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Another question we are constantly being asked is about remapping and correct set up and why this is better than a hand held unit.

Many people like the convenience of installing a map from a hand held unit (and are often ‘sold’ the same results as bespoke mapping, which invariably is not the case), but without checking it or seeing what it is doing for the car, the results are simply ‘hit and miss’. Put simply unless ecu software is properly checked and optimised to each car, you are unlikely to get the results you are expecting (or have been sold!)

Here’s a graph for an Astra VXR which we were asked to dyno which had a lower front mounted intercooler fitted, a full 70mm Remus Exhaust System and an unchecked map from a hand held unit. The resulting dyno figures show the map gave worse results than the factory software (where we have seen 270bhp on a car with exhaust and intercooler fitted):

Astra VXR Competitor Stage 3 : Before

This set up, correctly mapped should really have been producing at least 285bhp, not 252bhp!!

At the customer’s request, we changed the intercooler for one of our Full Height Front Mounted VXRacing Intercoolers and fitted a full 76mm system. Once properly remapped, datalogged and set up on the rolling road we achieved:

Astra VXR Courtenay Sport Stage 3 : After

And finally here are the before and after graphs, showing the differences. Much more power and torque right across the rev range, which will totally transform the drive of the car:

Astra VXR Stage 3 Comparison

On more than one occasion we have extolled the virtues of a good, free flowing 76mm sports exhaust system for Astra VXR to get the best performance results out of remapping correctly.

Well here is another classic example……..

The car in question is an Astra VXR 2.0 Turbo which was fitted with a Stage 1.5 Hybrid K04 turbo (with exhaust wheel cut back), a large full height front mounted intercooler and a ‘one-off’ made to the car exhaust system which in places reduced to 50-57mm.

Once mapped the results were as follows:

Astra VXR Stage 3 : Poor Exhaust System : Before

Results: 278 bhp and 318 lb ft torque.

Upon examining all the evidence from the rolling road and datalogging, we concluded that the exhaust system was the limiting factor. Some might say it was easy for us to blame the exhaust (which we didn’t supply)….. why could it not be the installed software??

Well, we could comfortably rule out software based on the fact that all our maps are optimised on the rolling road and datalogged. so we knew we couldn’t get any more ignition timing into the software or take any more fuel out (without risking safety).

So we had the car back a couple of months later and fitted our full 76mm sports exhaust system, changed nothing else and ran the car back on the same rolling road, resulting in the following:

Astra VXR Stage 3 : 76mm Exhaust System : After

Yes, no word of a lie results of 305bhp and 348 lb ft torque, aided by the Stage 1.5 hybrid turbo, the full 76mm system and the cold February dyno cell temperatures.

Here is the before and after graph. The gains speak for themselves. Lots more power and torque right across the rev range:

Astra VXR Stage 3 - Good Exhaust vs Poor Exhaust : Before and After Results

So if you are trying to decide on which exhaust system to fit to your Astra VXR, we think we’ve just made the decision much easier for you. A good exhaust system may cost a little more, but you will get the benefits from fitting it.

Courtenay Sport VX220 Turbo with a bespoke Garrett Build, strengthened rebuilt engine, Pro Alloy Chargecooler, full 3 inch exhaust system and full Z20LET engine management mapped by Courtenay Sport….. 360bhp

2 Bar Dyno Runs….. 580 bhp at the wheels….. More to Come…..

Courtenay Sport’s mapping engineer Stephan Klasen has a new project underway; An Astra H drag car……..

First dyno runs at 12psi producing 400 bhp. Target horsepower in excess of his Speedster Turbo.

This car should be quick!

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

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.

Had another Astra 1.9 SRi CDTi (150PS) in on the rolling road today.

What a fantastic car and engine combination. An ecu remap resulted in nice and safe 185 bhp with 330 lb ft torque; more than enough to trade blows with an Astra VXR! Plus 50 miles per gallon.

A remapped Astra H CDTi SRi (with a rear ARB and DAP spring set) has got to be the best cross-country hack around at the moment. Great chassis, plenty of go and it will leave your fuel card (credit card) in your wallet for that little bit longer!!

A customer asked for his Astra VXR to have a run up on our rolling road the other day, as he had recently bought it and was curious about the power and torque output of the car which was running a full 2.5″ Milltek exhaust system and an off the shelf ecu flash.

The ecu reflash had been carried out by an authorised dealer however it had not been check on a rolling road (as the installer did not have one).
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