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Corsa VXR Engine Build

This low mileage Corsa VXR was booked in with us recently for an engine rebuild. It was a very late car with a B16LER engine.

The whole process starts with removing the engine and gearbox from the car, separating the gearbox from the engine and then stripping the engine down to a bare block and head. The block is then rebored and honed to suit an oversize 79.5mm forged piston and to achieve the correct piston to bore clearance. Once it is fully cleaned the block is then rebuilt with new forged pistons and rings, steel rods, uprated ARP rod bolts, new big end bearings, new gaskets and head bolts. On such a low mileage engine (4k) the main bearings, timing belt, tensioner, pulleys, oil pump and water pump were all as new and could be refitted. On higher mileage engines we recommend that these are replaced as necessary. As necessary the valve stem seals are replaced and the valves reseated. If either of the block or head faces need refacing this is carried out at ther same time as is additional balancing work if required.

Once the engine is built back up with its ancillaries and timed up, it is refitted to the gearbox and then fitted back into the engine bay. Engine oil, suitable for running in and coolant are added and the engine is then run up and road tested. We recommend the addition of Evans PowerCool 180 Waterless Coolant as part of an engine rebuild.

It takes approximately a week for this type of work to be completed.

Here are some pictures of the process:

It’s been a while…….

since we have found some of these on a car, but occasionally it still happens.

Transport Blocks

Transport Blocks

They are the transport blocks which are fitted in between the front spring coils each side, especially on lowered cars, which prevent the springs from compressing keeping the chassis height higher allowing for lowered cars to be moved onto and off transporters more easily and to help the front valances clear better preventing damage. Thay are however meant to be removed by the dealerhsip when the car undergoes its PDI (Pre-Delivery Inspection) for obvious reasons……..

Vectra VXR Mapping Session

This Vectra VXR came to us for mapping having already had an Insignia VXR Turbo unit and an intercooler fitted. The cats had also been removed prior to its visit. Once in our rolling road bay, a set of uprated injectors were fitted and then the car was mapped and set up on the rolling road, achieving excellent figures; 329bhp and 406 lb ft torque. These numbers were about what was expected from a car running a factory water radiator, as oposed to an uprated water radiator, in between our Stage2+ (320-325bhp) and our Stage 3 (340bhp) packages.

More details on Vectra VXR tuning on our >>>> main website <<<<.

Vectra VXR on the Rolling Road

Vectra VXR on the Rolling Road

Astra VXR Rolling Road Health Check

It is always useful to have a car checked from time to time on the rolling road, as it can show up potential running issues.

We had this Astra H VXR Nürburgring brought in for a health check on the rolling road this week, due to it feeling ‘down on power’ after a manifold swap by the owner, so running it up and datalogging it should highlight any issues.

We carried out an initial check over of the vacuum pipes, recirculation valve and actuator just to make sure nothing physical was at fault which could cause a problem. The ecu was also checked for any stored trouble codes, again to see if there was anything that could cause a running issue.

Running the car up on the rolling road whilst datalogging found the turbo to be down on boost, making less bosst pressure than expected  and resulting in 255bhp and 290 lb ft torque down on what is expected from a Nurburgring with a remap.

Additional checks were carried out to the boost hoses and intercooler fittings, which showed no leaks or issues.

After further runs, the turbo was shown only to be capable of making a maximum of 20psi overboost, and unable to make the required boost at peak power (around 5,700rpm), so identifying the root cause of the problem to be a failing turbocharger.

Astra VXR Health Check

Astra VXR Health Check

Supercharged VX220 Mapping Session

Supercharged VX220 2.2 16v

Supercharged VX220 2.2 16v

A recent mapping session on a VX220 2.2 with a self-install supercharger conversion. Initially brought in a while ago for mapping the car achieved 216bhp, lower than the expected Stage 2 power due to a restrictive exhaust system identified during the first mapping session.

Brought back to us with a derestricted 2.5″ front pipe and cat section, we were able to improve the mapping with changes to the ignition and fuelling now that exhaust flow had improved resulting in gains to 242bhp, with the graphs showing improved power and torque right across the rev range.

Corsa VXR Blue Edition – Stage 2

We had this lovely low mileage Corsa VXR Blue Edition with us recently.

Corsa VXR Blue Edition

Corsa VXR Blue Edition

If it was feeling ‘blue’ before it arrived, it certainly wasn’t when it left, after having a full 3″ exhaust system fitted, NGK iridium plugs, a panel filter, large bore inlet pipe and uprated recirculation valve followed by ecu remapping and a full set up on the rolling road with datalogging and map optimisation.

Corsa VXR 3" Exhaust Fitted

Corsa VXR 3″ Exhaust Fitted

Achieving 223 bhp and 238lb ft torque runing on 99 Octane V Power Nitro+.

Corsa D VXR Engine Mounts

Due for imminent release, expected within the next 3 weeks, uprated engine mounts for Corsa D VXR models.

Corsa VXR Engine Mount Group

Corsa VXR Engine Mount Group

Pricing from £93.60 – £138.00 Further details to follow. Contact us now to pre-order yours.
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Which Oil? Engine and Gearbox

Valvoline SynPower 5w-40

Valvoline SynPower 5w-40

Engine Oil:

One question we are often asked with regards to turbocharged engines is which oil should be used?

There are many choices of oil on the market, and different people will give you different answers as to which is best and why.

For Pre-2011 Vauxhall/Opel cars the OE spec for oil is LL-A-025/LL-B-025 (Petrol/Diesel). For 2011 on models this spec has been replaced by GM Dexos2™ spec. Dexos2™ spec oil is backwards compatible.

Our advice for pre-2011 Vauxhall/Opel petrol 2.0 Turbo and 1.6 Turbo engines fitted with K03/K04/K06 turbo units is to use a high quality fully synthetic engine oil with a viscocity of 5w-40 for fast road and track day use, which meets or exceeds API:SM SN/CF and ACEA A3/B4 classifications. This can also be used in engines fitted with Garrett or similar turbo conversions.

Our suggested choice is Valvoline SynPower 5w-40 Fully Synthetic Engine Oil which we run in our road and trackday cars and which we have also run in Astra H VXR race cars without issue. Amsoil European Formula is another suggestion for high quality oil; one of many oils available.

It is suggested for engines used for hard use that oil temperature and useage are constantly monitored which will identify if a different grade of oil is required.

2011 onwards engines require a high quality oil meeting Dexos2™ spec.

The key is to use a high quality fully synthetic oil and to keep the oil in turbocharged engines changed regularly. On modified cars it is sensible to ignore the extended drain intervals that manufacturers suggest and stick to more frequent changes. Oil that is changed regularly keeps an engine clean. Our recommendation is 5,000 mile change intervals for a turbocharged engine, especially for cars experiencing hard use, but at worst 7,500-10,000 miles.

Valvoline 75w-90

Valvoline 75w-90

Gearbox Oil:

For manual gearboxes such as F20, F23, M32, F40 we suggest the use of a high quality fully synthetic gearbox oil, viscocity 75w-90.

Our choice is Valvoline SynPower TDL for fast road use or Amsoil MTG 75w-90 for fast road and trackday use where higher gearbox oil temperatures may be sustained.

Again with gearbox oil it is always worthwhile considering regular oil changes, especially on the M32 gearbox where a 20,000 mile oil change will do no harm.

Pagid S Performance Brake Pads

Pagid S


Street Legal Pagid S Performance Brake Pads.


Pagid S Sports brake pads have been specifically designed for high performance brake system usage on public roads, but it is no secret that their origin is the race track and where they truly belong. High friction, low fade characteristics and low pad wear over a wide temperature range make these pads ideal for use on public roads, track days and in club racing. R90 Approved for EU road use.

Now In Stock for Astra H VXR and Zafira B VXR

Also available for Astra G Turbo, Astra H 1.9 CDTi, Astra H 2.0 Turbo, Corsa D VXR and SRi 1.6 Turbo

Pagid S Performance Brake Pads

Pagid S Performance Brake Pads

Astra VXR Sprint

Built specifically for use as a track day car, this car was previously a Stage 3 car producing a useful 292bhp and had been fitted with our 3″ full exhaust, CSRacing Intercooler, Pro Alloy Water Rad, Wavetrac LSD, Alcon 4 Pot calipers with 356mm alloy belled discs, 292mm Rear Brake Upgrade, Whiteline Rear ARB, DAP Road Springs, direct route hose kit and Pro Race 1.2 alloys. Building on the track day specification, other modifications have included Recaro Pole Position Seats, Rear Cage and Sabelt Harnesses.

Astra VXR Sprint

Astra VXR Sprint

After a few engine changes including K06 turbo rework, Courtenay Klasen Inlet Manifold, Steel Rods, Turbosmart Actuator and Recirculation Valve and a few hours mapping on the rolling road we achieved a respectable 336bhp and 355 lb ft torque, all useable on track increases through the mid range and top end, with the ability to rev to 7,500 rpm.

Before and After Graph:

Stage 3 K04 v Stage 4 K06  Astra VXR

Stage 3 K04 v Stage 4 K06 Astra VXR

Turbosmart Actuators

Turbosmart Actuator

Turbosmart Actuator

Uprated Turbosmart Actuators are now in stock.

Uprated Turbosmart Internal Wastegate Actuators provide better turbo response and greater sensitivity when managing boost pressures, especially when bespoke mapping.


• Silicone diaphragm with Nomex reinforcement to withstand high temperatures.
• High grade, billet aluminum construction.
• Stainless steel rods for corrosion resistance.
• Locking Collar design cap allows for quick spring changes.
• Actuator Base Pressure can be changed with internal springs.
• Anodised Black Finish
• Available with 10 or 13PSI Actuator Springs


This uprated Internal Wastegate Actuator is suitable for KKK factory turbos with an internal wastegate, such as K03, K04 (VXR) and K06 as used on 2.0 Petrol Turbo Z20LEx engines Astra G, Astra H, Zafira A, Zafira B including VXR models where an uprated actuator is required.

Can be used for all stages of tune/mapping with just spring changes if additional actuator clamping pressure is required during mapping.

10PSI – For Astra H/Zafira B VXR from 240bhp – 285bhp
10PSI – For Astra H/Zafira B VXR from 305bhp-340bhp K04 and K06 Hybrid
13PSI – For Astra G/Zafira A 2.0Turbo for Stage 4 280-295bhp
13PSI – For Astra H/Zafira B VXR for Stage 3 290-295bhp

If you already run the 10PSI actuator, there is no need to purchase another actuator we can supply additional suitable springs to adjust the spring tension to 13psi if required for mapping.

Available with or without mounting bracket From £120.00 – £189.00

Corsa VXR Nürburgring Stage 2 Upgrade – Take 2

It has been a busy week for us for Corsa VXR tuning.

This Glacier White car is our second Corsa VXR Nürburgring Stage 2 Upgrade in a week. We fitted our full 3″ turbo back exhaust first:

Corsa VXR Nürburgring Exhaust Fitting

Corsa VXR Nürburgring Exhaust Fitting

Followed by custom mapping, datalogging (including ignition timing, knock retard, injectors, boost pressure, fuelling), map optimisation to suit the new exhaust and full rolling road set up:

Corsa VXR Nürburgring on the Rolling Road

Corsa VXR Nürburgring on the Rolling Road

Corsa VXR Mapping

A busy week for remapping Corsa VXRs on our rolling road with this A16 engined Corsa VXR in for mapping, injectors and set up earlier in the week, reaching a respectable 217bhp for a car with a 70mm cat back exhaust.

Corsa VXR on the Rolling Road

Corsa VXR on the Rolling Road

Garrett Built Astra G GSi Turbo 503bhp

Garrett Build Astra G GSi Turbo 503bhp

Garrett Build Astra G GSi Turbo 503bhp

Another Garrett build, with Garrett GT30 Turbo, V Band Manifold, Courtenay Klasen Cams and Inlet Manifold, Engine rebuild, 90mm AFM, injectors, 3″ exhaust; all the usual requirements for a Garrett conversion, previously mapped by us and making a respectable 490bhp; brought in for checking now its a little cooler. Up 13bhp to 503bhp due to the lower temperatures.

VXRacing Door Sill Trims

VXRacing Sill Trim Cover

VXRacing Sill Trim Cover

VXRacing VXR Door Sill Trims Now Available. As fitted to Astra VXRacing Editon models

Only £33.60 per pair

Another Garrett Build Astra H for Mapping

Astra H Van with Z20LEH VXR Engine

Astra H Van with Z20LEH VXR Engine

This Astravan with Z20LEH engine, steel rods and GTX2867 garrett build was brought in for mapping and full rolling road set up.

The map it was brought to us with (which was not our software) was checked first and shown to be running 320bhp, with some fuelling and ignition timing issues.

We switched to a 3 bar map sensor (from a standard 2.5 bar one) and recalibrated the map so the ecu could correctly read boost pressure as the 2.5bar map sensor will go out of range on capable of reading up to 22psi of boost, hence the change to a 3 bar sensor. Correctly recalibrated the ecu can then read up to 29.4psi boost presure.

Also changed were the 875cc injectors to a much more suitable 630cc injector for the required power, again with suitable ecu recalibration. 875cc injectors for the required power prove way too big, and cannot be controlled accurately enough for part throttle fuelling (essential on a fast road car) due to the spray pattern plus fuel consumption will be higher, again another consideration for a car with road manners. When checked and datalogged first this car was running at 0.88 lambda on cruise, so clearly the map needed some work at this point. This is too rich and can cause bore wash and potentially internal engine damage. Big injectors are fine for stand alone management and for race cars which do not run at part throttle or cruise, but were just incorrectly specced for this particular applcation.

With a couple of bits still to do and after mapping and set up the result for now is 390bhp and much better, more controlled fuelling at part throttle and cruise. Fuel consumption will improve as well as 630cc injectors control part throttle fuelling more accurately.

Why the change of injectors? For better road manners; in simple turns the bigger injector (875cc) does not atomise the fuel as efficiently at slow duty cycle/engine speeds. So a 630cc injector can provide more than enough fuel for the power but still return better fuel economy due to its ability to better atomise the fuel.

DAP Springs Astra J VXR

DAP Springs Astra J VXR

DAP Springs Astra J VXR

  • Manufacturered Exclusively for Courtenay Sport.
  • Probably the ultimate fast road springs for this chassis.
  • Lowers the VXR chassis by about 20-25mm.
  • For excellent road holding whilst maintaining good ride quality.

Priced at £183.95 per set.

Following our very successful and much acclaimed DAP R Astra H VXR spring kit we now have our DAP R Astra J VXR spring kit available.

Vauxhall set the bench mark very high with the original Astra J set up which didn’t make our job very easy however after an extensive period of development we have achieved what we feel is the ultimate fast road set up.

Visually the car now sits typically between 20-25mm lower. The straight line ride quality is slightly firmer but not at the detriment of ride quality and certainly does not feel crashy, however press hard into the corners and the suspension tightens, firming up giving more control through mind corner bumps and undulations whilst communicating with plenty of driver feel and feedback.

DAP Rs are wound from high tensile chrome silicone steel and are manufactured in a cold winding process for maximum durability in all weather conditions. They are powdered coated Diamond Black to give a very OE look and feel and have the DAP signature discreetly placed on them.

Corsa VXR Nürburgring Stage 2 Upgrade

This lovely 2012 Corsa Nürburgring in Lime Green Pearlescent was brought to us for a Stage 2 upgrade, so initially into the workshop and up in the air so the original exhaust could be removed to be replaced with the full 76mm (3″) turbo back stainless steel exhaust system:

Exhaust Fitting - Corsa Nürburgring

Exhaust Fitting – Corsa Nürburgring

and then onto the rolling road for custom mapping, datalogging (including ignition timing, knock retard, injectors, boost pressure, fuelling), map optimisation to suit the new exhaust and full rolling road set up:

Mapping on the Rolling Road - Corsa Nürburgring

Mapping on the Rolling Road – Corsa Nürburgring

Courtenay Sport at Trax 2014

A few pictures of our display at Trax 2014, Silverstone Circuit Sunday 7th September.
Thank you to everyone who came along on the day and for some fantatsic cars as part of the display.

Cambelt and Timing Information – Z20LEx Engines

Useful Gates Technical Information for Cambelt Timing on the Z20LEx 2.0 Turbo family of engines; Z20LET, Z20LEL, Z20LER and Z20LEH (Astra H VXR). This is not a ‘How To’ guide but additional technical information for those with enough mechanical competency to carry out a cam belt change.

Cambelt Change Cycle suggested by the manufacturer:
Z20LET :: 4 years* or 40,000 Miles*
Z20LEL :: 8 years* or 80,000 Miles*
Z20LER :: 8 years* or 80,000 Miles*
Z20LEH :: 8 years* or 80,000 Miles*
*Whichever occurs first.
Notes: The cambelt (timing belt), plastic inlet roller and tensioner are common between all the engines (i.e. the same parts). The only different is that the LEL/LER and LEH kits use a metal exhaust roller (LET uses a plastic exhaust roller). For this reason we suggest a 6 years* or 60,000 Miles* change cycle as best practice. Always use a new tensioner retaining bolt (torx head) with the LEL/LER/LEH engines.

What is Needed……
A good toolkit with a good selection of sockets, allen head sockets, male torx sockets, a 15mm spanner (or similar) to release tension on the auxiliary drive belt and a 17mm ½” drive socket and ratchet (makes turning the engine over to check tension much easier). For the later engines a very high quality T40 Male Torx ⅜” drive socket, and a ¼” drive E10 female torx socket (a slim one) is useful for removing the timing belt cover bolt next to the tensioner once the tensioner is in the ‘rest’ position.

Do not forget a suitable Camshaft Locking Tool (widely available).

On the later engines the cambelt tensioner retaining bolt has a very shallow torx head and if you are not careful the socket can slip and/or chew out the head of the bolt. We suggest akways replacing this bolt when fitting a new belt kit (often the kits are not supplied with the tensioner bolt!)

Remember the tensioner is tensioned ANTI-Clockwise!! We see far too many incorrectly tensioned cambelts.

Torque Settings (for reference):
Toothed belt tension roller to oil pump: 20Nm
Toothed belt guide roller to cylinder block (exhaust side): 25Nm
Toothed belt guide roller to cylinder block (inlet side): 25Nm
Toothed belt cover – upper part to rear toothed belt cover: 6Nm
Toothed belt cover – lower part to rear toothed belt cover: 6Nm

When changing the cam belt always check the water pump and replace if in any doubt, especially on later engines where the change cycle of the cam belt is longer.

Gates Technical Data Sheet on how to time up the engine:

PDF Timing Information

PDF Timing Information

Note: You will need a PDF reader for this file

Timing Belt Diagram Z20LEx

Timing Belt Diagram Z20LEx

Note: E&OE. The above Technical Guidelines are provided for information only. We accept no responsibility for any loss (consequential or otherwise), damage, injury howsoever caused relating to persons undertaking their own repairs. If unsure please seek the services of a professional.

The Courtenay Sport Blog

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