Sorry if this is a bit long, just thought I'd share my findings with anyone planning to get a chip for a Digifant!
I posted some time ago about whether or not to remove a chip I had in the ECU of my digi. In the end, I decided to change the ECU for a non-chipped one, as I suspected it was covering for a bad tuning set up. Several other jobs were done on the car at the same time as the ECU swap, and when I got it back, it felt much better (but any one of a number of changes could have caused this).
Since then, I've got the timing sorted on the car, and the CO there or thereabouts, and it drives like it should now. However I was intrigued yesterday when reading up on what powerchip actually does, and decided to try the chip again now that the car was running correctly, to see if it made any difference.
As many of us know, the Digifant is a pretty crude management system, and only a limited number of things can be changed by a new chip - specifically the rev limiter and the fuel maps.
I was interested to read that Digis tend to lean near the top end, and that one benefit of the chip was to adjust the map to account for this. People have also mentioned that the power delivery is smoother, and torque is better lower in the range, which I guess is also caused by the adjusted fuel map.
I'm not so interested in the increase in the rev limiter, as most of the power has gone before you reach that!
So, what I set out to test was:
1. Is there an increase in power lower in the rev range
2. Does the car accelerate more smoothly
3. Does the car pull any better at the top end
4. Is fuel economy affected
5. To sum it all up, does the car seem faster and is it nicer to drive?
The car - standard 8v Digi, other than a Jetex Panel filter. AFM is standard and unmodified, and tests within tolerances. Timing is correct.
The chip - The chip is in my old ECU, which is a DB code. The original chip on the bottom board has been replaced by the Powerchip. Swapping the ECU was a 5 minute job - would probably have been less if I didn't have to go into the house to get my 10mm socket!
Not very scientific, but I compared the car before and after by driving it hard (but safely of course) down some local country lanes. So, what did I find with the chip installed?
1. The car does seem to pull better from lower in the range. There was perhaps the tiniest hint of digilag before, but that's now gone.
2. The first thing I noticed was that the car just seemed smoother, and even more refined than normal. I didn't think there were any flatspots before, but I must have been wrong, as it feels a lot better now! I did however almost stall at a roundabout, as I didn't give it enough revs :embarassed: I'm putting this down to a change in the setup and I wasn't used to it
3. The car pulls a little better between 5.5k and 6k, but it didn't exactly blow me away, and isn't really worth waiting for (still change up at 5.5k!). However it did seem noticably more eager between 4.5k and 5k. I didn't get to the limiter, so I don't know what it was set at.
4. Economy for my little drive (37 miles) was 37.7mpg, which when adjusted for the speedo overread is about 34mpg. This compares with about 38mpg (adjusted to about 34.5mpg) for similar driving previously.
5. To sum up the power delivery is definitely smoother now, and having more power lower down makes it easier to drive 'normally'. Performance-wise, the chip probably just about shades it, but there is in reality only a subtle difference. That said, it now feels like a different car to drive - not necessarily in a bad way, but not in a good way either. Just different.
I think because my chip is free, it's probably worth leaving it in, however I would have been disappointed had I paid a lot of money for it. It has enough benefits to make it worthwhile, but not essential.
