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The Corsa VXR's 1.6 turbo runs port injectors that age badly, and a leaking or lazy one shows up as a rough idle, a misfire that only appears under load, a smell of fuel and poor running from cold. We change them as a matter of course before a remap, because a Stage 1 file asks the injectors for more fuel over a longer duty cycle and an injector that just survived standard boost will not survive the extra. A remapped Corsa D VXR makes around 210bhp and 300Nm from 192bhp, and the Corsa E around 230bhp.
Measured on our Mustang AWD rolling road in Maidstone. Wheel figures, drivetrain loss added for the flywheel numbers.At its release in 2007, the Corsa VXR was a very popular car for the person that wanted a quick car without having a deep pocket. With a small 1.6 turbocharged engine, it kept running costs relatively low whilst still providing the driver with a lot of power. This is why the Corsa, an already very popular hatchback, earned its place as one of the greatest hot hatches of the 2000s. Today, you can get an absolutely cracking deal on one of these cars. The VXR, especially the facelift model from late 2011 onwards, still looks modern and sporty on the roads now. There are however a couple of things that let this great car down… One of the big ones being the Corsa VXR injectors.
What’s Bad About The Corsa VXR Injectors?
Well out of the factory, the injectors are already too small for their application. The 12 point multi hole injector in good flowing condition is capable of supplying enough fuel for a soft stage 1 tune. Even then, you can’t be sure of the condition of the injectors because as the Corsa VXR gets older, more and more of them are racking up miles on the road. This means most injectors are becoming blocked up preventing as much fuel supplied into the cylinder.
The small injector size means that when a Corsa VXR is tuned, the injectors max out very quickly. When we say ‘maxed out’, we mean that the injector is supplying the maximum amount of fuel possible, however the engine is demanding more. This results in the air-fuel ratio running leaner than it should as well as causing the power also dropping off in the higher revs. Why does the engine need more fuel you may ask? Running it lean means it will generally run hotter which just isn’t safe. With more fuel we can then increase boost pressures further knowing that the air-fuel ratio (AFR) will be safe.
As this problem is so common, we always recommend upgrading the injectors before we tune the car as even if the injectors are in good flowing condition now, they are very likely to restrict our results and put unnecessary strain on the engine. This is a service that we can provide here at JF Automotive on the day of your performance software tune to make your life even easier (and your car even faster!).
Stage 1 With New Injectors
When this customer approached us, we recommended he upgraded his injectors before we tune the car to get both more performance and reliability from his VXR. After he looked into it himself he agreed and so we swapped the stock injectors for a set out of a Maserati. These were a lot better, so when we installed our stage 1 software with a pop and bang remap, the results were impressive. We saw that the car was now putting down nearly 30bhp more than manufacturer figures claim, whilst also raising the torque by over 100Nm! The dyno graph shows that our engine ECU remap also gives a much more consistent power delivery curve making for even more fun in the hot hatch.
If you have a Corsa VXR that you would like tuned, get in contact with us below.
Photos from the build
6 photos of this Vauxhall Corsa in our Maidstone workshop. Tap any to enlarge.
Questions we get asked
How do I know if my Corsa VXR injectors have gone?
Rough or hunting idle, a misfire under load rather than at idle, a fuel smell around the engine bay, hard starting from cold, and fuel trims sitting well away from zero. A leak-off test or live data confirms it.
Why change them before a remap rather than after?
A remap asks for more fuel across a longer duty cycle. An injector that was borderline at standard power will not hold up, and a lean condition on a boosted engine is the expensive kind of fault. Changing them first is cheaper than the alternative.
What does a remapped Corsa VXR make?
Around 210bhp and 300Nm from the 192bhp Corsa D, and around 230bhp from the 207bhp Corsa E. Modest gains by our standards, but the torque figure is what changes how the car drives.
Do all four injectors have to be changed?
Yes, as a set. One new injector against three worn ones gives uneven fuelling across the cylinders, which drives worse than four evenly tired ones.
