# Supercar Spitting (DD-353)

> Flames from a car's exhaust come from unburned fuel igniting in the hot exhaust system. It happens most when a driver lifts off the throttle or shifts hard, and some performance cars and tunes deliberately add fuel or retard ignition timing to create pops, bangs and flames. The footage shows supercars shooting flames from their exhausts at night.

- Department: Tech
- First published: 2024-10-24
- Last updated: 2024-10-24
- Permalink: https://detailenjoyer.com/case/supercar-spitting/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-353-F01**: Unburned fuel ignites in the exhaust. _(Write-up · Exhibit A (Cause))_
- **DD-353-F02**: Exhaust gases are very hot. _(Write-up · Exhibit B (Heat))_

## Write-up

Supercar exhausts can shoot flames when unburned fuel ignites. Pops and bangs often come on hard deceleration.

1. **Cause**: Unburned fuel ignites in the exhaust.
2. **Heat**: Exhaust gases are very hot.
3. **Timing**: Often on deceleration or shifts.
4. **Tuning**: Some tunes add pops on purpose.
5. **Name**: Often called backfire or afterfire.

## Related case files

- [Supercar Police (DD-249)](https://detailenjoyer.com/case/supercar-police/): I linked more supercars

## Reel vs. record

- **Note**: None needed.

## Video: Supercar Spitting: Supercar Exhausts Can Shoot Flames When Unburned Fuel Ignites

- Duration: 21.8 s · Published: 2024-10-24
- File: https://detailenjoyer.com/assets/videos/DBhr2Repm5J.mp4

### Transcript

Did you know, supercars spit fire, primarily due to unburned fuel, igniting in the exhaust system, a phenomenon that typically occurs during high performance driving. This happens when the engine is revved aggressively, often leading to incomplete combustion. When excess fuel enters the exhaust system, it can ignite due to the extremely high temperatures of the exhaust gases, particularly during rapid acceleration or deceleration. NOW YOU KNOW!

## Questions & answers

**Q: What burns in the exhaust?**  
A: Excess fuel. _(Source: Write-up · Exhibit A (Cause) · Wikipedia: Afterfire)_

**Q: When is it common?**  
A: Off throttle. _(Source: Write-up · Exhibit B (Heat) · Wikipedia: Afterfire)_

**Q: Can it be deliberate?**  
A: Pops and bangs. _(Source: Write-up · Exhibit C (Timing) · Wikipedia: Afterfire)_

**Q: What ignites it?**  
A: Heat. _(Source: Write-up · Exhibit D (Tuning) · Wikipedia: Afterfire)_

**Q: What is it often called?**  
A: Afterfire. _(Source: Write-up · Exhibit E (Name) · Wikipedia: Afterfire)_

## Sources

- [Wikipedia: Afterfire](https://en.wikipedia.org/wiki/Afterfire)

## Cite this case file

Easterling, Marcus. "Supercar Spitting." The Detail Department (DetailEnjoyer), case file DD-353, last updated Oct 24, 2024. https://detailenjoyer.com/case/supercar-spitting/