Put the Punto on the rollers yesterday just to show those Elise owners what a 1.2 can do, and was quite pleased with the results. However, I have a few questions for those of you with more technical knowledge than me.
Torque Curve - What would cause the dip around 3k revs? You can feel it when driving, seems to get a bit breathless then picks up again
Powertrain losses - They look consistant with other dynos for other cars, obviously a higher % as I didn’t start out with many Italian horses. Are they reasonable and if so what contributes? (e.g. 10 bhp tyres, 10 bhp gearbox, 10 bhp driveshafts etc) If not what could give such a low wheel bhp when the flywheel bhp seems to be close to expectations?
Been having an arguement where other Punto drivers say 15 bhp loss is about right and there’s something wrong if losses are over 30 bhp.
Shame the power drops off after 5.5k as the little beast revs to 6.5k
By the way it’s a Mk1 1.2 16v Sporting and it’s Fionas (I sneaked it away whilst she was up in Scotland )
By the way it’s a Mk1 1.2 16v Sporting and it’s Fionas (I sneaked it away whilst she was up in Scotland )
Colour matched to the Exige of course !!!
Was an enjoyable morning with the MLOC guys plus a cracking blast home. Was getting a bit worried when it went on as it was getting a bit close to bottoming out when they dropped it on the rollers. Mind you the smell of unburnt fuel when it was on full chat does make me more inclined to fit an emerald.
Spent the day getting it clean and back under its cover in the garage. Think its best to keep it under cover to prevent any more horses escaping !
p.s. anyone seen 24 missing horses - last seen around Leamington / Warwick. Reward given.
Those “transmission” losses are pure fantasy. Based on the the figures shown they represent a transmission of loss around 38%. If you were loosing that much power then it would have to go somewhere - most of this energy ends up as heat. Thats a huge amount of heat - did the transmission glow red ?
The major losses are through the tyres, the tyre walls are compressed unnaturally and in two places by the relatively small diameter rollers. If you want to win an ‘at the wheels’ power shootout, put 60 PSI in your tyres and run in the lowest possible gear, this will keep the roller speed low and the compression of the tyres at a minimum.
Thanks for the replies. Not trying to win anything. I was just interested to know if the losses were about right, and if not how could the wheel reading be so low when the flywheel is about right according to manufacture figures.
![http://i39.photobucket.com/albums/e163/sc_jones/Image3.jpg[/image]](http://i39.photobucket.com/albums/e163/sc_jones/Image3.jpg%5B/image%5D){kind=link}