Posts Tagged ‘ Corsa VXR ’

When is a 3″ Exhaust NOT a 3″ Exhaust?

We recently had a Corsa VXR in for mapping and rolling road set up. The car was previously fitted with (by another company) a Full 3″ Turbo Back Exhaust System and uprated intercooler – which should be ideal for performance.

Our K06 turbo, an 80mm air flow meter and some higher flow injectors were added into the mix (the engine had previously been strengthened with forged pistons and steel rods)…….

Imagine our surprise when no matter what we did software wise we could achieve more than 266bhp, when around 300bhp was the aim with the components we had.

So When is a 3″ Exhaust NOT a 3″ Exhaust??…..

When it looks like this:

Restrictive Centre Section

Restrictive Centre Section

You can see from the restriction caused by the baffles that narrow the bore of the exhaust through the centre pipe, that the bore size is greatly reduced. This obviously reduces flow, increases exhaust back pressure and hampers performance massively.

In fact when the car went from a Stage 1 Remap, to having this particular exhaust fitted the customer did report he thought that the car felt slower!

Not only was there a problem in the centre section, but the tail pipes had the same problem:

Restrictive Tail Pipe

Restrictive Tail Pipe

Needless to say once we had found the restriction we switched the cat back section for one of our Courtenay Piper developed 3″ systems, which does not feature restrictive internal baffles and finished off the mapping, successfully achieving 306bhp, gaining over 45bhp mid range, 40bhp peak to peak and 50 lbs ft torque mid range!

Corsa VXR Graph

Corsa VXR with K06 Turbo Before and After removing a poor flowing 3″ exhaust

Corsa VXR Injectors

There is a lot of information and mis-information on the internet regarding Corsa VXR injectors. We thought we would give an insight into the situation and some  facts. When mapping Corsa VXR, we can add injectors to Corsa VXR when mapping at any stage.

The Corsa VXR injector is a 12 point multi hole injector. If these injectors are in good flowing condition the engine is capable of running at Stage 3 which for us is power normally around the mid 230’s. Bosch’s flow rate for the injector also suggest this with its cc’s per minute rating. However there is a proviso……

As the cars/engines have got older this multi hole injector can start to block up, right down to the point where by when mapping at even Stage 1 we have seen injectors not capable of the supplying enough fuel, hence the injectors would read correctly as maxed out.

As most know we do not just flash maps on the car, we map all the cars on the dyno and optimise timing, fuelling & boost etc to the car. We use Can 2000 the GM data logger and programming tool. With this you see the injectors running not as a percentage but in real time terms i.e.  read in milliseconds.  Milliseconds are the time it takes for the injector to close, charge and open to fuel again. When the injector is maxed it runs out of time to carry out this operation so has to close before enough fuel is delivered. This is referred to as an injector running out of injection duty cycle or more commonly being “maxed out”. When the injector max’s the value locks as it has not got enough time to  deliver the fuel required before it needs to close to charge for the next opening. So if it was maxing at 5000 rpm it would show 24 milliseconds from 5000 rpm through to the limiter. If it was doing this at 5500 rpm it would show 21.81 milliseconds right through to the limiter and so on as a rev related sliding scale. If we see this on a car then the injectors are removed, cleaned or replaced with bigger injectors after all they are listed on the web site and we do sell them so why would we not use them?……

We have on a couple of occasions when customers’ funds would not allow, put the cars back to standard or reduced the rev limiter to a threshold that is within the duty cycle, until the customer can deal with the issue by means of an injector clean/change.

As regards to fuel pressure changes, the industry standard for injector measure is taken at 3 Bar. From this you can see what the injector will approximately flow for given power. So if you take an injector that is 395cc at 3 bar and fit it to a Corsa which runs a standard OE pressure of 3.3 bar this injector has a true flow rate in the Corsa of 415cc. In the ECU there is a factor that is changed to recalculate what injector size the car has got and also the static fuel pressure, this then re calculates the base fuelling curve value to the new injector size and pressure before you fine tune it in with fuel trims and target air fuel ratio etc.

Now if all the cars we mapped were race cars we would fit the biggest injectors we could as emissions are really never an issue with race cars even if they do run token cats, nor is part throttle fuelling, town driveability and fuel economy. These are however important for the bulk of our road driving customers.  Therefore if someone is close to the top end of an injector range let’s say an injector flowing at 415cc at 3.3  then we can change the fuel pressure to 4.5 bar, re correct the base map and now the injector will flow 485cc for more range and margin.  The alternative is an expensive injector change to the next size up which in the case of the Corsa would be 650cc at 3 bar or 682cc at the Corsa’s 3.3 bar. Nothing wrong in doing that, but it could be a bit over kill. I will explain; a smaller injector working at a high pressure verses a large injector working at low pressure will always yield better atomisation therefore better part throttle/transient fuelling which means in simple terms better economy. VW’s TFSi engine for example.

A perfect case of this was a 350 bhp Astra VXR running a correctly calculated 550cc injector returning on cruise 28mpg, however when fitted with a Astra VXR injector running at 4 bar corrected in the map the car’s economy went up to 34 mpg; in simple turns the bigger injector does not atomise the fuel as efficiently at slow duty cycle/engine speeds.

I hope this just gives in insight into our approach as we do data log,  but it’s not just a sweeping case of the injectors not  being capable at  any given stage.  We simply take each car as we find it given it’s condition and mileage etc and go from there.

Piper Exhaust for Corsa VXR Nürburgring

Corsa VXR Nurburgring Tail Trims

Corsa VXR Nurburgring Tail Trims

Working closely with Piper Exhausts, a 76mm stainless steel tailbox has been developed for the Corsa VXR Nürburgring. Added to the existing 76mm system for Corsa VXR, a full 76mm system is now available for this car, to help release maximum performance.

As with the current system, the first main cat is removed and options include twin or single silencer systems with or without a motorsport cat.

Cars fitted with a full system will require an ecu remap to ensure optimum safe running and to overcome any issues with the emissions, as the VXR Nürburgring is a Euro 5 compliant model from the factory and removing the large factory fitted pre cat and just using a high flow motorsport cat will require an ecu recalibration to give correct fuelling and emissions.

Piper offer a range of tail trims, however the options shown here, 4″ (100mm) Slash Cut, is probably one of the best.

Pricing is as follows:
Full 76mm System with Motorsport Cat* Twin Silencers £1385.00
Full 76mm System with Motorsport Cat* Single Silencer £1240.00
Deduct £255.00 for a completely decatted* system

Cat Back System Twin Silencers £750.00
Cat Back System Single Silencer £610.00

*Note: A motorsport cat will pass current UK MOT emissions. In some countries motorsport cats may not be road legal. Please comply with the relevant laws of your country. Removing both cats may not be road legal and will lead to an MOT emissions failure.


 

Milltek Exhaust for Corsa VXR Nürburgring

Corsa VXR Nürburgring

Corsa VXR Nürburgring

After the announcement by Milltek Sport of a 70mm twin outlet cat back exhaust system for the Corsa VXR Nürburgring, Courtenay Sport are pleased to confirm that a full 70mm (2.75 inch) stainless steel system is now available.

The system removes the existing Euro V compliant first catalyst (pre-cat) replacing it with straight through pipework, the second cat in the factory system is replaced with a high flow motorsport cat*, and the cat back system comprises of  a stainless steel performance exhaust system with a twin-box rear silencer design with twin outlets.

The system has been developed with three different Tailpipe tip options:

90mm Polished, 100mm Polished and 100mm Titanium

Regardless of which tailpipe option you choose, the system offers perfectly balanced sound quality.

The Corsa VXR Nürburgring exhaust is manufactured from the finest quality 14-16 gauge 2.75-inch T304 stainless steel and features TIG-welded joints, C.N.C. mandrel bending and offers a significant weight saving over the OEM exhaust.

This system will release additional power  and torque over a standard system but will require an ecu remap to ensure optimum performance and no issues with management light illumination due to the motorsport catalyst, and removal of the first catalyst. Additionally the second lambda sensor wiring will need extending to fit. The system will also be ideally suited for customers wishing to further tune their vehicles to over 300bhp.

This full system is available at £1950.00 inc VAT and UK Mainland Shipping.

The cat back system is £925.00 inc VAT and UK Mainland Shipping.

Pricing is for either the 90mm or 100mm polished tail trim option.
For Dual Titanium 100mm tail trim please add £125.00

Please contact us for more details or to order.

*Note: A motorsport cat will pass current UK MOT emissions. In some countries motorsport cats may not be road legal. Please comply with the relevant laws of your country.

Über Corsa Fires Salvo at UK Hot-Hatch Class

  • Max power now up to 205PS*, torque to 280Nm
  • Mechanical LSD for optimum traction
  • Significant upgrades to both chassis and brakes

These are the first official pictures of Vauxhall’s most powerful Corsa ever, the new VXR Nürburgring Edition, which goes on sale in late May and aims to raise the bar in the hot-hatch class for performance and dynamics.

Corsa VXR Nürburgring

Corsa VXR Nürburgring

At the heart of the Nürburgring is a re-worked version of the Corsa VXR’s existing 1.6-litre turbocharged engine which now produces 205PS* at 5,750rpm (up from 192PS) and 250-280Nm of torque (up from 230-266Nm).

Read more

Blue-Min’ Tasty VXR Joins New-Look Corsa Range

  • Limited edition Corsa VXR Blue joins new Corsa range
  • High-spec model with big cost saving on equipment vs. standard car
  • Bold styling features complement design refresh from rest of range

Corsa VXR Blue Limited Edition

Corsa VXR Blue Limited Edition


Luton – Hot on the heels of the new-look Corsa range, the Corsa VXR Blue Edition features new styling details, additional kit as standard and a head-turning paintjob, at a price that’ll send its rivals into a spin. Read more

The Courtenay Sport Blog

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