Mike454SS

iTrader: (4)

Does anyone know the plenum volume of the FAST 102 LSXr manifold off hand? I know it's larger than the stock LS3 manifold, but I don't know how much.

Thank you.

G8-4-speed

iTrader: (1)

Plenum is not much larger. It looks bigger but the ports are longer cutting into the what would-be a larger volume plenum. Port volume is about 830cc vs 600cc stock. Flow is about 10-12cfm over stock but port length is longer by about 1 3/4" due to the wrap-around, bell-mouth design. Just ruff data....

Mike454SS

iTrader: (4)

I got the answer from Comp, the plenum itself is 5.1 liters versus 3.7 stock. Thank you though, the numbers on the runners are very helpful. I'm already running the manifold, have had it for 2 years, I'm just trying to understand this http://forum.efilive.com/showthread....ighlight=B8036 better and possibly make my tune in my car a little better...I'm thinking that this manifold, plus my ported heads, is probably playing a bit of a role in some of what goes on in my tune.

Dyno Junkie

I'm very surprised that the FAST has both a larger plenum chamber and larger longer runners.
With these I would expect it to be quite an improvement on a LS3, however I am yet to see any conclusive data from either the quarter or dyno that it makes any power difference at all