Posts Tagged ‘ Mapping ’

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

Time Attack Set Up Check

We recently had the Courtenay Sport backked DCE Motorsport run Time Attack Astra VXR back for set-up check, after a spot of bad luck at the previous round at Donington Park. Some gravel ingress into the cambelt area caused severe damage to the engine, resulting in a last minute engine swap for the car, to ensure it was up and running for the final round at Brands Hatch on Sunday 29th September.

So with a borrowed ‘spare’ engine, Will and his pit crew worked tirelessly over the weekend and once the engine swap had been completed and all the ancillaries, turbo, manifolds and such like had been refitted the car came to us for a mapping session just to check and alter the parameters, due to the fact this engine was running slightly different compression than previously.

After a few hours set up, all is now well again and we’re looking forward to Brands Hatch. Good Luck to Will and the whole team.

The benefits of a full 3″ (76mm) exhaust system……

over just a 3″ (76mm) cat back exhaust system.

Had an Astra VXR in today, for an additional exhaust upgrade.

The car had previously been to us, not many weeks ago, for an ecu remap and rolling set up, having already had our 3″ (76mm) Cat back exhaust system fitted but running a standard pre-cat and main cat set up.

Our customer asked how to get further improvements out of his car and we suggested the addition of our 3″ (76mm) exhaust front section (straight through downpipe and cat), which removes the pre cat completely and utilises a motorsport main catalyst (all still UK MOT emissions friendly), making a full system.

Once the front exhaust section was fitted and the map altered on the rolling road, the differences are clear………..

Astra VXR Before and After Graph

Astra VXR Before and After Graph

Bear in mind, this car already had our 76mm cat back system fitted, so we were only adding the first half of the exhaust system, but the graph shows how restrictive the standard pre-cat and main cat are.

Gains across the rev range are: torque 20-30 lb ft, power 10-20 bhp and at 6,300 rpm a massive 30 bhp gain.

What’s more it completely transforms the car on the road.

VX220 Turbo Health Check

We had a VX220 Turbo booked in the other week as the customer had reported that the car seemed to be holding back on track. He thought it might be a fuelling issue and asked us to carry out a health check on the rolling road, datalog the ecu to see what the current map was doing and report back.

The car was running a ‘Stage 2′ ecu remap and has a full 2.5″ exhaust system. After our initial datalogging rolling road session we received a bit of a shock when we plotted the results ……..
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The Courtenay Sport Blog

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