i know its more efficient, but the higher the lobe seperation you lack power n/a???? so is the difference in spraying a 110 to a 112 minimal and the real difference is only when your speaking of built nitrous cars with a 112 or higher ?????

 

There is nothing about nitrous that would specifically lead to picking one lobe separation over another.

Rich

 

Well, other than the fact that a wider LSA lets you run more N2O.

 

ok say up to 150 shot on a 110 lsa ? so u mean alot of n2o like more than 150 with a wider lsa???

 

You can only spray as much nitrous as the engine is built for. The more overlap in the cam, the more nitrous goes out the exhaust valve before it closes. With a larger LSA, you get less overlap, so you "lose" less nitrous. You would compensate for the smaller LSA and the nitrous loss by increasing the amount of nitrous you spray, recognizing that some of it is blowing out the exhaust valve, and not being used.

As far as running NA, the wider LSA will improve the bottom end, but not make as much power at the top. If you are more interested in a big dyno number (peak HP), and not so interested in area under the curve, its fair to say the wider LSA will not give you as much peak HP. But it may be "faster". Depends on the full cam specs, the intended RPM power band, consideration of emissions, etc.

All of this seems to engender major arguements every time it is asked

 

I agree with Injuneer here.

Up to a 200 shot and you really aren't losing much out the exhuast. Once you start stepping across that line much more is getting lost. You can always jet up to compensate, but there are other factors to consider.

Think about it this way:

A 150 shot losing 5% (just a number I picked) isn't much hp loss = 7.5hp
A 200 shot losing 5% = 10hp
A 300 shot losing 5% = 15hp

Of course the losses wouldn't change at a linear rate (I just don't know the exact rate of loss) and the amounts could be greater than 5% loss.

 

Until you get to 200+ on the N2O shot the motor will not be hurt on most street cams, so run whatever LSA you need. There is a guy on the boards running in the 10's on his stock block LT with LE heads, a 125 shot and a cam with a LSA LESS than 110LSA. So the thing moves for a street car.

Now when you get into BIG N2O shots and lots of duration then you need to take the LSA out to get rid of the overlap AND make the valve events happen to help the upper RPM range of the motor.

Most times on a N2O cam the first thing you need to do is add exhaust duration from what is optimum on the NA combination. Also adding larger diameter headers helps as well.

Bret