Pointless or Worthwhile?
A downpipe upgrade is one of the most popular exhaust mods among car enthusiasts looking to get extra performance from their car.
You’ll often hear about downpipes being required for many “Stage 2” tunes, and aftermarket downpipes play a critical role in overcoming the restrictions present in many cars in stock form.
When opting for an aftermarket downpipe, you may hear some people say it’s a pointless endeavour without having the car remapped/tuned.
Is this the case, or is it still worthwhile?
It’s definitely not pointless upgrading your downpipe without a tune, however you may not reap all the benefits and it can in some cases present some issues.
Let’s take a look at the benefits and potential issues now.
Sub-Optimal Gains

Without a tune, you likely won’t unlock the full potential of a downpipe upgrade. A tune optimises your engine, resulting in better boost behaviour and maximising the power gains from the downpipe.
When you fit an aftermarket downpipe, it results in a greater flow rate of exhaust gases, helping your engine to ‘breathe’ more effectively. However, by itself, the ECU might not efficiently manage this change.
With a tune, parameters like fuelling, boost pressure, and ignition timing can be adjusted to match the improved exhaust flow, ensuring that the engine works harmoniously with the upgraded downpipe.
The tune can maximise power gains, enhances throttle response and decreases turbo lag to ensure you get the most bang for your buck from your aftermarket downpipe.
Check Engine Light (CEL)

Upgrading the downpipe, particularly one with without a catalytic converter, can lead to the Check Engine Light (CEL) triggering due to changes in emission levels. While this doesn’t necessarily denote a problem, it can be annoying.
In fact, in certain places like the UK – a Check Engine Light is an instant MOT fail!
Depending on your car, you may be able to use a code reader or software to clear the CEL light from the dash. Your tuner will also be able to do this for you, but if you’re just going to them for that then you’re as well getting your car tuned whilst there.
Can It Damage My Engine?

Generally speaking, sticking a downpipe on your car without a tune won’t cause instant catastrophic engine failure.
However, on many cars it can cause the engine to run lean depending how the ECU handles it. Most ECU’s can account for this to an extent and alter the fuelling, however for long term safety a tune is recommended to sort this issue.
Having your engine running lean isn’t a good idea, and can cause issues like pre-detonation and damage to components over time.
As such, to avoid potential damage to your engine, its recommend to get it tuned as soon as possible after fitting a downpipe. Ideally, get your tuner to fit it for you and then they can tune it right away.
If you do need to drive the car with the downpipe on before a tune, take it easy and don’t go pinning the throttle everywhere.
The Verdict
So should you always get your car tuned after fitting an aftermarket downpipe?
In almost all cases, we would certainly recommend it. Aside from the additional cost of getting a tune/remap, there really is no downsides and you prevent the chance of any potential damage or additional stress on your engine over time.
Plus, if you are fitting a downpipe then you are likely chasing power gains and you don’t want to be missing out on the full potential of the upgrade by running it with a stock or incompatible map on the car.
Happy modding!