Cam Theory

cleetus

Amateur Racer
Sep 5, 2006
180
0
0
NJ
Yes, you need a wider LSA (higher number) to spray it. If you look in the catalogs, most nitrous cams are in the 112-114 range.

I don't know the science behind it however.
 

cutlass389

Frequent Racer
Feb 2, 2009
684
0
0
NC
N20, much like forced induction cams are on wider LSA's(112-115) to reduce the overlap and therefore the amount of spray(or boost) that simply goes out the exhaust. An N/A motor needs more overlap to aid in filling the cylinders as they only have vacuum from the downward motion of the piston and atmospheric pressure to work with. Nitrous and positive pressure "shove" the A/F mixture in and so do not need any additional help. Although an LSA of 108 is a good all around N/A cam, for OPTIMAL cylinder filling purposes, the LSA should be a product of the cylinder volume versus the intake valve size. For example; a 350 with big port heads featuring 2.05" valves would produce the best results with an LSA of 108 whereas a 383 with 1.94" valves would put up the biggest numbers with an LSA of 104. The bigger the volume the intake valve must feed, the more overlap is required to aid in filling via the exhaust scavenging effect. This is completely ignoring other circumstances such as idle quality, street manners, vacuum assist accessories, etc which is why most "shelf" cams are ground on a 110 to make reasonable power but produce acceptable street manners. Say it with me now-compromise.
 

eldabo

Pro Stocker
Aug 10, 2006
1,811
0
0
Mobile,Alabama
compromise. LOL
 

MalibuRacing.com Gear

Stickers & Shirts!!