GR Yaris Tuning Guide
Toyota GR Yaris Tuning Guide
The Gen 1 Toyota GR Yaris comes with 256bhp from the factory and responds really well to tuning. Our dyno reads power at the wheels (whp) and we then convert that to a very accurate estimated flywheel figure. Below is the route we normally recommend, from simple bolt-ons right through to serious Syvecs big-power builds.
Baseline – Standard GR Yaris
0 Start hereBelow is a dyno graph of a completely standard GR Yaris making 212whp, which converts to an estimated 258bhp at the flywheel.
This gives you a solid reference point before any modifications are fitted. It also shows why the GR Yaris responds so well to tuning — even in standard form it already has a strong torque curve and a broad usable powerband.
Starting with a proper baseline means you can clearly see what each stage is adding, from simple bolt-ons and EcuTek calibration right through to hybrid turbo and Syvecs builds.
Stage 0 – Bolt-ons (Intake + Exhaust + GPF Delete + Intercooler)
0 Best first modsThe first parts to fit to your GR Yaris are the intake and exhaust system for both power and sound. The GPF-back exhaust does not make a huge difference to power at the lower end of the tuning ladder, but it massively improves the way the car sounds and feels.
We sell a variety of systems, but our own Whifbitz exhausts in stainless and lightweight titanium are by far the most popular.
The Eventuri and Infinity Design intakes are the two best intakes we have tested. Eventuri is the one we have used most and it has proven itself time and time again. Infinity Design is a newer product, but we are a development partner with them and it has also tested extremely well. Most other intakes don’t make any additional power at all and are mainly just for more induction noise.
We also highly recommend a GPF delete pipe. These normally free up around 5–10bhp, increase noise and make the engine feel more alive.
GPF-back systems: more sound, more character. Popular in Whifbitz stainless and titanium.
Shop exhausts
Keeps intake temps stable so the car makes more power more consistently.
Shop intercoolersAn upgraded intercooler is well worth fitting because it allows the engine to make more power more of the time by keeping intake air temperatures under control. We generally fit the Airtec Motorsport intercooler as it works really well, is good quality and reasonably priced. Forge Motorsport and Wagner Tuning intercoolers also perform very well.
Stage 1 – EcuTek Remap (330bhp)
1 Fast road sweet spotThe next step is to remap your GR Yaris using EcuTek. This lets us increase boost and optimise the calibration properly to unlock more power from the G16E-GTS engine. A totally standard car will normally make around 300bhp with a remap, while a car with the Stage 0 hardware above will usually make around 330bhp.
These figures are based on the highest octane fuel readily available in the UK, which is 99 RON. If you use 95 RON, expect to lose around 20–30bhp, so it is not recommended if you want the best result.
Stage 2 – Maximise the Standard Turbo (350bhp)
2 Top of stock turboThe next step is to maximise the standard turbo. To do this we fit Kelford 267EZ camshafts with Kelford valve springs, then carry out a custom EcuTek remap. This setup normally delivers around 350bhp.
This is the point where the factory turbo setup is properly maxed out and the car starts to feel like a serious fast road or track build.
Stage 3 – Turbo Upgrade (380bhp)
3 Hybrid turboThe next step is a larger turbocharger. We currently offer two routes: the Midland hybrid turbo, which typically produces 360–380bhp depending on the exact spec, or the Artec Sport 400, which has achieved up to 435bhp on pump fuel to date.
At this point a forged engine is strongly recommended if reliability is a priority.
If you want to go all out, this shows what is achievable with the Artec Sport 400 turbo. This particular car features a forged engine, Kelford EZ cams and valve springs, plus a sports cat, running 1.9 bar of boost. As the dyno graph shows, it makes serious power without sacrificing low-down performance. In our opinion this is one of the ultimate GR Yaris setups.
Syvecs ECU + Lamspeed Racing Garrett G25 Kits
4 Big powerThe next step up is to ditch the factory style turbo and move to a Lamspeed Racing turbo kit using the Garrett G25 range. The G25-550 is rated at 550bhp and the G25-660 at 660bhp, hence the names. To do this properly you need a Syvecs ECU because the factory ECU cannot control an external wastegate.
Syvecs also adds advanced engine safety features not available on the standard ECU. For example, if oil pressure drops it can limit RPM or even shut the engine down entirely to prevent serious damage. We can install and configure a Syvecs ECU at any stage of the tuning process, depending on the build.
G25-550 on 99 RON
The G25-550 is still extremely useable and in our experience gives away very little compared to stock and hybrid turbos in the lower rev range. This car made 363whp, which is an estimated 434bhp, at 1.9 bar on 99 RON.
G25-550 on E70
Here the G25-550 is run on E70 ethanol fuel and makes a stonking 419whp, which is around 500bhp, at 2.1 bar. This is a brilliant setup for big performance while still keeping strong response.
G25-660 on 99 RON
This graph shows the G25-660 route. On 99 RON at 2.0 bar this GR Yaris made 392whp, which is an estimated 467bhp. You gain more top-end power, but with some sacrifice in low-down response compared with the G25-550.
G25-660 on E70
Add ethanol and things get very serious. With E70 fuel at 2.6 bar, power jumps to 530whp, which is an estimated 628bhp. This is properly big power territory and exactly why the Syvecs route is so popular for extreme builds.
Reliability
! Read thisThis is a hot topic because the issue only affects a small percentage of engines. We have seen it first-hand, including a case where a completely standard GR Yaris was taken to 400bhp and failed after just two days. That car was running a Syvecs ECU with full datalogging and there were no warning signs before the failure.
We have carried out countless 400bhp conversions without issue, yet occasionally an engine fails unexpectedly and when it does it is often catastrophic, with the piston exiting through the side of the block and completely destroying the engine.
It is a difficult one because the vast majority of engines — around 99.9% — will be absolutely fine. However, a small number appear to have an underlying piston issue that may only show itself once the engine is pushed harder. We have also heard of completely standard engines failing, and we have had multiple cars into the workshop that suffered the same failure after around a 320bhp remap.
If you want proper peace of mind when tuning, the only true solution is to upgrade to forged pistons and rods. We offer a full in-house engine build service along with upgrades such as a closed-deck conversion, uprated head studs and a performance head gasket. With this setup in place, the G16E-GTS engine will comfortably handle 500bhp.
Next steps
→ Let’s build yoursIf you would like advice on tuning your Toyota GR Yaris, please get in touch. Whether you want a simple bolt-on package, a fast road EcuTek setup, a hybrid turbo conversion or a serious Syvecs big-power build, we can advise on the right route, supply the parts, fit them in-house and calibrate the car properly.