VX220 Turbo Power Upgrades
By Thorney Motorsport
Thorney Motorsport VX220 Turbo Tuning
Tuning a rear engined, rear wheel drive car is a very different process to front wheel drive - the emphasis has to be on smoothness and drive-ability even at the expense of peak power. However, we owned one of the first VX220 Turbos produced so, through constant development, we can give you both.
Thorney Motorsport Vauxhall VX220 Turbo - Stage 1 Power Upgrades - £399
ECU Re-Map. Approx +20BHP (+40BHP 3000-4500RPM)
We attach a GM Tech 2 diagnostics computer to you cars OBD port and drive it on an extensive test route. During this time, we log the cars ECU output and check for any irregularities or error codes from the ECU. Once we are happy that the car is performing as it should, we re-map the cars ECU with enhanced engine management code via the on board diagnostic port.
Our enhanced engine management code is the result of hundreds of hours of testing on road and track to gain the optimum performance for the car whilst still well within the realms of safety and longevity. Specifically for the VXT we have concentrated on ironing out the flat spots and irregularities in the standard map and added both torque and power all the way through the rev range. When before you were dropping to third gear to overtake you now can stay in fourth – it’s that big a difference. The big issue with the VXT is heat. The stage 1 map is written to maximise performance from the car without generating too much extra heat – the cars Achilles heel.
Thorney Motorsport Vauxhall VX220 Turbo - Stage 2 Power Upgrade
ECU Re-Map, Thorney Motorsport Turbo Back Exhaust System - Approx +30BHP (+45BHP 3000-4500RPM)
The standard exhaust system is very restrictive and effectively cuts what power we can gain from the ECU (it also sounds rubbish). The The Thorney Motorsport exhaust has been proven time and again (not least by Lotus and Vauxhall themselves) to add between 12-15bhp on its own. In fact it’s good Vauxhall adopted the system for the VXR220 – so you can safely say it’s the best.
The addition of the The Thorney Motorsport System allows us to use more aggressive maps on the ECU to generate a lot more power and torque – it really makes the standard VXT feel a bit lethargic. This level of tune is by far the most popular - the change is that dramatic. Another major benefit of using our exhaust is that its more efficient breathing draws more heat from the engine so more aggressive maps can be sued without the danger to heat levels. However, we still cap the power to 240bhp to make sure engine temperature safety levels are not exceeded.
Why do we not fit an induction kit?
It's simple really, the standard air mass meter on the VX220 Turbo is poor. Fitting an induction kit increases air flow velocity and will cause premature failure so we advise against it.
Why no dump valves?
Simple again, the VX220 Turbo's Turbocharger has a re-circulation valve. Replacing this with an External Dump Valve or VTA Dump Valve drops power and can cause irregular engine firing. If you want to sound like a WRC car then buy a Subaru.
Thorney Motorsport Vauxhall VX220 Turbo - Stage 3 Power Upgrade
ECU Re-Map, Thorney Motorsport Turbo Back Exhaust System, TMS Charge Cooler Kit, Supplemental Radiator - Approx +40BHP (+50BHP at 3,500RPM)
It's all about heat (getting bored of reading that yet?) and the ONLY sure fire way to drop this consistently is by fitting a charge cooler. A charge cooler works by running the air coming into the engine over a water filled core (think of it as a radiator with a water jacket) which cools it significantly better than a normal inter cooler.
Simple way to demonstrate this – blow on your finger. Now stick your finger in your mouth, take it out and blow on it again – feel cooler? That’s charge cooling. We retain the standard intercooler (it is very efficient) and mount a charge cooler behind so that the air coming into the engine is effectively cooled twice, this drops intake temps by 30% - significant. So significant is this drop that it means we can re-map the ECU much further and more importantly run the car without any fear of temperature related failures (the car ECU will back off when it gets too hot).
The bad news is that this is not a quick job and we’ll need your car for about 3 days as it means the removal of the front clam and various other bits to get all the plumbing in for the water pump and reservoir
Thorney Motorsport Vauxhall VX220 Turbo - Stage 4 Power Upgrade
ECU Re-Map, Thorney Motorsport Turbo Back Exhaust System, TMS Charge Cooler, Supplemental Radiator, Lightened Flywheel, Sachs Performance Clutch & VXR Astra Turbo, Uprated Actuator – Approx +50 bhp (+75bhp 3,500RPM)
You can go no further without massive engine modifications to this car. The stage 3 kit (which is all about keeping the engine cool and generating power) is supplemented with the real power upgrades to the engine. Sadly none of this is cheap – we will need your car for one full week.
We upgrade the turbo to the uit from the VXR Astra, its much stronger and allows us to run higher peak and held boost without problems. You can also upgrade to VXR Astra injectors although this depend on what kind of map you want on the car.
Added to this is our own lightened and balanced flywheel to maximise power delivery and smoothness. The ECU is then remapped to a peak boost of 19psi (standard turbo couldn’t take this level) and gives truly frightening power output. Fortunately we pride ourselves on the smoothness of our ECU maps and its very accessible power specifically written for track work.
The problem with this power level is that it’ll simply kill a standard clutch so we need to fit a Sachs performance clutch to cope. Happily this unit is nigh on bullet proof and can take over 500nm of torque but does mean taking the engine out so the labour time is high. We’ve been so impressed with this Sachs unit we now spec it to all our upgrades and recommend it even for lower power levels. It feels exactly the same as a standard clutch with just a heavier pedal feel to differentiate it.
The only way to make a VXT faster is to either change the turbo and all the engine internals or strap it to the wing of an F14 fighter!
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Assuming you don't actually have access to the US Navy's finest and your wallet is fat enough then you can go one stage further and have...
Thorney Motorsport Vauxhall VX220 Turbo - Stage 5 Power Upgrade
ECU Re-Map, Thorney Motorsport Turbo Back Exhaust System, TMS Charge Cooler, Supplemental Radiator, Lightened Flywheel, Sachs Performance Clutch, Roller Bearing Garrett GT28/30 Turbo, Uprated Actuator, TMS Forged Pistons, Forged Rods, Gas Flowed Head, Schrick Racing Cams – Approx 340BHP
Bat S**t Insane. We won’t actually fit this level of power to a VXT unless the AP Brakes, uprated suspension (Nitrons), some aerodynamic aids, LSD or traction control are also fitted. Its still in development but 350bhp and 450llb’s of torque is the aim.
It's very silly and only really for the very silly owner. If you need to ask how much then best go buy a Elise 240R (which cost £40k) because you’ll need to feel good about your badge when one of these comes past on the track.
We could go into lengthy detail about all the parts used and how they were selected through rigorous testing on our own cars or go into intricate detail about the 40 or so hours that goes into each conversion but frankly we'll run out of webspace, so if you really are interested in this (and we've done a few now so there are a few out there with a deathwish it seems) then best to give us a call.
