jlw2387

I have a set of VT Stage 1 NA cams for my car, and I just ordered a procharger. Do I need to worry about anything, or is the only difference that the blower cams would have helped make a little more power than my NA cams?

rmr1923

you'll still produce good power with the stage1 n/a cams, better than with your stock cams for sure. but the blower cams are specially designed for forced-induction applications, so if you went with the blower cams over the n/a cams, you'll see a significant increase in power (the exact number depends on your whole setup, but i'd guess anywhere from 25-50 hp). which procharger did you order (what psi)? and are you using stock heads or ported heads?

N2O98gt

they will work, just not as good as blower cams. With stage one's there is nothing to worry about either

lizzyfan

This explains the difference, this is a writeup Scott (2000gt4.6) did:
First of all, F/I cams, at least in my experence never seem to sound as agressive as a n/a cam. You can have a pretty wild FI cam and it doesn't sound nearly as lopy as a much less agressive n/a cam. This is because LSA gives you the "lope" that everyone loves so much.

The "blower" cams, or FI cams, have less overlap(and higher LSA)than a n/a cam. This is the primary difference, as you loose boost when you have more overlap.

Here is the complete VT stage 2 "blower" cam spec, alongside the VT stage 2 n/a spec:

.530/.570 lift 220/230 .50 duration 112 LSA +4*
.560/.575 lift 225/235 .50 duration108 LSA

Notice the LSA, is less (lower number)on the n/a cam. The lower number the LSA is, the less seperation there is between the exhaust and intake lobe centerline. Decreasing this number results in more overlap. A 4 cycle engine uses this overlap to allow fresh air to enter, and thus force the exhaust gases out.

Making this longer on a n/a setup allows for a 4 cycle engine to get more of the exhaust gases out and get more fresh air in. On a FI setup however, if the LSA is too large you are literally loosing boost right out of the exhaust(both valves open, no compression taking place)This results in a boost drop, and you loose horsepower. This is also why you are more often than not OK(not optimal)with running a n/a cam at lower boost levels. Once you crank it up however, you really start to loose boost and you needa progressvly smaller and smaller pulley to run the same amount of boost, which drops efficentcy, heats the incoming air, and generally makes it make less horsepower per boost (and pulley size).

You definatly do not want to run a n/a cam on a blower if you can help it, and most people have NOT had as good results as I have had running a n/a cam on a blower car.However, you can do it at lower boost levels, and the cam will sound more agressive do to thelower LSA number. I am somehow not loosing boost, but everyone else that has done this has to pulley up. Sometimes I wonder if VT didn't accidentally send me a blower cam intead of a n/a one.

oxfordgt

Lizzy is exactly right but he left out2 more power robbing aspect of a na cam with boost. lift and duration. You want a blower cam to lift less and close faster to prevent boost loss. With a long open period the boost will back back up into the intake and cause turbulance. All bad. Get blower cams if you can.

ottos

Hmm lope vs power.... just me i think i would take power