Readers will know that when we tested the CV8 Monaro last week, we were not blown away with the power. The Holden 6-speed manual press car had a peak power of 164kW at the wheels - that's a 27 per cent loss between the claimed 225kW flywheel figure and the power at the treads, as measured by a (lossy) Dyno Dynamics machine.
However, tuning experts ChipTorque suggested that 164kW was in about the ballpark for a manual 225, so we left it there.
But on the road, we were disappointed.
So when we heard that a private customer with a CV8 Monaro was about to have some dyno work undertaken - including a re-mapping of the standard engine management in real time - we leapt at the chance of spending the day watching it happen.
But, we have to say, while the power gain made on the car was staggeringly good, in some ways the session raises questions as well as answers.
The Car
Chad Johanson changed places from a turbo front-wheel drive Mazda MX6 Turbo to a rear-wheel drive big motha of a V8 - and he couldn't be happier. He bought one of the first Monaros available, and like pretty well everyone we've ever met, reckons that the shape is just beautiful.
But having previously taken the modification route with the Mazda, it wasn't long before he started having similar non-standard ideas about the big coupe.
The first step was to have a set of Wildcat extractors fitted. These flow into a dual 2½-inch stainless system, complete with hi-flow cats and straight-thru mufflers. The exhaust cost "a touch under $2000".
And did the new exhaust make any more power? Chad told us that while at first he wondered, once he'd had a chance to drive a manual 5.7 Gen III ute and then step back into his own car, he thought that his car felt much sharper. So he figured that there was a little more power than standard and probably a better throttle response. Not a huge lift, though...
On the Dyno
Chad thought that with a standard 5.7 putting out about 160-165kW at the wheels, his should be up a bit on that - auto trans notwithstanding. So he was disappointed when ChipTorque did multiple runs that averaged out at 152kW....
Hmmm. There's a few scenarios here. (1) Either the car had always been down in power, and the exhaust had only made up some of the shortfall, or, (2) the exhaust had actually dropped power - which doesn't stack up with his seat of the pants impression, or (3) the auto trans sucks a fair bit of grunt, compared with a manual.
The bottom line is that this car, apparently in the pink of health and driving fine, had 152kW at the wheels with these extractors and exhaust fitted.
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Note: All dyno figures in this story have been run in 3rd gear. For an instant power increase with a Dyno Dynamics, just run it in second gear. No, don't us ask us why; ask the dyno's manufacturer....
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Real Time Re-Mapping
The real-time software that is being used by ChipTorque for reprogramming the Gen III (LS1) engine was jointly developed by Dave Alexander (Silverwater Automotive in Sydney), and Lachlan Riddel and Mathew Spry of ChipTorque.
In this case, Lachlan Riddel chose a combination of off-the-shelf and real-time tuning. He looked at the very rich 10.7:1 air/fuel ratio that the Monaro uses at full load, he looked at the relatively mild 14-16 degrees ignition timing advance in the same conditions, and decided that it would expedite matters to do a chip on the bench before then running it in the ECU and fine-tuning it to suit the car and exhaust. (Premium unleaded will now be the required fuel of choice.)
Incidentally, and very importantly, ChipTorque can read real-time all of the engine's vital inputs and outputs by the use of a genuine GM Tech 2 service tool. So the ignition timing, the knock retard that the ECU is using, the intake air and coolant temps - and dozens of other factors - can all be read and logged straight out of the factory ECU.
In addition, an Autronic air/fuel ratio meter was plugged into an exhaust probe to read out real time air/fuel ratios, and ChipTorque also use a five-gas analyser. And, not content with that lot, they also use an audio-based knock detector and listen closely to the engine during all tuning work, so that incipient detonation can be heard.
This is a world away from doing an off-the-shelf chip with little or no dyno development work.
Factors that Lachlan Riddel alters includes the commanded air/fuel ratio (no problems with learning around the modification- the ECU is actively trying to attain the air/fuel ratio that has been specified!), the sensitivity of the knock sensor and the amount of timing that is pulled off when detonation is sensed, and the full-load and transient throttle ignition timing charts.
While we were not allowed to record the list of parameters able to be changed, we were able to view them - and they run to dozens.
So, with the 'best guess' program running in the emulator, the car was dyno'd again - all sensors in place recording, measuring and listening.
Power Gains, But...
And, immediately that the modified program was operating the engine, peak power lifted.
However, the gain also trailed off quickly at high rpm - the knock sensor was pulling back the timing as in this area Lachlan's prediction was incorrect. Note that there was never any danger of engine damage during this testing - Matthew Spry was driving the car on the dyno, Tech 2 tool immediately in front of him showing both timing and knock retard - and he was also listening intently through amplified bud-earphones to the sound of the engine.
With this level of equipment and the sophistication of this engine management system, the days of waiting for a distinct 'tink tink' to fill the air of the dyno room are long over....
Being able to tune the Gen III (LS1) engine in real time, it was an easy task for Lachlan to make the necessary mapping changes, restoring the droop at upper rpm to something a bit more consistent.
Results
So what did Chad end up with? He got what is the best improvement in power that we have ever seen on a mildly modified naturally aspirated car fitted with a new chip!
Peak power of the Monaro lifted by no less that 22kW (29hp) at the wheels!
That's a gain of 14.5 per cent!
When it drove in, the Monaro had a peak power of 152kW; when the real-time programming had been completed, the power had risen to 174kW.
And it gets even better than this. The gain isn't just a peaky, top-of-the-rev range lift. Nope. Here we're talking about a lift in kilowatts right through the working span of the engine.
But sure, there's a few things to remember here - this was not a standard Monaro, this was one that already had a set of extractors and an exhaust fitted. So you can't say that any bog-stock CV8 will pick up 22kW at the wheels with a custom ChipTorque re-tune. (Although we'd be prepared to bet that you'll still get a very good gain.)
But the other problem is more of a worry - over the manual 6-speed CV8 (which had 164kW at the wheels, remember), this car has been lifted in power by a much more modest 11kW. Ah, but what if had been the manual 6-speed had been fitted with the extractors and exhaust and then been real-time re-programmed?
Who knows? Aaaghh...
The uncertainties are always there in any form of car modifications - some cars respond better than other (apparently identical) cars, while others have more power to start with. It's bloody impossible to categorically state how other cars will respond - but we can say with certainty that this Monaro did astonishingly well with the custom re-program.
And one of the most interesting aspects is that after first driving the modified car, Chad wasn't commenting on the extra power so much as the revised shift feel. Cos you see, while he's playing with the engine management program, Lachlan also modified the auto trans maps a little to give snappier changes and better kickdown response. And while you can't sell dyno figures to show that sort of modification, in the real world of on-road driving, this is an area which is of huge importance.
And a week later, what did Chad think?
"My wife is probably the best indicator of how the car has been changed," says Chad. "She was right against spending the money, but now that she's driven the car, she's very happy with it. It drives smoother - it almost feels that now it is in tune and before it wasn't. She says 'I am so glad you did it!' "
"It feels like it uses a lot less throttle on cruise control - I guess that's the major increase in mid-range torque. And when you get stuck into it? It's now quicker than that Gen III manual ute I was telling you about."
"I really have tried to be picky for you, but honestly, I can't find any downsides."
"It's an incredible power gain for the money, but the best bit is the improvement in drivability right through the rev range - there's now performance right the way through."
So, for his $990, the owner of this car walked out with a stunning 14.5 per cent more power and a car which also drove with a much better auto transmission response and feel.
Happy? You betcha he is.
Contact:
www.chiptorque.com.au
