What is Turbo Lag and Turbo Spool? (and how to prevent it)
If you’re new to owning a turbocharged vehicle, two terms you’ll need to get used to are turbo lag and turbo spool. But although these two terms are often used in the same conversation, they are completely different things.
In this guide, we’ll explain everything you need to know about both terms and give you some helpful tips on how you can downsize both, but chances are you’ll only want to downsize one! Don’t you believe us? Keep reading.
What is Turbo Lag?
Turbo lag refers to the time difference between the moment you step on the accelerator and the moment the turbo kicks in and delivers additional air to your engine.
Understanding why turbo-lag exists requires a quick lesson in how turbos work. Turbos work by taking energy from the exhaust with an exhaust turbine and then transferring it to generate pressure in the intake pipes with a turbine on the intake side. This extra air increases the amount of energy your vehicle can produce.
But since this is a fairly large area to build up pressure in the intake pipes, it takes a little time to give you the power output you’re looking for. This delay is called turbo-lag.
How can you reduce Turbo Lag?
While you may think that you can’t reduce turbo lag since it depends on increasing the amount of exhaust the vehicle has before you can use it effectively, you would be wrong. Although it is impossible to completely eliminate turbo lag, it is not impossible to reduce it.
This is because your turbo system is not 100% efficient, and the more efficient you make it, the less turbo lag you will have. Below we highlight three different ways to reduce turbo lag.
1. Reduce the size of your exhaust downpipe
If you decrease your exhaust downpipe, your turbo lag will decrease, but the tradeoff is that your maximum power will also decrease. This is because a smaller downpipe increases the exhaust velocity, which increases the spool of your turbo.
While this increases the speed at which the turbo can accelerate, it also decreases overall airflow, reducing the overall efficiency of the turbo. You’ll have to find a balance somewhere, but if you have excessive turbo lag, this can be an effective way to reduce it.
2. Upgrade your wastegate
Upgrading your wastegate is all about improving the efficiency of your turbo. An improved wastegate gives you a more responsive unit, reducing turbo lag and giving you a more efficient turbo.
However, you may end up increasing the overall amount of noise your wastegate generates. It may not be a big deal for you but know that it is a possibility. Also, keep in mind that this will not be as effective as reducing the size of your exhaust pipe.
3. Upgrade your intercooler
The shorter the distance between the exhaust and the turbo, the less turbo lag you will have. Some units prioritize the shortest possible pipes over everything else, and if you opt for one of these units, you will reduce the amount of turbo lag you will have.
Just keep in mind that while there are no downsides to upgrading your intercooler and piping, you probably won’t see significant results when it comes to turbo lag. Instead, you’ll gain hundreds to tenths of a second off your turbo latency.
What is a turbo coil?
Turbo spool is the time from when the turbo starts to build up pressure until it reaches maximum pressure. As you can see, it is therefore very different from turbo lag: turbo lag occurs when you press the accelerator pedal until it starts generating power.
Additionally, the turbo spool is determined by the size of the engine and turbocharger. It can also be augmented with things like an upgraded turbo wheel, for example.
Summary
Turbo lag and turbo spool are two extremely different terms that you need to be aware of if you drive a turbocharged vehicle.
The good news is that if you’re looking to reduce turbo lag, you have a few options, just know that you’ll never eliminate it.
