Need input from those with a FMS cam

[FB71]

I need some input from those running a FMS comp (street) cam.
Preferrably, if your running it on a B6 with a ported head....but even if you have a stock B3 w/FMS cam it would be helpful.

I'm curious as to what RPM the camshaft starts to pull and where the peak torque is at. I'm trying to decide if I want to just install my cam with the stock sprocket or if I want to spend the time to try to re-machine the sprocket so that I can advance the cam about 4 degrees.

Any input would be appreciated!:p

I have the exact set up you're asking about. Noticeable change in torque from about 2500rpm up to rev limit. Cam installed with stock sprocket, straight up. Also running injectors from a 16V sohc 1.6 with a B8 throttle body, and 2.25 exhaust all the way back, with a cat from an EGT. Getting 33-34 mixed driving, 36 hwy (not easy on the throttle, cruise @ 75-80mph)

[blkfordsedan]

Do tell.......in your opinion, would 4 deg advanced be better? As a general rule, VE is improved and cylinder pressure increased. I'm 99.9 sure it would be an improvement and I think I figured out a Simple way to do it. My setup will be similar, except for the 16V injectors. Should I anticipate lean issues? What ECU you running?

Isn't yours an ATX as well?

[FB71]

Do tell.......in your opinion, would 4 deg advanced be better? As a general rule, VE is improved and cylinder pressure increased. I'm 99.9 sure it would be an improvement and I think I figured out a Simple way to do it. My setup will be similar, except for the 16V injectors. Should I anticipate lean issues? What ECU you running?

Isn't yours an ATX as well?

stock B6 PCM and VAF. Swapped to manual trans before engine swap. I haven't had any time to play with tuning, so I couldn't say what the pros and cons are. However, any advance in cam timing usually pushes the usuable torque range higher in the RPM band. I wanted torque at cruising RPM, which is around 3k for me, so straight up seems to work ok.

[blkfordsedan]

My understanding and experience has been advancing the cam will augment the lower RPM range at the expense of some top end. That's why I wanted to bring the cam range down a little to about 2500 to 5500/6000. Its been a year, but IIRC, my cruise RPM was about 2500 at 60 mph.

[FB71]

hmmm, maybe I got it backwards... not been thinking too clearly these past few weeks. I'll double check.

[FestYboy]

it's ok Jim, just one of the few signs that you're still human.

[blkfordsedan]

LOL, yeah its OK Jim. I knew what you meant. That happens to us old guys every now and then! I'm embarrased to admit, but I had to think about it for a couple days and draw myself a picture to determine if 4 degrees on cam sprocket equals 2 or 8 on the crank!
Actually, it doesn't really shift the torque curve on the RPM scale as much as it accentuates the curve on one side of the torque peak and diminishes it on the other.