Let's write this story backwards... that'll save you skipping to the last page!
Starting peak power: 136kW at the wheels. Peak power after the chip re-write: 144kW. Gain? 6 per cent. Cost? $700.
There, you can stop now and go read another article! Ahhh, but there's a sting in the tail of this tale, which puts a slightly different complexion on things...
The car was a current Ford Tickford TE50, the AUII model with a factory 220kW at the flywheel. The request was that the engine management's program be altered to better suit the pursuit of power - and to also better match the cat-back exhaust that had been added. Whether the exhaust actually made any difference to power on its ownsome isn't known - the car arrived with the (slightly raunchy sounding) pipework and new muffler already in place.
ChipTorque's Lachlan Riddel placed the car on the dyno and attached probes - one for inlet air temperature, and another attached to his ears. Well all right, indirectly attached to his ears, anyway. A spring clip containing a microphone was placed on an engine mount, being joined by a cable to an amplifier and thence to 'bud' style earphones. With a set of normal sound-reducing earmuffs over the top of the earphones, Lachlan is confident that he can detect detonation - and incipient detonation - better with this system then any combination of new-fangled flashing LEDs or flicking needles. And we largely agree with him...
After warming up the engine and discovering that there was very little fuel left in the tank - the low-fuel level warning kept beeping until cancelled - a baseline power-pull was made. Like I said, 136kW at the wheels.
Listening hard during the run, Lachlan was concerned that the engine seemed to be just on the edge of detonation - though not actually going tink-tink.
Next step was to plug the emulator into the external port of the EEC management and look at what sort of timing was being run. From reading the Autronic/Dyno Dynamics air/fuel ratio meter we already knew the fuelling strategy at full throttle - mega-rich with a ratio of around 10.2:1. This might be an OK air/fuel ratio if there was a supercharger bolted on to a standard compression engine running a heap of boost without intercooling... but this is almost black-smoke rich for a relatively unstressed naturally aspirated engine. Even one that dates back in its fundamental design a very long way indeed.
And when Lachlan plugged into the factory chip and could see the timing tables he was surprised - this model runs far more ignition advance than previous Tickford Windsor V8s. [And how much timing is that? And can we have a printout of the timing chart in plain English? And how much does the detonation sensor take off when it detects combustion problems? Dunno. One of the problems with taking this chip tuner approach - as opposed to say using the Kalmaker software for Holdens - is that chip-tuners can't (or won't) provide full details on what they are doing and what they can see.]
However, there was enough ignition timing in there that Lachlan suggested that - if anything - this engine would need to have some timing pulled out. Remembering also the incredibly rich fuelling that the engine was running, this became even more likely - lean-out the air/fuel ratio and an engine will detonate more easily.
Punching the laptop keys started to pull the full-throttle mixtures back, however the years of experience that ChipTorque has had with this type of tuning soon showed itself. Watching the process it was obvious that the mixtures were being leaned, a dyno run then made, assessment of the revised air/fuel ratios carried out, then - in this case - the engine leaned-out further. However, rather suddenly the air/fuel ratio numbers stopped going up (ie getting leaner) - instead, the AFR suddenly went a whole ratio richer! Lachlan said, "It's just gone into hot mode - the intake air temp is now well up and the fuel in the tank is probably 60 degrees C."
The repeated dyno runs, the small amount of fuel in the tank and the increasing coolant temp all conspired to tell the management to enrich the mixture. Without being able to see a full picture of all that the ECU was doing - Lachlan was working the whole time on just two or three maps - this could only be surmised. But it was a pretty good guess.
With the engine cooled down (just idling for a few minutes was sufficient), another dyno power run showed the mixtures again behaving as they were being directed to - high Elevens (eg 11.8 - 11.9:1) was the aim. However, as expected, by now the engine was starting to get rather close to detonation (not that I could hear any with my naked ears - the earphones are far more effective) and so Lachlan retarded the full-load timing by 1 degree below 4400 rpm and 1.5 degrees above this engine speed. The power on the dyno was showing 144kW by this stage, but the tuning process wasn't over yet.
Next up was the tuning of the transients - especially the ignition timing during high load variations. The dyno can be used to do this very effectively - the process basically involves standing on the throttle at a variety of loads and engine revs and listening for detonation (or that odd engine note that shows it to be close). During this tuning process 3 degrees of timing advance was removed - then Lachlan was happy that the engine was well within its detonation threshold.
Then back into the main office area with the laptop, punch some keys on the laptop and another PC, burn the chip (on Ford ECUs it's actually on an external, added adaptor board), then back into the car, new board plugged in. The car was re-started, warmed right up, and a final power curve drawn - that's the one shown here.
[And before the person who wrote to me last week to say that all comparative dyno graphs should have the lines overlaying each other at the bottom of the power curve decides to inform me of his brilliance again, that premise would apply only if the modifications being made change volumetric efficiency just at higher rpm - as of course most intake and exhaust mods do. But when a tuning change such as reducing over-richness is made, there's no reason at all why a similar percentage gain can't be made throughout the rev range. Not similar kilowatts gain - similar percentage...]
So that was it - a distinct and repeatable power gain of 6 per cent, 8kW at $87.50 a kilowatt. But here's where the twist in the tail comes. Remember the low fuel level in the tank? Well, there had been a communication stuff-up. Lachlan Riddel thought that the car had been fuelled with premium - but it turns out that the car had been delivered with only normal unleaded in the tank! The expected top-up with premium hadn't happened...
So, there're two ways of looking at it. (1) Wonders had been done in extracting that much extra power from lower grade fuel - and oh boy, wouldn't the car now be safe when filled with premium! Or (2) how much extra power would have been possible if some more timing had been able to be cranked into it (or, at minimum, not been taken out?). Looking at the figures on the dyno during the timing changes, I'd suggest perhaps only a few kilowatts more would have been achieved. It was the change in mixtures that made the big difference - and they'd be almost completely unaffected by the different fuels.
A final point. With the new adaptor board now fitted to the ECU, ChipTorque will re-tune the car further (eg if other mods are made) at the $105 an hour dyno time rate - you don't need to pay for the chip again. That makes the $700 outlay rather more favourable...
www.chiptorque.com.au
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