| Author | Message | ||
| Ulf Modig (Ulf308qv)
Junior Member Username: Ulf308qv Post Number: 58 Registered: 3-2001 |
I'm using Brisk LGS plugs in my 308qv. www.brisk.cz  | ||
| Rob Schermerhorn (Rexrcr)
Junior Member Username: Rexrcr Post Number: 223 Registered: 11-2002 |
Matt, if you want more theory and practice of "swirl" vs. "tumble" combustion chamber design, hours of reading can be found here: http://www.theoldone.com/articles/The_Soft_Head_1999/ There are many more articles, most fascinating is the design and build of a Pro Sock NHRA engine: pump racing fuel, 26:1 compression ratio, 500 CI, 1800 HP! | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 104 Registered: 8-2001 |
Rob is quite correct. Ferrari's Pent roof design, and the manner that the incoming charge tumbles is considerably different than the Quench type combustion chamber that most US autos use. In that respect, IMO, indexing would be a PITA, with very little to no results. I personally do not care for the use of varying thickness washers marketed for this as I feel they effect heat transfer, as well as plug protrusion into the chamber is less, giving the flame kernel less access. | ||
| Rob Schermerhorn (Rexrcr)
Junior Member Username: Rexrcr Post Number: 216 Registered: 11-2002 |
This is a great fine tune on a "wedge" type combustion chamber, typical in American V8 engines, which, because there are billion dollar industries catering to this design, one hears about indexing all the time. The idea is to compensate for relatively poor (poorer?) combustion burn efficiency by placing the light-off spark at the optimum location, which has painstakingly determined for each version of "wedge" head manufacturer. Wedge pushrod engines are cheap to manufacture commodity power plants. Ferrari engineers begin with a different design goal and philosophy, hence higher specific outputs in general, and currently, tops in the world. Ferrari's "pent roof" or hemispherical combustion chamber's designs benefits less or not at all to indexing. The basic designs are far more efficient, so a trick that works on a Ford, doesn't do a thing on a Ferrari. | ||
| jeff ryerson (Atheyg)
Junior Member Username: Atheyg Post Number: 160 Registered: 8-2002 |
Anyone tried indexing plugs on a Ferrari? If so which direction did you index them towards? Claims are 2-5% HP increase on some vehicles, is this possible on a Ferrari? |