Supercharging an NA VX220: what you need, what it costs and where it comes from

What "stage" means

Owners in a 2011 reply gave these meanings, then added that stage numbers are only a convenient label, since there are many ways to reach a given power:

• Stage 1: blower with no cooling for the intake charge. Once the air heats up, one owner said you can lose 30 to 40 bhp.
• Stage 2: blower with a charge cooler, usually with an exhaust, at roughly 260 bhp. The highest stage 2 car at a Dutch dyno day in 2012 was said to make about 259 PS.
• Beyond stage 2: everything else, in practice a bigger blower and engine work. See Is supercharging an NA worth it?

Where the parts come from

• From the US: the supercharger, inlet manifold, throttle body and the gasket between blower and manifold. In 2010 one owner said most people bought from one US dealer; in 2026 owners were buying second-hand from eBay and having them shipped, and a new-looking blower and manifold set was posted as a good find. Check the seller will post to the UK before you commit, and allow for import duty and shipping.
• From a UK specialist: the parts specific to our engine, such as the idler bracket, inlet support bracket, aux tensioner, belt, MAP sensor, injector plugs, the base map and the EGR blanking plate. See UK specialists and parts suppliers. In 2026 one owner said one of the two best-known suppliers could be difficult to reach at the moment and recommended the other.
• The front end: water pipes, header tank and the charge cooler core all have to be sourced in the UK, as nothing from the US donor car fits. Pro Alloy is the common kit. One 2026 owner thought it expensive and planned to try a cheaper core with 22 mm hose unions, which he hadn't fitted when he posted.
• Fitting: two UK businesses were named in 2026 as able to help with conversions (see the specialists guide). Owners in 2014 said that if you pay someone, the labour was good value compared with the learning curve, but several had done it themselves with help from other owners.

Using a ZZP kit as the base (2012)

One owner bought the US ZZP kit as the starting point for his own conversion and listed what was useful. This is one person's experience of a kit from that year, and the contents may have changed.

His conclusion was that the ZZP route was still a lot cheaper than buying every part he did use from the UK specialist, and he sold the parts he didn't need.

A fuller 2013 parts list, from the same family of conversions, is in the install guide's parts section.

Choices owners discussed

M62 or Harrop TVS1320

In 2026 a newcomer asked about the bigger Harrop unit. One experienced owner said it would need forged internals, as the standard bottom end is only good for around 250 bhp, and another said the sensible route was to get a working kit together with the M62 first. The Harrop is dearer. See Is supercharging an NA worth it? for what owners said about going beyond stage 2.

Throttle body

• The 2026 advice from one owner was to use the LSJ (Cobalt SS) throttle body, which needs the wires in its plug moving around (the install guide has the swap), and that supply from the UK specialists should be easy.
• The standard Z22SE throttle body can be used on the blower with an adaptor plate, but a newcomer assumed it would limit power. One owner who bought a car with the standard 54 mm body fitted found a 70 mm body made no noticeable difference on his set-up, and what improved it was a smaller pulley. That is a single car.
• US shipping for an LSJ body was over 400 dollars for one buyer in 2026. A US parts site was suggested as a cheaper source of aftermarket and remanufactured units; whether a remanufactured one keeps its electronics wasn't known.
• One buyer chose a 65 mm unit from the 2.4 Cobalt (the post gave a GM part number) after emailing the OBD Tuner supplier about compatibility. A reader pointed out that the 2.4 Captiva / Antara engines are a different, iron-block family, so check the donor carefully. We have not confirmed the fit.

Injectors

• The usual starting point is Z20LET injectors; blue VXR injectors were the next step. See Injectors for supercharged cars and Larger injectors: fitting.
• In 2026 an owner warned about fake injectors on online marketplaces and said a second-hand set from a running engine was more likely to be genuine. Specialists and a dedicated injector supplier were named as sources. The ideal, said one owner, is a good-quality injector sized for your power with a little headroom.

Idler bracket

• The belt has to be wrapped around an idler pulley beside the alternator. Owners said there are two designs, one mounting horizontally and one vertically, and one owner in 2026 thought the shop price high enough to consider making his own. Dimensions weren't given in the thread.
• A 2018 answer to a newcomer put it plainly: you don't replace the tensioner, you add an idler pulley, mounted on the alternator with longer bolts.

Dual-pass end plate

Dual pass makes the coolant go through the manifold core faster and keeps it cooler (2018 owner). Owners said the end plate can be bought as a new casting from ZZP, or the original end plate modified with some fabrication and aluminium welding, which one 2026 owner described as not hard. One owner's DIY plate worked but wasn't pretty. The Cobalt SS forums were suggested for how.

Pulley and servicing the blower

• ZZP sell a hub kit that lets you bolt on their pulleys, and a tool to remove and fit them. One 2026 owner said people make all sorts of claims for pulleys.
• A low-mileage donor blower with clean rotors (one buyer said his had about 10,000 miles) probably needs nothing beyond checking there is oil in it. The pulley size for a given power wasn't agreed, so use the mapper's advice.
• The donor oil cooler isn't used on our cars, owners said.

Wiring loom

One supplier-owner said in 2016 that he offered an exchange supercharger loom, which he called the hardest part of the conversion, plug and play. We haven't seen one. Ask the specialists.

Questions newcomers asked

A non-UK owner in 2018 asked about converting a Vectra C with the same engine, and wanted it to be reversible for an annual inspection. The replies are one or two owners each, so treat them as a pointer:

• Do I need new injectors? Yes, said both replies: the standard ones are not big enough. One said the standard injectors are good for around 190 bhp and a car on them will run short of fuel, which can wreck the engine.
• Can I use the standard cooling? The engine cooling stays as it is, but you need a charge cooler for the manifold or must run low power. The charge cooler water should be as cold as possible, not at engine temperature.
• Do I need a remap? Yes. With a tuner who can load a map quickly, putting the original map back is quick, which is one answer to the inspection question.
• Throttle body? You can use the original body if you make or buy an adaptor plate.
• Reliability? A 2013 owner said it is as reliable as a standard 2.2 if you stay under about 260 bhp and top up the oil more often.

Other ways to more power

• One 2026 owner converted his supercharged car to a home-built turbo and tried both together first. He said running the two together gave huge boost from 2,000 rpm but the blower was a restriction and the engine was better with the turbo alone. He thought the factory turbo car's iron-block engine offered no benefit over what he had.
• A 2016 post suggested a 2.4 engine swap for a naturally aspirated Speedster, and an owner replied that there is already one 2.4 supercharged, one 2.4 VVT with throttle bodies and one 2.5 in the UK, using the LE5 engine parts. We have no detail.
• Owners said to consider the cost of everything else, such as brakes, tyres and cooling, when adding power.