leonard

. Still, they almost never last long in terms of model years, Volvo's may end up being the most successful I5 in history.

why? do I5s not last as long an I4s or I6s?

ragtop

The Acura Vigor, and later the 2.5TL, both had the same I5 2.5L engine from 1992-1998ish, for a total of ~7 years of production. That's not all that short. I think it was near 175HP.

Other 6-cyl 2.5L engines put out right about the same power (323,325). The only 2.5L 4-cyl that I know of is the one Subaru uses, and its a F4, putting out about 160HP I think. So it doesn't seem like having an I5 configuration offers any power advantage over a 6-cyl of the same size. Maybe it's cheaper because of fewer moving parts???

netwiz

what about 60 degree V6's? I was under the impression that they were stable as well...

texan

leonard & ragtop- I was speaking not only in terms of production length and run, but also of how well received the motor is. The Volvo turbocharged I5's seem to be about the most well received 5 cylinders yet, people have no problems this time around with the strange cylinder layout once they drive one.

netwiz- 60 degree V6's are very well balanced, but they are not perfectly balanced like an inline 6 or the other cylinder configurations I mentioned. They have a little bit of end-to-end vibration, though with all the other NVH produced in a moving car, you probably won't be able to tell the difference between a well built 60 degree V6 and an inline 6 (aside from the exhaust note). And please also understand that most vibration and resonance produced with the popular cylinder layouts that aren't naturally balanced can be cancelled out with balancer shafts, so in effect we are talking about how natural the engine balances itself, not how smooth running it is after a good engineer solves the balance issues.