NA vs. FI Cam

[txarkitekt]

Hmmmm...I thought it was the exact opposite: FI cams require a tight (114-118) LSA and N/A cams can have wider (110-113) LSA...

N/A cams don't have to have even duration numbers, but I think they run better that way. FI cams should have an exahust bias. It is more favorable when running wrapped longtubes (RMT or S/C) and custom wrapped headers (for FMT).

[foggy]

Hmmmm...I thought it was the exact opposite: FI cams require a tight (114-118) LSA and N/A cams can have wider (110-113) LSA...

N/A cams don't have to have even duration numbers, but I think they run better that way. FI cams should have an exahust bias. It is more favorable when running wrapped longtubes (RMT or S/C) and custom wrapped headers (for FMT).

Txarkitekt, you have it backwards.114-118 is the wide lsa, 110-113 is a tighter lsa.
Lobe Separation Angle
Lobe Separation Angle, or LSA, is the number of degrees that separate the peak lift points of the cam's intake and exhaust lobes. LSA helps determine the cam's behavior; you can take a given set of lift and duration figures, change the LSA, and get cams with vastly different characteristics. Generally, a cam with wider LSA (112-116 degrees) offers less overlap between intake and exhaust opening and closing events. That translates into a wider rpm range, better idle quality, and higher engine vacuum, but at the cost of less torque at low and midrange rpm. A cam with a narrow LSA (104-108 degrees) offers greater low and midrange torque production, but with a narrower operating range, a choppy idle, and less engine vacuum.

For the street, you want a cam that offers a compromise--decent idle quality, respectable vacuum for operating power brakes and such, and good overall power production. separation. Again, much depends on the overall engine combination and intended use, but as a general rule, cams with a 110 to 112 degree LSA offer good power and decent street manners.

[SoHo48]

thanks....

[SoHo48]

Txarkitekt, you have it backwards.114-118 is the wide lsa, 110-113 is a tighter lsa.
Lobe Separation Angle
Lobe Separation Angle, or LSA, is the number of degrees that separate the peak lift points of the cam's intake and exhaust lobes. LSA helps determine the cam's behavior; you can take a given set of lift and duration figures, change the LSA, and get cams with vastly different characteristics. Generally, a cam with wider LSA (112-116 degrees) offers less overlap between intake and exhaust opening and closing events. That translates into a wider rpm range, better idle quality, and higher engine vacuum, but at the cost of less torque at low and midrange rpm. A cam with a narrow LSA (104-108 degrees) offers greater low and midrange torque production, but with a narrower operating range, a choppy idle, and less engine vacuum.

For the street, you want a cam that offers a compromise--decent idle quality, respectable vacuum for operating power brakes and such, and good overall power production. separation. Again, much depends on the overall engine combination and intended use, but as a general rule, cams with a 110 to 112 degree LSA offer good power and decent street manners.

meant to say thanks to this guy, dont want to be a post whore

[SS Killer]

Txarkitekt, you have it backwards.114-118 is the wide lsa, 110-113 is a tighter lsa.

That's what I thought... OK, thanks guys!