setting at a time and compare several laps. Record the change and observed behavior before keeping it.
Tip 3
Comparable conditions
Compare similar fuel loads, tires and track conditions. One lap alone does not establish that a setting is better.
Frequently asked questions
General guidance for practicing and consulting car-specific sources.